Issue 28, 2018

Operando deconvolution of photovoltaic and electrocatalytic performance in ALD TiO2 protected water splitting photocathodes

Abstract

In this work, we demonstrate that buried junction photocathodes featuring an ALD TiO2 protective overlayer can be readily characterized using a variation of the dual working electrode (DWE) technique, where the second working electrode (WE2) is spatially isolated from the hydrogen-evolving active area. The measurement of the surface potential during operation enables the operando deconvolution of the photovoltaic and electrocatalytic performance of these photocathodes, by reconstructing J–ΔV curves (reminiscent of photovoltaic JV curves) from the 3-electrode water splitting data. Our method provides a clearer understanding of the photocathode degradation mechanism during stability tests, including loss of the catalyst from the surface, which is only possible in our isolated WE2 configuration. A pn+Si/TiO2 photocathode was first investigated as a well behaved model system, and then the technique was applied to an emerging material system based on Cu2O/Ga2O3, where we uncovered an intrinsic instability of the Cu2O/Ga2O3 junction (loss of photovoltage) during long term stability measurements.

Graphical abstract: Operando deconvolution of photovoltaic and electrocatalytic performance in ALD TiO2 protected water splitting photocathodes

Supplementary files

Article information

Article type
Edge Article
Submitted
29 mar 2018
Accepted
05 iyn 2018
First published
05 iyn 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2018,9, 6062-6067

Operando deconvolution of photovoltaic and electrocatalytic performance in ALD TiO2 protected water splitting photocathodes

W. Cui, W. Niu, R. Wick-Joliat, T. Moehl and S. D. Tilley, Chem. Sci., 2018, 9, 6062 DOI: 10.1039/C8SC01453A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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