Reductive O-formylation of carbon dioxide and alcohols over porous phenanthroline-based polymer supported single iridium atom catalyst

The robust O-formylation of alcohols using carbon dioxide to produce valuable alkyl formats is a green method for achieving carbon capture and utilization. However, developing a highly efficient heterogeneous catalyst with outstanding stability remains a significant challenge. Herein, we report a porous phenanthroline-based polymer-supported single-iridium-atom catalyst (Ir/POP-Phen) for the O-formylation of various alcohols using carbon dioxide and molecular hydrogen. This catalyst demonstrates superior catalytic activity and substrate compatibility compared to previous homogeneous and heterogeneous systems. In the synthesis of bulk methyl formate, the turnover number (TON) and turnover frequency (TOF) reach up to 138,216 and 2,880 h^-1, respectively. Additionally, other types of alcohols are successfully converted into their corresponding alkyl formates. Notably, the Ir/POP-Phen catalyst exhibits high tolerance to water concentrations of up to 4,000 ppm during the O-formylation process and can be reused for four cycles without a significant decline in catalytic activity. This work offers insights into the rational design of heterogeneous catalysts for the O-formylation of alcohols.