Single-atomic-Co cocatalyst on (040) facet of BiVO4 toward efficient photoelectrochemical water splitting

Abstract

Monoclinic bismuth vanadate (BiVO4) shows promising application prospect in photoelectrochemical (PEC) water splitting on account of its relatively ideal band gap to harvest sunlight. However, the poor charge migrate property and sluggish water oxidation kinetics severely limit the PEC performance of BiVO4 photoelectrodes. In this work, BiVO4 photoanode with highly exposed (040) facets for superior charge transfer was prepared by a seed assisted hydrothermal method. Moreover, cobalt single atoms stabilized in N-doped carbon nanosheet (Co SAs-NC) was well modified on BiVO4 (040) (denoted as BiVO4 (040)/Co SAs-NC) with much improved water oxidation efficiency. The as-prepared BiVO4 (040)/Co SAs-NC photoanode generated 2.2 times higher photocurrent density than that of pristine BiVO4 (040) at 1.23 V vs. RHE, and presented nearly 100% charge injection efficiency. The detail kinetic measurements reveal that the modified Co SAs-NC cocatalyst effectively suppresses the carrier recombination and promotes the surface reaction kinetics. This work provides a promising strategy to fabricate composite photoanodes for solar energy conversion based on facet engineering matched with single-atomic-catalyst.