Electronic structure modulating for supported Rh catalysts toward CO2 methanation

• Published in: Catalysis today 2020-10, Vol.356, p.570-578
• Main Authors: Jiang, Yueyue, Lang, Junyu, Wu, Xuechen, Hu, Yun Hang
• Format: Article
• Language: English
• Subjects: CO2 methanation; Electronic structure; Oxide supports; Rh catalysts
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2020.01.029

[Display omitted] •TiO2 is the best support to constitute an effective Rh-based catalyst for CO2 hydrogenation.•The negatively charged Rh dispersed on TiO2 plays a critical role in the CO2 hydrogenation.•A possible mechanism of catalytic CO2 hydrogenation is proposed. Methanation of carbon dioxide is a promising approach to ameliorate greenhouse effect. Rhodium based catalysts have been intensively investigated due to its ability in cleavage of CO bond, but the role of support in the catalysts was underestimated. In this regard, we explored the methanation of CO2 over Rh catalysts with three metal oxide supports (TiO2, Al2O3, and ZnO). It was found that Rh/TiO2 exhibited the highest catalytic activity with product yield of 455 mmol gcat-1 h−1 (CH4 and CO) at 370 °C and 2 MPa, which is 2 and 14 times higher than Rh/A12O3 and Rh/ZnO, respectively. Moreover, the CH4 selectivity over Rh/TiO2 was higher than 95 %. The superior catalytic performance of Rh/TiO2 can be mainly attributed to its unique electronic structure associated with stronger Rh-TiO2 interaction and the existence of Ti3+ ions on TiO2.