Effect of K addition on physico-chemical properties and catalytic activity of a Ni-Al2O3 catalyst in the dry reforming of methane

MARÍA E. IRIARTE; MARÍA M. BARROSO-QUIROGA; ADOLFO E. CASTRO LUNA

Salamanca, España

Congreso; IX EuropaCat; 2009

European Federation of Catalysis Societies (EFCATS)

The effect of the amount of K loaded as activity modifier to a massive Ni-Al2O3 catalyst obtained via sol-gel for the dry reforming of methane (DRM) was studied. The unmodified catalyst (Ni) was prepared by a sol-gel method based in the hydrolysis and acid peptization with HNO3 of the precursors nickel and alumina alcoxides. The modified catalysts were obtained by the method of incipient wetness impregnation. In order to characterize the catalysts the following techniques were applied to fresh, reduced and used catalysts according to the case: BET, XRD, TPR, TPH, TPO and TEM. Methane-CO2 reforming was carried out with a conventional quartz fixed-bed tubular reactor. Our results confirm that the incorporation of potassium hinders the accumulation of carbon on the catalyst surface, increases the reducibility, probably modifying the metal-support interaction, and modifies neither the size nor the structure of the nickel particles. But it simultaneously decreases slightly de catalytic activity. It has been proposed that potassium migrates from the support to the surface of nickel and neutralizes a fraction of the most active sites for the reforming reaction producing, as a consequence, a decrease in methane conversion. An optimum in the amount of carbon deposition and the lower reduction in catalytic activity compared with the unmodified catalyst was observed for the catalyst modified with 0.5% of K.