Molecules

Research

Jump to: Review

15 pages, 7963 KiB

Open AccessArticle

Highly Sensitive and Selective Eco-Toxic 4-Nitrophenol Chemical Sensor Based on Ag-Doped ZnO Nanoflowers Decorated with Nanosheets

by Ahmad Umar, M. Shaheer Akhtar, Hassan Algadi, Ahmed A. Ibrahim, Mohsen A. M. Alhamami and Sotirios Baskoutas

Molecules 2021, 26(15), 4619; https://doi.org/10.3390/molecules26154619 - 30 Jul 2021

Cited by 12 | Viewed by 1968

Abstract

Herein, we have developed a novel sensing electrode to detect the eco-toxic 4-nitrophenol (4-NP). Ag-doped-ZnO nanoflowers were synthesized by facile hydrothermal method and examined by several characterization techniques in order to understand the morphology, crystal structure, composition, and surface properties. Morphological results were [...] Read more.

Herein, we have developed a novel sensing electrode to detect the eco-toxic 4-nitrophenol (4-NP). Ag-doped-ZnO nanoflowers were synthesized by facile hydrothermal method and examined by several characterization techniques in order to understand the morphology, crystal structure, composition, and surface properties. Morphological results were confirmed by the formation of Ag-doped ZnO nanoflowers decorated with nanosheets. Ag-doped ZnO/glassy carbon electrode (GCE) electrode-material-matrix was used for electrochemical sensing of toxic 4-NP. Under optimized conditions, Ag-doped ZnO/GCE modified electrode exhibits high-sensitivity and selectivity compared to the bare GCE electrode. The Ag-doped ZnO/GCE modified electrode exhibits high electrocatalytic oxidation towards 4-NP. Anodic peak current of 4-NP is increased linearly by increasing the concentration of nitrophenol. Additionally, Ag-doped ZnO/GCE shows a wide range of sensitivity from 10 µM to 500 µM, and a linear calibration plot with a good detection limit of 3 µM (S/N = 3). The proposed Ag-doped ZnO/GCE modified electrode showed high sensing stability. In addition, the oxidation mechanism was studied. The obtained results revealed that the Ag-ZnO/GCE electrode could be the promising sensing electrode for 4-NP sensing. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Figure 1

14 pages, 1789 KiB

Open AccessArticle

Formation of Molybdenum Blue Nanoparticles in the Organic Reducing Area

by Maria Myachina, Natalia Gavrilova and Victor Nazarov

Molecules 2021, 26(15), 4438; https://doi.org/10.3390/molecules26154438 - 23 Jul 2021

Cited by 12 | Viewed by 3048

Abstract

Molybdenum blue dispersions were synthesized by reducing an acidic molybdate solution with glucose, hydroquinone and ascorbic acid. The influence of the H/Mo molar ratio on the rate of formation of molybdenum particles was established. For each reducing agent, were determined the rate constant [...] Read more.

Molybdenum blue dispersions were synthesized by reducing an acidic molybdate solution with glucose, hydroquinone and ascorbic acid. The influence of the H/Mo molar ratio on the rate of formation of molybdenum particles was established. For each reducing agent, were determined the rate constant and the order of the particle formation and were established the conditions for the formation of aggregative stable dispersion with the maximum concentration of particles. The dispersed phase is represented by toroidal molybdenum oxide nanoclusters, which was confirmed by the results of UV/Vis, FTIR, XPS spectroscopy and DLS. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Figure 1

19 pages, 3296 KiB

Open AccessArticle

High Surface Area Mesoporous Silica Nanoparticles with Tunable Size in the Sub-Micrometer Regime: Insights on the Size and Porosity Control Mechanisms

by Federica Rizzi, Rachele Castaldo, Tiziana Latronico, Pierluigi Lasala, Gennaro Gentile, Marino Lavorgna, Marinella Striccoli, Angela Agostiano, Roberto Comparelli, Nicoletta Depalo, Maria Lucia Curri and Elisabetta Fanizza

Molecules 2021, 26(14), 4247; https://doi.org/10.3390/molecules26144247 - 13 Jul 2021

Cited by 25 | Viewed by 4405

Abstract

Mesoporous silica nanostructures (MSNs) attract high interest due to their unique and tunable physical chemical features, including high specific surface area and large pore volume, that hold a great potential in a variety of fields, i.e., adsorption, catalysis, and biomedicine. An essential feature [...] Read more.

