Coupling of charge transfer and photocatalytic oxidation in bridge mediated three-dimensional photoanodes via V(3d)-O(2p)-Co(3d) orbital synergistic hybridization

Engineering interatomic orbital hybridization to mediate the dynamic coupling of interfacial charge transfer and surface oxygen evolution remains a challenge in boosting the photoelectrochemical (PEC) water oxidation performance. Herein, a three-dimensional nanoporous network heterostructure of BiVO 4 /LaCoO 3 is fabricated by decorating BiVO 4 with LaCoO 3 perovskite single-crystalline quantum dots (PSC QDs). The enhanced interfacial built-in electric field in band-matched BiVO 4 /LaCoO 3 sharpens band bending, providing the driving force for interfacial charge transfer. Experiments and theoretical calculations reveal that V(3 d )-O(2 p )-Co(3 d ) synergistic orbital hybridization at BiVO 4 /LaCoO 3 interface provides a low-barrier hopping pathway for electron transitions, strengthens Co-O covalency, and optimizes the Co d -band center position. Co–O antibonding/bonding states shifting toward the Fermi level and Co 3+ -O 2− -Co 4+ double exchange facilitate efficient electron-hole separation, which regulate the electronic structure for BiVO 4 /LaCoO 3 . The BiVO 4 /LaCoO 3 photoanode achieves an enhanced photocurrent density of 4.19 mA cm −2 (vs. 2.01 mA cm −2 for BiVO 4 at 1.23 V vs. RHE). Meanwhile, online electrochemical test presents that the LaCoO 3 coupling on BiVO 4 provides rich active sites for the oxygen evolution reaction (OER), promoting the hole relaxation dynamics. Bridge-mediated coupling of charge transfer and photocatalytic oxidation via V(3 d )-O(2 p )-Co(3 d ) synergistic orbital hybridization is kinetically favorable, thus synergistically improving the PEC performance for BiVO 4 /LaCoO 3 . This work offers a valuable insight into the mechanism of interfacial charge transfer and OER during the PEC process. The built-in electric field in band-matched BiVO 4 /LaCoO 3 and V(3 d )-O(2 p )-Co(3 d ) synergistic orbital hybridization at BiVO 4 /LaCoO 3 interface provide a low-barrier hopping pathway for electron transitions, which is favorable for the fast OER. Download: Download high-res image (270KB) Download: Download full-size image