Synthesis, characterization and catalytic performance of Ni-MCM-41 and Ni-SBA-15 in carbon dioxide reforming of methane

Abstract

A series of nickel supported mesoporous silica SBA-15 and MCM-41 were synthesized using controlled grafting process by atomic layer deposition. The nickel precursor used was nickel acetonate. The structures of the nickel grafted catalysts were studied using various characterization methods including X-ray diffraction and nitrogen physisorption. The catalytic performances of the prepared catalysts were then investigated through carbon dioxide reforming of methane. The results revealed that optimum amount of nickel active sites on mesoporous silica supports (SBA-15 and MCM-41) are essential to maintain high catalytic properties and long term stability. The high catalytic performances of both Ni-SBA-15 and Ni-MCM-41 were likely due to the stability of the active sites dispersion and the amount of nickel active sites on the mesoporous silicas. This had thus enhanced the formation of nickel nano-clusters under reaction conditions. It also shows a general trend that SBA-15 has more superior catalytic performance and stability compared to MCM-41. This is likely due to the interconnected pores and the thick walls of SBA-15 compared to isolated pores and thinner walls of MCM-41 which may provide a huge advantage on the superior catalytic performance of SBA-15. In conclusion, both Ni-SBA-15 and Ni-MCM-41 prepared by grafting method showed reasonably high catalytic activity, stability and moderate H2/CO ratio thus making them promising catalysts for carbon dioxide reforming of methane.