Efficient conversion of CO2 to methane using thin-layer SiOx matrix anchored nickel catalysts

Abstract

Hydrogenation of CO₂ toward methane is a promising alternative for CO₂ utilization and the development of highly efficient catalysts is the key factor for CO₂ methanation. Herein, thin-layer SiO_x matrix anchored nickel species catalysts (Ni/SiO_x) with high specific surface area and a unique electronic/geometric structure have been successfully fabricated via a hydrothermal strategy. Ni₃Si₂O₅(OH)₄, with a typical layered structure and uniformly dispersed nickel sites, is an ideal precursor for Ni/SiO_x catalysts for enhanced CO₂ adsorption and chemical activation. The highly dispersed Ni active sites with suitable metal-support interactions with the SiO_x matrix can promote CO₂ conversion. Moreover, the pore structure and surface physicochemical properties of the Ni/SiO_x samples can be tuned by changing the Ni/Si molar ratio. The optimized Ni/SiO_x-2 catalyst shows outstanding catalytic efficiency with CO₂ conversion of 64.2% and CH₄ selectivity of 91.4% as well as excellent long-term (200 h) thermal stability for CO₂ methanation under the conditions of 400 °C and the high gas hourly space velocity (GHSV) of 90 000 mL g_cat⁻¹ h⁻¹. These findings can open new avenues towards the development of new-type nanomaterials in catalysis, especially renewable C1 chemistry transformations.