Robust nanosheet-assembled Al2O3-supported Ni catalysts for the dry reforming of methane: the effect of nickel content on the catalytic performance and carbon formation

Robust nanosheet-assembled Al2O3 (NA-Al2O3) catalysts with a hierarchical hollow microsphere architecture for loading Ni nanoparticles (namely, the Ni/(NA-Al2O3) catalyst) with various Ni loadings (3–20 wt%) were successfully fabricated and used for the dry reforming of methane (DRM). The effect of Ni loadings on the catalytic performance and carbon formation of Ni/(NA-Al2O3) catalysts was studied. The catalysts were characterized by various methods. The results indicate that enhancing the loading of Ni increases the Ni nanoparticle size and initial catalytic activity, and simultaneously declines the nickel dispersion and the interaction between Ni and the carrier. The long-time stability test shows that Ni loading of 5 wt% is considered to be the optimal Ni loading over Ni/(NA-Al2O3) catalysts for the DRM reaction. Further enhancing the Ni loading to 10 or 20 wt% results in almost constant catalytic activity, but increases carbon formation due to the larger nanoparticle size of Ni and the weaker interaction of partial nickel species with the carrier.