Novel edge-capped ZrO₂ nanoparticles onto V₂O₅ nanowires for efficient photosensitized reduction of chromium (Cr (VI)), photoelectrochemical solar water-splitting, and electrochemical energy storage applications

Novel edge-capped ZrO₂ nanoparticles on V₂O₅ nanowires were successfully synthesized through a simple, eco-friendly, and inexpensive hydrothermal technique. The as-prepared nanostructures were characterized using various measurements to study their structural, morphological, optical, and surface properties. Furthermore, photoelectrochemical water oxidation, photocatalytic performance for Cr(VI) reduction, and electrochemical energy storage were studied. The surface morphology analysis revealed the edge-capped ZrO₂ nanoparticles on the V₂O₅ nanowires. The optical analysis showed that the heterostructure formation between ZrO₂ and V₂O₅ could tune the bandgap (2.05 eV) of the composite. Due to the improved separation efficacy of the photoexcited charge carriers and greater surface area, compared to the pure materials, the ZrO₂/V₂O₅ (ZV) composite displayed considerable improvement in photocatalytic Cr(VI) reduction performance, as well as excellent reusability performance (70.5 % after 4 cycles), thus facilitating its wastewater treatment. The ZV electrode displayed approximately 1.6- and 5.8-fold improvement in specific capacitance over the ZrO₂ and V₂O₅ electrodes, respectively. Furthermore, the ZV electrode exhibited the lowest charge resistance under light illumination conditions. From the linear sweep voltammetry curve analysis, the ZV electrode possessed an improved photocurrent density (5.363 mA cm⁻²), demonstrating approximately 33- and 3.5-times improvement in photocurrent density over the pristine electrodes.