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Nano Research

Article Title

Gold/WO3 nanocomposite photoanodes for plasmonic solar water splitting

Keywords

tungsten trioxide, gold nanoparticle, surface plasmon resonance, electron-charging, plasmonic solar waterspitting

Abstract

A facile electron-charging and reducing method was developed to prepareAu/WO3 nanocomposites for plasmonic solar water splitting. The preparationmethod involved a charging step in which electrons were charged into WO3under negative bias, and a subsequent reducing step in which the stored electronswere used to reductively deposit Au on the surface of WO3. The electron-chargedWO3 (c-WO3) exhibited tunable reducibility that could be easily controlled byvarying the charging parameters, and this property makes this method a universalstrategy to prepare metal/WO3 composites. The obtained Au/WO3 nanocompositeshowed greatly improved photoactivity toward the oxygen evolution reaction(OER) when compared with WO3. After Au decoration, the OER photocurrentwas improved by a percentage of over 80% at low potentials (1.0 V vs. SCE). Oxygenevolution measurements were performed to quantitatively determine the Faradayefficiency for OER, which reflected the amount of photocurrent consumed bywater splitting. The Faraday efficiency for OER was improved from 74% at theWO3 photoanode to 94% at the Au-8/WO3 composite photoanode, and this isthe first direct evidence that the Au decoration significantly restrained the anodicside reactions and enhanced the photoelectrochemical (PEC) OER efficiency.The high photoactivity of the composite photoanode toward OER was ascribedto the plasmon resonance energy transfer (PRET) enhancement and the catalyticenhancement of Au nanoparticles (NPs).

Graphical Abstract

Publisher

Tsinghua University Press

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