Fabrication of TiOx/Sb2Se3/p-NiOx photocathode for efficient photoelectrochemical water reduction

Abstract

Photoelectrochemical (PEC) water splitting directly converts solar energy into clean and sustainable hydrogen energy, representing a promising and effective technique for solving the world's energy crisis. A hole transfer layer (HTL) plays a vital role for extracting holes from a semiconductor layer to a back electrode in PEC cells for water splitting. In this work, a TiOx/Sb2Se3/NiOx photocathode was fabricated by using p-NiOx as HTL. We show that the electrical properties of NiOx films can be well adjusted by the pulsed laser deposition technique. By systematically adjusting the electrical properties of the NiOx HTL and passivating the surface defects through coating with the TiOx layer, we achieved a high photocurrent density of up to −18.08 mA cm−2 at 0 V vs a reversible hydrogen electrode (RHE), an onset potential of 0.43 V vs RHE, and a half-cell solar to hydrogen conversion efficiency of 1.01% for the TiOx/Sb2Se3/NiOx photocathode. This work demonstrated NiOx as a potential hole transport material for a cost-effective Sb2Se3 PEC cell.