This review describes an overview on much of the recent work in catalytic methanation of CO2 and its future prospects.

Mesostructured silica nanoparticles (MSN) and Ni loaded onto MSN (Ni/MSN) for the methanation of CO2 were prepared by the sol-gel and impregnation methods. Catalytic testing was conducted in the temperature range of 423-723 K under atmospheric pressure in the presence of H2. Ni supported on MSN was compared with others types of support such as MCM-41 (Mobile Crystalline Material), HY (protonated Y zeolite), SiO2 and γ-Al2O3. The activity of CO2 methanation followed the order: Ni/MSN > Ni/MCM-41 > Ni/HY > Ni/SiO2 > Ni/γ-Al2O3. The nitrogen physisorption and pyrrole adsorbed IR spectroscopy results indicated that the high activity of Ni/MSN is due to the presence of both intra-and interparticle porosity which led to the high concentration of basic sites. In addition, the correlation between N-H band intensity and the turnover frequency revealed that the methanation activity increased with increasing of the concentration of basic sites. The presence of defect sites or oxygen vacancies in MSN was responsible for the formation of surface carbon species, while Ni sites dissociated hydrogen to form atomic hydrogen. The surface carbon species then interacted with atomic hydrogen to form methane. The Ni/MSN catalyst performed with good stability and no deactivation up to 200 h.

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Surface oxygen basic sites are vital to the CO2 activation in dry reforming of methane.

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Catalytic dry reforming of methane (DRM) is a promising way for renewable syngas production due to the utilization of both CO2 and CH4 greenhouse gases. Current approaches were made to improve the catalytic activity and coke resistance by introducing a second metal into the Ni‐based catalytic system. This bimetallic catalytic system showed a significant improvement in coke resistance due to the synergistic effect of both metals towards the reaction. This review summarizes recent developments in bimetallic catalysts in DRM which focused on the evaluation of catalysts, deactivation studies, and reaction mechanisms of developed bimetallic catalysts.

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