Catalysts

10 pages, 2211 KiB

Open AccessFeature PaperArticle

Phase Transformation of Zr-Modified LaNiO₃ Perovskite Materials: Effect of CO₂ Reforming of Methane to Syngas

by Tatiparthi Vikram Sagar, Nakka Lingaiah, Potharaju S. Sai Prasad, Nataša Novak Tušar and Urška Lavrenčič Štangar

Catalysts 2024, 14(1), 91; https://doi.org/10.3390/catal14010091 - 22 Jan 2024

Cited by 3 | Viewed by 1254

Abstract

Zr-modified LaNiO₃ catalysts (LaNi_xZr_1−xO₃; 0 ≤ x ≤ 1) are synthesized by the sol–gel method. The physio-chemical properties of materials are investigated using different characterization techniques and evaluated for the CO₂ reforming of methane to [...] Read more.

Zr-modified LaNiO₃ catalysts (LaNi_xZr_1−xO₃; 0 ≤ x ≤ 1) are synthesized by the sol–gel method. The physio-chemical properties of materials are investigated using different characterization techniques and evaluated for the CO₂ reforming of methane to syngas. Interestingly, the characterization studies revealed the phase transformation from La-Zr pyrochlore to La-Ni perovskite depending on the Ni:Zr ratio in the material. The formation of the pyrochlore phase is observed for high-Zr-containing catalysts, thus leading to the production of bulk NiO. The formation of La-Ni perovskite is observed for high-Ni-containing catalysts and the ZrO₂ acted as a support. The formation of La-Ni perovskite supported on ZrO₂ enhanced the Ni dispersion of the catalysts. The high dispersion of Ni enhanced the catalytic activity, and LaNi_0.8Zr_0.2O₃ showed the best performance among all of the studied catalysts in terms of conversions and the H₂/CO ratio. Full article

(This article belongs to the Special Issue Surface Microstructure Design for Advanced Catalysts)

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11 pages, 2128 KiB

Open AccessArticle

Organocatalysts for the Synthesis of Cyclic Carbonates under the Conditions of Ambient Temperature and Atmospheric CO₂ Pressure

by Yeongju Seong, Sanghun Lee, Seungyeon Cho, Yoseph Kim and Youngjo Kim

Catalysts 2024, 14(1), 90; https://doi.org/10.3390/catal14010090 - 22 Jan 2024

Viewed by 1310

Abstract

2–(1H–1,2,4–Triazol–3–yl)phenol (CAT–1) was used as an organocatalyst for the coupling reaction of CO₂ and epoxides at an ambient temperature and atmospheric CO₂ pressure (1 bar). This compound has a structure in which a hydrogen bond donor, a [...] Read more.

2–(1H–1,2,4–Triazol–3–yl)phenol (CAT–1) was used as an organocatalyst for the coupling reaction of CO₂ and epoxides at an ambient temperature and atmospheric CO₂ pressure (1 bar). This compound has a structure in which a hydrogen bond donor, a hydrogen bond acceptor, and another hydrogen bond donor are adjacent in sequence in a molecule. The binary catalytic system of CAT–1/nBu₄NI showed TON = 19.2 and TOF = 1.60 h⁻¹ under 1 bar CO₂ at room temperature within 12 h using 2–butyloxirane. Surprisingly, the activity of CAT–1, in which phenol and 1H–1,2,4–triazole are chemically linked, showed a much greater synergistic effect than when simply mixing the same amount of phenol and 1H–1,2,4–triazole under the same reaction conditions. In addition, our system showed a broad terminal and internal epoxide substrate scope. Full article

(This article belongs to the Special Issue Catalysis on Stable Molecules (CO₂, CO, CH₄, N₂, NH₃) Activation and Their Transformation, 2nd Edition)

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16 pages, 5621 KiB

Open AccessArticle

Catalytic Reductive Degradation of 4-Nitrophenol and Methyl orange by Novel Cobalt Oxide Nanocomposites

by Hawra A. Bukhamsin, Hassan H. Hammud, Chawki Awada and Thirumurugan Prakasam

Catalysts 2024, 14(1), 89; https://doi.org/10.3390/catal14010089 - 21 Jan 2024

Cited by 3 | Viewed by 1662

Abstract

Cobalt oxide nanocomposites were synthesized and used for the catalytic degradation of 4-nitrophenol (4-NP) and methyl orange (MO). Cobalt oxide nanocomposites PyroHAB9 was prepared by heating cobalt acetylacetonate complex HAB9 at 300 °C, while PyroHAB19 was prepared by heating cobalt acetylacetonate–carboxymethyl cellulose complex [...] Read more.

Cobalt oxide nanocomposites were synthesized and used for the catalytic degradation of 4-nitrophenol (4-NP) and methyl orange (MO). Cobalt oxide nanocomposites PyroHAB9 was prepared by heating cobalt acetylacetonate complex HAB9 at 300 °C, while PyroHAB19 was prepared by heating cobalt acetylacetonate–carboxymethyl cellulose complex at 300 °C. FTIR indicated the presence of Co₃O₄ species, while Raman spectrum indicated the presence of graphite in PyroHAB19. The SEM morphology of nanocomposites exhibited irregular spherical shape nanoparticles with sizes ranging between 20 to 60 nm. Additionally, nanowires were also seen in HAB19. Also, 2Ɵ peaks in PXRD revealed the formation of Co₃O₄ in HAB19. Cyclic voltammetry indicated enhanced electrochemical redox activity of HAB19. The structures of the nanocomposites were related to their catalytic activities. The turnover frequency (TOF) values of the catalytic reduction of p-nitrophenol (P-NP) and methyl orange (MO) were greater for HAB19 compared to HAB9 nano-catalysts. Also, the TOF values of the catalytic reduction of MO were greater than that of P-NP by both nano-catalysts. It is obvious that the rate constants of catalytic reductions for MO by metal oxide nanocomposites were greater than the corresponding rate constants for PNP. The highest rate constant was found for PyroHAB19 in MO reduction. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanostructured Catalysts, 2nd Edition)

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14 pages, 2681 KiB

Open AccessArticle

Hydrocarbon-Rich Bio-Oil Production from Ex Situ Catalytic Microwave Co-Pyrolysis of Peanut Shells and Low-Density Polyethylene over Zn-Modified Hierarchical Zeolite

by Zheng Dong, Yuanchong Yue, Jianmei Bai, Kun Chen, Mei Wang and Quan Bu

Catalysts 2024, 14(1), 88; https://doi.org/10.3390/catal14010088 - 21 Jan 2024

Viewed by 1340

Abstract

Peanut shells, a major economic and oil crop in China, boast an abundant availability and remarkably high lignin content compared to other agricultural residues. Previous work indicated that the modified hierarchical zeolite (Zn-ZSM-5/MCM41) was effective in promoting the conversion of intermediate macromolecules during [...] Read more.

