Meng He

Electrocatalytic hydrogenation offers a promising route to value‐added chemicals, yet mass transport limitations at industrial current densities remain a critical challenge. Here, we introduce a cyclodextrin‐regulated interfacial microenvironment that delivers a Faradaic efficiency (FE) of up to 88% for pyrazine hydrogenation at −100 mA cm ⁻² . The hydroxyl‐rich outer surface disrupts the ordered hydrogen‐bond network by inhibiting the reorientation of interfacial H ₂ O, facilitating the migration of the reactant to the electrode surface. Simultaneously, the hydrophobic cavities selectively recognize and bind substrates via host–guest interactions, creating oriented shuttle channel that lowers the transfer energy barrier and accelerates mass transport kinetics. This strategy can be extended to diverse hydrogenation reactions and to other deuteration reactions with improved FE at −100 mA cm ⁻² . Moreover, the synthesis of deuterated piperazines and their conversion into deuterium‐labeled drugs highlights their practical potential. This work provides a general interfacial engineering strategy to overcome mass transport bottlenecks in electrosynthesis, with broad implications for the production of high‐value chemicals and isotopically labeled compounds.

Electrocatalytic hydrogenation offers a promising route to value‐added chemicals, yet mass transport limitations at industrial current densities remain a critical challenge. Here, we introduce a cyclodextrin‐regulated interfacial microenvironment that delivers a Faradaic efficiency (FE) of up to 88% for pyrazine hydrogenation at −100 mA cm ⁻² . The hydroxyl‐rich outer surface disrupts the ordered hydrogen‐bond network by inhibiting the reorientation of interfacial H ₂ O, facilitating the migration of the reactant to the electrode surface. Simultaneously, the hydrophobic cavities selectively recognize and bind substrates via host–guest interactions, creating oriented shuttle channel that lowers the transfer energy barrier and accelerates mass transport kinetics. This strategy can be extended to diverse hydrogenation reactions and to other deuteration reactions with improved FE at −100 mA cm ⁻² . Moreover, the synthesis of deuterated piperazines and their conversion into deuterium‐labeled drugs highlights their practical potential. This work provides a general interfacial engineering strategy to overcome mass transport bottlenecks in electrosynthesis, with broad implications for the production of high‐value chemicals and isotopically labeled compounds.

Electrocatalytic deuteron-dechlorination of trichloroacetic acid (TCAA) in D₂O provides a green route to synthesize commercial acetic-d₃ acid-d (AA-d₄). Synthesizing AA-d₄ with a high Faradaic efficiency (FE) and reaction rate is highly challenging because of the difficult C−Cl bond deuteration of the 2-monochloroacetic-2,2-d₂ acid-d (MCAA-d₃) intermediate. Here, a quaternary ammonium salt surfactant-modified low-coordination copper electrocatalyst is designed, achieving TCAA-to-AA-d₄ with a 91% selectivity, 91% FE and 0.59 mmol h⁻¹ reaction rate at −100 mA cm⁻². Mechanistic and kinetic studies reveal that the surfactant enhances the adsorption of MCAA-d₃ through electrostatic forces and increases the electron deficiency of Cu^δ+ sites, which accelerates electron transfer and promotes C−Cl bond activation, increasing the AA-d₄ selectivity. Surfactant-induced low D₂O coverage suppresses D₂ formation, improving the FE. AA-d₄ electrosynthesis (1.84 g) with a 30 mmol h⁻¹ reaction rate and 65% FE at 600 mA cm⁻² and deuterated drug applications demonstrate promising potential.

The semi-hydrogenation of alkynes to alkenes, especially acetylene to ethylene, is an essential transformation that delivers raw materials and scaffolds for synthetic industries. Electrocatalytic hydrogenation, which is green and mild, provides an alternative strategy to the conventional hydrogenation process, which relies on high temperature, high pressure and flammable H₂. This protocol describes an electrocatalytic semi-hydrogenation method to synthesize olefins with water as the hydrogen source under ambient temperature and pressure. Electrocatalytic semi-hydrogenation involves the adsorption and activation of alkynes and the cathodic generation of the active hydrogen (H*) intermediate from water dissociation, followed by the addition of H* to an adsorbed alkyne to yield an alkene. This process is generally assisted by Cu-based electrocatalysts (sulfur-modified Cu and Cu nanoparticles) and commercially available reaction vessels and is performed under a direct-current or constant potential power supply. Here we provide detailed procedures for catalyst design synthesis, alkene electrosynthesis and electrochemical in situ/ex situ spectroscopies for investigating reaction mechanisms. The semi-hydrogenation procedure can be performed within hours; it can also be flexibly adapted to synthetic procedures performed in batch or flow reactors and for various reaction times to meet the adjustable capacity requirements for fine or bulk chemicals. Compared with conventional approaches, the electrocatalytic semi-hydrogenation method eliminates the need for expensive and toxic hydrogenation reagents and conditions with elevated temperature and pressure. Our electrocatalytic semi-hydrogenation strategy has various advantages as a sustainable and alternative method to existing methods, including high alkene selectivity, operational simplicity, substrate universality and easily reproducible functional group compatibility.

The electrochemical hydrogenolysis of nitromethane in water could provide a sustainable route for accessing methylamine, one of the simplest alkyl amines and most commonly used bulk chemicals. However, present efforts achieve only methylamine selectivities below 10% due to the ineffective N–O bond activation of the N-methylhydroxylamine intermediate. Here we design a copper electrocatalyst with abundant low-coordination sites to enable the conversion of nitromethane to methylamine with 99% selectivity and 97% Faradaic efficiency at a low potential. The low-coordination copper sites induce a large dipole moment upon N-methylhydroxylamine adsorption to promote N‒O hydrogenolysis. Altering the pH changes the rate-determining step, resulting in a pH-dependent volcano trend for methylamine production. We demonstrate ampere-level production of 1.5 mol of methylamine alongside easy product purification, gram-scale synthesis of deuterated methylamine and drugs, and hydrogenolysis of other N‒O bonds. This work offers a promising, general approach to alkyl N–O bond hydrogenolysis that could compete with traditional thermochemical routines.

Electrochemical deuteration utilizing D₂O is a promising room-temperature strategy for synthesizing deuterated molecules. At present, high Faradic efficiencies (FEs) at high reaction rates are extraordinarily significant but highly challenged. Here, high-curvature low-coordinated copper nanotips (LC-Cu NTs) are designed to enable electroreductive deuteration of α-deuterio aryl acetonitriles, in situ generated from fast α-H/D exchange of acetonitriles in D₂O, to α,β-deuterio arylethyl primary amines with 90% FE and 0.11 mmol h^-1 cm^-2, greatly outperforming the reported data and other Cu counterparts. The increased electric fields of the nanotips concentrate nitriles and K⁺(D₂O)_n, and low-coordination sites promote nitriles and D₂O adsorption, thus facilitating nitrile deuteration with an excellent reaction rate. The higher coupling energy barrier of active hydrogen atoms at low-coordination sites restricts the D₂ evolution, accounting for the outstanding FE. The wide substrate scope, easy gram-scale synthesis, and facile preparation of d₄-melatonin with enhanced antitumor and antioxidation effects highlight its great promise. Furthermore, the application of LC-Cu NTs in other deuteration reactions with improved reaction rates and FEs rationalizes the design concept.