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

A group of Ni/SiO 2 catalysts was prepared via the complexed-impregnation method with different amounts of citric acid (Ni–C/SiO 2 ). The Ni–C/SiO 2 and Ni/SiO 2 prepared by the conventional impregnation method were respectively tested for carbon dioxide reforming of methane (CDR) at CO 2 /CH 4 = 1.0, a gas hourly space velocity of 60 000 mL·g –1 ·h –1, and a reaction temperature of 750 °C. The characterization results indicated that Ni–C/SiO 2 showed higher Ni dispersion and stronger Ni–support interaction than Ni/SiO 2 . As a result, superior anti-coke and anti-sintering of Ni were obtained over the Ni–C/SiO 2 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/SiO 2 with a molar ratio of citric acid to Ni of 2.0 for the CDR testing within the time on stream of 100 h.