Theoretical prediction of WS2-confined metal atoms for highly efficient acetylene hydrogenation to ethylene

Abstract

Precise regulation of atomic and electronic structures of two-dimensional tungsten disulfide (WS₂) is significant for rational design of high-performance and low-cost catalyst for acetylene hydrogenation to ethylene (AHE), yet remains a major challenge. Herein, we report that by substituting a W atom of WS₂ with a series of transition metal atoms, sulfur vacancy-confined Cu in the WS₂ basal plane (Cu@WS₂-Sv) is theoretically screened as a superior non-noble metal-based catalyst with higher activity, selectivity, and stability for the AHE than other candidates. The co-adsorption of C₂H₂ and H₂ and hydrogenation of C₂H₃* to C₂H₄* are revealed as the key steps establishing a volcano-like activity trend among the candidates, which present Cu@WS₂-Sv as the optimum catalyst combined with molecular dynamics and reaction kinetics analyses. The kinetically more favorable desorption of C₂H₄ than the over hydrogenation path validates a higher selectivity toward C₂H₄ over C₂H₆. Furthermore, a machine-learning model reveals the significant effect of d-electron number and electronegativity of the metal heteroatoms in modulating the AHE activity.