Formation of the Active State of Catalysts Based on Nickel-Substituted Copper Aluminates Ni_xCu_1-xAl₂O₄ (x = 0.1–0.5) and their Catalytic Properties in the Dry Reforming of Methane Reaction

Ni_xCu_1-xAl₂O₄ (x = 0.1–0.5) catalysts, obtained by co-precipitation method from nickel, copper and aluminum water nitrate solution with followed drying and calcination in air at 750°C were synthesized. They are characterized by a spinel structure, in which nickel and copper ions are stabilized. Reducing of obtained catalysts in a hydrogen-containing medium and further work in the dry reforming of methane reaction leads to formation of highly dispersed particles of Ni⁰–Cu⁰ alloy. Up to 28 wt % of active phase are formed and stabilized on the spinel surface. The investigation of the influence of catalyst composition on their activity in the DRM reaction accompanied the long tests on stream showed that the Ni_0.35Cu_0.65Al₂O₄ catalyst demonstrates highest activity. At 750°C and contact time of τ = 30 ms, total convertion of CH₄ is 89%, the CO₂ conversion is 86%, the hydrogen yield is 48%, the H₂/CO ratio is 0.75. This catalyst is stably working in the DRM reaction mixture for 20 h. The regularities of the formation of active state for this catalyst were studied by the XRD method in situ.

synthesisgas, CH₄, CO₂, copperaluminates modified by nickel, catalyst, Ni⁰–Cu⁰ alloy, DRM reaction