- Published
- 2021-04-27
- Venue
- ACS Catalysis, vol. 11, no. 9, pp. 5762-5775
- Cited by
- 288
- Open access
- No free copy found
- DOI
- 10.1021/acscatal.0c05468
Abstract
Cr cation doping in the support of the Ru/CeO 2 catalyst with a Cr/Ce molar ratio of 1:9 dramatically improved the CO 2 methanation activity at low temperatures, with the turnover frequency value on Ru/Ce 0.9 Cr 0.1 O x at 150 °C being 5.3 times higher than that on Ru/CeO 2 . X-ray diffraction and Raman spectroscopy results confirmed the Cr 3+ doping in the lattice of the CeO 2 support. Thus, more reactive surface oxygen formed on the Ce 0.9 Cr 0.1 O x support, and the Ru/Ce 0.9 Cr 0.1 O x catalyst contained more oxygen vacancies and hydroxyl groups during the reduction process than the Ru/CeO 2 catalyst. In situ Fourier transform infrared spectroscopy and temperature-programed surface reaction revealed that CO 2 methanation on both Ru/Ce 0.9 Cr 0.1 O x and Ru/CeO 2 catalysts followed the formate and CO* pathways, with the former being dominant at low temperatures. The formate pathway was identified, in which CO 2 interacted with surface hydroxyl groups to produce adsorbed bicarbonates; then, the bicarbonates were further converted to formates, followed by the formation of CH 4 * . Cr 3+ doping increased the number of surface oxygen vacancies and hydroxyl groups, thus increasing the amount of bicarbonates and formates. Consequently, Cr doping strongly promoted the formate pathway, greatly improving the activity of the Ru/Ce 0.9 Cr 0.1 O x catalyst at low temperatures.