Catalytic performance of Ni catalysts for steam reforming of methane at high space velocity

Three Ni-based catalysts, namely Ni/ZrO2/Al2O3, Ni/La–Ca/Al2O3 and Ni0.5Mg2.5AlO9 catalysts were prepared, tested and characterized for steam reforming of methane (SRM), especially at high space velocities. Experimental results demonstrated that Ni0.5Mg2.5AlO9 catalysts showed excellent catalytic activity, e.g., the high reaction performance (i.e., activity and stability) at a very short residence time of 20ms. For the accompanied water gas shift (WGS) reaction with the SRM at the steam to methane ratio of 3:1, the overall hydrogen yield depended on both the CH4 conversion and the CO2 selectivity. The results showed that CO2 selectivity had opposite trend compared with CH4 conversion in such a short-contact process. Catalyst characterizations by XRD, SEM-EDS, TEM and TGA suggested that the good performance of nickel catalysts was closely related with the good dispersion of the active component. The nano-sized nickel particles in strong interaction with the supports would lead to the good dispersion, thereafter having a slight tendency to sintering, and then to coking.