Systematic Investigation of BiVO4/FeOOH Photoanode via Experimental and Theoretical Approach and Constructing Tandem Photoelectrochemical Cell With CuO/AlOx/RuO2 Photocathode for Solar Water Splitting.

Abstract

Photoelectrochemical (PEC) water splitting is an effective approach for green hydrogen production. For practical applications, it is essential to use a PEC cell in a two-electrode configuration at zero bias, which is achieved by utilizing both photoanode and photocathode in a tandem manner, which provides sufficient photovoltage and maximum optical absorption. Here, to construct a PEC tandem device, the BiVO4/FeOOH photoanode and CuO/AlOx/RuO2 photocathode were taken. Here, the BiVO4/FeOOH photoanode delivers a higher photocurrent density of ~2.96 mA cm-2, which is ~2.7-fold higher than pristine BiVO4 (1.08 mA cm-2 at +1.23 VRHE). The theoretical results show that the continuous distribution of DOS in the conduction band after the loading of FeOOH provides evidence for facile electron transfer in BiVO4/FeOOH. Besides, the CuO/AlOx/RuO2 photocathode exhibits a photocurrent density of -2 mA cm-2 at +0.3 VRHE. After constructing the BiVO4/FeOOH || CuO/AlOx/RuO2 tandem device, it produced a photocurrent density of ~0.4 mA cm-2 at zero bias with a photovoltage of ~0.65 V, and at +1 V, the two-electrode tandem device showed ~3.5 mA cm-2. These findings highlight the potential of tandem PEC devices as a sustainable and efficient solution for scalable green hydrogen production.

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