Nickel.cobalt bimetallic catalysts prepared from hydrotalcite-like compounds for dry reforming of methane

NieCo/Mg(Al)O alloy catalysts with different Co/Ni molar ratios have been prepared from Ni-and Co-substituted Mg-Al hydrotalcite-like compounds (HTlcs) as precursors and tested for dry reforming of methane. The XRD characterization shows that Ni-Co-Mg-Al HTlcs are decomposedby calcination into Mg(Ni,Co,Al)O solid solution, and by reduction finely dispersed alloy particles are formed. H-2-TPR indicates a strong interaction between nickel/cobalt oxides and magnesia, and the presence of cobalt in Mg(Ni,Co,Al)O enhances the metal-support interaction. STEM-EDX analysis reveals that nickel and cobalt cations are homogeneously distributed in the HTlcs precursor and in the derived solid solution, and by reduction the resulting Ni-Co alloy particles are composition-uniform. The Ni-Co/Mg(Al)O alloy catalysts exhibit relatively high activity and stability at severe conditions, i.e., a medium temperature of 600 degrees C and a high space velocity of 120000 mL g(-1) h(-1). In comparison to monometallic Ni catalyst, NieCo alloying effectively inhibits methane decomposition and coke deposition, leading to a marked enhancement of catalytic stability. From CO2-TPD and TPSR, it is suggested that alloying Ni with Co favors the CO2 adsorption/activation and promotes the elimination of carbon species, thus improving the coke resistance. Furthermore, a high and stable activity with low coking is demonstrated at 750 degrees C. The hydrotalcite-derived Ni-Co/Mg(Al)O catalysts show better catalytic performance than many of the reported Ni-Co catalysts, which can be attributed to the formation of Ni-Co alloy with uniform composition, proper size, and strong metal-support interaction as well as the presence of basic Mg(Al)O as support. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

NieCo/Mg(Al)O alloy catalysts with different Co/Ni molar ratios were prepared from Ni-and Co-substituted Mg-Al hydrotalcite-like compounds as precursors. These catalysts showed high activity and stability in dry reforming of methane, effectively inhibiting methane decomposition and coke deposition. Alloying Ni with Co promoted CO2 adsorption/activation and the elimination of carbon species, resulting in improved coke resistance. Hydrotalcite-derived Ni-Co/Mg(Al)O catalysts exhibited better catalytic performance compared to other Ni-Co catalysts.