Ni-Ci oxygen evolution catalyst integrated BiVO4 photoanodes for solar induced water oxidation

Abstract

A nickel-based oxygen evolution catalyst, nickel-bicarbonate (Ni-Ci), was electrochemically deposited for varying intervals on the surface of W-doped BiVO₄ in a 0.1 M bicarbonate electrolyte at neutral pH conditions. Optimally deposited Ni-Ci successfully catalyzed the photoelectrochemical water oxidation of W-doped BiVO₄ photoelectrodes under benign pH conditions as evidenced by an enhanced photocurrent during photocurrent–potential characterizations. Efficient charge-transfer at the electrode–electrolyte interface in the presence of the Ni-Ci catalyst improved the kinetics of the W-doped BiVO₄ photoanodes. The W-doped BiVO₄ photoanodes integrated with a Ni-Ci oxygen evolution catalyst exhibited a large cathodic shift (∼371 mV) in the onset potential for water oxidation and maintained a stable photocurrent.