Robust Ni x Sn/ZSM-12 Catalysts with Zeolite as the Support and Sn as the Promoter for Acetylene Semi-hydrogenation

The synthesis of ethylene from semi-hydrogenation ofacetyleneis significant for the upgrading of coal. Different kinds of materials(SiO2, & gamma;-Al2O3, and ZSM-12)-supportedNi catalysts were prepared and evaluated for the acetylene hydrogenation.It demonstrated that the Ni/ZSM-12 catalyst with synergistic effectof B (Bro''nsted) acid and L (Lewis) acid sites can promote semi-hydrogenationof acetylene better than those over Ni/SiO2 and Ni/& gamma;-Al2O3 catalysts, in which both only have L acid sites.However, the pure Ni/ZSM-12 still exhibited low selectivity of ethyleneand poor stability; thus, the Sn promoter was introduced into theNi/ZSM-12 catalyst. Due to the geometric and electronic effects, theNi(7)Sn/ZSM-12 sample achieves higher yield of ethylene (92.51%)with ethylene selectivity of 92.51% and acetylene conversion of 100%at 250 & DEG;C, which is an increase of 19.38% over the samples withoutSn addition. Moreover, the stability of the Ni7Sn/ZSM-12catalyst (100 h) is much better than those catalysts without Sn (14h). This is because the carbon deposition over the Sn-containing catalystwas light hydrocarbons that could be removed at high temperature whilethe pure Ni/ZSM-12 catalyst produced heavy hydrocarbons. The outstandingperformance of Ni7Sn/ZSM-12 was further illustrated byDFT calculations, which originates from its facilely accessible hydrogendissociation, lower ethylene adsorption energy, and higher energybarrier for the formation of C2H5* intermediate.

Automated summary

The improvement of catalysts is crucial for the synthesis of ethylene via the semi-hydrogenation of acetylene. The Ni(7)Sn/ZSM-12 catalyst, with added Sn, exhibits enhanced activity and stability, achieving 92.51% ethylene selectivity and 100% acetylene conversion at 250°C.