Creating chemisorption sites for enhanced CO2 chemical conversion activity through amine modification of metalloporphyrin-based hypercrosslinked polymers

The weak physical adsorption of CO 2 in porous organic polymers (POPs) leads to the low utilization of CO 2 in catalysis, calling for the need to develop materials to ensure higher adsorption of CO 2 to achieve high conversion efficiency. In this regard, hydrazine (HZ) was successfully introduced into metalloporphyrin-based hypercrosslinked polymers (HCPs) by post-modification to create abundant CO 2 chemisorption sites in structures for efficient adsorption (Qst value up to 34.7 kJ/mol) and chemical conversion of CO 2 under ambient conditions. The HZ-modified material (HCP-TPP-Co-HZ) exhibits high catalytic performance for different molecular sizes of epoxide substrates with excellent yields (reaching 98 % of propylene oxide), much superior than that of HCP-TPP-Co-SO 3 H (64 %), which can be ascribed to the abundant chemisorption sites for CO 2 reactants. Moreover, HCP-TPP-Co-HZ has good stability and shows excellent recycling performance (more than 5 times) for the coupling of CO 2 with substituted epoxides at room temperature and atmospheric pressure. This strategy to introduce amine groups as CO 2 chemisorption sites has been demonstrated to be a new pathway for the design of efficient HCPs catalysts for chemical conversion of CO 2 .