| 초록 |
NiMgGa-layered double hydroxide (NMG-LDH) was synthesized as an efficient catalyst precursor for dry reforming of methane which shows high stability at low temperature (~600°C). NMG-LDH was transformed to Ni3Ga intermetallic structure after the reduction pre-treatment, which exhibited high CH4 (~48%) and CO2 (~52%) conversion as well as high stability compared to other reported monometallic Ni-based catalysts under similar reaction conditions. The stability of Ni3Ga intermetallic catalysts was superior to that of monometallic catalysts (Ni/MgO or Ga/MgO) due to high coke resistance property. The formation of unique intermetallic carbide (Ni3GaCx) during the reaction was responsible for the outstanding stability compare to the conventional Ni monometallic phase. The formation of Ni3GaCx intermetallic carbide structure was confirmed by XRD, HR-TEM, and XAS analysis. In situ XRD analysis was investigated to elucidate formation mechanism of Ni3GaCx structure and reaction mechanism on the Ni3GaCx during the reaction. Carburization of Ni3Ga by CH4 and oxidation of Ni3GaCx by CO2 make a redox cycle, resulting in high activity and stability. |
