Synergism in NiMoO_x precursors essential for CH ₄/CO₂ dry reforming

Ni-Mo₂C(CP) and Ni-Mo₂C(MM) catalysts were prepared through carbonization of NiMoO_x 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 NiMoO_x precursors. It was found that Ni-Mo₂C(CP) has better Ni dispersion than Ni-Mo ₂C(MM). With smaller Ni particles and higher CH₄ dissociation rate, Ni-Mo₂C(CP) performs better than Ni-Mo ₂C(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-Mo ₂C effective for CH₄/CO₂ reforming.