Peanut shells, a major economic and oil crop in China, boast an abundant availability and remarkably high lignin content compared to other agricultural residues. Previous work indicated that the modified hierarchical zeolite (Zn-ZSM-5/MCM41) was effective in promoting the conversion of intermediate macromolecules during the lignin pyrolysis reaction and enhancing the yield and selectivity of liquid products. Thereby, this study aims to improve the quality of liquid products in the ex situ catalytic microwave co-pyrolysis of peanut shells and LDPE by utilizing Zn-ZSM-5/MCM41. Employing a compound center experimental design, we optimized reaction conditions through response surface analysis. The impact of microwave pyrolysis temperature and the catalyst-to-feedstock ratio on yield distribution and liquid product selectivity was explored. Results indicated a marginal increase in liquid product yield with rising pyrolysis temperatures. Moreover, an initial increase followed by a subsequent decrease in liquid product yield was observed with an increase in the catalyst-to-feedstock ratio. Optimal conditions of 450 °C and a catalyst-to-peanut hull ratio of 2.34% yielded the highest bio-oil yield at 34.25%. GC/MS analysis of the bio-oil revealed a peak in hydrocarbon content at 68.36% under conditions of 450 °C and a catalyst-to-feedstock ratio of 13.66%. Additionally, the quadratic model effectively predicted bio-oil yield and the selectivity for major chemical components. This study underscores the potential of Zn-ZSM-5/MCM41 in optimizing liquid product quality during catalytic co-pyrolysis, offering insights into bio-oil production and its chemical composition. Full article

(This article belongs to the Special Issue Catalytic Pyrolysis of Lignocellulosic Biomass)

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22 pages, 4320 KiB

Open AccessFeature PaperArticle

Water Oxidation over Au-Pd/TiO₂ as a Substitute for Iridium-Based Catalysts

by Khaja Wahab and Hicham Idriss

Catalysts 2024, 14(1), 87; https://doi.org/10.3390/catal14010087 - 21 Jan 2024

Cited by 1 | Viewed by 1078

Abstract

Water oxidation is one of the most important reactions needed for a transition to a green economy. The reaction relies on extracting electrons from oxygen anions and is commonly studied using homogenous catalysts based on Ru or Ir metals. Because of Ir scarcity [...] Read more.

Water oxidation is one of the most important reactions needed for a transition to a green economy. The reaction relies on extracting electrons from oxygen anions and is commonly studied using homogenous catalysts based on Ru or Ir metals. Because of Ir scarcity and its relative instability in acidic environments, metals to replace it are sought after. In this study, we have synthesized Au-Pd-based catalysts deposited on TiO₂ with different ratios in order to mimic IrO₂ valence orbitals (Ir5d) by the hybrid valence orbitals of Au5d and Pd4d and compared their heterogeneous catalytic activity for the evolution of O₂ from water in the presence of cerium ammonium nitrate (CAN). Au-Pd-based catalysts were found to be active at a particular nominal atomic ratio. At an atomic ratio of 1 Au to 2 Pd and 1 Au to 3 Pd, the catalysts were active and stable for oxygen production from water. Long-term runs up to 20,000 min still showed the expected stoichiometry between O₂ production and CAN consumption (1 to 4). However, catalysts with a reverse ratio were not active. Also, the monometallic catalysts were found to be not active for the reaction. We link the reason for the activity of Au-Pd with this specific ratio to the shape and energy position of their valence band that might be similar to those of IrO₂ particles. While the turnover numbers of the Au-Pd-based catalysts were found to be lower than those of IrO₂-based catalysts, on the same support in a heterogenous system, there is considerable potential upon further optimization for these two metals to replace IrO₂ for a water oxidation reaction. Full article

(This article belongs to the Special Issue Feature Papers in Catalytic Materials)

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12 pages, 1653 KiB

Open AccessArticle

Catalytic Conversion of Cyclopentanone into Dimethyl Adipate over Solid Basic Catalysts with Dimethyl Carbonate

by Irene Martínez-Salazar, Ana Orozco-Saumell, Manuel López Granados and Rafael Mariscal

Catalysts 2024, 14(1), 86; https://doi.org/10.3390/catal14010086 - 20 Jan 2024

Viewed by 1399

Abstract

The synthesis of dimethyl adipate (DAP), a stable configuration of adipic acid, from biomass-derived cyclopentanone (CPO) and dimethyl carbonate (DMC) constitutes an attractive greener route than petroleum-based industrial processes. Solid basic catalysts such as MgO, Mg₅(CO₃)₄(OH)₂ [...] Read more.

The synthesis of dimethyl adipate (DAP), a stable configuration of adipic acid, from biomass-derived cyclopentanone (CPO) and dimethyl carbonate (DMC) constitutes an attractive greener route than petroleum-based industrial processes. Solid basic catalysts such as MgO, Mg₅(CO₃)₄(OH)₂·4H₂O, KOCH₃ and Ca(OCH₃)₂ have been used achieving a DAP yield up to 30% at 533 K. In addition to the type of catalyst, other operating conditions such as the substrate, reaction time, temperature and CPO concentration have been studied. The methylation of DAP and CPO and the self-aldol condensation of CPO to form dimers and oligomers are reactions that occur in parallel with the production of DAP. It has been established that the main challenge is the self-aldol condensation of CPO. It has been identified that at short reaction times, to prevent methylation, and at dilute concentrations, to avoid CPO self-condensation, the DAP formation rate is much higher than these other competitive reactions. Finally, it should be noted that a DAP productivity up to 3.45 g·gcat⁻¹·h⁻¹ has been achieved under mild conditions. Full article

(This article belongs to the Special Issue Catalytical Methods for the Production of Fine and Bulk Chemicals and Biomaterials from Biomass)

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16 pages, 4003 KiB

Open AccessFeature PaperArticle

3D-Printed Monoliths Based on Cu-Exchanged SSZ-13 as Catalyst for SCR of NO_x

by Elisabetta M. Cepollaro, Stefano Cimino, Marco D’Agostini, Nicola Gargiulo, Giorgia Franchin and Luciana Lisi

Catalysts 2024, 14(1), 85; https://doi.org/10.3390/catal14010085 - 19 Jan 2024

Viewed by 1135

Abstract

Monoliths manufactured by Direct Ink Writing containing 60% SSZ-13 (SiO₂/Al₂O₃ = 23) and SiO₂ with 10% laponite as a binder were investigated as self-standing structured catalysts for NH₃-SCR of NO_x after a short (4 [...] Read more.

