Enhanced photoelectrochemical water oxidation performance by altering the interfacial charge transfer path†
Abstract
Herein, a cocatalyst was extensively used to enhance the photocatalytic water oxidation performance. In a cocatalyst/semiconductor system, charge transfer between a semiconductor and cocatalyst is a crucial process for the photoelectrochemical (PEC) water oxidation performance; however, the influence of surface states on charge transfer has rarely been discussed. In this study, Al2O3 was inserted into the CoPi/Ti-Fe2O3 interface to fabricate a CoPi/Al2O3/Ti-Fe2O3 photoanode. CoPi/Al2O3/Ti-Fe2O3 showed a notable improvement in the photocurrent density. A combination of UV–vis diffuse reflectance spectroscopy (DRS), surface photovoltage spectroscopy (SPS), chopped light photocurrent, and photocurrents under different chopped light frequencies was used to study the real role of Al2O3 in the charge transfer process. It was found that Al2O3 passivated the surface states of Ti-doped Fe2O3, leading to a better interfacial charge transfer between Ti-doped Fe2O3 and CoPi, resulting in the enhanced PEC water oxidation performance.