Carbon-based Lewis acid-base and BrØnsted acid sites for efficient catalytic CO2 fixation under mild conditions

Non-metal carbon-based materials are promising candidates for catalytic CO2 fixation and conversion. However, the current catalytic systems usually require harsh reaction conditions, which are highly energy consuming. Developing efficient catalytic materials for CO2 conversion under mild reaction conditions remains challenging. In this study, a type of carbon-based catalytic materials (BPO4@BCN-T) with Lewis acid-base and Br & Oslash;nsted acid sites were rationally designed and synthesized by doping with B, N, P main group elements. These materials serve as efficient solid catalysts for atom-economic cycloaddition of CO2 with various epoxides giving rise to useful cyclic carbonate products under mild reaction conditions. Typically, BPO4@BCN-800 achieves excellent yield (up to 99 %) for this reaction in the presence of KI cocatalyst under 0.1MPa CO2 pressure and/or at room temperature. Furthermore, a cooperating CO2 enrichment-conversion mechanism facilitated by Lewis acid-base and Br & Oslash;nsted acid sites is proposed for the current catalytic system. Additionally, this catalyst is recyclable and reusable for up to five cycles without significant loss in catalytic activity. This study indicates that incorporating Br & Oslash;nsted acid and Lewis acid-base sites to carbon materials is an effective strategy to provide efficient catalysts for CO2 fixation and conversion in a way of low energy-consuming.