Monoliths manufactured by Direct Ink Writing containing 60% SSZ-13 (SiO₂/Al₂O₃ = 23) and SiO₂ with 10% laponite as a binder were investigated as self-standing structured catalysts for NH₃-SCR of NO_x after a short (4 h) and prolonged (24 h) ion exchange with copper and then compared with pure SSZ-13 exchanged under the same conditions. The catalysts were characterized by morphological (XRD and SEM), textural (BET and pore size distribution), chemical (ICP-MS), red-ox (H₂-TPR), and surface (NH₃-TPD) analyses. The silica-based binder uniformly covered the SSZ-13 particles, and copper was uniformly distributed as well. The main features of the pure Cu-exchanged SSZ-13 zeolite were preserved in the composite monoliths with a negligible contribution of the binder fraction. NH₃-SCR tests, carried out on both monolithic and powdered samples in the temperature range of 70–550 °C, showed that composite monoliths provided very good activity, and that the intrinsic activity of SSZ-13 was enhanced by the hierarchical structure of the composite material. Full article

(This article belongs to the Special Issue Exclusive Papers of the Editorial Board Members and Topical Advisory Panel Members of Catalysts in Section "Catalytic Materials")

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29 pages, 9554 KiB

Open AccessFeature PaperReview

Biocatalysis for the Synthesis of Active Pharmaceutical Ingredients in Deep Eutectic Solvents: State-of-the-Art and Prospects

by Ningning Zhang, Pablo Domínguez de María and Selin Kara

Catalysts 2024, 14(1), 84; https://doi.org/10.3390/catal14010084 - 19 Jan 2024

Cited by 4 | Viewed by 3485

Abstract

Biocatalysis holds immense potential for pharmaceutical development as it enables synthetic routes to various chiral building blocks with unparalleled selectivity. Therein, solvent and water use account for a large contribution to the environmental impact of the reactions. In the spirit of Green Chemistry [...] Read more.

Biocatalysis holds immense potential for pharmaceutical development as it enables synthetic routes to various chiral building blocks with unparalleled selectivity. Therein, solvent and water use account for a large contribution to the environmental impact of the reactions. In the spirit of Green Chemistry, a transition from traditional highly diluted aqueous systems to intensified non-aqueous media to overcome limitations (e.g., water shortages, recalcitrant wastewater treatments, and low substrate loadings) has been observed. Benefiting from the spectacular advances in various enzyme stabilization techniques, a plethora of biotransformations in non-conventional media have been established. Deep eutectic solvents (DESs) emerge as a sort of (potentially) greener non-aqueous medium with increasing use in biocatalysis. This review discusses the state-of-the-art of biotransformations in DESs with a focus on biocatalytic pathways for the synthesis of active pharmaceutical ingredients (APIs). Representative examples of different enzyme classes are discussed, together with a critical vision of the limitations and discussing prospects of using DESs for biocatalysis. Full article

(This article belongs to the Special Issue Catalytic Procedures for the Synthesis of Pharmaceutical Active Compounds in Deep Eutectic Solvents)

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14 pages, 3915 KiB

Open AccessArticle

An Analysis of Fixed-Bed Catalytic Reactors Performances for One-Stage Butadiene Synthesis from Ethanol

by Alma Valentina Brosteanu, Ionut Banu and Grigore Bozga

Catalysts 2024, 14(1), 83; https://doi.org/10.3390/catal14010083 - 18 Jan 2024

Viewed by 1213

Abstract

The present study assesses, using a theoretical approach, the performances of two widely used fixed-bed reactors for the ethanol-to-butadiene (ETB) one-stage (Lebedev) process: multibed adiabatic reactors (MBAR) with inter-bed heating and a multitubular reactor (MTR). The mathematical model consists of mass and heat [...] Read more.

The present study assesses, using a theoretical approach, the performances of two widely used fixed-bed reactors for the ethanol-to-butadiene (ETB) one-stage (Lebedev) process: multibed adiabatic reactors (MBAR) with inter-bed heating and a multitubular reactor (MTR). The mathematical model consists of mass and heat conservation equations at catalyst particle and particle bed scales, coupled with a published kinetic model specific for a modified MgO–SiO₂ catalyst. The process simulations at the level of catalyst particle have shown that the inter-phase concentration and temperature gradients are negligible, the only physical step with a limiting influence on process kinetics being the internal diffusion. A simplified version of the reactor model was also formulated, including empirical expressions developed in the study for the calculation of internal effectiveness factors. The reactor simulations highlighted that the MBAR with inter-bed heating by injection of hot reactants provides worse butadiene (BD) yields as a consequence of reduced reaction times (due to reactant by-pass of catalyst beds). The MBAR with inter-bed heating using heat exchangers provides better performances but inferior to those of MTR if the number of catalyst beds is less than six. A preliminary optimization study for the MBAR and MTR is also presented. The results showed that the maximization of BD yield has the drawback of a low BD production rate, whereas the maximization of BD production rate corresponds to a relatively low BD yield and high ethanol and inert recycles. A trade-off between the two extreme cases can be attained by maximizing the income generated by reactor operation. Full article

(This article belongs to the Section Catalytic Reaction Engineering)

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19 pages, 5424 KiB

Open AccessArticle

Insights into the Mechanism, Regio-/Diastereoselectivities and Ligand Role of Nickel-Initiated [3+2] Cycloadditions between Vinylcyclopropane and N-Tosylbenzaldimine

by Weihua Mu, Lin Zhu, Shuya **a, Xue Tan, Liangfei Duan, Guanghao Meng and Guo Liu

Catalysts 2024, 14(1), 82; https://doi.org/10.3390/catal14010082 - 18 Jan 2024

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Abstract

Density functional theory (DFT) was employed to explore the reaction mechanism, regio- and diastereoselectivities of nickel-initiated [3+2] cycloaddition between vinylcyclopropane (VCP) and N-tosylbenzaldimine assisted by phosphine ligands. Four different binding modes of the nickel center to VCP substrate were explored during the [...] Read more.

Density functional theory (DFT) was employed to explore the reaction mechanism, regio- and diastereoselectivities of nickel-initiated [3+2] cycloaddition between vinylcyclopropane (VCP) and N-tosylbenzaldimine assisted by phosphine ligands. Four different binding modes of the nickel center to VCP substrate were explored during the ring-opening of VCP, among which the C,C_anti and C,C_syn modes were verified to be the most accessible ones. Further explorations about four different phosphine ligand-assisted reactions based on the two most probable binding modes show that the difference in binding mode of bi- and monodentate phosphine ligands can vary the optimal reaction pathway, especially in the [3+2] cycloaddition process between the ring-opened intermediate and N-tosylbenzaldimine. The formation of C–C and C–N bonds between N-tosylbenzaldimine and the ring-opened intermediate through [3+2] cycloaddition is found to be stepwise, with the former acting as the rate-determining step (RDS) in most cases. Computed free energy barriers of RDS transition states on the optimal path I or II not only give out good predictions for reaction rates and half-lives, but also provide reasonable explanations for the major generation of cis-pyrrolidine. Noncovalent interaction analyses of key stationary points suggest the rate is influenced by both electronic effects and steric hindrance, while the diastereoselectivity is mainly controlled by electronic effects. Full article

(This article belongs to the Special Issue Organometallic Homogeneous Catalysis)

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19 pages, 2014 KiB

Open AccessArticle

A Cluster-Type Self-Healing Catalyst for Stable Saline–Alkali Water Splitting

by Haiming Wang and Sheng Chen

Catalysts 2024, 14(1), 81; https://doi.org/10.3390/catal14010081 - 18 Jan 2024

Viewed by 1074

Abstract

In electrocatalytic processes, traditional powder/film electrodes inevitably suffer from damage or deactivation, reducing their catalytic performance and stability. In contrast, self-healing electrocatalysts, through special structural design or composition methods, can automatically repair at the damaged sites, restoring their electrocatalytic activity. Here, guided by [...] Read more.

