Turnip-Inspired BiVO4/CuSCN Heterojunction Photoanode for Highly Efficient Photoelectrochemical Water Splitting

Abstract

Inspired by the functions and structures of the root and stalk of a turnip, a novel BiVO4/CuSCN heterojunction was constructed for photoelectrochemical water splitting, by initially fabricating bulky BiVO4 film (the root) and subsequently depositing p-type CuSCN nanorods (the stalk) on top. This BiVO4/CuSCN photoanode produced an enhanced photocurrent density of 1.78 mAcm-2 and hole injection efficiency of 82% at the potential 1.23 V vs. RHE. About 45% increase in photocurrent density coupled with a dramatic cathodic shift (~220 mV) in onset potential compared with bare BiVO4. The heterojunction also possesses external quantum efficiency of approximately 33% in the range from 350-450 nm with fairly high solar energy conversion efficiency (0.5%). The unique electrode architecture design favors the facile water splitting process over conventionally fabricated electrode by providing the more active sites and facilitates transportation and consumption of photoinduced holes, open a new route for the high-efficiency photoanodes. Figure 1