Comparison of catalytic properties of Ni/CeO2 and Ni/La2O3 prepared by low-temperature oxidation

An attempt was made with rare earth intermetallic compounds to prepare highly active catalysts by low-temperature oxidation. CeNi5 was chosen as the starting material, because works on LaNi5 have shown that surface area increase and Ni crystallite growth are closely related to oxidation rate, and because the Ce oxidation rate is much higher than that of La. It was found that low-temperature oxidation of CeNi5 was accompanied by an increase in surface area without the growth of Ni crystallites. The reaction rate of CO hydrogenation per Ni weight was about 500-fold higher for Ni/CeO2 than for Ni/La2O3 at 535 K. This was connected with increased Ni surface area (180-fold) and high turnover frequency (2.8-fold). Moreover, C2 and C3 products increased with increasing conversion of Ce oxidation. (author)