Mesoporous silica nanostructures (MSNs) attract high interest due to their unique and tunable physical chemical features, including high specific surface area and large pore volume, that hold a great potential in a variety of fields, i.e., adsorption, catalysis, and biomedicine. An essential feature for biomedical application of MSNs is limiting MSN size in the sub-micrometer regime to control uptake and cell viability. However, careful size tuning in such a regime remains still challenging. We aim to tackling this issue by develo** two synthetic procedures for MSN size modulation, performed in homogenous aqueous/ethanol solution or two-phase aqueous/ethyl acetate system. Both approaches make use of tetraethyl orthosilicate as precursor, in the presence of cetyltrimethylammonium bromide, as structure-directing agent, and NaOH, as base-catalyst. NaOH catalyzed syntheses usually require high temperature (>80 °C) and large reaction medium volume to trigger MSN formation and limit aggregation. Here, a successful modulation of MSNs size from 40 up to 150 nm is demonstrated to be achieved by purposely balancing synthesis conditions, being able, in addition, to keep reaction temperature not higher than 50 °C (30 °C and 50 °C, respectively) and reaction mixture volume low. Through a comprehensive and in-depth systematic morphological and structural investigation, the mechanism and kinetics that sustain the control of MSNs size in such low dimensional regime are defined, highlighting that modulation of size and pores of the structures are mainly mediated by base concentration, reaction time and temperature and ageing, for the homogenous phase approach, and by temperature for the two-phase synthesis. Finally, an in vitro study is performed on bEnd.3 cells to investigate on the cytotoxicity of the MNSs. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Graphical abstract

11 pages, 5098 KiB

Open AccessArticle

Coating Cellulosic Material with Ag Nanowires to Fabricate Wearable IR-Reflective Device for Personal Thermal Management: The Role of Coating Method and Loading Level

by Mohsen Gorji, Saeedeh Mazinani, Abdol-Rahim Faramarzi, Saeedeh Ghadimi, Mohammadreza Kalaee, Ali Sadeghianmaryan and Lee D. Wilson

Molecules 2021, 26(12), 3570; https://doi.org/10.3390/molecules26123570 - 11 Jun 2021

Cited by 13 | Viewed by 2816

Abstract

Textiles coated with silver nanowires (AgNWs) are effective at suppressing radiative heat loss without sacrificing breathability. Many reports present the applicability of AgNWs as IR-reflective wearable textiles, where such studies partially evaluate the parameters for practical usage for large-scale production. In this study, [...] Read more.

Textiles coated with silver nanowires (AgNWs) are effective at suppressing radiative heat loss without sacrificing breathability. Many reports present the applicability of AgNWs as IR-reflective wearable textiles, where such studies partially evaluate the parameters for practical usage for large-scale production. In this study, the effect of the two industrial coating methods and the loading value of AgNWs on the performance of AgNWs-coated fabric (AgNWs-CF) is reported. The AgNWs were synthesized by the polyol process and applied onto the surface of cotton fabric using either dip- or spray-coating methods with variable loading levels of AgNWs. X-ray diffraction, scanning electron microscopy (SEM), infrared (IR) reflectance, water vapor permeability (WVP), and electrical resistance properties were characterized. The results report the successful synthesis of AgNWs with a 30 μm length. The results also show that the spray coating method has a better performance for reflecting the IR radiation to the body, which increases with a greater loading level of the AgNWs. The antibacterial results show a good inhibition zone for cotton fabric coated by both methods, where the spray-coated fabric has a better performance overall. The results also show the coated fabric with AgNWs maintains the level of fabric breathability similar to control samples. AgNWs-CFs have potential utility for cold weather protective clothing in which heat dissipation is attenuated, along with applications such as wound dressing materials that provide antibacterial protection. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Graphical abstract