In electrocatalytic processes, traditional powder/film electrodes inevitably suffer from damage or deactivation, reducing their catalytic performance and stability. In contrast, self-healing electrocatalysts, through special structural design or composition methods, can automatically repair at the damaged sites, restoring their electrocatalytic activity. Here, guided by Pourbaix diagrams, foam metal was activated by a simple cyclic voltammetry method to synthesize metal clusters dispersion solution (MC/KOH). The metal clusters-modified hydroxylated Ni-Fe oxyhydroxide electrode (MC/Ni_xFe_yOOH) by a facile Ni-Fe metal–organic framework-reconstructed strategy, exhibiting superior performance toward the oxygen evolution reaction (OER) in the mixture of MC/KOH and saline–alkali water (MC/KOH+SAW). Specifically, using a nickel clusters-modified hydroxylated Ni-Fe oxyhydroxide electrode (NC/Ni_xFe_yOOH) for OER, the NC/Ni_xFe_yOOH catalyst has an ultra-low overpotential of 149 mV@10 mA cm⁻², and durable stability of 100 h at 500 mA cm⁻². By coupling this OER catalyst with an efficient hydrogen evolution reaction catalyst, high activity and durability in overall SAW splitting is exhibited. What is more, benefiting from the excellent fluidity, flexibility, and enhanced catalytic activity effect of the liquid NC, we demonstrate a self-healing electrocatalysis system for OER operated in the flowing NC/(KOH+SAW). This strategy provides innovative solutions for the fields of sustainable energy and environmental protection. Full article

(This article belongs to the Topic Nanomaterials and Catalysts for Clean Fuels and Sustainable Energy)

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5 pages, 198 KiB

Open AccessEditorial

CO₂ Capture, Utilization and Storage: Catalysts Design

by Leonarda Francesca Liotta and Hong**g Wu

Catalysts 2024, 14(1), 80; https://doi.org/10.3390/catal14010080 - 18 Jan 2024

Cited by 2 | Viewed by 1431

Abstract

Today, the problem of CO₂ emission into the atmosphere is one of the most urgent and complex challenges facing humanity [...] Full article

(This article belongs to the Special Issue CO2 Capture, Utilization and Storage: Catalysts Design)

17 pages, 9238 KiB

Open AccessArticle

Influence of the La_0.2Sr_0.7Ti_0.95Ni_0.05O₃ (LSTN) Synthesis Method on SOFC Anode Performance

by Moran Dahan, Ludmila Fadeev, Hagay Hayun, Michael Gozin, Yaniv Gelbstein and Brian A. Rosen

Catalysts 2024, 14(1), 79; https://doi.org/10.3390/catal14010079 - 18 Jan 2024

Viewed by 1197

Abstract

Solid oxide fuel cells are characterized by a high efficiency for converting chemical energy into electricity and fuel flexibility. This research work focuses on develo** durable and efficient anodes for solid oxide fuel cells (SOFCs) based on exsolving nickel from the perovskite structure. [...] Read more.

Solid oxide fuel cells are characterized by a high efficiency for converting chemical energy into electricity and fuel flexibility. This research work focuses on develo** durable and efficient anodes for solid oxide fuel cells (SOFCs) based on exsolving nickel from the perovskite structure. A-site-deficient La- and Ni-doped strontium titanates (La_0.2Sr_0.7Ti_0.95Ni_0.05O_3−δ, LSTN) were synthesized using four different techniques and mixed with Ce_0.8Gd_0.2O_2−δ (GDC) to form the SOFC anode. The synthesis routes of interest for comparison included solid-state, sol-gel, hydrothermal, and co-precipitation methods. LSTN powders were characterized via XRD, SEM, TPR, BET and XPS. In situ XRD during reduction was measured and the reduced powders were analyzed using TEM. The impact of synthesis route on SOFC performance was investigated. All samples were highly durable when kept at 0.5 V for 48 h at 800 °C with H₂ fuel. Interestingly, the best performance was observed for the cell with the LSTN anode prepared via co-precipitation, while the conventional solid-state synthesis method only achieved the second-best results. Full article

(This article belongs to the Topic Advances in Inorganic Synthesis)

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16 pages, 5344 KiB

Open AccessArticle

Surface Modification of Fe-ZSM-5 Using Mg for a Reduced Catalytic Pyrolysis Temperature of Low-Density Polyethylene to Produce Light Olefin

by Yincui Li, Ting Liu, Shengnan Deng, **ao Liu, Qian Meng, Mengxue Tang, Xueying Wu and Huawei Zhang

Catalysts 2024, 14(1), 78; https://doi.org/10.3390/catal14010078 - 18 Jan 2024

Viewed by 1670

Abstract

Although the catalytic pyrolysis of low-density polyethylene (LDPE) to produce light olefin has shown potential industrial application advantages, it has generally suffered when using higher pyrolysis temperatures. In this work, Mg-modified Fe-ZSM-5 was used for catalytic conversion of LDPE to obtain light olefin [...] Read more.

Although the catalytic pyrolysis of low-density polyethylene (LDPE) to produce light olefin has shown potential industrial application advantages, it has generally suffered when using higher pyrolysis temperatures. In this work, Mg-modified Fe-ZSM-5 was used for catalytic conversion of LDPE to obtain light olefin in a fixed bed reactor. The effects of catalyst types, pyrolysis temperatures, and Mg loading on the yield of light olefin were investigated. The 1 wt% Mg loading slightly improved the yield of light olefin to 38.87 wt% at 395 °C, lowering the temperature of the pyrolysis reaction. We considered that the higher light olefin yield of Fe-Mg-ZSM-5 was attributed to the introduction of Mg, where Mg regulated the surface acidity of the catalyst, inhibited the secondary cracking reaction, and reduced coking during the pyrolysis process. Furthermore, the addition of Mg also dramatically reduced the average particle size of Fe oxides from 40 nm to 10 nm, which is conducive to a lower catalytic reaction temperature. Finally, the spent catalyst could be easily regenerated at the conditions of 600 °C in airflow with a heating rate of 10 °C/min for 1 h, and the light olefin yield remained higher than 36.71 wt% after five cycles, indicating its excellent regeneration performance. Full article

(This article belongs to the Topic Valorizing Waste through Thermal and Biological Processes for Sustainable Energy Production)

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19 pages, 18285 KiB

Open AccessArticle

Surface Redox Reaction for the Synthesis of NiPt Catalysts for the Upgrading of Renewable Ethanol/Methanol Mixtures

by Joachim Pasel, Friederike Woltmann, Johannes Häusler and Ralf Peters

Catalysts 2024, 14(1), 77; https://doi.org/10.3390/catal14010077 - 17 Jan 2024

Viewed by 1028

Abstract

Mixtures of ethanol and methanol being synthesized from CO₂ and green H₂ can serve as sustainable base chemicals for a number of chemical processes. Amongst these processes, the catalytically supported synthesis of CO₂-neutral C₄ to C₁₀ alcohols [...] Read more.

