An active and stable nickel-based catalyst with embedment structure for CO2 methanation

The CO2 methanation catalyst with high activity and stability has attracted significant attention from industrial and academic community. In this work, a highly active and stable Ni@HZSM-5 catalyst was synthesized by hydrothermal method using conventional Ni/SiO2 catalyst as unique silicone source. The Ni@HZSM-5 showed high activity and excellent stability during 40 h CO2 methanation reaction, comparing to the conventional Ni/SiO2 and Ni/HZSM-5 catalysts prepared by impregnation method. After a prolonged reaction, the Ni@HZSM-5 still maintain similar nickel content and the structure of active nickel to fresh catalyst, due to the special embedment structure. Meanwhile, it is found that the nickel active phase of the Ni@HZSM-5 catalyst donates more electrons to zeolite, resulting in higher BE values, lower wavenumber and weak intensity of CO bands. Hence, the Ni@HZSM-5 catalyst can prevent the formation of volatile metal-molecule intermediates (gaseous Ni(CO)(x)), which resulted in serious sintering and loss of the supported nickel in conventional Ni catalysts. All obtained catalysts were characterized by XRD, SEM-EDS, TEM, XRF, BET, TGA, in situ CO-DRIFTS and in situ XPS.