Preparation and structural characterisation of SBA-15 supported nickel catalysts via sol-gel nickel oxide coatings for dry reforming of methane

Supported nickel catalysts have been prepared by coating mesoporous silica with nickel oxide through a sol-gel coating technology, other than the conventional impregnation procedure. Sol-gel nickel oxide coatings were first synthesized using nickel nitrate and lactic acid as precursors and then, deposited on the support of mesoporous silica SBA-15. Various synthetic parameters, such as the nickel/lactic acid molar ratio for the synthesis of the sol-gel coatings and the nickel/SBA-15 ratio for the preparation of the catalysts, were investigated. Scanning electron microscopy and energy-dispersive X-ray analysis, X-ray diffraction, thermal analysis and attenuated total reflection fourier transform infrared spectroscopy were used to characterise the nickel oxide sol-gel coatings and the resulting supported catalysts. The catalytic activity was tested using the Catlab integrated system. Results showed that this sol-gel coating route produces uniform nickel oxide thin films and leads to a good distribution of the nickel oxide on the mesopore surface of SBA-15. Compared with the catalyst prepared by impregnation with nickel nitrate salt solutions, the catalysts prepared through the sol-gel coating route are superb in nickel loading and distribution. The mesostructure of the supported catalysts remain unchanged after calcinations at elevated temperatures. Moreover, their catalytic activity towards the dry reforming of methane reaction is higher at temperatures lower than 700°C.