Selenium-Modified MoS 2 Supported on Silicalite-1 for Water Gas Shift Catalysis

Résumé fourni par la source

Molybdenum disulfide is a sulfur-tolerant candidate for the water gas shift (WGS) reaction, but its performance is often limited by insufficient exposure and stability of edge sites. This study explores the role of silicalite-1 (S-1), an inert, purely siliceous MFI zeolite, in promoting MoS 2 dispersion and increasing the density of accessible edge sites, thereby enhancing catalytic performance in the WGS reaction. Furthermore, it demonstrates that selenium modification of MoS 2 further amplifies these support-induced effects. Samples were prepared by impregnation with a Mo precursor for MoS 2 /S-1 and with Mo and Se precursors for MoS 1.75 Se 0.25 /S-1 followed by sulfidation, yielding highly dispersed few-layer MoS 2 -derived domains on the silicalite-1 support. Raman spectroscopy indicates that Se incorporation promotes a mixed 1T′/2H phase compared to predominantly 2H MoS 2 on silicalite-1 support. In situ H 2 18 O adsorption FTIR measurements indicate enhanced water affinity for the MoS 1.75 Se 0.25 /S-1 sample. Under continuous-flow WGS (250−450 °C), supported catalysts strongly outperform bulk analogues. The MoS 1.75 Se 0.25 /S-1 sample exhibited the highest cumulative amount of CO converted of 54, 98, and 143 mmol g −1 after 12 h on stream at 250, 350, and 450 °C, respectively, highlighting the beneficial combination of zeolite-enabled dispersion and Se-driven electronic/phase modification under WGS conditions.

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