MoO3 altered ZnO: A suitable choice for the photocatalytic removal of chloro-acetic acids in natural sunlight exposure

Abstract

The MoO 3 coated ZnO photocatalysts were synthesized for the optimum harvesting of the absorbed ultraviolet sunlight photons by initially permeating Mo 6+ ions at the surface of presynthesized ZnO and finally transformed to MoO 3 by thermal treatment in the air. The absorption spectra of the synthesized powders revealed the extension of the absorption edge in the visible region whereas, the photoluminescence spectroscopy established the supporting role of the MoO 3 coating in gradually plummeting the excitons recombination. The growth of additional peaks in Raman as well as x-ray photoelectron spectra and the appearance of the corresponding low-intensity reflection substantiated the surface prevalence of MoO 3. The absence of the individual particles of MoO 3 in FESEM and the verification of coated layer by HRTEM images validated the authenticity of the adopted synthetic route. The electrochemical evaluation of the synthesized powders under illumination revealed the complete elimination of photocorrosion and the synergic role of the MoO 3 layer for improved trap and transfer of charge carriers. The evaluation of the flat-band potentials of the coated powders by Mott-Schottky analysis revealed the suitability of the conduction band edges for the generation of superoxide anion radicals. The photocatalytic activity of the synthesized powders was assessed for the removal of chloro derivatives (mono-, di-, trichloroacetic acids) in comparison to pure acetic acid. A significant effect of the stability, polarity and stereochemical structure of the substrate on the photocatalytic removal process was observed and discussed. The experimental evidences from the timescale chemical analysis were interpreted for the identification of the reactive oxygen species (ROS) involved in the degradation/mineralization process. The validation of the Langmuir-Hinshelwood kinetic model was also examined. Efforts were made to estimate the plausible route of the degradation/mineralization process.

New Electrospun ZnO:MoO3 Nanostructures: Preparation, Characterization and Photocatalytic Performance

“…To the best of our knowledge, the development of ZnO:MoO 3 nanostructures by the electrospinning-calcination method and then their testing for dye degradation have not been reported in the literature so far. Similar systems have been obtained by other methods, such as coating of MoO 3 altered ZnO, by surface metal impregnation [12], ZnO@MoO 3 core/shell nanocables by the electrodeposited method [13], and 1D/1D ZnO@h-MoO 3 synthesized via the solid state impregnation-calcination method [14].…”

MoO3@ZnO Nanocomposite as an Efficient Anode Material for Supercapacitors: A Cost Effective Synthesis Approach

“…Compared to pure phase ZnO (peaks are observed at binding energies of 1022 and 1045 eV @ XPS-Database), there is a peak shift to higher binding energy in MoZ-12, implying a change in MoZ’s chemical bonding due to interaction between ZnO and the MoO 3 layer. ,− The peak at 528.9 eV in O 1s spectra corresponds to the electronic states of O 1s. The deconvoluted O 1s spectra show Zn-O, Mo-O, and lattice O that interconnected to both MoO 3 and ZnO (O latt ) and adsorbed oxygen bands at binding energies of 528.5, 529.6, 530.6, and 531.5 eV, respectively. , …”

“…The deconvoluted O 1s spectra show Zn-O, Mo-O, and lattice O that interconnected to both MoO 3 and ZnO (O latt ) and adsorbed oxygen bands at binding energies of 528.5, 529.6, 530.6, and 531.5 eV, respectively. 39,40 3.2. Electrochemical Performance.…”

The evaluation of the photocatalytic activity of magnetic and non-magnetic polymorphs of Fe 2 O 3 in natural sunlight exposure: A comparison of photocatalytic activity

“…The EIS spectra provide a deep insight to the resistance offered by the material to the transfer of electrons to the electrode surface and separation of the electron-hole pair [68,69]. The comparison of the EIS Nyquist plots of the exposed and pre-exposed α-Fe 2 O 3 , under illumination, is presented in Fig.…”