CO2 Hydrogenation Over Bulk and Loaded NiFe Catalysts: The Effect of Carrier

The structure and surface properties of bulk and loaded bimetallic nickel–iron (NiFe) catalysts were studied in detail by various characterization technologies, such as X-ray diffraction, scanning electron microscopy, nitrogen porosimetry, temperature-programmed reduction, and temperature-programmed desorption mass-spectrometry. We demonstrate the dependence of the catalytic activity of bulk NiFe catalysts against the Ni/Fe ratio. Based on the experimental observations, the possible mechanism of carbon dioxide (CO2) hydrogenation to methane (CH4) on the surface of the active bulk catalyst and that loaded on carbon nanotubes was proposed. The CO2 conversion and CH4 selectivity mainly depend on the nature of the carrier. Based on the example of the catalysts loaded on carbon carriers, the effect of surface morphology on the CO2 conversion and CH4 selectivity is shown. We showed the role of the initial carriers, namely, crystal structure, texture, and surface morphology, on the formation of active sites of nanocomposite NiFe catalysts based on the alumina with different porosities.