Nickel Nanoparticles Anchored by Nano-ZrO2 on SiO2 for CO2 Methanation

ZrO2 is an effective support for CO2 methanation, but its low surface area limits the dispersion and thus activity and stability of the Ni/ZrO2 catalyst. Herein, a ZrO2/SiO2 support was constructed by dispersing nano-ZrO2 on high-surface-area SiO2 to improve the activity and anti-sintering capability of the Ni catalysts. The results showed that SiO2 stabilized the nano-ZrO2, which further provided favorable sites for dispersing and stabilizing Ni species. Ni/0.4ZS exhibited decent performance among the Ni/xZS catalysts (x was the mass ratio of ZrO2 to SiO2) due to the increased dispersion of Ni. Moderate CeO2 promoter addition further improved the activity and resistance to deactivation due to the increased dispersion of Ni NPs and the enhanced adsorption of CO2. XPS and DFT results indicated that the composite support strengthened the electronic interaction between Ni species and the support. Furthermore, based on the experimental and DFT results, it is proposed that additional geometric stabilization of Ni species may be provided by the spatially constrained sites between adjacent nano-ZrO2 particles. These findings demonstrated that constructing nano-ZrO2 on SiO2 was an effective strategy for developing active and stable Ni-based catalysts for CO2 methanation.