Mixtures of ethanol and methanol being synthesized from CO₂ and green H₂ can serve as sustainable base chemicals for a number of chemical processes. Amongst these processes, the catalytically supported synthesis of CO₂-neutral C₄ to C₁₀ alcohols is of increasing importance as, e.g., iso-butanol can be used as a drop-in fuel or after dehydration to produce iso-butene as a feedstock for the synthesis of plastics. 2-ethyl-hexanol can be further refined into solvents, tensides, or monomers. In this respect, NiPt alloys on an activated carbon support were found to be active and stable catalysts for the synthesis of iso-butanol following the Guerbet reaction scheme. In this study, two different routes are applied to the synthesis of these NiPt catalysts: a more conventional one based on the impregnation of Ni and Pt salts and an advanced path with a surface redox reaction between elemental Ni on the support and Pt ions in a polar solution. The experimental evaluation shows that the Pt particles from the surface redox reaction being exposed on the Ni particles are more active than those on the impregnated catalysts due to their high surface energy. Their specific space-time yields are 10–20 times higher. Full article

(This article belongs to the Special Issue Recent Applications of Metal Catalysts in Organic Synthesis, 2nd Edition)

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12 pages, 2036 KiB

Open AccessFeature PaperArticle

Effect of the Heterovalent Sc³⁺ and Nb⁵⁺ Do** on Photoelectrochemical Behavior of Anatase TiO₂

by Elena S. Siliavka, Aida V. Rudakova, Tair V. Bakiev, Anna A. Murashkina, Petr D. Murzin, Galina V. Kataeva, Alexei V. Emeline and Detlef W. Bahnemann

Catalysts 2024, 14(1), 76; https://doi.org/10.3390/catal14010076 - 17 Jan 2024

Viewed by 1022

Abstract

In this study, we explored the effect of either Nb or Sc do** at a concentration range of 0.0–1.0 at.% on the physical–chemical and photoelectrochemical behavior of TiO₂ anatase electrodes. This behavior was characterized by work function, flat band potential, donor density, [...] Read more.

In this study, we explored the effect of either Nb or Sc do** at a concentration range of 0.0–1.0 at.% on the physical–chemical and photoelectrochemical behavior of TiO₂ anatase electrodes. This behavior was characterized by work function, flat band potential, donor density, spectral dependence of photocurrent and stationary photocurrent measurements. All experimental results are interpreted in terms of the formation of the shallow delocalized polaron states in the case of Nb do** and deep acceptor states induced by Sc do** on TiO₂ anatase. Full article

(This article belongs to the Special Issue Exclusive Papers of the Editorial Board Members and Topical Advisory Panel Members of Catalysts in Section "Photocatalysis")

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19 pages, 3920 KiB

Open AccessReview

Preparation of Mesoporous Zeolites and Their Applications in Catalytic Elimination of Atmospheric Pollutants

by Chuchen Miao, Lanyi Wang, Shengran Zhou, Di Yu, Chunlei Zhang, Siyu Gao, Xuehua Yu and Zhen Zhao

Catalysts 2024, 14(1), 75; https://doi.org/10.3390/catal14010075 - 17 Jan 2024

Cited by 1 | Viewed by 1446

Abstract

With increasing environmental awareness, the issue of atmospheric pollution has gained significant attention. Specifically, three types of atmospheric pollutants, namely, nitrogen oxides, volatile organic compounds, and carbon monoxide, have become the focus of widespread concern. In addressing these pollutants, mesoporous zeolites have emerged [...] Read more.

With increasing environmental awareness, the issue of atmospheric pollution has gained significant attention. Specifically, three types of atmospheric pollutants, namely, nitrogen oxides, volatile organic compounds, and carbon monoxide, have become the focus of widespread concern. In addressing these pollutants, mesoporous zeolites have emerged as promising materials due to their large specific surface area, which enables effective dispersion of active sites, and their large pore volume, which facilitates efficient diffusion. This article provides a comprehensive overview of the preparation methods of mesoporous zeolites and their applications in removing nitrogen oxides, volatile organic compounds, and carbon monoxide. It also highlights the challenges and limitations faced by the application of mesoporous zeolites in pollutant removal and emphasizes their potential as efficient catalysts. Full article

(This article belongs to the Special Issue Catalysts for Mobile Source: Low-Carbon and Pollution Emission Control)

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11 pages, 1353 KiB

Open AccessFeature PaperArticle

Sulfonic Resins as Catalysts for the Oxidation of Alcohols with H₂O₂/KBr

by Vicente Dorado, Clara I. Herrerías and José M. Fraile

Catalysts 2024, 14(1), 74; https://doi.org/10.3390/catal14010074 - 17 Jan 2024

Viewed by 1120

Abstract

Sulfonic resins can replace homogeneous sulfonic acids in the oxidation of alcohols with the H₂O₂/KBr system. The performance of different resins was tested with methyl 9(10)-hydroxystearate, a secondary fatty alcohol. The structural features of the resin were more important [...] Read more.

Sulfonic resins can replace homogeneous sulfonic acids in the oxidation of alcohols with the H₂O₂/KBr system. The performance of different resins was tested with methyl 9(10)-hydroxystearate, a secondary fatty alcohol. The structural features of the resin were more important than the acid strength for the catalytic performance of this reaction. The optimization of the reaction conditions allows the recovery of the resin, although regeneration is required due to the active role of KBr, and a significant loss of sulfonic groups can be detected after nine runs. In the case of primary fatty alcohols, the oxidation leads to carboxylic acids, which are esterified with the starting alcohol under the acidic conditions. For cyclic secondary alcohols, the steric hindrance around the hydroxyl group seems to be important for the efficiency of the oxidation to ketone. Full article

(This article belongs to the Special Issue Advances in the Catalytic Behavior of Ion-Exchange Resins)

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16 pages, 15264 KiB

Open AccessArticle

Dyes Degradation Using Cooper-Nickel Ferrite and Its Tunable Structural and Photocatalytic Properties

by Ila Gabriele Diniz Dias de Azevedo, Marco Antonio Morales Torres, Carlson Pereira de Souza and André Luis Lopes Moriyama

Catalysts 2024, 14(1), 73; https://doi.org/10.3390/catal14010073 - 17 Jan 2024

Viewed by 1003

Abstract

Water pollution is a serious worldwide problem. Among its pollutants, dyes that are overused by various types of industries and are resistant to conventional effluent treatments stand out. In this study, mixed copper and nickel ferrites Ni_xCu_(1-x)Fe₂O [...] Read more.

