Glycine-based solution combustion synthesis of Ni/Al2O3 catalyst: Decomposition of methane

In this study, the methane decomposition to hydrogen and carbon nanofibers over nickel catalysts synthesized by solution combustion synthesis (SCS) using glycine as a fuel was explored. High percentage catalysts, 90%Ni/10%Al2O3 (wt%), were synthesized through the solution combustion method using the C2H5NO2-Ni(NO3)2·6 H2O-Al(NO3)3·9 H2O mixture. Thermodynamic analysis enabled the determination of the adiabatic combustion temperatures and the quantities of gaseous products, which were influenced by the process's technological aspects. The impact of the key parameters of synthesis on the yields of hydrogen and carbon nanofibers was investigated through a design of experiments approach. The catalyst samples were tested in a methane decomposition reaction at 550°C and a pressure of 1 atm in a fixed-bed vertical reactor. The catalysts and carbon nanofibers were investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, low-temperature nitrogen adsorption, and X-ray diffraction. Optimal parameters of SCS (550°C, 1 °C/min, 40 min, φ=0.55) ensuring high specific yield of hydrogen (34.3 molH2/gcat) and carbon nanomaterials (205.9 g/gcat) were determined.