CO₂ Reforming of Methane over Ni⁰/La₂O₃ Catalyst Without Reduction Step: Effect of Calcination Atmosphere

La-Ni precursor prepared by EDTA-cellulose method was calcined under different atmosphere (Air or Ar), and the catalysts were characterized by various techniques. In this study, the possibility of reduction free catalyst for dry reforming of methane was investigated as well. It was observed that LaNiO₃ perovskite structure was formed under the calcination of Air atmosphere, while Ni⁰/La₂O₃-C structure was obtained under the calcination of Ar atmosphere due to the reducing and the oxidizing agents generated by the decomposition of organic species under inert atmosphere. It was found that even if LaNiO₃-Ar had much larger size of nickel particle than LaNiO₃-Air, the remained carbon species derived positive effect: the interfacial area among carbon, La₂O₃ and Ni⁰ could lead to synergetic sites such as basic sites, which enhanced resistance to carbon deposition. Furthermore, the higher CH₄ activation energy and basicity of LaNiO₃-Ar catalyst might ascribe to equilibrium between CH₄ decomposition and CO₂ gasification rates. Thus, it is suggested that remained carbon species in Ar calcined catalyst did not negatively affect the catalytic activity, but it affected stability positively.