Development of stable bimetallic catalysts for carbon dioxide reforming of methane

Using a coprecipitation method to form Ni–Me–Al–Mg–O composite, Ni–Me (Me = Co, Fe, Cu, or Mn) bimetallic catalysts were prepared for carbon dioxide reforming of methane. Catalyst screening with the reforming reaction showed that Ni–Co bimetallic catalyst had superior performance in terms of activity and stability to other Ni–Me combinations. In a 2000 h stability test under the conditions of 750 °C, 1 atm, and GHSV of 110,000 mL/gcat-h (0.05 g of catalyst and 5.5 L/h gas flow rate), Ni–Co catalyst showed very stable performance with very low carbon formation. Reducing Ni and Co content from 6.1 and 9.3 to 3.6 and 4.9 mol% (metal base), respectively, rendered to completely eliminate carbon deposition for up to 250 h. Catalyst characterization was conducted using ICP-MS, BET, XRD, H2-TPR, CO2-TPD, CO-chemisorption, TEM, and TG. It is believed that the synergy between Ni and Co can significantly improve catalyst performance and reduce carbon formation. A high metal dispersion or small ensemble size can be enhanced by reducing the Ni–Co content. The high activity and excellent stability of Ni–Co catalyst was closely related to its high metal dispersion, strong metal–support interaction, and formation of stable solid solutions.