Dual-Functional CuO-Decorated Bi_3.84W_0.16O_6.24/Bi₂WO₆ Nanohybrids for Enhanced Electrochemical Hydrogen Evolution Reaction and Photocatalytic Cr(VI) Reduction Performance

The development of dual-functional nanohybrid-based electrocatalysts/photocatalysts for producing renewable energy and removing heavy metal pollutants describes an environmentally sustainable technique to address the challenges in energy and environment applications. Herein, we adopted microwave-assisted synthesis to develop CuO-decorated Bi 3.84 W 0.16 O 6.24 /Bi 2 WO 6 (CuO/biphase-BW) dual-functional nanohybrids for electrochemical hydrogen evolution reaction (HER) and photocatalytic Cr(VI) reduction applications. CuO nanoparticles with ∼50 nm were uniformly distributed on an octahedron-shaped bismuth tungstate analyzed via a high-resolution transmission electron microscope technique. Biphase bismuth tungstate optimization was meticulously controlled via the amount of copper precursor added to the reaction. Among synthesized materials, CuO 1.0 /biphase-BW catalysts exhibit excellent HER activity in neutral media (0.5 M Na 2 SO 4 ) with a relatively low overpotential of 111 mV at a current density of 10 mA/cm 2, and also it exhibits a lower Tafel slope of 237 mV/dec. Moreover, CuO 1.0 /biphase-BW catalyst-coated carbon cloth exhibits good conductivity and excellent electrochemical stability for 24 h. Maximum photocatalytic reduction of aqueous Cr(VI) was achieved on the CuO 1.0 /biphase-BW catalyst. It is worth mentioning that the tremendous activity of the synthesized electrocatalyst/photocatalyst can be ascribed to the formation and electronic interaction of CuO with biphase Bi 3.84 W 0.16 O 6.24 /Bi 2 WO 6, thus increasing its surface-active sites and charge transfer. Our work provides a facile and effective way to engineer dual-functional nanohybrids for efficient water splitting in a neutral medium and reducing toxic (Cr(VI)) metal.