TY - JOUR
T1 - Enhancing interfacial charge transfer in a WO3/BiVO4photoanode heterojunction through gallium and tungsten co-doping and a sulfur modified Bi2O3interfacial layer
AU - Prasad, Umesh
AU - Young, James L.
AU - Johnson, Justin C.
AU - McGott, Deborah L.
AU - Gu, Hengfei
AU - Garfunkel, Eric
AU - Kannan, Arunachala M.
N1 - Funding Information:
Financial support from Arizona State University is acknowledged. This work was authored in part by the National Renewable Energy Laboratory (NREL), operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. The authors acknowledge research support from the HydroGEN Advanced Water Splitting Materials Consortium, established as part of the Energy Materials Network under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, under Contract No. DE-AC36-08GO28308 to the NREL. J. C. J. acknowledges the Solar Photochemistry Program of the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences and Geosciences for transient absorption experiments. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government and the publisher, by accepting the article for publication, acknowledge that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.
Publisher Copyright:
© The Royal Society of Chemistry 2021.
PY - 2021/8/7
Y1 - 2021/8/7
N2 - Photoanodes containing a WO3/BiVO4heterojunction have demonstrated promising photoelectrochemical water splitting performance, but the ability to effectively passivate the WO3/BiVO4interface has limited charge transport and collection. Here, the WO3/BiVO4interface is passivated with a sulfur-modified Bi2O3interfacial layer with a staggered band edge alignment to facilitate charge transfer and lifetime. Additionally, BiVO4was co-doped with Ga3+at Bi3+sites and W6+at V5+sites (i.e., (Ga,W):BiVO4) to improve the light absorption and photogenerated charge carrier concentration. The optimized WO3/S:Bi2O3/(Ga,W):BiVO4photoanode exhibited a photocurrent density of 4.0 ± 0.2 mA cm−2compared to WO3/(Ga,W):BiVO4with 2.8 ± 0.12 mA cm−2at 1.23 VRHEin K2HPO4under simulated AM 1.5G illumination. Time-resolved photoluminescence spectroscopic analysis of the WO3/S:Bi2O3/(Ga,W):BiVO4electrode validated the enhanced interfacial charge transfer kinetics. Inoperandofemto- and nano-second transient absorption spectroscopy confirmed the presence of long-lived photogenerated charge carriers and revealed lower recombination initially due to rapid charge separation of WO3/S:Bi2O3/(Ga,W):BiVO4. The distribution and role of sulfur was further investigated using EDAX, XPS and TOF-SIMS depth profiling. Finally, a Co-Pi co-catalyst layer was added to achieve a photocurrent of 5.1 ± 0.25 mA cm−2and corresponding H2generation rate of 67.3 μmol h−1cm−2for the WO3/S:Bi2O3/(Ga,W):BiVO4/Co-Pi photoanode.
AB - Photoanodes containing a WO3/BiVO4heterojunction have demonstrated promising photoelectrochemical water splitting performance, but the ability to effectively passivate the WO3/BiVO4interface has limited charge transport and collection. Here, the WO3/BiVO4interface is passivated with a sulfur-modified Bi2O3interfacial layer with a staggered band edge alignment to facilitate charge transfer and lifetime. Additionally, BiVO4was co-doped with Ga3+at Bi3+sites and W6+at V5+sites (i.e., (Ga,W):BiVO4) to improve the light absorption and photogenerated charge carrier concentration. The optimized WO3/S:Bi2O3/(Ga,W):BiVO4photoanode exhibited a photocurrent density of 4.0 ± 0.2 mA cm−2compared to WO3/(Ga,W):BiVO4with 2.8 ± 0.12 mA cm−2at 1.23 VRHEin K2HPO4under simulated AM 1.5G illumination. Time-resolved photoluminescence spectroscopic analysis of the WO3/S:Bi2O3/(Ga,W):BiVO4electrode validated the enhanced interfacial charge transfer kinetics. Inoperandofemto- and nano-second transient absorption spectroscopy confirmed the presence of long-lived photogenerated charge carriers and revealed lower recombination initially due to rapid charge separation of WO3/S:Bi2O3/(Ga,W):BiVO4. The distribution and role of sulfur was further investigated using EDAX, XPS and TOF-SIMS depth profiling. Finally, a Co-Pi co-catalyst layer was added to achieve a photocurrent of 5.1 ± 0.25 mA cm−2and corresponding H2generation rate of 67.3 μmol h−1cm−2for the WO3/S:Bi2O3/(Ga,W):BiVO4/Co-Pi photoanode.
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U2 - 10.1039/d1ta03786b
DO - 10.1039/d1ta03786b
M3 - Article
AN - SCOPUS:85111601450
SN - 2050-7488
VL - 9
SP - 16137
EP - 16149
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 29
ER -