Effect of Ni loading method on the deactivation of Ni/Al2O3 catalysts prepared via mechanochemical synthesis for dry reforming of methane

In this study, 5 wt% Ni/Al 2 O 3 catalysts were prepared via mechanochemical route using both one-pot synthesis and conventional impregnation to compare their deactivation behavior in the dry reforming of methane reaction. While the Ni loading method affected metal dispersion, the Ni reducibility remained similar in both catalysts. After the 100-hour reaction, spent catalyst characterization revealed that the impregnated catalyst was more susceptible to deactivation through coke formation and sintering. In the impregnated catalyst, Ni particles are primarily located on the external surface. These exposed Ni particles are likely larger than those located inside the pores and are more susceptible to coke growth and subsequent deactivation due to the lack of spatial constraints. Conversely, the Ni particles in the one-pot synthesized catalyst were embedded within the alumina, providing resistance to sintering and coke formation. These results demonstrate that the Ni loading method influences the spatial distribution of Ni particles. Consequently, it affects the deactivation behavior in the dry reforming of methane.