2D-reduced graphene oxide induced bi-functional plasmonic CuBi2O4/RGO/BiVO4/Au heterostructure for visible light driven photoelectrochemical water splitting

This study presents an exploration of bifunctional heterostructures of different photoactive materials with complementary attributes CuBi₂O₄/RGO/BiVO₄/Au for visible-light-driven photoelectrochemical water splitting. The materials swapping in sequential layering within the fabricated bifunctional photoelectrode CuBi₂O₄/RGO/BiVO₄/Au manifested a pivotal character in altering the dynamics of the photoelectrode from photoanode to photocathode. Among all designed photoelectrodes, CuBi₂O₄/RGO/BiVO₄/Au exhibited the highest current density (with UV cutoff filter (400 nm)) of 0.15 mA/cm⁻² at onset potential of 0.69V_Ag/AgCl with the maximum approach up to 0.25 mA/cm², and without UV cut-off filter - 0.50 mA/cm², verifying 50% evolution of oxygen and hydrogen within the less energetic and major portion of solar light. The incorporation of reduced graphene oxide (RGO) and CuBi₂O₄ with BiVO₄ resulted in enhanced catalytic output and rapid photogenerated charge mobility attributes during the visible-light-driven oxygen (OER) and hydrogen evolution (HER) reactions. In contrast, the introduction of Au nanoparticles to this heterojunction magnified the photogenerated electron generation by thermionic emission and tunneling, resulting in high efficiency of overall water splitting. The heterojunction CuBi₂O₄/RGO/BiVO₄/Au minimized the recombination rate of photogenerated electron-hole pairs and thus assisted charge separation by broadening the visible light absorption range. Under constant potential, the chronoamperometric measurements indicated the stable current flow over time and thus it facilitated the effective utilization of bifunctional CuBi₂O₄/RGO/BiVO₄/Au photoelectrode for sleek and expeditious solar-driven water splitting with 9.1 PEF%,0.036 ABPE%, 25 IPCE%, and 20 IQE%.