YFeO3 Photocathodes for Hydrogen Evolution

The behavior of YFeO3 thin-film electrodes under illumination is investigated for the first time. YFeO3 thin films on F-doped SnO2 (FTO) electrodes were prepared by two different methods ( A) deposition of nanoparticles synthesized by the so-called ionic liquid route at 1000 degrees C followed by sintering at 400 degrees C and (B) spin coating of a sol-gel precursor followed by a heat treatment at 640 degrees C. Method A provides highly texture films with exquisite orthorhombic phase purity and a direct band gap transition at 2.45 eV. On the other hand, method B results in very compact and amorphous films. XPS confirmed a Fe3+ oxidation state in both films, with a surface composition ratio of 70: 30 Y:Fe. Both materials exhibit cathodic photocurrent responses arising from hydrogen evolution in alkaline solutions with an onset potential of 1.05 V vs. RHE. The complex behavior of the photoresponses is rationalized in terms of recombination losses, band edge energy tails and hindered transport across the oxide thin film. (C) 2017 The Authors. Published by Elsevier Ltd.