A Bismuth Vanadate鈥揅uprous Oxide Tandem Cell for Overall Solar Water Splitting

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• 作者：Pauline Bornoz ; Fatwa F. Abdi ; S. David Tilley ; Bernard Dam ; Roel van de Krol ; Michael Graetzel ; Kevin Sivula
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：July 31, 2014
• 年：2014
• 卷：118
• 期：30
• 页码：16959-16966
• 全文大小：329K
• ISSN：1932-7455

文摘

Through examination of the optoelectronic and photoelectrochemical properties of BiVO<sub>4sub> and Cu<sub>2sub>O photoelectrodes, we evaluate the feasibility of a BiVO<sub>4sub>/Cu<sub>2sub>O photoanode/photocathode tandem cell for overall unassisted solar water splitting. Using state-of-the-art photoelectrodes we identify current-matching conditions by altering the photoanode active layer thickness. By further employing water oxidation and reduction catalysts (Co-Pi and RuO<sub>xsub>, respectively) together with an operating point analysis, we show that an unassisted solar photocurrent density on the order of 1 mA鈥塩m<sup>鈥?sup> is possible in a tandem cell and moreover gain insight into routes for improvement. Finally, we demonstrate the unassisted 2-electrode operation of the tandem cell. Photocurrents corresponding to ca. 0.5% solar-to-hydrogen conversion efficiency were found to decay over the course of minutes because of the detachment of the Co-Pi catalyst. This aspect provides a fundamental challenge to the stable operation of the tandem cell with the currently employed catalysts.