BiVO4 photoanode modification by synergic dual-conjugated organic materials

Abstract

Organic conjugated materials have presented considerable application potential in the field of photoelectrochemical (PEC) water splitting. In this study, two organic conjugated materials, two dimension carbon nitride (2D-C 3 N 4 ) and organic cobalt molecular catalyst ((H 3 O) 6 ·[Co 4 (H 2 O) 4 (HPMIDA) 2 (PMIDA) 2 )]·2H 2 O) (OCM), are fabricated in turn on the surface of bismuth vanadate (BVO) photoanode. Basing on the synergistic effect of 2D-C 3 N 4 and OCM, the PEC property of the modified BVO photoanode increases three times higher than that of bare BVO photoanode at 1.23 V vs. RHE by increasing reaction active surface, promoting charge separation, and reducing reaction overpotential. This study shows that organic conjugated materials can not only form an effective heterojunction system with semiconductor materials and improve surface catalytic activity, but also assemble easily by the strong affinity between g-C 3 N 4 and OCM. Therefore, it provides a novel and efficient modification method by dual-conjugated organic materials to improve the PEC performance of photoelectrodes. • Development of 2D-C 3 N 4 /organic cobalt molecular dual-conjugated water oxidation catalyst. • 2D-C 3 N 4 /organic cobalt molecular catalyst modified BiVO 4 photoanode was prepared by first time. • A synergistic effect was found between conjugated 2D-C 3 N 4 and organic cobalt molecular. • A photocurrent density of BiVO 4 photoanode increased three times after dual-conjugated molecular modification.