Ambient-condition acetylene hydrogenation to ethylene over WS2-confined atomic Pd sites

Abstract

Ambient-condition acetylene hydrogenation to ethylene (AC-AHE) is a promising process for ethylene production with minimal additional energy input, yet remains a great challenge due to the difficulty in the coactivation of acetylene and H₂ at room temperature. Herein, we report a highly efficient AC-AHE process over robust sulfur-confined atomic Pd species on tungsten sulfide surface. The catalyst exhibits over 99% acetylene conversion with a high ethylene selectivity of 70% at 25 ^oC, and a record space-time yield of ethylene of 1123 mol_C2H4 mol_Pd⁻¹ h⁻¹ under ambient conditions, which is nearly four times that of the typical Pd₁Ag₃/Al₂O₃ catalyst, and exhibiting superior stability of over 500 h. We demonstrate that the confinement of Pd-S coordination induces positively-charged atomic Pd^δ+, which not only facilitates C₂H₂ hydrogenation but also promotes C₂H₄ desorption, thereby enabling a high conversion of C₂H₂ to C₂H₄ at room temperature while suppressing over-hydrogenation to C₂H₆.