Metasurfaces for photochemistry

As society transitions away from fossil fuels to renewable energy sources we will need to find new ways to generate fuels and feedstocks. Solar light-driven reactions could be harnessed to generate renewable fuels and chemicals with net-zero emissions at the scale required by industry. However many important chemical reactions, like the reduction of carbon dioxide, are complex and involve multiple competing intermediate steps with different possible outcomes and products. In order to selectively produce valuable fuels and chemicals we need to be able to selectively enhance different reaction pathways. Optical metasurfaces offer unprecedented control of optical energy at the nanoscale, enabling new ways to harness light to efficiently and selectively catalyze chemical reactions. This chapter provides a tutorial approach to the principles of photocatalysis and artificial photosynthesis and the use of resonant metasurfaces in driving and enhancing chemical reactions. We provide a conceptual understanding of the physicochemical energy transfer processes involved, an overview of the design and characterization of metasurfaces for chemistry, and the outlook for practical devices.