Ni-FeO_x synergy induced by metal-support interaction on Ni-impregnated incineration bottom ash for effective tar...

The incineration bottom ash (IBA) was impregnated with nickel to catalyze toluene (tar surrogate) steam reforming. A toluene conversion of >80 % was achieved at 800℃ without activity decay in a 100-h test for 15 %Ni/IBA. An activation stage was observed for Ni/IBA catalysts in the initial 50 ∼ 400 min under different reaction conditions. A series of experiments and characterizations were performed to explore the possible mechanisms for the activation. It was found that the iron species in IBA gradually migrated to the catalyst surface and formed a Ni-FeO_x complex owing to the metal-support interaction. The synergy of Ni-FeO_x played an important role in improving the activity of Ni/IBA due to the enhanced lattice oxygen activity. Additionally, Ni/IBA catalysts showed a much lower coke deposition rate than Ni/Al₂O₃ (1.12 vs. 3.45 mg-C/g_cat∙h) because of the variable states of FeO_x and the abundant basic sites caused by the alkali and alkaline earth metals contained in IBA.