A breath of fresh air for atmospheric CO2 utilisation: a plasmon-assisted preparation of cyclic carbonate at ambient conditions

Abstract

The increase of CO₂ levels is becoming a global problem in the 21^st century, leading to current requests for new advanced materials and methods of CO₂ utilisation. Here, we propose a hybrid plasmonic catalyst for the transformation of CO₂ to carbonates in quantitative yields under ambient conditions, in contrast to the commonly applied elevated temperature and pressure. The proposed catalyst presents a combination of gold nanoparticles modified by triazabicyclodec-5-ene (TBD). TBD is responsible for CO₂ fixation, forming a zwitterionic adduct near the plasmonic surface. The terminating stage, namely the interaction of the zwitterionic adduct with the epoxide, is pumped by plasmonic triggering and is the first example of plasmon-assisted CO₂ cycloaddition. Taking advantage of the proposed catalyst, we achieved an unprecedented turnover number, turnover frequency, and apparent quantum yield, even in the case of air as a CO₂ source and light as an energy input. Control experiments, including variation of illumination conditions and temperature, prove that the photochemical pathway proceeds through plasmon excitation.