Ceria-Supported Cobalt Catalyst for Low-Temperature Methanation at Low Partial Pressures of CO.

The direct catalytic conversion of atmospheric CO to valuable chemicals is a promising solution to avert negative consequences of rising CO concentration. However, heterogeneous catalysts efficient at low partial pressures of CO still need to be developed. Here, we explore Co/CeO as a catalyst for the methanation of diluted CO streams. This material displays an excellent performance at reaction temperatures as low as 175 °C and CO partial pressures as low as 0.4 mbar (the atmospheric CO concentration). To gain mechanistic understanding of this unusual activity, we employed in situ X-ray photoelectron spectroscopy and operando infrared spectroscopy. The higher surface concentration and reactivity of formates and carbonyls-key reaction intermediates-explain the superior activity of Co/CeO as compared to a conventional Co/SiO catalyst. This work emphasizes the catalytic role of the cobalt-ceria interface and will aid in developing more efficient CO hydrogenation catalysts.