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

• Published in: Chemistry : a European journal Vol. 24; no. 69; pp. 18436 - 18443
• Main Authors: Mateo, Diego, De Masi, Deborah, Albero, Josep, Lacroix, Lise‐Marie, Fazzini, Pier‐Francesco, Chaudret, Bruno, García, Hermenegildo
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 10.12.2018
• Subjects: Carbon dioxide; Chemical reduction; Chemistry; CO2 methanation; Gold; Irradiation; Low temperature; Methanation; Methane; Nanoparticles; Organic chemistry; photocatalysis; plasmon band; Substrates; Synergism; Temperature effects; Ultraviolet radiation; visible light
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201803022

Au and Ru nanoparticles (NPs) have been deposited on Siralox® substrate by impregnation and chemical reduction, respectively (Au‐Ru‐S). The as‐prepared material is very active in the selective CO2 methanation to CH4 at temperatures below 250 °C. In addition, Au‐Ru‐S shows enhanced CH4 production upon irradiation with UV/Vis light starting at temperatures higher than 200 °C, although the contribution of the photoassisted pathway of CH4 production decreases as the temperature increases. Thus, a maximum CH4 production of 204 mmol gRu−1 at 250 °C upon 100 mW cm−2 irradiation was achieved. Control experiments, in which Ru‐S and Au‐S materials were used, revealed that Ru NPs are the CO2 methanation active sites, while Au NPs contribute by harvesting light, mainly visible as a consequence of the strong Au plasmon band centered at 529 nm. The visible light absorbed by the plasmonic band of Au NPs could make them act ass local heaters of the neighboring Ru NPs, increasing their temperature and enhancing CH4 production. Au and Ru nanoparticles supported on Siralox® have been prepared and used in a low‐temperature photoassisted CO2 methanation reaction. The CH4 production is notably enhanced upon light irradiation at temperatures below 250 °C. This improvement arises from the synergy between the Ru nanoparticles, which act as actives sites, and the Au plasmon band absorption in the visible region (see picture).