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Near-Complete Suppression of Surface Recombination in Solar Photoelectrolysis by “Co-Pi” Catalyst-Modified W:BiVO4

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journal contribution
posted on 2011-11-16, 00:00 authored by Diane K. Zhong, Sujung Choi, Daniel R. Gamelin
The influence of an earth-abundant water oxidation electrocatalyst (Co-Pi) on solar water oxidation by W:BiVO4 has been studied using photoelectrochemical (PEC) techniques. Modification of W:BiVO4 photoanode surfaces with Co-Pi has yielded a very large (∼440 mV) cathodic shift in the onset potential for sustained PEC water oxidation at pH 8. PEC experiments with H2O2 as a surrogate substrate have revealed that interfacing Co-Pi with these W:BiVO4 photoanodes almost completely eliminates losses due to surface electron–hole recombination. The results obtained for W:BiVO4 are compared with those reported recently for Co-Pi/α-Fe2O3 photoanodes. The low absolute onset potential of ∼310 mV vs RHE achieved with the Co-Pi/W:BiVO4 combination is promising for overall solar water splitting in low-cost tandem PEC cells, and is encouraging for application of this surface modification strategy to other candidate photoanodes.

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