Promoting dry reforming of methaneviabifunctional NiO/dolomite catalysts for production of hydrogen-rich syngas

Abstract

Extensive effort has been focused on the advancement of an efficient catalyst for CO2reforming of CH4to achieve optimum catalytic activity together with cost-effectiveness and high resistance to catalyst deactivation. In this study, for the first time, a new catalytic support/catalyst system of bifunctional NiO/dolomite has been synthesized by a wet impregnation method using low-cost materials, and it shows unique performance in terms of amphoteric sites and self-reduction properties. The catalysts were loaded into a continuous micro-reactor equipped with an online GC-TCD system. The reaction was carried out with a gas mixture consisting of CH4and CO2in the ratio of 1 : 1 flowing 30 ml min−1at 800 °C for 10 h. The physicochemical properties of the synthesized catalysts were determined by various methods including X-ray diffraction (XRD), N2adsorption-desorption, H2temperature-programmed reduction (H2-TPR), temperature-programmed desorption of CO2(TPD-CO2), and temperature-programmed desorption of NH3(TPD-NH3). The highest catalytic performance of the DRM reaction was shown by the 10% NiO/dolomite catalyst (CH4& CO2conversion,χCH4;χCO2∼ 98% and H2selectivity,SH2= 75%; H2/CO ∼ 1 : 1 respectively). Bifunctional properties of amphoteric sites on the catalyst and self-reduction behaviour of the NiO/dolomite catalyst improved dry reforming of the CH4process by enhancing CH4and CO2conversion without involving a catalyst reduction step, and the catalyst was constantly active for more than 10 h.