Spatially engineered WO₃ nanofibers on BivO₄: a route to high-efficiency photoelectrochemical water splitting
Author(s)
Type
Journal Article
Abstract
This study employs aerosol-assisted chemical vapor deposition (AACVD) to fabricate WO3/BiVO4 heterojunction photoanodes with an inverted architecture (WO3 atop BiVO4). The unique permeable nanofiber morphology of WO3 provides a solution to enhance water oxidation performance. By correlating precursor volume (10–40 mL) and spatial position within the deposition chamber (inlet/mid/outlet) with film properties, we demonstrate that a midreactor position yields “grass-like” WO3 nanofibers (diameter: 100–230 nm, length: 3.5–3.98 μm), enabling dual functionality: (i) > 50% light transmittance to the underlying BiVO4 absorber, and (ii) electrolyte penetration into the heterointerface between WO3 and BiVO4. In contrast, rod-like WO3 produced near the inlet causes severe light scattering, reducing the incident photon-to-current efficiency (IPCE) by six times above wavelengths of 350 nm. Optimized samples, produced with a deposition volume of 30 mL to deposit WO3 atop of BiVO4 positioned in the middle of the deposition chamber (i.e., WO3-30/BiVO4-mid), achieve a photocurrent density of 0.82 mA·cm–2 at 1.23 VRHE under 1 sun irradiance, which is 121% higher than single-layer BiVO4 (0.37 mA·cm–2) and exceeds some conventional WO3-under/BiVO4 heterojunctions in which WO3 is underneath BiVO4. Transient absorption spectroscopy confirms prolonged carrier lifetimes in our unique heterostructure through improved charge-carrier separation. This work challenges current traditional heterojunction design rules for the WO3/BiVO4 system by showcasing how permeable WO3 nanostructures atop BiVO4 photoanodes can improve light harvesting and facilitate charge-carrier separation to significantly improve activity.
Date Issued
2025-12-08
Date Acceptance
2025-11-20
Citation
ACS Applied Energy Materials, 2025, 8 (23), pp.17334-17345
ISSN
2574-0962
Publisher
American Chemical Society (ACS)
Start Page
17334
End Page
17345
Journal / Book Title
ACS Applied Energy Materials
Volume
8
Issue
23
Copyright Statement
© 2025 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0 .
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/41383364
Subjects
WO3/BiVO4 heterojunction
aerosol-assisted chemical vapor deposition (AACVD)
charge carrier separation
inverted architecture
permeable nanofibers
photoelectrochemical water splitting
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2025-11-25