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

Abstract

Comprehensive SummaryAlkenols are important intermediates for the industrial manufacture of various commodity 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. With 2‐methyl‐3‐butyn‐2‐ol as a model alkynol, Cu3P 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, Cu3P 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 Cu3P 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 Cu3P surfaces account for the excellent electrocatalytic performance.This article is protected by copyright. All rights reserved.

Electroplated Electrodes for Continuous and Mass‐Efficient Electrochemical Hydrogenation

“…[8] As a result, e. g. Zhang et al could achieve the efficient semi-hydrogenation of a broad scope of alkynes with sulfide-derived copper catalysts. [9,10] However, only few examples of ECH protocols are known that are able to maintain high performances, particularly against the competing hydrogen evolution reaction (HER), at catalyst loadings < 0.5 mg cm À 2 , current densities > 100 mA cm À 2 or electrode areas > 10 cm 2 , especially when using non-PGM metal catalysts [9,[11][12][13] These limitations result in usually exiguous catalyst mass activities only rarely surpassing the mark of 50 g g cat À 1 h À 1 for small organic molecules. [3,11,12] However, especially for scaled-up reactors, a low total catalyst amount is highly desirable to minimize process cost.…”

Promoting Electrocatalytic Semihydrogenation of Alkynols to Alkenols over a Bimetallic CuAu Alloy Catalyst

“…Electrochemical technology has emerged as a powerful and environmentally benign approach for hydrogenation reactions. It can be ideally driven by renewable energy (e.g., wind, solar, hydro) under ambient conditions while utilizing H 2 O as the hydrogen source for hydrogenation. , For electrocatalytic semihydrogenation of alkynols, Zhang and co-workers reported semihydrogenation of 2-methyl-3-butyne-2-ol (MBY) to 2-methyl-3-butan-2-ol (MBE) over copper (Cu) nanoarrays, delivering MBE with a high FE of 95% at −0.15 V vs RHE . However, the competitive hydrogen evolution reaction (HER) at high potential results in a narrow potential window (range <100 mV) for retaining high FEs of MBE .…”