Fast interfacial hole consumption suppresses space–charge layer trap filling in BiVO₄ photoanodes
File(s)
Supporting information
Author(s)
Type
Journal Article
Abstract
Photoelectrochemical (PEC) oxidation of biomass-derived organics (e.g., glycerol) can outperform water oxidation while coproducing value-added chemicals. However, the kinetic basis of this enhanced performance, such as hole consumption dynamics and space–charge–layer (SCL) trap filling under PEC operating conditions, remains poorly understood. Using BiVO4 as a model photoanode, we combine operando optical and photocurrent spectroscopies, including trap-selective pump-push photocurrent (PPPC) mapping, to track bulk and interfacial charge-carrier dynamics over the femtosecond-to-second (fs–s) time scale. Overall, we show that glycerol oxidation accelerates interfacial hole consumption, lowering the surface-hole density required to sustain a given photocurrent, thereby suppressing SCL trap filling and trap-mediated recombination. Glycerol increases the per-hole turnover frequency 32-fold (∼3.5 to ∼113.2 s–1) and the photocurrent density at 1.23 VRHE from ∼0.5 to ∼1.3 mA cm–2, while formic acid and dihydroxyacetone are the dominant quantified liquid products. Spatially resolved PPPC mapping (over ∼20 mm2) shows that glycerol also suppresses localized trap-filled hot spots. Glycerol leaves the dominant early time bulk carrier dynamics largely unchanged while suppressing the microsecond buildup of trapped electrons in the SCL. These results highlight microsecond time-scale kinetic competition between interfacial hole consumption and SCL trap filling as a key design principle for PEC oxidation of renewable organics.
Date Issued
2026-07-01
Date Acceptance
2026-06-09
Citation
Journal of the American Chemical Society, 2026, 148 (25), pp.26322-26332
ISSN
0002-7863
Publisher
American Chemical Society (ACS)
Start Page
26322
End Page
26332
Journal / Book Title
Journal of the American Chemical Society
Volume
148
Issue
25
Copyright Statement
© 2026 The Authors. Published by American Chemical Society This publication is licensed under a Creative Commons Attribution 4.0 International License.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/42319808
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2026-06-19