Promotion effect of the rare earth metals (cerium, lanthanum, and yttrium) on the catalytic performance of Ni/Al₂O₃ catalyst fabricate via the neoteric one-pot hydrothermal method for methane decomposition

Catalytic methane decomposition is an economical and green procedure to procreate CO_x-free hydrogen as a renewable energy source. This paper describes the mesoporous high surface area Ni/Al₂O₃ catalysts enhanced with the rare earth metals (cerium, lanthanum, and yttrium) fabricated via neoteric one-pot hydrothermal strategy, and the co-catalysts performance in the methane decomposition process, explores. This comparative study shows that Yttria exhibited dramatic catalytic activity and thermal stability among the above promoters. The maximum CH₄ conversions of 61.16, 68.61, and 63.74 % have been obtained over the 50Ni-xY/Al₂O₃ (x = 2.5, 5, and 10 wt%) at 650 °C and GHSV = 24000 mL.(h.g_cat)⁻¹, respectively. The optimal sample (5 wt% Y-doped) reveals a superior lifetime in high-temperature stability tests after 10 h. Moreover, the analysis of carbon nanofiber's textural properties indicates that Y loading leads to highly graphitized (I_D/I_G = 1.22 to 0.98) and the formation of a carbon lattice with supreme crystallization.