Predictive Model for the Design of Plasmonic Metal/Semiconductor Composite Photocatalysts

We demonstrate the design of composite plasmonic metal/semiconductor photocatalysts, which show enhanced visible light photocatalytic activity compared to the semiconductor alone. We show that the overlap between the illumination source spectrum, semiconductor absorbance spectrum and metal nanoparticle surface plasmon resonance spectrum provides a useful descriptor for predicting the relative rate enhancements induced by metal surface plasmons for composite photocatalysts with similar arrangements of metal and semiconductor building blocks. We also show that optical simulations can be used to predict the value of the descriptor of photocatalytic activity for any arbitrary combination of illumination source, semiconductor, and plasmonic metal, and therefore guide the formulation of optimal composite photocatalysts. We have used optical simulations to identify optimal plasmonic nanostructures for a few model semiconductors.