YFeO3 Photocathodes for Hydrogen Evolution

María Isabel Díez-García,Verónica Celorrio,Laura Calvillo,Devendra Tiwari,Roberto Gómez,David J Fermín

doi:10.1016/j.electacta.2017.06.025

María Isabel Díez-García, Verónica Celorrio + Show 4 more

Open Access

https://doi.org/10.1016/j.electacta.2017.06.025

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Abstract

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 2.45eV. 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 1.05V 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.

Highlights

Photoelectrochemical (PEC) water splitting can potentially offer a viable and scalable approach for solar energy conversion into fuels
We describe the synthesis and properties of YFeO3 as a photocathode for hydrogen evolution reaction under alkaline conditions
YFeO3 thin films electrodes were prepared by two different methodologies, sintering of phase-pure nanoparticles (NP) and compact (C) films by sol-gel

Summary

Introduction

Photoelectrochemical (PEC) water splitting can potentially offer a viable and scalable approach for solar energy conversion into fuels This approach is commonly seen in competition with integrating photovoltaic modules to water electrolyzers (PC-EC); two mature technologies which can deliver solar-to-hydrogen (STH) efficiencies in the range of 10-12%. A number of materials have been reported as photocathodes for hydrogen evolution, including Si [7,8], Cu2O [9,10], GaP [11], and InGaN [12]. In these studies, the stability of the semiconductor surface under operation conditions is crucially important. The materials are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, diffuse reflectance and electron microscopy

Experimental Section

Instrumentation

Results and Discussion

Conclusions