Rational H2 Partial Pressure over Nickel/Ceria Crystal Enables Efficient and Durable Wide-Temperature-Zone Air-Level CO2 Methanation

• Published in: Chemistry : a European journal p. e202402516
• Main Authors: Yang, Chaoyang, Zhang, Junlei, Liu, Weiping, Cheng, Yao, Yang, Xueyi, Wang, Wanglei
• Format: Journal Article
• Language: English
• Published: Germany 21.08.2024
• Subjects: Ni/CeO2; In situ FTIR tests; H2/CO2 partial pressure ratios; Reinforced formate pathway; Air-level CO2 methanation
• ISSN: 1521-3765; 1521-3765
• DOI: 10.1002/chem.202402516

On the way to carbon neutrality, directly catalyzing atmospheric CO2 into high-value chemicals might be an effective approach to mitigate the negative impacts of rising airborne CO2 concentrations. Here, we pioneer the investigation of the influence of the H2/CO2 partial pressure ratio (PPR) on air-level CO2 methanation. Using Ni/CeO2 as a case catalyst, increasing H2/CO2 PPR significantly improves low-temperature CO2 conversion and high-temperature CH4 selectivity, i.e., from 10 of H2/CO2 PPR on, CO2 is completely methanized at 250 °C, and nearly 100% CH4 selectivity is achieved at 400 °C. 100-hour stability tests demonstrate the practical application potential of Ni/CeO2 at 250 °C and 400 °C. In-situ DRIFTS reveal that reinforced formate pathway by increasing H2/CO2 PPR is responsible for the high CH4 yield. In contrast, even though the CO pathway dominated CO2 conversion on Ni is enhanced by rising H2/CO2 PPR, but at a high reaction temperature, the promoted CO desorption still leads to lower CH4 selectivity. This work offers deep insights into the direct air-level CO2 resourceization, contributing to the achievement of airborne CO2 reductions.