The impact of Rh, La, Sm, and Au on the development of Ni/Al 2 O 3 catalysts in the dry reforming of methane to produce synthesis gas

Dry reforming of methane (DRM) is a viable strategy for converting two potent greenhouse gases, CH4 and CO2, into synthesis gas (H2 and CO), which serves as a precursor for methanol, hydrogen, and Fischer–Tropsch fuels. However, catalyst deactivation due to carbon deposition and sintering remains a major challenge. This study examines Ni/γ-Al2O3 catalysts individually promoted with Rh, La, Sm, or Au to evaluate their role in the DRM for syngas production. Detailed characterizations (BET, UV–Vis, TGA, SEM, TEM, XRD, XPS, and cyclic TPR-TPD-TPR) revealed that Rh and La improved Ni dispersion and reducibility. Rh-promoted catalysts showed the best catalytic performance, stability, and the least carbon accumulation, as confirmed by catalyst activity studies, CHN, TGA, and TPR data. Process optimization via central composite design predicted 98% CH4 and 97% CO2 conversion at 828.5 °C and an H2/CO ratio of 1.038, which was validated by experimental runs performed under these conditions depicting very good agreement with the results predicted by the model.