Lamellar-structured fibrous silica as a new engineered catalyst for enhancing CO2 methanation

[Display omitted] •The support’s structure affecting pore dimension and deposition of Ni particles.•The lamellar structure of CHE-SM enhances the metal-support interaction.•Ni/CHE-SM obtained high CO2 conversion (88.6%) compared to Ni/CHE-S41 (82.9%).•Ni/CHE-SM depicts the highest coke formation resistance during 50 h stability test.•The high basicity and strong MSI were beneficial in suppressing carbon deposition. Recently, Centre of Hydrogen Energy (CHE) has developed new structures of fibrous mesoporous silica nanoparticles (FMSN) and fibrous Mobil composition of matter-41 (FMCM-41) called CHE-SM and CHE-S41, respectively. Both are used as a support, along with adding 5 wt% Ni as active metal and examined on carbon dioxide (CO2) methanation. The low angle x-ray diffraction (XRD) and transmission electron microscopy (TEM) results proved that Ni/CHE-S41 possessed a hexagonal structure while Ni/CHE-SM was discovered in a lamellar structure. In addition, the XRD and N2 adsorption–desorption revealed that Ni particles were deposited on the surface of CHE-SM due to the smaller support pore size (4.41 nm) than the average Ni particles diameter (5.61 nm) resulting in higher basicity and reducibility. Meanwhile, Ni/CHE-S41 revealed deposition of Ni particles in the pore due to difference in support pore size (4.89 nm) compared to average Ni particles diameter (4.01 nm). Consequently, Ni/CHE-SM performed higher CO2 conversion (88.6 %) than Ni/CHE-S41 (82.9%) at 500 °C, while both achieved 100 % selectivity towards methane. Furthermore, the Ni/CHE-SM displayed excellent resistance towards coke formation during 50 h stability test at 500 °C. It is confirmed as Ni/CHE-SM exhibited a weight loss of 0.469% in TGA analysis and a G:D band ratio of 0.43 in Raman spectroscopy, both of which were lower than the corresponding values of Ni/CHE-S41 (0.596% weight loss and 0.74 G:D band ratio). These properties of Ni/CHE-SM are beneficial in methane production field as coke formation could affect the equilibrium of CO2 methanation process.