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

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 MoS2 dispersion and increasing the density of accessible edge sites, thereby enhancing catalytic performance in the WGS reaction. Furthermore, it demonstrates that selenium modification of MoS2 further amplifies these support-induced effects. Samples were prepared by impregnation with a Mo precursor for MoS2/S-1 and with Mo and Se precursors for MoS1.75Se0.25/S-1 followed by sulfidation, yielding highly dispersed few-layer MoS2-derived domains on the silicalite-1 support. Raman spectroscopy indicates that Se incorporation promotes a mixed 1T′/2H phase compared to predominantly 2H MoS2 on silicalite-1 support. In situ H218O adsorption FTIR measurements indicate enhanced water affinity for the MoS1.75Se0.25/S-1 sample. Under continuous-flow WGS (250−450 °C), supported catalysts strongly outperform bulk analogues. The MoS1.75Se0.25/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.