Highly dispersed Ni/MgO-mSiO2 catalysts with excellent activity and stability for dry reforming of methane

Highly dispersed Ni catalyst and alkaline promoters supported by mesoporous SiO2 nanospheres were synthesized and applied as an active and stable catalyst for dry reforming of methane (DRM). The as-prepared Ni/MgO-mSiO2 catalyst showed stable conversions of CH4 and CO2 around 82% and 85% in 120 h of DRM reaction, which was superior in performance compared to similar catalysts in literatures. Based on the transmission electron microscope (TEM) images, energy-dispersive spectroscopy (EDS), CO-pulse adsorption, temperature programmed reduction of the oxidized catalysts by hydrogen (H2-TPR), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of CO2 (CO2-TPD), and thermal gravitational analysis (TGA), the promotion effect of MgO on the Ni catalyst was systematically studied. The introduction of Mg2+ in synthesis enhanced the interaction between Ni2+ and mSiO2, which led to a high dispersion of active centers and a strong "metal-support" interactions to inhibit the sintering and deactivation of Ni at reaction temperatures. On the other hand, Ni and MgO nanoparticles formed adjacently on mSiO2, where the "Ni-MgO" interface not only improved the Ni0 distribution and promoted the cracking of CH4 but also promoted the activation of CO2 and the elimination of carbon deposits. A high and stable conversion of CH4 and CO2 were then achieved through the synergistic effect of Ni catalyst, MgO promoter, and mSiO2 support.