Promotional Effect of Ni on a CrOx Catalyst Supported on Silica in the Oxidative Dehydrogenation of Propane with CO2

Abstract As CrO x catalysts supported on the SBA‐15 support (Cr/Si) are highly active, they represent potentially promising catalysts for the oxidative dehydrogenation of propane with CO 2 (ODHP). However, reduction of the active sites (Cr 3+ ) during the reaction is known to lead to severe deactivation. The findings reported herein indicate that after the addition of 0.5 wt % Ni to 10 wt % Cr/Si (0.5 Ni‐Cr/Si), the catalytic activity was stable and the selectivity was high. Reduced CrO x was easily regenerated by the addition of Ni, as evidenced by a three‐step H 2 ‐temperature programmed reduction analysis. In addition, ex situ XPS results revealed that Cr 3+ was maintained only in the Ni‐promoted catalyst whereas Cr 3+ was easily reduced to Cr 2+ in the non‐promoted catalyst during the reaction. The role of the Ni added to the catalyst elucidates that Ni induces the dissociation of CO 2 to CO and activated O (O* ads ). Then, the generated O* ads regenerates the reduced CrO x . Consequently, the Ni‐promoted Cr/Si catalyst enhances the catalytic stability of propylene in the ODHP reaction.