Enhancing\nElectrocatalytic Semihydrogenation of Alkynes\nvia Weakening Alkene Adsorption over Electron-Depleted Cu Nanowires

Electrochemical semihydrogenation (ESH) of alkynes to\nalkenes is\nan appealing technique for producing pharmaceutical precursors and\npolymer monomers, while also preventing catalyst poisoning by alkyne\nimpurities. Cu is recognized as a cost-effective and highly selective\ncatalyst for ESH, whereas its activity is somewhat limited. Here,\nfrom a mechanistic standpoint, we hypothesize that electron-deficient\nCu can enhance ESH activity by promoting the rate-determining step\nof alkene desorption. We test this hypothesis by utilizing Cu–Ag\nhybrids as electrocatalysts, developed through a welding process of\nAg nanoparticles with Cu nanowires. Our findings reveal that these\nrationally engineered Cu–Ag hybrids exhibit a notable enhancement\n(2–4 times greater) in alkyne conversion rates compared to\nisolated Ag NPs or Cu NWs, while maintaining over 99% selectivity\nfor alkene products. Through a combination of operando and computational\nstudies, we verify that the electron-depleted Cu sites, resulting\nfrom electron transfer between Ag nanoparticles and Cu nanowires,\neffectively weaken the adsorption of alkenes, thereby substantially\nboosting ESH activity. This work not only provides mechanistic insights\ninto ESH but also stimulates compelling strategies involving hybridizing\ndistinct metals to optimize ESH activity.