Ni-Ru-containing mixed oxide-based composites as precursors for ethanol steam reforming catalysts: Effect of the synthesis methods on the structural and catalytic properties

Ethanol steam reforming catalyst's precursors, i.e., nanocomposites of complex oxides with the general formula [Pr_0.15Sm_0.15Ce_0.35Zr_0.35O₂ + LaMn_0.45Ni_0.45Ru_0.1O₃] (1:1 by mass), were synthesized by three different methods. It was shown that two synthesis methods - ultrasonic dispersion and sequential polymeric method, lead to the formation of the nanocomposite perovskite-fluorite system with the specific surface area up to 50 m²/g. Reduction of samples at 400-500°C lead to the formation of Ni-Ru alloy nanoparticles strongly bound with the surface of oxide nanocomposite. Catalytic tests in ethanol steam reforming reaction at 500-600°C showed the highest specific activity of the sample prepared by the sequential polymeric method due to the location of Ni- and Ru-containing perovskite mainly on the surface of the composite providing a high concentration of active metal centers. At higher temperatures for all samples, ethanol conversion approached 100% with hydrogen yield varying in the range of 65-75%. A study of spent catalysts confirmed the absence of carbon deposits after long-term catalytic tests at 650°C.