Unbiased Spontaneous Solar Fuel Production using Stable LaFeO3 Photoelectrode

This is the final version of the article. Available from Springer Nature via the DOI in this record.Photoelectrochemical (PEC) water splitting to produce solar fuel (hydrogen) has long been considered as the Holy Grail to a carbon-free hydrogen economy. The PEC concept to produce solar fuel is to emulate the natural photosynthesis using man made materials. The bottle-neck in realising the concept practically has been the difficulty in identifying stable low-cost semiconductors that meet the thermodynamic and kinetic criteria for photoelectrolysis. We have fabricated a novel p-type LaFeO3photoelectrode using an inexpensive and scalable spray pyrolysis method. Our nanostructured LaFeO3photoelectrode results in spontaneous hydrogen evolution from water without any external bias applied. Moreover, the photoelectrode has a faradaic efficiency of 30% and showed excellent stability over 21 hours. From optical and impedance data, the constructed band diagram showed that LaFeO3can straddle the water redox potential with the conduction band at -1.11 V above the reduction potential of hydrogen. We have fabricated a low cost LaFeO3photoelectrode that can spontaneously produce hydrogen from water using sunlight, making it a strong future candidate for renewable hydrogen generation.We acknowledge EPSRC-DTP for Ph D student ship to GSP. The financial support was provided by Engineering and Physical Science Research Council, UK (EPSRC) under the research grant No EP/P510956/1 and EP/R512801/1. We also acknowledge UKIERI-DST2016-17-0089 project for partly funding the present work. NSG Pilkington Glass Ltd. is acknowledged for kindly providing the FTO substrates for this work. The funders had no role in study design, data collection and analysis or preparation of the manuscript