Efficient photocathode performance of lithium ion doped LaFeO3 nanorod arrays in hydrogen evolution

Abstract

Most of the photocathode semiconductors that can be used for hydrogen production are difficult to prepare or get corroded in the electrolyte of an aqueous solution. Hence it is a huge challenge to develop stable photoelectrochemical (PEC) hydrogen evolution systems. Perovskite-type LaFeO₃, as a new p-type semiconductor, is used in the PEC hydrogen evolution reaction and shows excellent stability. We synthesized a high-purity LaFeO₃ nanorod array on an FTO substrate and its bandgap is 2.14 eV. Moreover, the carrier migration efficiency of a LaFeO₃ photocathode is improved by doping with Li ions, and the doping effect also causes a red-shift of the optical maximum absorption edge. As a result, the photocurrent density of the Li-doped LaFeO₃ photocathode is increased from −30 μA cm⁻² (LaFeO₃) to −50 μA cm⁻² at 0.4 V (vs. RHE). Herein, the Li-doped LaFeO₃ show great potential as a PEC photocathode for achieving an efficient, stable and inexpensive PEC hydrogen evolution reaction.