Amorphous Interface-Confined Acetylene Semireduction under Industrially Relevant Acetylene-Lean Feeds

Conventional catalysts are typically crystalline, with well-exposed active sites where competing reactions can readily occur, for example, parasitic hydrogen evolution and C–C coupling during electrochemical removal of trace acetylene from acetylene-lean streams.

Here, we create an interface-confined reaction environment for selective acetylene semireduction into ethylene by introducing an amorphous corona onto crystalline Cu catalysts using electron-withdrawing ligands. The corona, with tunable chemistry and thickness, enriches acetylene near the catalyst surface while stabilizing active sites and key intermediates, thereby regulating reaction pathways. The optimized system achieves near-unity ethylene selectivity with strongly suppressed parasitic reactions, enabling efficient acetylene removal to below 5 ppm for 310 h.