Enhanced photoelectrochemical water splitting and photocatalytic water oxidation of Cu2O nanocube-loaded BiVO4 nanocrystal heterostructures

Reducing the fast recombination of photogenerated electron-hole pairs of semiconductor photocatalyst is very important to improve its photocatalysis. In this paper we fabricate Cu2O nanocube-decorated BiVO4 nanocrystal (denoted as BiVO4@Cu2O nanocrystal@nanocube) heterostructure photocatalyst by coupling n-type BiVO4 with p-type Cu2O. The BiVO4@Cu2O nanocrystal@nanocube photocatalysts show superior photocatalytic activities in photoelectrochemical (PEC) activity and photocatalytic water oxidation to BiVO4 photocatalysts under visible light illumination. The BiVO4@Cu2O nanocrystal@nanocube heterostructure electrode achieves the highest photocurrent density of ∼ 10 μA cm−2 at 0 V versus Ag/AgCl, 5 times higher than that of BiVO4 nanocrystal electrode (∼ 2 μA cm−2). The light induced evolution rate of O2 generation for BiVO4@Cu2O nanocrystal@nanocube heterostructures is as high as 150 μmol h−1100 mg cat−1, more than 3 times higher than that (48 μmol h−1100 mg cat−1) of BiVO4 nanocrystals. The enhanced photocatalysis activities of the BiVO4@Cu2O nanocrystal@nanocube photocatalysts are attributed to the efficient separation of the photoexcited electron-hole pairs caused by inner electronic field (IEF) of p-n junction. This study opens up new opportunities in designing photoactive materials with highly enhanced performance for solar energy conversion.