A High-Performance Ni/SiO2 Prepared by the Complexed-Impregnation Method with Citric Acid for Carbon Dioxide Reforming of Methane

A group of Ni/SiO2 catalysts was prepared via the complexed-impregnation method with different amounts of citric acid (Ni-C/SiO2). The Ni-C/SiO2 and Ni/SiO2 prepared by the conventional impregnation method were respectively tested for carbon dioxide reforming of methane (CDR) at CO2/CH4 = 1.0, a gas hourly space velocity of 60 000 mL.g(-1).h(-1), and a reaction temperature of 750 degrees C. The characterization results indicated that Ni-C/SiO2 showed higher Ni dispersion and stronger Ni-support interaction than Ni/SiO2. As a result, superior anti-coke and anti-sintering of Ni were obtained over the Ni-C/SiO2 during the period of CDR operation. Importantly, a highly active and stable catalyst was obtained by optimizing the amount of citric acid added, and an unobservable deactivation was exhibited over Ni-C/SiO2 with a molar ratio of citric acid to Ni of 2.0 for the CDR testing within the time on stream of 100 h.