Effects of metal loading and support for supported cobalt catalyst

Abstract

Several series of supported cobalt catalysts were synthesized with different loadings and supports. These catalysts were studied by in situ diffuse reflectance Fourier transformed infrared (DRIFT) spectroscopy during the CO2 hydrogenation reaction. The catalysts were also characterized by Ultraviolet visible near-infrared (UV–vis–NIR) spectroscopy and X-ray diffraction (XRD). The nature of interaction between cobalt and the support was determined by calcining the catalysts at elevated temperature and observing changes, if any, by UV–vis–NIR spectroscopy. The reduced catalysts did not possess cobalt oxide phases or cobalt-support compounds, except for the niobia supported cobalt catalyst, where cobalt niobate was readily formed. During reaction adsorbed CO and formate species were observed. The intensity and presence of the adsorbed species was dependent on the specific supported cobalt catalyst. The highest activity was observed for high loadings of cobalt supported on ceria followed by magnesia, alumina, zirconia, silica, titaina and niobia. At low loadings, however, ceria supported cobalt catalyst possessed a lower activity. Thus, the choice of the supports and the loading of the active metal are important while designing the supported cobalt catalysts.