The SiO2 supported bimetallic Ni-Ru particles: A good sulfur-tolerant catalyst for methanation reaction

The long-term stabilities and the sulfur tolerances of SiO2 supported Ni and NiRu catalysts in the methanation reaction were examined. The presence of H2S molecules (10 ppm (v/v)) in the syngas led to fast deactivation of Ni/SiO2 catalyst, because the adsorption of S blocked the active sites as well as accelerated the sintering and the oxidation of Ni particles. The effect of Ru on the reduction of S adsorption over the supported Ni-based catalyst depended on its geometric instead of electronic factor. The S adsorption could only be weakened when S bound with both Ni and Ru atoms simultaneously. The formation of such state was more favorable on the polyethylene glycol (PEG)-additive method derived NiRu/SiO2 catalyst with small bimetallic Ni-Ru particles. As a result, this catalyst could stabilize for 127 h in H2S-containing methanation reaction, which was similar to 1.6-5.8-fold longer than those of PEG-free method derived NiRu/SiO2 catalyst (similar to 79 h) with separated Ru and Ni/SiO2 catalyst (similar to 22 h). (C) 2014 Elsevier B.V. All rights reserved.