TY - JOUR
T1 - Facet effect on the photoelectrochemical performance of a WO3/BiVO4 heterojunction photoanode
AU - Liu, Yang
AU - Wygant, Bryan R.
AU - Kawashima, Kenta
AU - Mabayoje, Oluwaniyi
AU - Hong, Tae Eun
AU - Lee, Sang Geul
AU - Lin, Jie
AU - Kim, Jun Hyuk
AU - Yubuta, Kunio
AU - Li, Wenzhang
AU - Li, Jie
AU - Mullins, C. Buddie
N1 - Funding Information:
The authors acknowledge the generous support of the United States Department of Energy, Basic Energy Sciences (Grant no. DE-FG02-09ER16119 ) and also the Welch Foundation through grant F-1436 . Yang Liu thanks Xiaole Chen, Hugo Celio, Karalee Jarvis, and Raluca Gearba for the characterization assistance. We also acknowledge the China Scholarship Council (CSC) scholarship under the State Scholarship Fund.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/5/15
Y1 - 2019/5/15
N2 - Different WO3 facets have different surface energies and electronic structures, and exhibit different water oxidation abilities and photocatalytic performance as a result. Because of the material's limited photoresponse region, loading a narrow bandgap material on WO3 is a generally known method for improving photo-harvesting. In this paper, we have synthesized WO3 films with different crystal facet ratios. After loading BiVO4 on these WO3 films, we measured the photoelectrochemical (PEC) performance to investigate the effects of WO3 facet choice on the heterojunction film electrode's performance. We found that a high-intensity ratio of the (002) WO3 facet in X-ray diffraction (XRD) leads to a more negative onset potential and higher photocurrents in a lower potential region. The ultraviolet photoelectron spectra show a lower work function for the 002-dominant WO3 film compared to other WO3 films, which may result in a higher quasi-fermi level for the heterojunction electrode. Based on the XRD results, the high-intensity ratio of the (002) WO3 facet preferentially exposes the (020) BiVO4 facet, which may be a reason for the better charge extraction observed at low applied potential and high faradic efficiency on PEC water splitting. Together, this results in a high hole injection efficiency for 002-dominant WO3/BiVO4 films compared with WO3/BiVO4 films favoring other WO3 facet ratios.
AB - Different WO3 facets have different surface energies and electronic structures, and exhibit different water oxidation abilities and photocatalytic performance as a result. Because of the material's limited photoresponse region, loading a narrow bandgap material on WO3 is a generally known method for improving photo-harvesting. In this paper, we have synthesized WO3 films with different crystal facet ratios. After loading BiVO4 on these WO3 films, we measured the photoelectrochemical (PEC) performance to investigate the effects of WO3 facet choice on the heterojunction film electrode's performance. We found that a high-intensity ratio of the (002) WO3 facet in X-ray diffraction (XRD) leads to a more negative onset potential and higher photocurrents in a lower potential region. The ultraviolet photoelectron spectra show a lower work function for the 002-dominant WO3 film compared to other WO3 films, which may result in a higher quasi-fermi level for the heterojunction electrode. Based on the XRD results, the high-intensity ratio of the (002) WO3 facet preferentially exposes the (020) BiVO4 facet, which may be a reason for the better charge extraction observed at low applied potential and high faradic efficiency on PEC water splitting. Together, this results in a high hole injection efficiency for 002-dominant WO3/BiVO4 films compared with WO3/BiVO4 films favoring other WO3 facet ratios.
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U2 - 10.1016/j.apcatb.2018.12.058
DO - 10.1016/j.apcatb.2018.12.058
M3 - Article
AN - SCOPUS:85059193085
SN - 0926-3373
VL - 245
SP - 227
EP - 239
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
ER -
