Hydrogenation of CO2 to Methanol: Importance of Metal-Oxide and Metal-Carbide Interfaces in the Activation of CO2

摘要

The high thermochemical stability of CO2 makes it very difficult to achieve the catalytic conversion of the molecule into alcohols or other hydrocarbon compounds, which can be used as fuels or the starting point for the generation of fine chemicals. Pure metals and bimetallic systems used for the CO2 → CH3OH conversion usually bind CO2 too weakly and, thus, show low catalytic activity. Here, we discuss a series of recent studies that illustrate the advantages of metal-oxide and metal-carbide interfaces when aiming at the conversion of CO2 into methanol. CeOx/Cu(111), Cu/CeOx/TiO2(110), and Au/ CeOx/TiO2(110) exhibit an activity for the CO2 → CH3OH conversion that is 2-3 orders of magnitude higher than that of a benchmark Cu(111) catalyst. In the Cu-ceria and Au-ceria interfaces, the multifunctional combination of metal and oxide centers leads to complementary chemical properties that open active reaction pathways for methanol synthesis. Efficient catalysts are also generated after depositing Cu and Au on TiC(001). In these cases, strong metal-support interactions modify the electronic properties of the admetals and make them active for the binding of CO2 and its subsequent transformation into CH3OH at the metal-carbide interfaces.