Ni-based catalysts have been widely used for the CO₂ reforming of methane (CRM) process, but deactivation is their main problem. This study created an alternative electronic Ni-NiO-CeO₂ interaction on the surface of 5 wt% Ni-5 wt% CeO₂/Al₂O₃-MgO (5Ni5Ce(xh)/MA) catalysts to enhance catalytic potential simultaneously with coke resistance for the CRM process. The Ni-NiO-CeO₂ network was developed on Al₂O₃-MgO through layered double hydroxide synthesis via our ammonia vapor diffusion impregnation method. The physical properties of the fresh catalysts were analyzed employing FESEM, N₂ physisorption, and XRD. The chemical properties on the catalyst surface were analyzed employing H₂-TPR, XPS, H₂-TPD, CO₂-TPD, and O₂-TPD. The CRM performances of reduced catalysts were evaluated at 600 °C under ambient pressure. Carbon deposits on spent catalysts were determined quantitatively and qualitatively by TPO, FESEM, and XRD. Compared to 5 wt% Ni-5 wt% CeO₂/Al₂O₃-MgO prepared by the traditional impregnation method, the electronic interaction of the Ni-NiO-CeO₂ network with the Al₂O₃-MgO support was constructed along the time of ammonia diffusion treatment. The electronic interaction in the Ni-NiO-CeO₂ nanostructure of the treated catalyst develops surface hydroxyl sites with an efficient pathway of OH* and O* transfer that improves catalytic activities and coke oxidation.

Carbon dioxide hydrogenation is an attractive route for converting greenhouse gases into valuable fuels and chemicals. In this work, the effect of manganese (Mn) promoter loading on Co/SiO2 catalysts was systematically investigated for CO2 hydrogenation under mild reaction conditions. Catalysts with different Mn loadings (1–7 wt%) were synthesized using the incipient wetness impregnation method and characterized by XRD, BET, TEM, H2-TPR, and CO2-TPD techniques. The introduction of Mn significantly influenced the physicochemical properties of the catalysts, including metal dispersion, surface basicity, and reducibility. The BET analysis revealed a gradual decrease in surface area with increasing Mn loading due to partial pore blocking, while H2-TPR results indicated enhanced reducibility associated with Co–Mn interactions. CO2-TPD results demonstrated that Mn addition increased the strength of basic sites, which facilitates CO2 adsorption and activation. Catalytic testing at 230 °C and atmospheric pressure showed that the 20CS5Mn catalyst exhibited the lowest methane selectivity and favors to produce C5+ selectivity. The reaction pathway is proposed to proceed through a reverse water–gas shift (RWGS) reaction followed by Fischer–Tropsch-like hydrogenation of CO intermediates on cobalt active sites. Although the selectivity toward C5+ hydrocarbons remained relatively low, Mn promotion was found to slightly enhance hydrocarbon chain growth compared with the unpromoted catalyst.