Abstract

A novel series of nickel (Ni) loaded on Fibrous Mesoporous Silica Nanoparticles (CHE-SM) support with varying Ni contents ( x =1 - 30 wt%) were synthesized, denoted as x Ni/CHE-SM and then investigated for carbon dioxide (CO 2 ) methanation. The catalysts underwent comprehensive characterization using XRD, N 2 adsorptiondesorption, FESEM, FTIR-KBr, H 2 -TPR, and CO 2 -TPD techniques. The XRD and FESEM analyses confirmed the structural integrity of CHE-SM, irrespective of the Ni loading. However, the size of the nanocrystalline NiO particles appeared to be influenced by the Ni loading. Notably, 20Ni/CHE-SM exhibited the highest CO 2 conversion of 92% at 350 degrees C, demonstrating its potential for low-temperature activation. H 2 -TPR and CO 2 -TPD results revealed favorable NiO reduction at lower temperatures, indicating medium-strength basicity that facilitated efficient CO 2 and H 2 adsorption and activation. Consequently, 20Ni/CHE-SM exhibited superior catalytic performance compared to other catalysts, with lower activation energy (61.5 kJ/mol). Kinetic studies focusing on 20Ni/CHE-SM indicated a molecular adsorption mechanism of CO 2 and H 2 on a single site after evaluation using four Langmuir-Hinshelwood models. This result was attributed to the high amount of medium strength basicity possessed by the 20Ni/CHE-SM catalyst which provided an abundance of adsorption sites, resulting in greater fractional coverage of reactants and enhancing the CH 4 formation rate.