22 pages, 5466 KiB

Open AccessArticle

Physico-Chemical Properties of Inorganic NPs Influence the Absorption Rate of Aquatic Mosses Reducing Cytotoxicity on Intestinal Epithelial Barrier Model

by Valeria De Matteis, Makarena Rojas, Mariafrancesca Cascione, Stefano Mazzotta, Gian Pietro Di Sansebastiano and Rosaria Rinaldi

Molecules 2021, 26(10), 2885; https://doi.org/10.3390/molecules26102885 - 13 May 2021

Cited by 5 | Viewed by 2380

Abstract

Noble metals nanoparticles (NPs) and metal oxide NPs are widely used in different fields of application and commercial products, exposing living organisms to their potential adverse effects. Recent evidences suggest their presence in the aquifers water and consequently in drinking water. In this [...] Read more.

Noble metals nanoparticles (NPs) and metal oxide NPs are widely used in different fields of application and commercial products, exposing living organisms to their potential adverse effects. Recent evidences suggest their presence in the aquifers water and consequently in drinking water. In this work, we have carefully synthesized four types of NPs, namely, silver and gold NPs (Ag NPs and Au NPs) and silica and titanium dioxide NPs (SiO₂ NPs and TiO₂ NPs) having a similar size and negatively charged surfaces. The synthesis of Ag NPs and Au NPs was carried out by colloidal route using silver nitrate (AgNO₃) and tetrachloroauric (III) acid (HAuCl₄) while SiO₂ NPs and TiO₂ NPs were achieved by ternary microemulsion and sol-gel routes, respectively. Once the characterization of NPs was carried out in order to assess their physico-chemical properties, their impact on living cells was studied. We used the human colorectal adenocarcinoma cells (Caco-2), known as the best representative intestinal epithelial barrier model to understand the effects triggered by NPs through ingestion. Then, we moved to explore how water contamination caused by NPs can be lowered by the ability of three species of aquatic moss, namely, Leptodictyum riparium, Vesicularia ferriei, and Taxiphyllum barbieri, to absorb them. The experiments were conducted using two concentrations of NPs (100 μM and 500 Μm as metal content) and two time points (24 h and 48 h), showing a capture rate dependent on the moss species and NPs type. Then, the selected moss species, able to actively capture NPs, appear as a powerful tool capable to purify water from nanostructured materials, and then, to reduce the toxicity associated to the ingestion of contaminated drinking water. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Figure 1

15 pages, 2322 KiB

Open AccessFeature PaperArticle

Catechol-Containing Schiff Bases on Thiacalixarene: Synthesis, Copper (II) Recognition, and Formation of Organic-Inorganic Copper-Based Materials

by Pavel Padnya, Ksenia Shibaeva, Maxim Arsenyev, Svetlana Baryshnikova, Olga Terenteva, Igor Shiabiev, Artur Khannanov, Artur Boldyrev, Alexander Gerasimov, Denis Grishaev, Yurii Shtyrlin and Ivan Stoikov

Molecules 2021, 26(8), 2334; https://doi.org/10.3390/molecules26082334 - 17 Apr 2021

Cited by 26 | Viewed by 6034

Abstract

For the first time, a series of catechol-containing Schiff bases, tetrasubstituted at the lower rim thiacalix[4]arene derivatives in three stereoisomeric forms, cone, partial cone, and 1,3-alternate, were synthesized. The structure of the obtained compounds was proved by modern physical methods, [...] Read more.

