Ag-ZnO/PANI nanocomposite was prepared via the sol-gel technique following in situ oxidative polymerization of polyaniline (PANI). XRD, UV-Vis, and FT-IR spectroscopy were employed to study the crystal size, bandgap energy, and bond structure of as-synthesized nanocomposites. The mean crystallite size of the nanocomposite determined from XRD was 35.68 nm. Photocatalytic degradation of malachite green (MG) dye using as-synthesized photocatalysts was studied under visible light irradiation. The highest degradation efficiency was recorded for Ag-ZnO/PANI nanocomposites (98.58%) than Ag-ZnO nanoparticles (88.23%) in 120 min. The kinetics of photocatalytic degradation of MG follows pseudo-first-order reaction with rate order of 1.16 10−2 min−1. Moreover, the photocatalytic activity of Ag-ZnO/PANI nanocomposites was evaluated and compared with Ce-Cd oxide, electrospun P(3HB)-TiO2, and with other catalysts in the literature. The optimal conditions for photocatalytic degradation are as follows: the concentration of malachite green (0.2 g/l), pH (8), and the concentration of catalyst load (0.2 g/l) under visible light with an irradiation time of 120 min.

/pdf/polyaniline-supported-ag-doped-zno-nanocomposite-synthesis-4b2hf2r08m.pdf

Polyaniline Supported Ag-Doped ZnO Nanocomposite: Synthesis, Characterization, and Kinetics Study for Photocatalytic Degradation of Malachite Green

In this study, the physical properties of ZnO were facile controlled by the synthesis method with the addition of capping and precipitation agents. As-prepared ZnO samples had different morphologies such as carnation flower-like ZnO (CF-ZnO), rose-flower-like ZnO (RF-ZnO), rod-like ZnO (R-ZnO), and nanoparticle ZnO (N-ZnO) and were characterized by SEM, XRD, N2 adsorption/desorption isotherms, FT-IR, and DR/UV-vis. All samples had a crystallite structure of hexagonal wurtzite type. The CF-ZnO and RF-ZnO samples had the hierarchical structure like a carnation flower and a beautiful rose, respectively. R-ZnO was composed of many hexagonal rods and few spherical particles, while N-ZnO microstructures were made up of nanoparticles with approximately 20-30 nm, exhibiting the largest surface area, pore volume, and pore width among as-prepared samples, and their crystal size and bandgap energy were 17.8 nm and 3.207 eV, respectively. The catalytic performances of ZnO samples were evaluated by degradation of Tartrazine (TA) and Caffeine (CAF) under low UV irradiation (15 W). N-ZnO showed a high photocatalytic activity compared to other samples. Besides, the reaction kinetics was investigated by the first-order kinetic model, and the catalytic performance of ZnO was evaluated through several organic pollutants.

/pdf/facile-controlling-of-the-physical-properties-of-zinc-oxide-4bpae17pev.pdf

Facile Controlling of the Physical Properties of Zinc Oxide and Its Application to Enhanced Photocatalysis.

Investigation of shape effect of silver nanostructures and governing physical mechanisms on photo-activity: Zinc oxide/silver plasmonic photocatalyst

Enhanced photocatalytic degradation of Acid Blue 1 using Ni-Decorated ZnO NPs synthesized by sol-gel method: RSM optimization approach

In this study, ZnO/g-C3N4 nanocomposites were prepared via a physical mixing-calcination process for improved degradation of dyes under visible light irradiation. The BET surface area, pore volume, crystal size, and pHpzc of the ZnO/g-C3N4 composite were 3.9 m2/g, 0.034 cm3/g, 18.1 nm, and 7.7, respectively. Although the morphology of the ZnO/g-C3N4 composite was very different from that of pure g-C3N4, their average pore sizes were similar. The Eg of the ZnO/g-C3N4 composite (3.195 eV) was slightly lower than that of ZnO (3.195) but much higher than that of g-C3N4 (2.875). The interface interaction of ZnO and g-C3N4, which was revealed by oscillations of Zn-C, benefited the transport of photoinduced charge carriers and reduced the recombination of electron-hole. As the result, the ZnO/g-C3N4 composite had higher photocatalytic activity than ZnO and g-C3N4. Its degradation efficiency (DE) value for methylene blue (MB) in 90 min and rate constant were 93.2 % and 0.025 min‑1, respectively. In addition, the effects of ZnO/urea molar ratio, catalyst dosage, solution pH, and concentration of dye on photocatalytic degradation of MB were completely investigated. The photocatalytic performance of the ZnO/g-C3N4 composite was evaluated by the degradation of other persistent organic compounds, also compared to other catalysts in the literatures. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Nanocomposite ZnO/g-C3N4 for Improved Degradation of Dyes under Visible Light: Facile Preparation, Characterization, and Performance Investigations

