Operando deconvolution of photovoltaic and electrocatalytic performance in ALD TiO2 protected water splitting photocathodes.
Chem Sci
; 9(28): 6062-6067, 2018 Jul 28.
Article
en En
| MEDLINE
| ID: mdl-30079219
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 J-V 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.
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01-internacional
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MEDLINE
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En
Revista:
Chem Sci
Año:
2018
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Article