New insight and countermeasure for sulfur poisoning on nickel-based catalysts during dry reforming of methane

Dry reforming of methane (DRM) is the method to convert two greenhouse gases to synthesis gas. The nickel-based catalysts used in the DRM are extremely easily poisoned by H2S in the feed gas, however, the associated poisoning process is not clear. In this work, a mechanism for poisoning the Ni/Al2O3 catalyst by elemental sulfur migration was proposed, and silica was added to the catalyst to prolong the sulfur tolerance of the catalyst. From the characterizations of the catalyst with different methods, it was noted that the main factor accelerating catalyst poisoning was the formation and migration of elemental sulfur. The catalyst Ni/Al2O3 with 1.0 % SiO2 exhibited improved sulfur tolerance. The addition of SiO2 inhibits the growth of Ni particles during the reduction process, and the smaller Ni particles lead to less coke and a longer period of sulfur tolerance.