Photoelectrochemical performance of TiO2 nanotube arrays modified with Ni2P Co-catalyst

Abstract Solar-driven water splitting to produce hydrogen is an important solution to the problem of energy shortage and environmental pollution. The photolysis of water to produce hydrogen requires highly efficient and stable photocatalysts, and the anode used as catalyst for oxygen evolution is a bottleneck in this process. In this paper, the a-TNTAs/Ni2P composite photo-anode was constructed by electrodeposition to anchor the Ni2P co-catalyst for oxygen evolution at the active site of TiO2 nanotube arrays (TNTAs). The a-TNTAs/Ni2P delivered excellent oxygen evolution at a photocurrent density of 1.058 mA cm-2, an improvement of 2.78 times, 13.2 times, and 15.8 times over a-TNTAs, TNTAs/Ni2P, and TNTAs photo-anodes, respectively. The Mott-Schottky curve showed that Ni2P as co-catalyst for oxygen evolution accelerated the rates of separation and transfer of the photogenerated electrons. This research provides a simple and efficient method to promote the OER performance of optical semiconductors.