Ultrasound assisted preparation and characterization of Ag supported on ZnO nanoparticles for visible light degradation of methylene blue dye

Alcohols (bioalcohols) is a class of chemicals that are used as a feedstock for the manufacturing of a large number of valuable intermediates in industrially important processes. Currently, sustainable technologies for selective conversion of alcohols utilize “green” oxidants, mainly, ambient air or oxygen. Due to the high affinity of oxygen towards silver, the latter serves as an active component of supported heterogeneous catalysts. In this review, we consider Ag-based catalysts that participate in gas- or liquid-phase oxidation of alcohols. Oxidation of methanol, ethanol, ethylene glycol, propylene glycol, glycerol, benzyl and allyl alcohols is mostly considered. A particular attention is paid to selective photooxidation of alcohols over Ag-based catalysts. We discuss the catalyst composition in terms of (1) the state of the active component, (2) the nature of the substrate, (3) support nature, and (4) the strength of the metal–support interactions.

Ag-Based Catalysts in Heterogeneous Selective Oxidation of Alcohols: A Review

The cysteine capped ZnO/graphene oxide (CCZG) composite was successfully synthesized by co-precipitation method. The as synthesized CCZG was characterized by X-ray diffraction, diffused reflectance spectra, scanning electron microscopy, transmission electron microscope, Fourier transform-infra red spectral studies. The photocatalytic result reveals that the CCZG composite exhibited enhanced photocatalytic activity towards degradation of Rhodamine B (RhB) under compact fluorescent lamp (CFL) light irradiation. It is found that increase the graphene oxide content in the composite increases the photocatalytic activity which is higher than bare CCZ. The improved photocatalytic activity reduces the recombination of photogenerated charges and high dye adsorption ability of the composites. Further the mineralization of RhB dye has been confirmed by TOC analysis. A mechanism was also proposed for the degradation of RhB by CCZG under CFL light.

Visible light driven photodegradation of Rhodamine B using cysteine capped ZnO/GO nanocomposite as photocatalyst

In this work, we have prepared polyacrylonitrile (PAN) polymer nanofibers by electrospinning method. The surface of the electrospun PAN nanofibers membrane has been functionalized with ZnO-Ag heterostructure nanoparticles by using three different chemical pathways such as reflux, blending, hydrothermal methods and accordingly the prepared composite nanofibers membranes were named as PAN/ZnO-Ag (R), PAN/ZnO-Ag (B) and PAN/ZnO-Ag (H) respectively. The obtained heterostructure nanoparticles functionalized PAN nanofibers membranes were characterized using ATR-FTIR, XRD, FESEM and TEM analytical techniques. From the FESEM and TEM images it was clearly observed that 20-30 nm size spherical nanoparticles have been decorated uniformly on the surface of PAN nanofibers. XRD study confirmed the formation of ZnO-Ag mixed/hybrid nanoparticles on PAN nanofibers surface. The ZnO-Ag heterostructure nanoparticles functionalized PAN nanofibers membranes were used for antibacterial application. It was observed from inhibition zone study that the ZnO-Ag heterostructure nanoparticles functionalized PAN nanofibers membrane shows excellent antibacterial properties towards both gram-negative Escherichia coli and gram-positive Micrococcus luteus bacteria than their single component counterparts. Thus this study demonstrated the simple and cost-effective approach to develop antibacterial functional membrane that has many potential applications in water and air filtration, protective mask, textile and packaging industries.

https://iopscience.iop.org/article/10.1088/1361-6528/ab045d/pdf

Surface functionalization of electrospun PAN nanofibers with ZnO-Ag heterostructure nanoparticles: synthesis and antibacterial study.

Zinc oxide supported silver nanoparticles as a heterogeneous catalyst for production of biodiesel from palm oil

Powder samples of Ag/ZnO nanocomposite containing different amounts of Ag were synthesized by co-precipitation method. The synthesized samples were characterized by XRD, SEM, EDX and TEM techniques. The XRD results revealed that all the samples show wurtzite hexagonal phase of ZnO. The TEM micrographs of the samples showed that size of Ag-ZnO nanoparticles was in the range of 30–50 nm. Catalytic activity was tested using liquid-phase selective oxidation of benzylic alcohols to aldehydes. The influence of some parameters such as optimum weight of Ag, catalyst dosage, oxidant and various solvents were studied. The superior catalytic performance of the Ag/ZnO nanocomposite was observed in microwave condition compared to that performed in reflux condition. The catalysts were recycled three times in the oxidation of alcohols and little change in the conversion efficiency was observed. The highly dispersed Ag metal particles on ZnO surface was considered to be responsible for the catalytic activity.

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Synthesis, characterization and study of catalytic activity of Silver doped ZnO nanocomposite as an efficient catalyst for selective oxidation of benzyl alcohol

N Modirpanah

Papers

Synthesis, characterization and study of catalytic activity of Silver doped ZnO nanocomposite as an efficient catalyst for selective oxidation of benzyl alcohol