For the first time, a series of catechol-containing Schiff bases, tetrasubstituted at the lower rim thiacalix[4]arene derivatives in three stereoisomeric forms, cone, partial cone, and 1,3-alternate, were synthesized. The structure of the obtained compounds was proved by modern physical methods, such as NMR, IR spectroscopy, and HRMS. Selective recognition (K_b difference by three orders of magnitude) of copper (II) cation in the series of d-metal cations (Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺) was shown by UV-vis spectroscopy. Copper (II) ions are coordinated at the nitrogen atom of the imine group and the nearest oxygen atom of the catechol fragment in the thiacalixarene derivatives. High thermal stable organic-inorganic copper-based materials were obtained on the base of 1,3-alternate + Cu (II) complexes. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Graphical abstract

24 pages, 6986 KiB

Open AccessArticle

Antibacterial and Photocatalytic Properties of ZnO Nanoparticles Obtained from Chemical versus Saponaria officinalis Extract-Mediated Synthesis

by Maria Antonia Tănase, Maria Marinescu, Petruta Oancea, Adina Răducan, Catalin Ionut Mihaescu, Elvira Alexandrescu, Cristina Lavinia Nistor, Luiza-Izabela **ga, Lia Mara Diţu, Cristian Petcu and Ludmila Otilia Cinteza

Molecules 2021, 26(7), 2072; https://doi.org/10.3390/molecules26072072 - 4 Apr 2021

Cited by 20 | Viewed by 3499

Abstract

In the present work, the properties of ZnO nanoparticles obtained using an eco-friendly synthesis (biomediated methods in microwave irradiation) were studied. Saponaria officinalis extracts were used as both reducing and cap** agents in the green nanochemistry synthesis of ZnO. Inorganic zinc oxide nanopowders [...] Read more.

In the present work, the properties of ZnO nanoparticles obtained using an eco-friendly synthesis (biomediated methods in microwave irradiation) were studied. Saponaria officinalis extracts were used as both reducing and cap** agents in the green nanochemistry synthesis of ZnO. Inorganic zinc oxide nanopowders were successfully prepared by a modified hydrothermal method and plant extract-mediated method. The influence of microwave irradiation was studied in both cases. The size, composition, crystallinity and morphology of inorganic nanoparticles (NPs) were investigated using dynamic light scattering (DLS), powder X-ray diffraction (XRD), SEM-EDX microscopy. Tunings of the nanochemistry reaction conditions (Zn precursor, structuring agent), ZnO NPs with various shapes were obtained, from quasi-spherical to flower-like. The optical properties and photocatalytic activity (degradation of methylene blue as model compound) were also investigated. ZnO nanopowders’ antibacterial activity was tested against Gram-positive and Gram-negative bacterial strains to evidence the influence of the vegetal extract-mediated synthesis on the biological activity. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Figure 1

10 pages, 3673 KiB

Open AccessArticle

Investigation of Structural and Luminescent Properties of Sol-Gel-Derived Cr‑Substituted Mg₃Al_1−xCr_x Layered Double Hydroxides

by Ligita Valeikiene, Inga Grigoraviciute-Puroniene, Arturas Katelnikovas, Aleksej Zarkov and Aivaras Kareiva

Molecules 2021, 26(7), 1848; https://doi.org/10.3390/molecules26071848 - 25 Mar 2021

Cited by 1 | Viewed by 1715

Abstract

In the present work, Cr-substituted Mg₃Al_1−xCr_x layered double hydroxides (LDHs) were synthesised through the phase conversion of sol-gel-derived mixed-metal oxides in an aqueous medium. The chromium substitution level in the range of 1 to 25 mol% was investigated. [...] Read more.

In the present work, Cr-substituted Mg₃Al_1−xCr_x layered double hydroxides (LDHs) were synthesised through the phase conversion of sol-gel-derived mixed-metal oxides in an aqueous medium. The chromium substitution level in the range of 1 to 25 mol% was investigated. It was demonstrated that all synthesised specimens were single-phase LDHs. The results of elemental analysis confirmed that the suggested synthetic sol-gel chemistry approach is suitable for the preparation of LDHs with a highly controllable chemical composition. The surface microstructure of sol-gel-derived Mg₃Al_1−xCr_x LDHs does not depend on the chromium substitution level. The formation of plate-like agglomerated particles, which consist of hexagonally shaped nanocrystallites varying in size from approximately 200 to 300 nm, was observed. Optical properties of the synthesised Mg₃Al_1−xCr_x LDHs were investigated by means of photoluminescence. All Cr-containing powders exhibited characteristic emission in the red region of the visible spectrum. The strongest emission was observed for the sample doped with 5 mol% Cr³⁺ ions. However, the emission intensity of samples doped with 1–10 mol% Cr³⁺ ions was relatively similar. A further increase in the Cr³⁺ ion concentration to 25 mol% resulted in severe concentration quenching. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Figure 1

