Thermocatalytic decomposition of CH4 over Ni/SiO2•MgO catalysts prepared via surfactant-assisted urea precipitation method

The supported Ni catalysts on the magnesium silicate were synthesized via a co-precipitation method using urea. The influences of several factors such as time of urea decomposition (6-24 h), urea concentration (0.25-1 M), calcination temperature (600-800 degrees C), and the type of the surfactant (PVA and PEG) on the textural attributes and catalytic performance of the catalysts were investigated in details. XRD, BET, SEM, H-2-TPR, and TPO were performed for synthesized catalysts characterization. The results showed that the variation of process factors led to significant changes in the surface properties of samples and resulted in the different catalytic performance in this reaction. With increasing the time of urea decomposition from 6 h to 24 h, urea concentration from 0.25 M to 1 M, and calcination temperature from 600 degrees C to 800 degrees C, the Ni/SiO2 center dot MgO catalyst showed a decrease in surface area and good thermal stability. In particular, the best performance sample was obtained; the one with decomposition time of 24 h, the urea concentration of 0.5 M and the catalyst calcination temperature of 700 degrees C, with the specific area of 223.8 m(2).g(-1), and the methane conversion of 67% at GHSV of 24000 mL.h(-1).g(cat)(-1) and 600 degrees C.

Automated summary

Supported Ni catalysts on magnesium silicate were synthesized via co-precipitation using urea. Factors such as urea decomposition time, concentration, calcination temperature, and surfactant type significantly influenced the surface properties and catalytic performance. Optimal performance was observed at urea decomposition time of 24 h, urea concentration of 0.5 M, and calcination temperature of 700 degrees C for the Ni/SiO2 dot MgO catalyst with good thermal stability and decreased surface area.