Carbon dioxide reforming of methane over K-modified Ni-Al2O3 catalysts. Effect of the potassium content

Abstract

The influence of the potassium content on the performance of a Ni-Al2O3 catalyst, prepared by a sol–gel method, in the CO2 reforming of methane was studied. For this purpose, catalytic activity and resistance to carbon depositionweremeasured. The characterization techniques used were BET surface area, X-ray diffraction, Transmission ElectronMicroscopy (TEM), Temperature-Programmed Reduction (TPR) and Temperature-Programmed Oxidation (TPO). The CO2 reforming of methane was carried out at 750oC and at a CO2/CH4 ratio of 1. K-modified catalystswere prepared by incipient wetness impregnation. The effects of K addition on the physicochemical properties were studied at different potassiumcontents, from0 to 1 wt.%K. Compared to the unmodified catalyst, the introduction of K showed constant but slightly less activity, a lowering in the hydrogen yield and a lower carbon deposition after the same operation period. Our results showed the highest increase in resistance to carbon accumulation at a K load of 0.5 wt.%.