Plasmonic Chemistry and Catalysis: Opportunities for Selective and Sustainable Chemical Conversion
Metal nanoparticles are used as commercial thermal catalysts for many chemical reactions.. These thermal reactions usually require relatively high temperatures, and the distribution of the products is governed by the ground-state free-energy landscape. They offer limited opportunities to tune the product selectivity. We recently made an important breakthrough by showing that relatively small plasmonic metal nanoparticles, illuminated with visible light, can activate chemical reactions on their surfaces in an alternative mechanism. We showed that these chemical transformations are driven by the energetic charge carriers that are formed on the surface of the nanostructures upon their interaction with resonant light and transferred from plasmonic nanoparticles to the reacting adsorbates. This has led to an entirely new field of chemical conversion, often referred to as plasmonic catalysis. Unlike in the case of phonon-driven reactions, it is in principle possible to change (and improve, through targeted design of nanostructures) the product selectivity compared with phonon-driven thermal reactions. I will discuss: (i) the physical features of plasmonic nanoparticles that make them ideal for the charge transfer mediated reactions, (ii) the mechanism of charge-carrier driven chemical transformations on metals, (iii) the mechanisms behind the plasmon-induced charge injection processes, (iv) the approaches to engineer these nanostructures so that they can support specific chemical transformations to make value-added products with high selectivity and at lower temperatures.