Water pollution is a serious worldwide problem. Among its pollutants, dyes that are overused by various types of industries and are resistant to conventional effluent treatments stand out. In this study, mixed copper and nickel ferrites Ni_xCu_(1-x)Fe₂O₄ (x = 0, 0.2, 0.4, 0.6, 0.8 e 1.0), were produced by the EDTA-Citrate complexation method, characterized and applied in photocatalysis with methylene blue (MB) and rhodamine B (RhB) dyes, varying the reaction pH between 2, 6 and 10. The ferrites with the highest percentages of copper had a tetragonal structure, while those with the highest percentages of nickel had a cubic structure, all with inverse spinel and all presenting bandgap values lower than 2 eV. Samples with higher percentages of copper (x = 0 and 0.2) at pH 10 showed degradation of approximately 55% for RhB and 40% for MB. A mixture of MB and RhB was also evaluated, showing a greater removal of methylene blue due to its preferential adsorption on the surface of the material. In this way, mixed copper and nickel ferrites proved promising as catalysts in photocatalytic processes. Full article

(This article belongs to the Special Issue Nanostructured Materials Used for Catalytic Treatment of Hazardous Organic Dye Polluted Wastewater)

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1 pages, 136 KiB

Open AccessCorrection

Correction: Hasan et al. Synthesizing and Characterizing a Mesoporous Silica Adsorbent for Post-Combustion CO₂ Capture in a Fixed-Bed System. Catalysts 2023, 13, 1267

by Hind F. Hasan, Farah T. Al-Sudani, Talib M. Albayati, Issam K. Salih, Hamed N. Harharah, Hasan Sh. Majdi, Noori M. Cata Saady, Sohrab Zendehboudi and Abdelfattah Amari

Catalysts 2024, 14(1), 72; https://doi.org/10.3390/catal14010072 - 17 Jan 2024

Viewed by 727

Abstract

In the original publication [...] Full article

22 pages, 6286 KiB

Open AccessArticle

Fe₃O₄-CdO Nanocomposite for Organic Dye Photocatalytic Degradation: Synthesis and Characterization

by Ahlam Albeladi, Zaheer Khan, Shaeel Ahmed Al-Thabaiti, Rajan Patel, Maqsood Ahmad Malik and Shilpa Mehta

Catalysts 2024, 14(1), 71; https://doi.org/10.3390/catal14010071 - 17 Jan 2024

Cited by 2 | Viewed by 1577

Abstract

In this study, pure CdO nanoparticles, magnetic Fe₃O₄ nanoparticles, and Fe₃O₄-CdO nanocomposites were prepared via a solution combustion method using cetyltrimethylammonium bromide (CTAB) as a template. These prepared nanomaterial samples were characterized by X-ray diffraction (XRD), [...] Read more.

In this study, pure CdO nanoparticles, magnetic Fe₃O₄ nanoparticles, and Fe₃O₄-CdO nanocomposites were prepared via a solution combustion method using cetyltrimethylammonium bromide (CTAB) as a template. These prepared nanomaterial samples were characterized by X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron microscopy (XPS), transmittance electron microscopy (TEM), and scanning electron microscopy (SEM) analysis. XRD patterns confirmed the purity and the crystalline nature of the prepared samples. FTIR and Raman spectra observed the metal-oxygen (M-O) bond formation. UV-vis DRS studies were performed to investigate the optical properties and the bandgap energy determination. The surface morphology and the size of the pure CdO nanoparticles, magnetic Fe₃O_4, and nanocomposites of Fe₃O₄-CdO were determined via TEM and SEM analysis. Under optimum experimental conditions, the Fe₃O₄-CdO nanocomposites were applied for photocatalytic activity against Methylene blue dye. Under visible light irradiation, Fe₃O₄-CdO nanostructures showed an efficient photocatalytic degradation of 92% against Methylene blue organic dye and showed excellent stability for multiple cycles of reuse. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Environmental Purification)

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16 pages, 6946 KiB

Open AccessArticle

Enhancing Catalytic Efficiency in Long-Chain Linear α-Olefin Epoxidation: A Study of CaSnO₃-Based Catalysts

by Min Zhang, Hongwei **ang and **aodong Wen

Catalysts 2024, 14(1), 70; https://doi.org/10.3390/catal14010070 - 17 Jan 2024

Viewed by 1088

Abstract

This investigation explores the synthesis of advanced catalysts for epoxidizing long-chain linear α-olefins, a pivotal process in the chemical industry for generating critical intermediates. Employing a hydrothermal technique, we developed four distinct catalysts (CS-1–4), methodically modulating the Ca/Sn ratio to elucidate its impact [...] Read more.

This investigation explores the synthesis of advanced catalysts for epoxidizing long-chain linear α-olefins, a pivotal process in the chemical industry for generating critical intermediates. Employing a hydrothermal technique, we developed four distinct catalysts (CS-1–4), methodically modulating the Ca/Sn ratio to elucidate its impact on the catalysts’ physicochemical properties. Our research uncovered that an escalated Ca/Sn ratio induces a morphological shift from octagonal to cubic structures, concomitant with a diminution in particle size and an enhancement in specific surface area. Significantly, the CS-3 catalyst outperformed others in 1-octene epoxidation, an efficacy attributed to its augmented surface alkalinity and proliferation of medium-strength alkaline sites, likely emanating from increased surface oxygen defects. Subsequent hydrogen reduction of CS-3 further amplified these oxygen defects, yielding a 10% uptick in catalytic activity. This correlation underscores the potential of oxygen defect manipulation in optimizing catalytic efficiency. Our findings contribute a novel perspective to the development of robust, high-performance catalysts for α-olefin epoxidation, seamlessly aligning with the principles of sustainable chemistry. Full article

(This article belongs to the Special Issue Advanced Research of Perovskite Materials as Catalysts)

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23 pages, 4563 KiB

Open AccessReview

Advances in Cross-Coupling Reactions Catalyzed by Aromatic Pincer Complexes Based on Earth-Abundant 3d Metals (Mn, Fe, Co, Ni, Cu)

by Jesús Antonio Cruz-Navarro, Arturo Sánchez-Mora, Juan S. Serrano-García, Andrés Amaya-Flórez, Raúl Colorado-Peralta, Viviana Reyes-Márquez and David Morales-Morales

Catalysts 2024, 14(1), 69; https://doi.org/10.3390/catal14010069 - 16 Jan 2024

Cited by 1 | Viewed by 1889

Abstract

The increase of noble-metal-free catalysis in organic chemistry is a trending topic in constant growth due to the price increase of noble metals and their scarce abundance. As a result, many earth-abundant transition-metal complexes containing nickel, iron, or cobalt have been successfully applied [...] Read more.

