(509av) Enhanced Activity and Stability of MgO-Promoted Ni/Al2O3 Catalyst for Dry Reforming of Methane

Highly dispersed Ni nanoparticles were deposited on Al₂O₃ particles by atomic layer deposition (ALD) and various amounts of MgO were loaded on Ni/Al₂O₃ catalysts by incipient wetness method for dry reforming of methane. MgO was found to increase the basic sites and basic strength of catalyst surface, which provided additional surface oxygen species and assisted the adsorption and activation of CO₂. Although the formation of NiO-MgO during the calcination of incipient wetness didn’t improve the overall reducibility, Ni originated from NiO-MgO after reduction formed intimate interaction with MgO, which could inhibit Ni nanoparticles from sintering and provide sufficient metal-support interface for CO₂ activation. The MgO-promoted Ni/Al₂O₃ demonstrated a methane reforming rate of 1780 L_CH4h^-1g_Ni^-1 at 850 °C, which is 26% higher than that of the pristine Ni/Al₂O₃. The higher CO₂ activity enhanced the oxidation rate of the surface carbon from the side-reactions, thus resulting in a higher reforming rate and inhibiting coke formation, especially the detrimental graphitic encapsulating carbon on the active nickel surface.