Advances in fundamentals and application of plasmon-assisted CO₂ photoreduction

Artificial photosynthesis of hydrocarbons from carbon dioxide (CO2) has the potential to provide renewable fuels at the scale needed to meet global decarbonization targets. However, CO2 is a notoriously inert molecule and converting it to energy dense hydrocarbons is a complex, multistep process, which can proceed through several intermediates. Recently, the ability of plasmonic nanoparticles to steer the reaction down specific pathways and enhance both reaction rate and selectivity has garnered significant attention due to its potential for sustainable energy production and environmental mitigation. The plasmonic excitation of strong and confined optical near-fields, energetic hot carriers and localized heating can be harnessed to control or enhance chemical reaction pathways. However, despite many seminal contributions, the anticipated transformative impact of plasmonics in selective CO2 photocatalysis has yet to materialize in practical applications. This is due to the lack of a complete theoretical framework on the plasmonic action mechanisms, as well as the challenge of finding efficient materials with high scalability potential. In this review, we aim to provide a comprehensive and critical discussion on recent advancements in plasmon-enhanced CO2 photoreduction, highlighting emerging trends and challenges in this field. We delve into the fundamental principles of plasmonics, discussing the seminal works that led to ongoing debates on the reaction mechanism, and we introduce the most recent ab initio advances, which could help disentangle these effects. We then synthesize experimental advances and in situ measurements on plasmon CO2 photoreduction before concluding with our perspective and outlook on the field of plasmon-enhanced photocatalysis.