The increase of noble-metal-free catalysis in organic chemistry is a trending topic in constant growth due to the price increase of noble metals and their scarce abundance. As a result, many earth-abundant transition-metal complexes containing nickel, iron, or cobalt have been successfully applied in the homogeneous catalysis of a wide number of cross-coupling reactions, and the use of pincer complexes based on these earth-abundant metals was recently explored, affording interesting results. Thus, this review provides a general overview of earth-abundant 3D pincer complexes and their application during the last decade as catalysts in cross-coupling reactions such as Kumada–Corriu, Suzuki–Miyaura, Sonogashira, C–S cross-coupling, and C–N bond-forming reactions. Full article

(This article belongs to the Special Issue Organometallic Homogeneous Catalysis)

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4 pages, 189 KiB

Open AccessEditorial

Mono- and Bimetallic Nanoparticles in Catalysis

by Elena A. Redina and Olga A. Kirichenko

Catalysts 2024, 14(1), 68; https://doi.org/10.3390/catal14010068 - 16 Jan 2024

Cited by 2 | Viewed by 1163

Abstract

The catalytic applications of supported mono- and bimetallic nanoparticles are wide on the laboratory, pilot plant and industrial scale [...] Full article

(This article belongs to the Special Issue Mono- and Bimetallic Nanoparticles in Catalysis)

12 pages, 2061 KiB

Open AccessArticle

Synergistic Effect of Structure and Morphology of ZSM-5 Catalysts on the Transformation of Methanol to Propylene

by Wei Zhang, Kangzhou Wang, **nhua Gao, **ao**g Yong and Yanlong Gu

Catalysts 2024, 14(1), 67; https://doi.org/10.3390/catal14010067 - 15 Jan 2024

Viewed by 1295

Abstract

Here, the efficient synthesis of propylene from methanol was achieved using a series of HZSM-5 catalysts. The effect of the structure and morphology of ZSM-5 on the conversion of methanol to propylene was studied. The structure and physicochemical properties of the synthesized catalysts [...] Read more.

Here, the efficient synthesis of propylene from methanol was achieved using a series of HZSM-5 catalysts. The effect of the structure and morphology of ZSM-5 on the conversion of methanol to propylene was studied. The structure and physicochemical properties of the synthesized catalysts were analyzed by multiple characterization techniques. The characterization results revealed that the alumina content rationally modified the acid properties of ZSM-5. When using a ZSM-5 catalyst with a hexagonal single crystal and a Si/Al ratio of 177, the selectivity of propylene reached 39.7% at 480 °C. Furthermore, the formation of methane was reduced. This provides a clue for catalyst design to enable the selective transformation of methanol into propylene. Full article

(This article belongs to the Special Issue Catalytic Conversion of Low Carbon Alkane)

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13 pages, 2810 KiB

Open AccessArticle

Pd-Bi-Based Catalysts for Selective Oxidation of Glucose into Gluconic Acid: The Role of Local Environment of Nanoparticles in Dependence of Their Composition

by Mariya P. Shcherbakova-Sandu, Andrey A. Saraev, Alexey S. Knyazev and Irina A. Kurzina

Catalysts 2024, 14(1), 66; https://doi.org/10.3390/catal14010066 - 15 Jan 2024

Viewed by 1099

Abstract

Palladium–bismuth nanomaterials are used in various chemical applications such detectors, electrodes, and catalysts. Pd-Bi catalysts are attracting widespread interest because these catalysts enable the production of valuable products quickly and efficiently, and are environmentally friendly. However, the composition of the catalyst can have [...] Read more.

Palladium–bismuth nanomaterials are used in various chemical applications such detectors, electrodes, and catalysts. Pd-Bi catalysts are attracting widespread interest because these catalysts enable the production of valuable products quickly and efficiently, and are environmentally friendly. However, the composition of the catalyst can have a significant impact on its catalytic performance. In this work, we identified a correlation between the composition of the catalyst and its efficiency in converting glucose into sodium gluconate. It was found that the conversion decreases with increasing bismuth content. The most active catalyst was the 0.35Bi:Pd sample with a lower bismuth content (glucose conversion of 57%). TEM, SEM, EXAFS, and XANES methods were used to describe, in detail, the surface properties of the xBi:Pd/Al₂O₃ catalyst samples. The increase in particle size with increasing bismuth content, observed in the TEM micrographs, was associated with the low melting point of bismuth (271 °C). The SEM method showed that palladium and bismuth particles were uniformly distributed over the surface of the support in close proximity to each other, which allowed us to conclude that an alloy of non-stoichiometric composition was formed. The EXAFS and XANES methods established that bismuth was located on the surface of the nanoparticle predominantly in an oxidized state. Full article

(This article belongs to the Section Nanostructured Catalysts)

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10 pages, 8171 KiB

Open AccessArticle

Hydrochloric Acid Catalyzed Hydrothermal Treatment to Recover Phosphorus from Municipal Sludge

by Kai Liu, Yang Xue, Yawei Zhai, Lisong Zhou and Jian Kang

Catalysts 2024, 14(1), 65; https://doi.org/10.3390/catal14010065 - 15 Jan 2024

Viewed by 1102

Abstract

Resource utilization of sludge is critical because traditional sludge treatment methods cause a large amount of nutrient loss. This study investigated the impact of hydrochloric acid quantity, reaction temperature, and time on phosphorus release and migration from municipal sludge during hydrothermal treatment and [...] Read more.

Resource utilization of sludge is critical because traditional sludge treatment methods cause a large amount of nutrient loss. This study investigated the impact of hydrochloric acid quantity, reaction temperature, and time on phosphorus release and migration from municipal sludge during hydrothermal treatment and designed a sludge disposal method for the recovery and utilization of phosphorus resources. We know that hydrochloric acid destroys the complexation of calcium and phosphorus precipitates, leading to the selective transfer of phosphorus to the liquid phase, and that the addition of 1–5% hydrochloric acid corresponds to a phosphorus extraction rate in the range of 0.3–98%. When hydrochloric acid is added, a change in temperature and reaction time has a negligible effect on phosphorus. Phosphorus can be recovered using the liquid product obtained under the optimal hydrothermal reaction conditions (adding 5% HCl at 205 °C for 30 min). After adjusting the pH value and adding the magnesium source, struvite (MgNH₄PO₄·6H₂O) can be precipitated quickly and with high purity. At a cost of USD 27.8/ton of sludge, this method can recover 94% of the phosphorus in the sludge, and the bioavailable phosphorus ratio of the product is 93%, therefore, providing an important alternative to existing phosphorus recovery technologies. Full article

(This article belongs to the Special Issue Catalytic Conversion of Municipal Solid Wastes(MSW) for the Efficient and Clean Utilization of All Components)

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14 pages, 3652 KiB

Open AccessArticle

Identification of Aniline-Degrading Bacteria Using Stable Isotope Probing Technology and Prediction of Functional Genes in Aerobic Microcosms

by Baoqin Li, Muhammad Usman Ghani, Weimin Sun, **aoxu Sun, Huaqing Liu, Geng Yan, Rui Yang, Ying Huang, Youhua Ren and Benru Song

Catalysts 2024, 14(1), 64; https://doi.org/10.3390/catal14010064 - 15 Jan 2024

Viewed by 1336

Abstract

Aniline, a vital component in various chemical industries, is known to be a hazardous persistent organic pollutant that can cause environmental pollution through its manufacturing, processing, and transportation. In this study, the microcosms were established using sediment with a history of aniline pollution [...] Read more.

