Reductive Transformation of CO2 to Organic Compounds.

Abstract

Carbon dioxide is a major greenhouse gas and a safe, abundant, easily accessible, and renewable C1 resource that can be chemically converted into high value-added chemicals, fuels and materials. The preparation of urea, organic carbonates, salicylic acid, etc. from CO₂ through non-reduction conversion has been used in industrial production, while CO₂ reduction transformation has become a research hotspot in recent years due to its involvement in energy storage and product diversification. Designing suitable catalysts to achieve efficient and selective conversion of CO₂ is crucial due to its thermodynamic stability and kinetic inertness. From this perspective, the redistribution of charges within CO₂ molecules through the interaction of Lewis acid/base or metal complexes with CO₂, or the forced transfer of electrons to CO₂ through photo- or electrocatalysis, is a commonly used effective way to activate CO₂. Based on understanding of the activation/reaction mechanism on a molecular level, we have developed metal complexes, metal salts, inorganic/organic salts, ionic liquids, as well as nitrogen rich and porous materials as efficient catalysts for CO₂ reductive conversions. The goal of this personal account is to summarize the catalytic processes of CO₂ reductive conversion that have been developed in the past 7 years: 1) For the reductive functionalization of CO₂, the major challenge lies in accurately adjusting reaction parameters (such as pressure) to achieve high catalytic efficiency and the product selectivity; 2) For photocatalytic or electrocatalytic reduction of CO₂, how to suppress competitive hydrogen evolution reactions and improve catalyst stability are key points that requires continuous attention.