Enhanced stability of Ni/SiO2 catalyst for CO2 methanation: Derived from nickel phyllosilicate with strong metal-support interactions

Nowadays more and more significant technologies have been developing to save energy and reduce emissions. CO2 methanation has been an attractive process to reduce CO2-emissions since it consumes CO2 with H2 derived from renewable energy sources to produce CH4. However, the poor stability of Ni-based catalyst for CO2 methanation is still challenging. Herein, two Ni/SiO2 catalysts with different structure and catalytic properties were prepared by different methods. The Ni/SiO2-AEM nanocatalyst with a lamellar structure of nickel phyllosilicate was synthesized by a facile ammonia-evaporation method (AEM), which can conveniently and uniformly disperse nickel species on SiO2. Upon reduction of nickel phyllosilicate, it can disperse and confine small sized Ni particles (4.2 nm) in the silica support with a high surface area of 446.3 m2/g, leading to the Ni/SiO2-AEM catalyst achieving a high yield of methane with long-term stability of 100 h under the GHSV of 10,000 mL/(gcat h) and another 60 h with the GHSV increased to 30,000 mL/(gcat h) at 370 °C. In comparison, the Ni/SiO2-IM catalyst prepared by the impregnation method obtained lower yield of methane and worse stability under identical conditions. The results indicate that the catalyst with high surface area and strong metal-support interactions can improve stability.