Promoting dry reforming of methane via bifunctional NiO/dolomite catalysts for production of hydrogen-rich syngas.

Extensive effort has been focused on the advancement of an efficient catalyst for CO 2 reforming of CH 4 to 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 CH 4 and CO 2 in the ratio of 1 : 1 flowing 30 ml min -1 at 800 °C for 10 h. The physicochemical properties of the synthesized catalysts were determined by various methods including X-ray diffraction (XRD), N 2 adsorption-desorption, H 2 temperature-programmed reduction (H 2 -TPR), temperature-programmed desorption of CO 2 (TPD-CO 2 ), and temperature-programmed desorption of NH 3 (TPD-NH 3 ). The highest catalytic performance of the DRM reaction was shown by the 10% NiO/dolomite catalyst (CH 4 & CO 2 conversion, χ CH 4 ; χ CO 2 ∼ 98% and H 2 selectivity, S H 2 = 75%; H 2 /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 CH 4 process by enhancing CH 4 and CO 2 conversion without involving a catalyst reduction step, and the catalyst was constantly active for more than 10 h.