Using anthropogenic carbon dioxide (CO₂) as a feedstock for the production of synthetic fuel has gained significant attention in recent years. Among the various CO₂ conversion pathways, the production of synthetic natural gas via CO₂ methanation holds promise because of its potential for both carbon recycling and renewable energy storage. Nickel (Ni) and ruthenium (Ru) are the dominant metals employed as catalysts in the CO₂ methanation reaction. This review summarizes the research landscape of Ni- and Ru-based catalysts over the last ten years. Bibliometric analysis revealed that China has the highest number of publications, the Chinese Academy of Sciences is the foremost academic institution, and the International Journal of Hydrogen Energy is the leading journal in this area of research. The publication trend revealed that research on Ni-based catalysts is published at almost four times the rate of Ru-based catalysts. Despite growth in research, problems with catalyst stability and kinetics still exist. The latest research on various catalytic systems, including supported, bimetallic, and single-atom catalysts and the fundamental challenges associated with the CO₂ methanation process are reviewed. This review provides a new angle for future studies on catalysts based on non-noble Ni and noble Ru metals and opens the way for additional research in this area.

The catalytic dehydrogenation of perhydro-dibenzyltoluene (H18-DBT) to dibenzyltoluene (DBT) on a Pt/Al ₂ O ₃ catalyst was investigated using ¹ H NMR spectroscopy and GC-MS.

The catalytic activity increased with a small addition of Ba, La and Ce on SiO₂–Al₂O₃ supported Ni catalysts for CO₂ methanation.

The drive to utilize ammonia as a carbon-free hydrogen source necessitates the development of effective, non-precious metal catalysts for ammonia decomposition. We successfully synthesized a series of Ce-based perovskite oxides (CeXO₃; X = Co, Ni, Fe) via combustion method using citric acid. These catalyst precursors were tested for NH₃ decomposition to study the effect of the perovskite structure on catalytic activity. The results were directly compared to corresponding impregnated catalysts, X/CeO₂, which had similar metal concentrations. A remarkable enhancement in catalytic performance was observed with the perovskite catalysts, particularly at lower temperatures, relative to their impregnated counterparts. The exception was the CeFeO₃ catalyst, which exhibited lower activity, likely due to the formation of metal nitrides. Both CeNiO₃ and CeCoO₃ showed good NH₃ decomposition activity, but CeNiO₃ emerged as the most active catalyst at lower temperatures. This superior performance attributed to the presence of oxygen vacancies—confirmed by Raman and XPS analyses—and enhanced metal reducibility at lower temperatures, both of which accelerate NH₃ decomposition. Furthermore, CeNiO₃ also displayed a high surface metal concentration. These Ce-based perovskite materials are cost-effective, easily synthesized, and highly stable; hence, they are attractive candidates for large-scale hydrogen production.