Enhanced low-temperature activity of CO2 methanation: Effect of metal oxide support on the performance of Ni-based catalysts
Cristina Italiano, L. Pino, Domenico Maccarrone, Antonio Vita
Abstract
The methanation of carbon dioxide via the Sabatier process is attracting growing attention for power-to-gas (P2G) application. In the current study, a series of 25 wt% Ni-based catalysts were synthesized using solution combustion synthesis (SCS) to investigate the influence of the support on the methanation performance. The results showed that Ni/CeO 2 -ZrO 2 catalyst exhibited superior activity, achieving 72.5 % and 95.5 % CO 2 conversion at 250 °C and 300 °C, respectively, while maintaining excellent stability over 100 h of time-on-stream. CO 2 -TPD analysis revealed that weak-to-moderate basic sites played a key role in enhancing catalytic activity. This is consistent with XPS results, which indicated a high concentration of surface hydroxyl groups and oxygen vacancies, responsible for the enhanced basicity of the CeO 2 -ZrO 2 support. Additionally, the CO-chemisorption measurements confirmed improved Ni dispersion, further contributing to efficient H 2 activation. In situ DRIFT-MS studies identified a reaction pathway involving CO 2 adsorption as carbonate and bicarbonate species, followed by stepwise hydrogenation to methane via formate intermediates. The correlation between turnover frequency (TOF) and the number of weak-to-moderate basic sites supports a dual-site reaction mechanism, where basic sites facilitate CO 2 activation and Ni sites promote H 2 dissociation, both contributing to the remarkable low-temperature carbon dioxide methanation activity.