Zinc oxide (ZnO) has been known as an excellent photocatalyst for the degradation of a variety of organic pollutants under UV irradiation. This work describes a synthesis of ZnO nanoparticles via a facile precipitation method, and Ag was doped into Ag/ZnO nanocomposite to improve the photocatalytic degradation of BPA under visible light irradiation. The obtained ZnO nanoparticles were 20 nm in size and had a relatively high surface area and pore volume, 26.2 m2/g and 0.48 cm3/g, respectively. The deposition of Ag led to a decrease in the surface area, pore volume, and band gap energy ( ) of ZnO nanoparticles. However, the photocatalytic activity of Ag/ZnO composite in the case increased. The performance of ZnO was compared with Ag/ZnO composites at the different molar ratios, and the kinetic reaction of BPA in these catalysts was investigated by the first-order kinetic model. The sample of Ag/ZnO-10 composite had the highest catalytic activity and showed the degradation efficiency, reaction rate, and degradation capacity of 100% in 120 min, 0.014 min-1, and 40 mg/g, respectively. In comparison, the effects of Ag/ZnO molar ratio, catalyst dosage, solution pH, and concentration of BPA on photocatalytic degradation were investigated. Additionally, the photocatalytic performance of Ag/ZnO-10 composite was evaluated by the degradation of other persistent organic compounds such as phenol, tartrazine, and methylene blue and compared to other catalysts in literature.

/pdf/facile-preparation-of-zno-nanoparticles-and-ag-zno-wpt5prcpew.pdf

Facile Preparation of ZnO Nanoparticles and Ag/ZnO Nanocomposite and Their Photocatalytic Activities under Visible Light

Zinc oxide (ZnO) has been shown as a potential photocatalyst under ultraviolet (UV) light but its catalytic activity has a limitation under visible (Vis) light due to the wide bandgap energy and the rapid recombination of electrons and holes. Thus, hierarchical structure Au/ZnO composites were fabricated by the hydrothermal method and chemical reduction method for enhanced photocatalytic performance under visible light. As-prepared composites were characterized by UV-vis diffuse reflectance spectra (DR/UV-Vis), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and electron paramagnetic resonance (EPR). The Au/ZnO-5 composite showed the highest adsorption among as-prepared samples in the range of 250-550 nm, having bandgap energy of 0.13 eV. Au nanoparticles of about 3-5 nm were well dispersed on hierarchical flower ZnO with approximately 10-15 μm. The EPR signal at on both ZnO and Au/ZnO samples was attributed to oxygen vacancy Vo•, but the presence of Au led to a decrease in signal strength of Au/ZnO composite, showing the degradation efficiency (DE) and reaction rate of 99.2% and 0.109 min-1, respectively; these were larger than those of other samples. The effects of reaction parameters and oxidizing agents on photocatalytic performance were investigated and showed that the presence of H2O2 and O2 could improve the reaction of composite. In addition, the kinetic and photocatalytic mechanism of tartrazine (TA) on catalysts were studied by the first-order kinetic model and characterized analyses.

/pdf/preparation-of-hierarchical-structure-au-zno-composite-for-4c092k9ik8.pdf

Preparation of Hierarchical Structure Au/ZnO Composite for Enhanced Photocatalytic Performance: Characterization, Effects of Reaction Parameters, and Oxidizing Agent Investigations

Van Duong Le

Papers

Facile Preparation of ZnO Nanoparticles and Ag/ZnO Nanocomposite and Their Photocatalytic Activities under Visible Light

Preparation of Hierarchical Structure Au/ZnO Composite for Enhanced Photocatalytic Performance: Characterization, Effects of Reaction Parameters, and Oxidizing Agent Investigations