Review

Jump to: Research

39 pages, 8402 KiB

Open AccessReview

Green Synthesis and Applications of ZnO and TiO₂ Nanostructures

by Rosana A. Gonçalves, Rosimara P. Toledo, Nirav Joshi and Olivia M. Berengue

Molecules 2021, 26(8), 2236; https://doi.org/10.3390/molecules26082236 - 13 Apr 2021

Cited by 64 | Viewed by 12070

Abstract

Over the last two decades, oxide nanostructures have been continuously evaluated and used in many technological applications. The advancement of the controlled synthesis approach to design desired morphology is a fundamental key to the discipline of material science and nanotechnology. These nanostructures can [...] Read more.

Over the last two decades, oxide nanostructures have been continuously evaluated and used in many technological applications. The advancement of the controlled synthesis approach to design desired morphology is a fundamental key to the discipline of material science and nanotechnology. These nanostructures can be prepared via different physical and chemical methods; however, a green and ecofriendly synthesis approach is a promising way to produce these nanostructures with desired properties with less risk of hazardous chemicals. In this regard, ZnO and TiO₂ nanostructures are prominent candidates for various applications. Moreover, they are more efficient, non-toxic, and cost-effective. This review mainly focuses on the recent state-of-the-art advancements in the green synthesis approach for ZnO and TiO₂ nanostructures and their applications. The first section summarizes the green synthesis approach to synthesize ZnO and TiO₂ nanostructures via different routes such as solvothermal, hydrothermal, co-precipitation, and sol-gel using biological systems that are based on the principles of green chemistry. The second section demonstrates the application of ZnO and TiO₂ nanostructures. The review also discusses the problems and future perspectives of green synthesis methods and the related issues posed and overlooked by the scientific community on the green approach to nanostructure oxides. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Figure 1

28 pages, 7376 KiB

Open AccessReview

Plasma Synthesis of Advanced Metal Oxide Nanoparticles and Their Applications as Transparent Conducting Oxide Thin Films

by Hong Yong Sohn and Arun Murali

Molecules 2021, 26(5), 1456; https://doi.org/10.3390/molecules26051456 - 7 Mar 2021

Cited by 11 | Viewed by 3511

Abstract

This article reviews and summarizes work recently performed in this laboratory on the synthesis of advanced transparent conducting oxide nanopowders by the use of plasma. The nanopowders thus synthesized include indium tin oxide (ITO), zinc oxide (ZnO) and tin-doped zinc oxide (TZO), aluminum-doped [...] Read more.

This article reviews and summarizes work recently performed in this laboratory on the synthesis of advanced transparent conducting oxide nanopowders by the use of plasma. The nanopowders thus synthesized include indium tin oxide (ITO), zinc oxide (ZnO) and tin-doped zinc oxide (TZO), aluminum-doped zinc oxide (AZO), and indium-doped zinc oxide (IZO). These oxides have excellent transparent conducting properties, among other useful characteristics. ZnO and TZO also has photocatalytic properties. The synthesis of these materials started with the selection of the suitable precursors, which were injected into a non-transferred thermal plasma and vaporized followed by vapor-phase reactions to form nanosized oxide particles. The products were analyzed by the use of various advanced instrumental analysis techniques, and their useful properties were tested by different appropriate methods. The thermal plasma process showed a considerable potential as an efficient technique for synthesizing oxide nanopowders. This process is also suitable for large scale production of nano-sized powders owing to the availability of high temperatures for volatilizing reactants rapidly, followed by vapor phase reactions and rapid quenching to yield nano-sized powder. Full article

(This article belongs to the Special Issue Inorganic Nanochemistry)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Inorganic Nanochemistry

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (10 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI