Insight into the anti-coking ability of NiM/SiO2 (M=ZrO2, Ru) catalyst for dry reforming of CH4 to syngas

Abstract The development of Ni-based catalysts with outstanding anti-coking ability is necessary for realizing the industrial application of dry reforming of CH4 (DRM) to syngas. Here, a facile combustion method with unique characteristic was employed to prepare the Ni/SiO2 catalyst with different promoters (ZrO2 or Ru). The effects of Ni particle size and promoter (ZrO2 or Ru) on the anti-coking ability of Ni/SiO2 catalyst were examined. The XRD and TEM results showed that improved Ni dispersion can be obtained via the facile combustion method, accompanying with enhanced metal-support interaction and CO2 adsorption capacity confirmed by H2-TPR and CO2-TPD, respectively. In comparison with Ni-IMP catalyst (prepared via the traditional impregnation method), the carbon deposition over Ni–C catalyst (prepared via the combustion method) decreased by 67% (from 2.7 to 0.9 mg carbon deposition·g−1CH4) as a result of the small Ni particles. The H2-TPR and XPS results revealed the interaction between promoter (ZrO2 and Ru) and Ni. The addition of ZrO2 can enhanced the CO2 activation ability of catalyst and the formed oxygen species can facilitate the elimination of carbon species, further decreasing the carbon deposition compared with Ni–C catalyst. The best catalytic performance with least carbon deposition (only 0.4 mg carbon deposition·g−1 CH4) is achieved on the NiRu–C catalyst. The slower CH4 dissociation rate and the improved CO2 activation benefited from Ru can bring in the better balance between the carbon formation and elimination, leading to the best anti-coking ability of catalyst.