Dual Modification of a BiVO4 Photoanode for Enhanced Photoelectrochemical Performance.

Bismuth vanadate (BiVO4 ) has triggered extensive interest in photoelectrochemical (PEC) water splitting, owing to its narrow band gap and sufficiently positive valence band. However, some defects still exist to block the solar utilization efficiency and hydrogen evolution kinetics. Herein, the NiMoO4 semiconductor is combined with a BiVO4 photoanode, for the first time, and excellent PEC performance is achieved on the basis of heterojunction formation and favorable conductivity of NiMoO4 . In addition, it has been demonstrated that NiMoO4 promotes the light absorption ability, charge separation efficiency, and surface charge-transfer efficiency comprehensively. To further improve the photoconversion efficiency, cobalt phosphate, as an oxygen evolution reaction cocatalyst, is deposited on the above electrode and achieves a much enhanced utilization efficiency of 1.18 %, with a photocurrent density of 5.3 mA cm-2 at 1.23 V versus a reversible hydrogen electrode; this exceeds most results reported to date. This rational and unique photoanode construction provides a new thread for the photoelectrode designation.