Trace CO elimination in H2-rich streams with a wide operation temperature window: Co deposited CuO–CeO2 catalysts

• Published in: Physical chemistry chemical physics : PCCP Vol. 24; no. 4; pp. 2070 - 2079
• Main Authors: Qiu, Zhihuan, Guo, Xiaolin, Mao, Jianxin, Zhou, Renxian
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 28.01.2022
• Subjects: Carbon monoxide; Catalysts; Cerium oxides; Cobalt oxides; Copper oxides; Fuel cells; High temperature; Hydrogen fuels; Low temperature; Methanation; Oxidation; Temperature
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d1cp05121k

This work provides a new strategy to eliminate trace CO in H2-rich gas in a wide operation temperature window for the application of hydrogen fuel cells. We engineered Co deposited CuO–CeO2 catalysts with a Co/(Cu + Ce) molar ratio of 1/1 that manages to maintain the CO level at below 100 ppm from 85 to 240 °C in the H2-rich reformate stream. CO-PROX and CO methanation reaction respectively occurred in the low and high temperature ranges. Multiple characterization techniques demonstrate that the molar ratio of Co/(Cu + Ce) significantly affects the synergistic interactions between the Cu, Co and Ce species, and ultimately the CO oxidation and CO methanation reactions. At low reaction temperatures, the Cu–Ce interaction mainly dominates the CO-PROX process, while at high reaction temperatures, CO methanation reaction takes place due to the reduction of Co3O4 to Co0 and the Co–Ce interaction takes charge of the CO methanation. Moreover, the increment of Co/(Cu + Ce) from 1/2 to 1 gives rise to the reprecipitation of the partially dissolved Cu species on Co3O4, which strengthens the Cu–Co interaction and stabilizes surface Cu+ and Co3+, thus promoting the low temperature CO-PROX catalytic performance.