Graphitic Nature Governs CO2 Hydrogenation Reactions on Platinum@Carbon Nanocomposites

In this study, we discuss the influence of carbon support on the performance of platinum nanoparticles (Pt-NPs) in gas-phase CO 2 hydrogenation towards industrially demanding CO production. To this end, Pt-supported on graphite oxide, carboHIPE, activated carbon, multiwalled carbon nanotubes (MWCNT), and graphite of different specific surface areas and degree of graphitization were synthesized with identical loading per unit surface area (25 µg Pt/m 2 of support) to reveal the contribution of the carbon support. All Pt@carbon nanocomposites were selective to CO at temperatures above 800 K, however, we found an additional correlation between their catalytic performance and the degree of graphitization of the support. Graphite-supported platinum (Pt@Graphite) has the highest TOF and the lowest activation energy among the studied nanocomposites due to the increasing electron donation from the carbon support to the Pt nanoparticles, which facilitates CO 2 adsorption on Pt by shifting its d-band centre towards the Fermi level. Our study shows that beside surface area, porosity, thermal stability, a further parameter needs to be taken into consideration, as the Pt/C interface has significant effect at the atomic level on the activity of carbon-supported catalysts in gas-phase CO 2 hydrogenation towards CO production.