Plasmon enhanced water splitting mediated by hybrid bimetallic Au-Ag core-shell nanostructuresElectronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03625e

• Main Authors: Erwin, William R, Coppola, Andrew, Zarick, Holly F, Arora, Poorva, Miller, Kevin J, Bardhan, Rizia
• Format: Journal Article
• Language: English
• Published: 09.10.2014
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c4nr03625e

In this work, we employed wet chemically synthesized bimetallic Au-Ag core-shell nanostructures (Au-AgNSs) to enhance the photocurrent density of mesoporous TiO 2 for water splitting and we compared the results with monometallic Au nanoparticles (AuNPs). While Au-AgNSs incorporated photoanodes give rise to 14× enhancement in incident photon to charge carrier efficiency, AuNPs embedded photoanodes result in 6× enhancement. By varying nanoparticle concentration in the photoanodes, we observed ∼245× less Au-AgNSs are required relative to AuNPs to generate similar photocurrent enhancement for solar fuel conversion. Power-dependent measurements of Au-AgNSs and AuNPs showed a first order dependence to incident light intensity, relative to half-order dependence for TiO 2 only photoanodes. This indicated that plasmonic nanostructures enhance charge carriers formed on the surface of the TiO 2 which effectively participate in photochemical reactions. Our experiments and simulations suggest the enhanced near-field, far-field, and multipolar resonances of Au-AgNSs facilitating broadband absorption of solar radiation collectively gives rise to their superior performance in water splitting. In this work, we employed wet chemically synthesized bimetallic Au-Ag core-shell nanostructures (Au-AgNSs) to enhance the photocurrent density of mesoporous TiO 2 for water splitting and we compared the results with monometallic Au nanoparticles (AuNPs).