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Controlling the phase, crystallinity, and microstructure and fabricating a facet isotype heterojunction with a proscribed reduction− oxidation facet exposure factor have a strong constructive effect toward photoexciton separation and migration. In this respect, here diverse synthetic courses such as calcination (BiVO 4 -C), hydrothermal treatment (BiVO 4 -H), and a reflux method (BiVO 4 -R) are introduced to fabricate various hierarchical morphologies of highly crystalline monoclinic scheelite bismuth vanadate (BiVO 4 ) with different redox facet exposure factors that have been well established by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy analysis. The analytical and experimental investigations revealed superior photocatalytic upshots of a BiVO 4 -R {040/110} facet isotype heterojunction toward levofloxacin (LVF) detoxification (71.2%, 120 min) and the water oxidation reaction (530.6 μmol, 120 min) relative to BiVO 4 -C (42.3%, 434.2 μmol) and BiVO 4 -H (60.4%, 494.8 μmol). Accordingly, the BiVO 4 -R {040/110} facet isotype heterojunction (145.6 μA/cm 2 ) expressed an enhanced photocurrent in comparison to pristine BiVO 4 -C (75.5 μA/cm 2 ) and BiVO 4 -H (113.1 μA/cm 2 ). The superior photocatalytic redox efficiency was attributed to well-exposed {040} reduction and {110} oxidation facets and a superior relative {040} facet exposure factor provoking an enhanced charge carrier separation over a BiVO 4 -R {040/110} facet isotype heterojunction. The spatial exciton separation over the BiVO 4 -R sample was well established by numerous analytical and experimental investigations. The effectual associations among physicochemical, photoelectrochemical properties, {040/110} facet isotype heterojunction, relative reduction−oxidation facet exposure factor, and photocatalytic performances of fabricated BiVO 4 microstructures were well established, and the upshots of this research were discussed finely. The research signifies an effectual direction for morphology and relative reduction−oxidation facet exposure factor controlled fabrication of facet isotype heterojunction based materials for superior photocatalysis and could be advantageous for supplementary research areas.

To surmount incompatibility provoked efficiency suppression of an anisotype heterojunction and to pursue an improved intrinsic photocatalytic activity by manipulating oriented transfer of photoinduced charge carriers, an In 2 S 3 /BiVO 4 (1:1) n−n isotype heterojunction was fabricated successfully through a simple twostep calcination method, followed by a wet-chemical deposition method. The formation of an n−n isotype heterojunction was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV− visible diffuse reflectance spectroscopy. The photocatalytic efficiency of the In 2 S 3 / BiVO 4 catalyst was examined over degradation of oxytetracycline hydrochloride (O-TCH) and oxygen (O 2 ) evolution reaction. Consequently, an n−n In 2 S 3 /BiVO 4 isotype heterojunction exhibits a superior O-TCH degradation efficiency (94.6%, 120 min) and O 2 evolution (695.76 μmol, 120 min) of multiple folds as compared to the pure BiVO 4 and In 2 S 3 solely. This is attributed to the proper band alignment and intimate interfacial interaction promoted charge carrier separation over the n−n isotype heterojunction. The intimate interfacial contact was confirmed by transmission electron microscopy (TEM), high-resolution TEM, and field emission scanning electron microscopy analysis. The proper band alignment was confirmed by Mott−Schottky analysis. The photoelectrochemical linear sweep voltammetric study shows a superior photocurrent density (269 μA/cm 2 ) for In 2 S 3 / BiVO 4 as compared to those for pristine BiVO 4 and In 2 S 3 , which is in good agreement with the photocatalytic results. Furthermore, the superior charge antirecombination efficiency of the n−n isotype heterojunction was established by photoluminescence, electrochemical impedance spectroscopy, Bode analysis, transient photocurrent, and carrier density analysis. The improved photostability of the heterojunction was confirmed by chronoamperometry analysis. An orderly corelationship among physicochemical, electrochemical, and photocatalytic properties was established, and a possible mechanistic pathway was presented to better understand the outcome of the n−n isotype heterojunction. This study presents an effective way to develop new n−n isotype heterojunction-based efficient photocatalysts and could enrich wide applications in other areas.

Crystal facet engineering, a trending technique to acquire superior exciton pair anti-recombination and interfacial charge pair separation via an inherent functional exposed facet isotype junction, is the current research hotspot. Selectively controlling facet exposure factor with Schottky energy barrier architecture across discerned exposed functional facet attested to facilitate electron injection-separation via a shorter barrier height and closer surface distance. In this context, a {040/110}-BiVO 4 @Ag@CoAl-LDH Z-scheme isotype heterostructure with elevated {040} facet exposure factor tailored a {040/110} crystal facet isotype junction, and {040}-BiVO 4 functional facet/metallic Ag 0 nano-island semiconductor−metal selective Schottky contact was fabricated meticulously via a three-step reflux, photoreduction, followed by an in situ coprecipitation method. Inherent attribution of crystal facet isotype junction and minor semiconductor−metal Schottky barrier toward the nature of exciton pair separation and elevated photoredox activity was neatly demonstrated and well inferred, which is the novelty of the present research. The ternary isotype heterostructure corroborates impressive gemifloxacin detoxification (89.72%, 90 min) and O 2 generation (768 μmol, 120 min), which are multiple folds that of respective pure and binary isotype heterostructures. The bottom-up photoredox activity was well ascribed to shorter Schottky barrier hot electron channelization provoked superior exciton pair separation and well attested via linear sweep voltammetry (315 μA), photoluminescence, electrochemical impedance spectroscopy, Bode, carrier density, and transient photocurrent analysis. The research illustrates a novel insight and scientific basis for the rational design of crystal facet isotype junction and selective Schottky contact vectorial electron shuttling promoted Z-scheme charge transfer dynamics isotype heterostructure systems toward photocatalytic energy-environmental remediation.

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