Nanoporous BiVO4 photoanodes with dual-layer oxygen evolution catalysts for solar water splitting

Bismuth vanadate (BiVO4) has a band structure that is well-suited for potential use as a photoanode in solar water splitting, but it suffers from poor electron-hole separation. Here, we demonstrate that a nanoporous morphology (specific surface area of 31.8 square meters per gram) effectively suppre...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2014-02, Vol.343 (6174), p.990-994
Main Authors: Kim, Tae Woo, Choi, Kyoung-Shin
Format: Article
Language:English
Subjects:
Catalysts
Chemical compounds
Chemical reactions
Materials science
Organic Chemistry
Scientific Concepts
Water
Online Access:Get full text
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Summary:Bismuth vanadate (BiVO4) has a band structure that is well-suited for potential use as a photoanode in solar water splitting, but it suffers from poor electron-hole separation. Here, we demonstrate that a nanoporous morphology (specific surface area of 31.8 square meters per gram) effectively suppresses bulk carrier recombination without additional doping, manifesting an electron-hole separation yield of 0.90 at 1.23 volts (V) versus the reversible hydrogen electrode (RHE). We enhanced the propensity for surface-reaching holes to instigate water-splitting chemistry by serially applying two different oxygen evolution catalyst (OEC) layers, FeOOH and NiOOH, which reduces interface recombination at the BiVO4/OEC junction while creating a more favorable Helmholtz layer potential drop at the OEC/electrolyte junction. The resulting BiVO4/FeOOH/NiOOH photoanode achieves a photocurrent density of 2.73 milliamps per square centimenter at a potential as low as 0.6 V versus RHE.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1246913