Catalytic performance of Mn-promoted Ni/MgO catalysts in CO_2 reforming of toluene used as model compound of tar produced from biomass: Influence of preparation methods

摘要

Catalytic performance of Mn-promoted Ni/MgO catalysts prepared by different methods wasrninvestigated in CO_2 reforming of toluene. By XRD, H_2-TPR and TEM analysis and reforming tests,rncatalysts made by either conventional impregnation or precipitation methods in which Mn(NO_3)_2·4H_2Ornwas used as the start precursor behaved similarly in catalytic performance, Mg_6MnO_8phase was presentrnin all the calcined catalysts which caused worse activities in reforming tests. In contrast, by using arnmechanic milling method in which MnO was initially added by physical milling with MgO as a supportrnand then the calcined support was impregnated with nickel nitrate, the main crystalline phase of Mnrnspecies was α-Mn_2O_3 which worked as a support, after reduction, Ni can distribute well on both MnOrnand MgO, in this case, more Ni particles can be obtained because the interaction between Ni and MnOrnwas less strong than that with MgO, therefore, a better performance than Ni/MgO and other catalysts canrnbe yielded.