Construction of the Co/MnO catalyst surface active sites for efficient dry reforming of methane (DRM) at low-temperature

The xCo/MnO catalysts were prepared by impregnation method and used for the low-temperature CH 4 /CO 2 dry reforming (DRM) reaction in this study. The introduction of the Co species not only inhibited the growth of the MnO support particles, improved the reducibility of the catalyst precursors, promoted the formation and uniform dispersion of the Co 0 active centers, but also significantly increased the concentration of the oxygen vacancies and basic site density on the catalysts surface. In the xCo/MnO catalysts, the electronic effects between the Co and Mn species constructed a Co 0 -oxygen vacancy synergistic active centers with Mn 3+ -□-Co 0 structure, which promoted the adsorption and activation of the reactant molecules CH 4 and CO 2 on the corresponding catalysts. Therefore, the low-temperature DRM activity of the xCo/MnO catalysts had been effectively enhanced. The 15Co/MnO catalyst with a Co loading of 15 wt% exhibited the best DRM catalytic performances. Under atmospheric pressure, the conversions of CH 4 and CO 2 could reach 66 % and 40 % at 600 °C, respectively, while at 700 °C, the conversion rates of CH 4 and CO 2 further increased to 91.1 % and 55.9 %. In addition, the 15Co/MnO catalyst had good stability and regeneration performance. The introduction of the Co species effectively inhibited the growth of the MnO crystalline phase and promoted the uniform dispersion of the Co 0 species. CH 4 was cleaved on the Co 0 active sites, and CO 2 was adsorbed at the alkaline sites. The oxygen vacancies captured O in CO 2 to promote the C O bonds cleavaged. The Co 0 and oxygen vacancies synergistically catalyzed DRM reaction on the xCo/MnO, which significantly enhanced its low-temperature DRM activity. The Co loading in the xCo/MnO catalysts achieved precise control of the DRM performances by regulating the oxygen vacancy concentration, basic sites number, and Co–Mn electronic effects. • XCo/MnO catalysts with high DRM performances at low temperature were prepared. • Introduction of the Co species can improve abundant Co 0 active centers to be formed. • Interaction between the Co and Mn species can be affected by the Co loading. • Electronic effects between the Co and Mn species promoted the oxygen vacancies and basic sites to be formed.