Bifunctional metal doping engineering of Ni-supported alumina catalyst for dry methane reforming

Increasing the basicity of catalysts using basic promoters is known to be effective in retarding rapid coke deposition on catalysts, which is the biggest obstacle to the commercialization of dry methane reforming (DRM). In this study, we investigated the doping of various basic metals (Mg, Ca, Sr, Ba, and La) in nickel-supported alumina catalysts and found that Sr, an element that has drawn less attention than others, has the greatest effect on coke formation resistance. The highest coke resistance attributes more to the small nickel particle size, high reducibility, and strong interaction between the active metal and support, than to the basicity of the catalysts. Furthermore, except for Mg, metal doping was efficient for improving the thermal stability of the catalysts, which is beneficial for maintaining the nickel particle size and mesoporous structure, leading to long-term reaction stability. Under the reaction conditions of accelerated coke formation, the catalytic activity of Ni/Sr-MA was maintained for 50 h without performance decline and coke formation-mediated reactor blockage. This discovery offers new opportunities to develop effective nickel-based DRM catalysts with coke resistance by comprehensively considering the nickel particle size, acidity/basicity, reducibility, and strong interaction between the active metal and the support. • Basic metal doping was efficient for improving the thermal stability. • Sr-doped Ni catalyst showed highest coke resistance for DRM reaction. • The basicity of the catalysts is not the only factor affecting the coke resistance. • Ni size, reducibility, and Ni-support interaction of the catalysts are crucial factors in DRM.