Synergism in NiMoOx precursors essential for CH4/CO2 dry reforming

Ni-Mo2C(CP) and Ni-Mo2C(MM) catalysts were prepared through carbonization of NiMoOx precursors prepared by co-precipitation (CP) and mechanical mixing (MM), respectively. Different preparation methods lead to different chemical compositions, reduction properties, as well as carbonization process of NiMoOx precursors. It was found that Ni-Mo2C(CP) has better Ni dispersion than Ni-Mo2C(MM). With smaller Ni particles and higher CH4 dissociation rate, Ni-MO2C(CP) performs better than Ni-Mo2C(MM) in CH4/CO2 reforming. It is deduced that nickel is better stabilized in NiMoO4 than in NiO, and the sintering of metallic nickel during high-temperature carburization is less severe with NiMoO4(CP). Based on the results, we address for the first time the key roles of NiMoO4 as a precursor for the formation of Ni-Mo2C effective for CH4/CO2 reforming. (C) 2013 Elsevier B.V. All rights reserved.