Acidic Electrocatalytic Semihydrogenation of Alkynols to Alkenols on Copper Phosphide at Industrial‐Level Current Density

Comprehensive Summary Alkenols are important intermediates for the industrial manufacture of various commodities and fine chemicals. At present, alkenols are produced via thermocatalytic semihydrogenation of corresponding alkynols using precious metal Pd‐based catalysts in pressurized hydrogen atmosphere. In this work, we highlight an efficient electrocatalytic strategy for selectively reducing alkynols to alkenols under ambient conditions. Using 2‐methyl‐3‐butyn‐2‐ol as a model alkynol, Cu 3 P nanoarrays anchored on Cu foam remarkably deliver an industrial‐level partial current density of 0.79 A·cm –2 and a specific selectivity of 98% for 2‐methyl‐3‐buten‐2‐ol in acidic solution. Over a 40‐runs stability test, Cu 3 P nanoarrays maintain 90% alkynol conversion and 90% alkenol selectivity. Even in a large two‐electrode flow electrolyser, the single‐pass alkynol conversion and alkenol selectivity of Cu 3 P nanoarrays exceed 90%. Moreover, this selective electrocatalytic hydrogenation approach is broadly feasible for the production of various water‐soluble alkenols. Electrochemical analyses, theoretical simulation and electrochemical in‐situ infrared investigations together reveal that exothermic alkynol hydrogenation, facile alkenol desorption and formation of active H on Cu 3 P surfaces account for the excellent electrocatalytic performance.