Aniline, a vital component in various chemical industries, is known to be a hazardous persistent organic pollutant that can cause environmental pollution through its manufacturing, processing, and transportation. In this study, the microcosms were established using sediment with a history of aniline pollution as an inoculum to analyze the aniline biodegradation under aerobic conditions through stable isotope probing (SIP) and isopycnic density gradient centrifugation technology. During the degradation assay, aniline that was ¹³C-labeled in all six carbons was utilized to determine the phylogenetic identity of the aniline-degrading bacterial taxa that incorporate ¹³C into their DNA. The results revealed that aniline was completely degraded in the microcosm after 45 and 69 h respectively. The bacteria affiliated with Acinetobacter (up to 34.6 ± 6.0%), Zoogloea (up to 15.8 ± 2.2%), Comamonas (up to 2.6 ± 0.1%), and Hydrogenophaga (up to 5.1 ± 0.6%) genera, which are known to degrade aniline, were enriched in the heavy fractions (the DNA buoyant density was 1.74 mg L⁻¹) of the ¹³C-aniline treatments. Moreover, some rarely reported aniline-degrading bacteria, such as Prosthecobacter (up to 16.0 ± 1.6%) and Curvibacter (up to 3.0 ± 1.6%), were found in the DNA-SIP experiment. Gene families affiliated with atd, tdn, and dan were speculated to be key genes for aniline degradation based on the abundance in functional genes and diversity in different treatments as estimated using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States version 2 (PICRUSt2) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). This study revealed the functional bacteria and possible degradation genes for aniline degradation in simulated polluted environments through SIP. These findings suggest that important degrading bacteria for the transformation of aniline and potential degradation pathways may be useful in the effective application of bioremediation technologies to remediate aniline-contaminated sites. Full article

(This article belongs to the Special Issue Microbial Biocatalysis, 2nd Edition)

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12 pages, 6889 KiB

Open AccessArticle

Unraveling FeO_x Nanoparticles Confined on Fibrous Mesoporous Silica Catalyst Construction and CO Catalytic Oxidation Performance

by Guobo Li, Weiwei Feng, Yiwei Luo, Jie Yan, Yining Cai, Yiling Wang, Shule Zhang, Wenming Liu and Honggen Peng

Catalysts 2024, 14(1), 63; https://doi.org/10.3390/catal14010063 - 14 Jan 2024

Viewed by 1193

Abstract

Catalytic oxidation is used to control carbon monoxide (CO) emissions from industrial exhaust. In this study, a mesoporous silica material, KCC-1, was synthesized and used as a carrier with a high specific surface area to confine active component FeO_x nanoparticles (NPs), and [...] Read more.

Catalytic oxidation is used to control carbon monoxide (CO) emissions from industrial exhaust. In this study, a mesoporous silica material, KCC-1, was synthesized and used as a carrier with a high specific surface area to confine active component FeO_x nanoparticles (NPs), and the CO catalytic oxidation performance of x%Fe@KCC-1 catalysts (x represents the mass loading of Fe) was studied. The experimental results showed that due to its large specific surface area and abundant mesopores, the FeO_x NPs were highly dispersed on the surface of the KCC-1 carrier. The particle size of FeO_x was very small, resulting in strong interactions between FeO_x NPs and KCC-1, which enhanced the catalytic oxidation reaction on the catalyst. The FeO_x loading improved the CO adsorption capability of the catalyst, which facilitated the catalytic oxidation of CO, with the 7%Fe@KCC-1 catalyst achieving 100% CO conversion at 160 °C. The CO catalytic removal mechanism was investigated by a combination of in-situ DRIFTS and DFT calculations. This study advances scientific understanding of the application potential of nano-catalysts in important oxidation reactions and provides valuable insights into the development of efficient CO oxidation catalysts. Full article

(This article belongs to the Special Issue Catalysts for Mobile Source: Low-Carbon and Pollution Emission Control)

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28 pages, 8399 KiB

Open AccessFeature PaperArticle

Green Fabrication of ZnO Nanoparticles and ZnO/rGO Nanocomposites from Algerian Date Syrup Extract: Synthesis, Characterization, and Augmented Photocatalytic Efficiency in Methylene Blue Degradation

by Kamilia Madi, Derradji Chebli, Hakima Ait Youcef, Hichem Tahraoui, Abdallah Bouguettoucha, Mohammed Kebir, Jie Zhang and Abdeltif Amrane

Catalysts 2024, 14(1), 62; https://doi.org/10.3390/catal14010062 - 13 Jan 2024

Cited by 5 | Viewed by 2058

Abstract

This innovative article provides a detailed description of the successful biosynthesis of zinc nanoparticles (ZnO-NPs) using an aqueous extract of Algerian Date Syrup, also known as molasses. A meticulous process was carried out to determine the optimal calcination temperature for ZnO-NPs, a crucial [...] Read more.

This innovative article provides a detailed description of the successful biosynthesis of zinc nanoparticles (ZnO-NPs) using an aqueous extract of Algerian Date Syrup, also known as molasses. A meticulous process was carried out to determine the optimal calcination temperature for ZnO-NPs, a crucial step in the preparation of these nanoparticles. The study was further extended by creating ZnO/rGOx nanocomposites through a hydrothermal method, varying the concentrations of reduced graphene oxide (rGO) at 5%, 10%, and 15%. The characteristics of the nanocomposites were thoroughly explored, encompassing chemical, optical, and morphological aspects, using sophisticated analysis techniques such as scanning electron microscopy (SEM), UV-visible diffuse reflectance spectroscopy (UV DRS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). These analyses provided an in-depth understanding of the structure and properties of the nanocomposites. The centerpiece of this study is the evaluation of the photocatalytic degradation capacity of ZnO-NPs and ZnO/rGOx nanocomposites. These materials have demonstrated their ability to act as cost-effective and environmentally friendly photocatalysts for wastewater treatment. Experiments on methylene blue degradation under UV irradiation were conducted, yielding impressive results: a degradation efficiency of 86.6% was achieved in 140 min using 1 g/L of ZnO-NPs, and this rate reached 100% with the ZnO/rGO catalyst in the same time frame, highlighting its superiority as a photocatalyst. Furthermore, this study examined the variables affecting the photocatalysis experiment, including the solution’s pH and the amount of catalyst. The results revealed that the ZnO/rGO photocatalyst reached its optimal efficiency under neutral pH conditions and at a concentration of 1 g/L, providing crucial information for practical use of these materials. This enriched article highlights the promising potential of ZnO-NPs and ZnO/rGOx nanocomposites as efficient photocatalysts for methylene blue degradation, paving the way for significant environmental applications in wastewater treatment. Full article

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