Role of base in CO2 hydrogenation to formate over a Ru(III) solid micellar catalyst

Abstract

The catalytic conversion of CO2 to formate is generally performed under basic conditions. While the specific role of amines may not always be clearly defined, they have been the preferred additives to enhance activity and conversion. In this work, we demonstrate that during CO2 hydrogenation to formate over a Ru(III) solid micellar catalyst, the base acts as a promoter by improving the sluggish heterolytic H2 dissociation. Kinetic experiments revealed that it is crucial to direct CO2 speciation towards bicarbonate to ensure formate generation, and that there is a strong dependence of the hydrogenation rate on H2 and TEA availability. H2-D2 isotope scrambling showed a fourfold increase in the presence of the base. Screening of different bases evidenced the unique promoting effect of TEA.