Effects of Promoter on NiMgAl Catalyst Structure and Performance for Carbon Dioxide Reforming of Methane

Abstract

Catalysts were prepared by adding different types of promoter (Co, Ir, or Pt) to the supported nickel catalyst NiMgAl samples. These catalysts were characterized by H2 temperature-programmed reduction (H2- TPR), CO2/CH4 temperature-programmed surface reactions (CO2/CH4-TPSR), and CO2 temperature- programmed desorption (CO2-TPD). The effects of the catalyst structure on catalytic performance in the methane dry reforming reaction with carbon dioxide were investigated. The addition of a small amount of promoter (Pt or Ir) can lower the reduction temperature of the nickel active component, and enhance performance in the methane dry reforming reaction. The catalysts with Co or Ir promoter feature lower activation energies than the unmodified NiMgAl catalyst. The activation energy was 51.8 kJ∙mol - 1 for the NiMgAl sample, decreasing to 26.4 kJ∙mol - 1 for the NiPtMgAl catalyst, which showed overall better catalytic performance. Results of CH4-TPSR and CO2-TPSR demonstrate that the NiPtMgAl catalyst can generate more active carbon species on the catalyst surface. The CO2-TPD results show that adding a promoter can increase the CO2 adsorbed/desorbed amount compared with the unmodified NiMgAl catalyst over the same reaction temperature range.