A Bismuth Vanadate-Cuprous Oxide Tandem Cell for Overall Solar Water Splitting

作者：Bornoz Pauline; Abdi Fatwa F; Tilley S David; Dam Bernard; van de Krol Roel; Graetzel Michael; Sivula Kevin^*

来源：Journal of Physical Chemistry C, 2014, 118(30): 16959-16966.

DOI：10.1021/jp500441h

Through examination of the optoelectronic and photoelectrochemical properties of BiVO4 and Cu2O photoelectrodes, we evaluate the feasibility of a BiVO4/Cu2O 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 RuOx, respectively) together with an operating point analysis, we show that an unassisted solar photocurrent density on the order of 1 mA cm(-2) 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.

• 出版日期2014-7-31