Selective Reduction of CO2 to Methanol via Hydrosilylation Boosted by a Porphyrinic Metal-Organic Framework

Methanol has been widely used in organic synthesis and fuel fields. The capture and selective reduction of CO2 to methanol can not only decrease CO2 concentrations but also produce methanol as a value-added chemical and fuel. Herein, the selective reduction of CO2 to methanol via hydrosilylation was reported to be accelerated by a porphyrinic metal-organic framework (Ir-PCN-222). Catalytic results showed that Ir-PCN222 was efficient for CO2 reduction. Under atmospheric CO2 pressure, the turnover frequency was up to 157 h-1 and the turnover number could reach up to 1875 with a decrease in catalyst. The catalytic reactions could also be accomplished under a low CO2 concentration (15% CO2 and 85% N2) with more than 99% conversion and 99% selectivity. The reaction mechanism was studied by density functional theory calculations and molecular dynamics simulations, revealing that the concentration balance between CO2 and hydrosilanes around the catalytically active iridium porphyrin units in the confined catalytic spaces of Ir-PCN-222 played an important role in the product selectivity.