Publication Date

2016

Journal or Book Title

ACS Central Science

Abstract

Metal oxides that absorb visible light are attractive for use as photoanodes in photoelectrosynthetic cells. However, their performance is often limited by poor charge carrier transport. We show that this problem can be addressed by using separate materials for light absorption and carrier transport. Here, we report a Ta:TiO2|BiVO4 nanowire photoanode, in which BiVO4 acts as a visible light-absorber and Ta:TiO2 acts as a high surface area electron conductor. Electrochemical and spectroscopic measurements provide experimental evidence for the type II band alignment necessary for favorable electron transfer from BiVO4 to TiO2. The host–guest nanowire architecture presented here allows for simultaneously high light absorption and carrier collection efficiency, with an onset of anodic photocurrent near 0.2 V vs RHE, and a photocurrent density of 2.1 mA/cm2 at 1.23 V vs RHE.

DOI

10.1021/acscentsci.5b00402

Volume

2

Pages

80-88

Issue

2

Funder

This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231(P-Chem). We would like to thank Dr. Ethan Crumlin at the Advanced Light Source for assistance with APXPS measurements and helpful discussions. J.R. gratefully acknowledges the support of the National Science Foundation Graduate Research Fellowship Program (NSF GRFP) under Grant No. DGE-0802270 and the UC Berkeley Chancellor’s fellowship. H.L. and A.L.B. thank the Center for Hierarchical Manufacturing (CMMI-0531171). The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

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