Dry (CO2) reforming of methane over zirconium promoted Ni-MgO mixed oxide catalyst: Effect of Zr addition

Abstract

Dry (CO2) reforming of methane (DRM) for syngas production has gained great attraction since it utilizes two major green house gases (CH4, CO2). However, this process is still far from commercialization due to the catalyst deactivation by coking and metal sintering. In this present work, we have prepared a series of Zr promoted Ni/MgO catalysts using Incipient wetness impregnatiom (IWI) method and applied for (DRM) reaction at temperature range of 500–800 °C. The prepared fresh and spent catalysts were fully characterized with various adsorption and spectroscopic techniques such as XRD, BET-SA, ICP-OES, H2-TPR, CO2-TPD, N2O-pulse chemisorption, SEM, TEM, TGA and O2-TPO. Reduced samples TEM analysis revealed that Zr modified catalysts possessed smaller Ni particles size and N2O-pulse chemisorption results showed that Ni dispersion is improved with Zr addition compared to Ni/MgO. In addition, CO2-TPD analysis confirmed that the basicity gradually increases with the addition of Zr and it enhances the CO2 adsorption capacity. DRM experimental results demonstrated that among all the tested catalysts Ni/3Zr/MgO exhibited remarkable activity and stable conversion with CH4 (78 %), CO2 (91 %) and H2/CO ratio (0.92) over a period of 70 h time on stream without deactivation. Further, CH4-temperature programmed surface reaction (TPSR) proved that Zr promoter significantly decreases the CH4 dissociation energy which could be due to smaller Ni particles, strong metal-support interaction and high Ni metal dispersion.