Promoting Effect of CeO2and MgO for CO2Reforming of Methane over Ni-ZnO Catalyst

Abstract

The purpose of this study was to find out the effect of CeO2 and MgO (as a promoter) on CO2 reforming of methane or dry reforming of methane (DRM) for the production of synthesis gas. In this aspect, CeO2 and MgO promoted Ni-nanoparticles supported ZnO catalyst was prepared by surfactant induced hydrothermal method, using cetyltrimethylammonium bromide (CTAB) as surfactant, morphology controlling agent and polyvinylpyrrolidone (PVP) as size controlling agent. The prepared catalysts were characterized by BET-Surface area, X-ray diffraction study (XRD), Scanning Electron Microscropy (SEM), Transmission Electron Microscopy (SEM), Inductively coupled plasma atomic emission spectroscopy (ICPAES), Temperature Programmed Reduction (TPR), X-ray Photoelectron Spectroscopy (XPS) and Thermogravimetric Analysis (TGA) techniques. Highly basic nature of MgO and excellent redox properties of CeO2 increased nickel dispersion and created strong metal-support interaction, which effectively reduced the coke deposition on the catalyst surface. MgO promoted Ni-ZnO catalyst showed better low temperature activity compared to CeO2 promoted Ni-ZnO catalyst for DRM and Ni-MgO/ZnO catalyst also exhibited better coke resistivity, because of comparatively smaller nickel nanoparticles. Both the promoted catalysts showed more than 24 h of time on stream (TOS) stability at 800 °C without any significant deactivation of the catalysts. The catalysts produced H2/CO ratio 0.99 at 800 °C during the TOS.