Probing the differential methane decomposition behaviors of n-Ni/SiO₂, n-Fe/SiO₂ and n-Co/SiO₂ catalysts prepared by co-precipitation cum modified Stöber method

n-Ni/SiO₂, n-Fe/SiO₂ and n-Co/SiO₂ nano-catalysts were prepared by co-precipitation cum modified Stöber method and applied for thermocatalytic decomposition of methane in order to investigate their thermal stability and activity to produce greenhouse gas free hydrogen and nano-carbon. The mean particles sizes of the produced nano-catalysts obtained from BET analysis are 32.19 nm, 30.26 nm and 49.92 nm, respectively. Temperature programmed methane decomposition were conducted as a preliminary catalytic examination and further isothermal analyses were performed at 700 °C, 600 °C and 500 °C. Production of hydrogen at each experimental temperatures and corresponding carbon yield were measured. Among the three catalysts inspected, n-Ni/SiO₂ was found to be the most efficient one for thermocatalytic methane decomposition. Furthermore, significant catalytic stability was observed with n-Ni/SiO₂ at 500 °C and 600 °C. While, the rapid deactivation of the n-Fe/SiO₂ and n-Co/SiO₂ catalysts are attributed to particle agglomeration and the irregular formation of nano-carbon due to metal fragmentation. Physical and chemical characteristics of the produced nano-catalysts were investigated by N₂ adsorption-desorption measurement (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM) and hydrogen-temperature programmed reduction (H₂-TPR). Produced nano-carbon were inspected with TEM, FESEM and XRD.