p‐Block Antimony Single‐Atom Tuned Copper Sites for Boosting Electrocatalytic Semi‐Hydrogenation of 2‐methyl‐3‐butyn‐2‐ol

ABSTRACT Electrocatalytic semi‐hydrogenation of alkynes using water as the proton source at mild conditions is a highly attractive alternative to conventional methods, yet remains challenged by the competition of hydrogen evolution and over‐hydrogenation. Herein, we report an antimony‐copper single‐atom alloy nanowires (Sb 1 Cu NWs) as a robust and highly efficient electrocatalyst for selective electrosynthesis of 2‐methyl‐3‐buten‐2‐ol (MBE) via the semi‐hydrogenation reaction of 2‐methyl‐3‐butyn‐2‐ol (MBY) in H 2 O. The Sb 1 Cu NWs set a new record, achieving an MBE production rate of 1749.6 µmol cm −2 h −1 and a Faraday efficiency (FE) of 98%. Moreover, they maintain an FE above 80% across a broad potential window, outperforming previously reported catalysts. In situ electrochemical studies combined with theory calculations reveal that Sb single atoms can not only hamper the competing hydrogen evolution reaction by reconstructing a connected hydrogen‐bond network but also optimize the adsorption/desorption energetics of intermediates on Cu sites, thereby accelerating the conversion of MBY to MBE. Finally, a coupled system was designed to simultaneously realize the electrochemical semi‐hydrogenation of MBY and the oxidation of polyethylene terephthalate to produce MBE and formic acid, showing a lower potential at the same current density than that of coupled with anodic oxygen evolution, in an economical manner.