NiO/M-Sil-1 Catalysts by In-Situ Coupled Assembly of Metal Oxides and Silicalite-1 Zeolite with Improved Stability for Methane Steam Reforming Reaction.

Abstract

NiO/M-Sil-1 catalysts were successfully prepared by in situ coupled assembly of metal oxides and silicalite-1 zeolite. All the NiO/M-Sil-1 samples had high surface areas, which resulted from the uniform dispersion and small particle size of the active components. Zr-doped Ni/M-Sil-1 exhibited a 20% lower NiO average particle size and a 6% lower NiO reduction temperature compared with those of the nondoped catalysts. Consequently, the Ni/Zr-Sil-1 catalyst exhibited the best catalytic performance, with the CO selectivity in methane steam reforming drastically decreasing by 11.5%, H₂ concentration in the reformed gas increasing by about 1.7%, and H₂/CO molar ratio increasing by 0.8. Moreover, its initial methane conversion efficiency was 99.8% and was retained by 97.7% after a 578 h continuous stability test. Furthermore, the traditional water/carbon molar ratio in methane steam reforming reduced from 3-5 to 2, and the methane conversion remained above 98.1%, with a high thermal stability that substantially increased the energy efficiency.