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° C followed by sintering at 400° C and (B) spin coating of a sol-gel precursor followed by a heat treatment at 640° 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.VC gratefully acknowledges the Royal Society and the UK National Academy by the support through the Newton International Fellows program and EPSRC via the UK Catalysis Hub (EP/K014706/1 and EP014714/1). DT and DJF is grateful to EPSRC for funding through the PVTEAM Programme (EP/L017792/1), as well as to the Institute of Advanced Studies of the University of Bristol for the Research Fellowship. Electron microscopy studies were carried out both at the SSTTI of The University of Alicante and at the Chemical Imaging Facility of the University of Bristol with equipment partly funded by EPSRC (EP/K035746/1 and EP/M028216/1). MIDG is grateful to the Doctorate School of the University of Alicante for a travel grant. The Alicante team acknowledges the Spanish Ministry of Economy and Competitiveness for financial support through project MAT2015-71727-R (FONDOS FEDER)