Catalytic hydrogenation of CO2 from air via porous silica-supported Au nanoparticles in aqueous solution

The conversion of the ubiquitous greenhouse gas CO2 to valuable organic products is much sought after. Herein, the hydrogenation of CO2 to C1 products with an 80% yield in water is reported using a novel catalyst, porous-silica-supported Au nanoparticles (Au/SiO2). In the presence of a Lewis acid, boric acid, the Au/SiO2 catalyst enables an efficient conversion of amine-captured CO2 to methanol, formate, and formamide. A mechanistic study involving isotopic labelling suggests that methanol production in the catalytic process arises from the direct hydrogenation of formate. Most importantly, this one-pot, two-step process is able to convert CO2 in air at ambient pressures to C1 products in the absence of an organic solvent. Furthermore, the catalyst is readily recycled without further purification or reactivation and shows no significant decrease in catalytic activity after four reaction cycles in a reusability test.