ABSTRACT
The photocatalytic performance of a semiconducting catalytic system is strongly influenced by charge-carrier separation rate, charge transport properties, surface area, utilization of light energy, and interface bonding. Herein, a series of bismuth vanadate (BiVO4) samples were prepared via hydrothermal method by changing the volume ratios of ethelene glycol and ethanol as a solvent mixture for bismuth precursors. Further, the optimized BiVO4 sheets with hierarchical morphology were used to construct an interface with rod-like g-C3N4 materials, which was confirmed by HRSEM and HRTEM. Due to the formation of an effective interface bonding between BiVO4/g-C3N4, the photoinduced charge carrier's recombination rate was suppressed as confirmed by the PL analysis. The prepared BiVO4/g-C3N4 sample were used to assess the photodegradation efficiency of Rhodamine B (RhB) under direct sunlight irradiation and the photocatalysts degraded ~92.8% of RhB within 2 h. The TOC measurements revealed a 66.4% mineralization efficiency for RhB. In addition, the radical trapping experiments demonstrated that superoxide and hydroxyl radicals are the main reactive species for the degradation. Based on the experimental evidences, a plausible charge transfer mechanism has been proposed. The enhanced photocatalytic activity has been mainly attributed to the inhibition of the recombination rate, enhanced charge carrier transfer efficiency, and high rate of production of reactive species.
Subject(s)
Bismuth , Environmental Pollutants , Nitriles , Sunlight , VanadatesABSTRACT
An effective heterojunction with robust charge separation and enormous degradation efficiency is the major task for photocatalyst preparation. In this study, we have prepared the FeCo2O4-loaded g-C3N4 nanosheet by the sol-gel-assisted calcination method for photo-Fenton-like degradation under visible-light irradiation by activating persulfate. The nanocomposite exhibits a higher charge separation efficiency than pure g-C3N4 and FeCo2O4 for the degradation reaction against naproxen drugs. An effective interaction between the nanoparticles increases the degradation efficiency up to 91% with a synergistic index of 73.62%. Moreover, the nanocomposite exhibits a 78% mineralization efficiency against the naproxen pollutant under visible-light irradiation. For practical implementation, the degradation reaction was tested with various pH values, different water sources (DI, lake, and tap water), and light sources (LED (visible)/direct sunlight (UV-visible)). Moreover, the possible degradation mechanism predicted by the elemental trapping experiment and the recycling experiment clearly revealed that the heterojunction composite has a high enough degradation stability.
ABSTRACT
Herein, a strong redox ability photocatalyst of CdCuS solid solution composited with pyrochlore like Bi2Zr2O7 has been fabricated by the simple hydrothermal method. The robust CdCuS solid solution materials perform the supporting role to the Bi2Zr2O7 nano materials. The structural, optical, valence and vibrational states of the prepared heterostructure materials were analyzed using various characterization techniques. The photocatalytic activity of the as-synthesized Bi2Zr2O7/CdCuS heterostructure has been verified under direct solar light and ambient conditions. The synthesized Bi2Zr2O7/CdCuS nano combination exhibits a better photocatalytic activity for the removal of methylene blue and 4-nitrophenol organic probe molecules. The heterostructure formation between the samples is confirmed by HRTEM analysis. The improved rate of the photocatalytic reaction of the samples is attributed to the formation of heterostructures at the interface. The close interfacial contact between the two materials discloses the effective charge transfer, which leads to suppressed charge carrier recombination. The enhanced photo catalytic activity of redox-mediator-free-Bi2Zr2O7/CdCuS heterostructure, possibly will be credited to the robust redox ability and the several charge transfer channels in the tight contact. The chief radicals produced in the catalytic reduction reaction have been predicted by the scavenger trapping methods and the results are discussed in detail. The obtained information from this study on Bi2Zr2O7/CdCuS delivers some new visions for the design of active photocatalysts with multiple benefits.
ABSTRACT
The BiFeO3/V2O5 has been successfully synthesized by simple annealing of BiFeO3 nanoplates and V2O5 nanoflower. The phase, structural, optical properties and chemical state of the BiFeO3, V2O5 and different composition of BiFeO3/V2O5 samples were comparatively characterized by various spectroscopic and microscopic techniques. The prepared catalyst exhibits unique photo catalytic and post-oxidation/reduction ability for removal of various (MB, Phenol, CV, RhB) water organic pollutants. Compared to pure BiFeO3 and V2O5, the different Wt % of BiFeO3/V2O5 composition exhibited higher photo catalytic activity. The fortunate BiFeO3/V2O5 interface hybrid photo catalyst makes a significant impact in the enhancement of photo catalytic reaction. This remarkable efficiency could be ascribed to the synergistic effect between the V2O5 petals and BiFeO3 plates. The exceptional morphology, increased surface area, uniformity, less-agglomerated spreading could increase the ability of visible light response, which lead the improved electron transport ability and the higher charge separation. The enhanced rate of photo generated charge carriers separations were evinced by the EIS and PL spectrum measurements. The allowed radical trapping experiment divulge that the hole (h+), and super oxide radical (O2-) are the minimized effect in degradation, on the other hand hydroxyl radical (OH) is plays the foremost role and act as the active radicals in the catalytic organism. In relations of above investigation, a probable photo degradation mechanism of the as-synthesized photo catalyst is carefully explicated. This effort delivers an effective approach to design and fabricate the efficient photo catalyst through integrating of materials, which has a potential for industrial waste water purification.
