Synergism of Au and Ru Nanoparticles in Low-Temperature Photoassisted CO2 Methanation

Abstract

[EN] Au and Ru nanoparticles have been deposited on Siralox® substrate by impregnation and chemical reduction, respectively (Au-Ru-S). The as-prepared material has demonstrated to be very active for the selective CO2 metanation to CH4 at temperatures below 250 oC. In addition, Au-Ru-S exhibits CH4 production enhancement upon UV-Vis light irradiation starting at temepratures higher than 200 oC, although the contribution of the photoassisted pathway of CH4 production decreases as temperature increases. Thus, a maximum CH4 production of 204 mmol/gRu at 250 oC upon 100 mW/cm2 irradiation was achieved. Control experiments using Ru-S and Au-S materials revealed that Ru nanoparticles are the CO2 methanation active sites, while Au NPs contribute harvesting light, mainly visible as consequence of the strong Au plasmon band centrered at 529 nm. The visible light absorbed by Au NPs plasmon could act as local heaters of neighbouring Ru NPs, increasing their temperature and enhancing CH4 production.