Plasmonically-assisted nanoarchitectures for solar water splitting: Obstacles and breakthroughs

The rising demand for sustainable and efficient solar energy conversion strategies has triggered the development of a myriad of semiconductor-based composite systems for photocatalytic water splitting. Plasmonic nanostructures recently emerged as a promising alternative to conventionally used photosensitizers (e.g., organic dyes) that complement semiconductors as they can uniquely harness the energy of visible photons through the excitation of the localized surface plasmon resonance (LSPR). Provided the solid foundation of the mechanisms with which the plasmonic enhancement effects occur, we herein review the recent progress in the field of plasmonic water splitting by classifying different obstacles and breakthroughs made over the past decade and a half. While plasmonic nanostructures initially served to expand the light harvesting spectrum of semiconductors, rational designs and advanced fabrication techniques have increasingly improved the light absorption capabilities of the plasmonic metal/semiconductor hybrid architectures as a whole. More recently, the use of various analytical tools has allowed a more fundamental issue of short hot carrier lifetime to be tackled which, in turn, has brought about great interest in optimizing the structures and interfaces for more efficient charge transfer. Other issues associated with the field include the complexity of fabrication methods, limited choices in material selection, and cost effectiveness. The review ends with perspectives on future steps to be taken namely the incorporation of co-catalysts, the possibility of using plasmonic heating to assist the catalytic activities, and further investigation of the direct interfacial charge transfer mechanism driven by chemical interface damping (CID). (C) 2017 Elsevier Ltd. All rights reserved.