Conversion of CO2 to Methanol and Ethanol on Pt/CeOx/TiO2(110): Enabling Role of Water in C-C Bond Formation

The surface chemistry of alcohol synthesis from CO2 hydrogenation has been investigated using kinetic testing, ambient pressure X-ray photoelectron spectroscopy (AP-XPS), and DFT calculations over a multicomponent system, where Pt and ceria nanoparticles coexisted on a titania template, Pt/CeOx/TiO2(110). Due to its high ability to bind and activate CO2 , not seen for typical Cu-ZnO catalysts, the Pt- CeOx-TiO2 interface is excellent for the hydrogenation of CO2 to methanol, with some ethanol also being produced (21% selectivity). The results of AP-XPS and DFT calculations indicate that the active state involves a mixture of Ti4+/Ti3+ , Ce3+ , and Pt0/ Pt+. A fast pathway for the formation of CH3O species is only plausible when Ce3+ and Pt are present. The addition of water to the reaction feed facilitates the first hydrogenation of CO2 and substantially enhances the surface coverage of C-containing species (CH3O, HCOO, CO3 , CHx), facilitating the formation of C-C bonds and the production of ethanol (38% selectivity).

Automated summary

The surface chemistry of alcohol synthesis from CO2 hydrogenation was investigated over a Pt/CeOx/TiO2 catalyst, which showed high selectivity towards methanol and ethanol. The addition of water promoted the formation of C-C bonds and enhanced the production of ethanol.