TiO2/BiVO4 Nanowire Heterostructure Photoanodes Based on Type II Band Alignment

Joaquin Resasco; Hao Zhang; Nikolay Kornienko; Nigel Becknell; Hyunbok Lee; Jinghua Guo; Alejandro L Briseno; Peidong Yang

doi:10.1021/acscentsci.5b00402

TiO2/BiVO4 Nanowire Heterostructure Photoanodes Based on Type II Band Alignment

ACS Cent Sci. 2016 Feb 24;2(2):80-8. doi: 10.1021/acscentsci.5b00402. Epub 2016 Feb 3.

Authors

Joaquin Resasco¹, Hao Zhang¹, Nikolay Kornienko¹, Nigel Becknell¹, Hyunbok Lee², Jinghua Guo³, Alejandro L Briseno⁴, Peidong Yang⁵

Affiliations

¹ Department of Chemical Engineering and Department of Chemistry, University of California , Berkeley, California 94720, United States.
² Department of Physics, Kangwon National University , Chuncheon-si, Gangwon-do 200-701, South Korea.
³ Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
⁴ Department of Polymer Science & Engineering, Conte Polymer Research Center, University of Massachusetts , Amherst, Massachusetts 01003, United States.
⁵ Department of Chemical Engineering and Department of Chemistry, University of California, Berkeley, California 94720, United States; Materials Sciences Division and Kavli Energy NanoSciences Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States; Materials Sciences Division and Kavli Energy NanoSciences Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.

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/cm(2) at 1.23 V vs RHE.