Selectivity

Physics

Electrode

Organic chemistry

Combinatorial chemistry

Reagent

Gibbs free energy

Adsorption

Faraday efficiency

Catalysis

Electrolysis

Physical chemistry

Inorganic chemistry

Alkene

Chemistry

Alkyne

Sulfur

Electrolyte

Electrochemistry

Thermodynamics

Science Advances

Efficient electrocatalytic alkyne semihydrogenation with potential/time-independent selectivity and Faradaic efficiency (FE) is vital for industrial alkene productions. Here, sulfur-tuned effects and field-induced reagent concentration are proposed to promote electrocatalytic alkyne semihydrogenation. Density functional theory calculations reveal that bulk sulfur anions intrinsically weaken alkene adsorption, and surface thiolates lower the activation energy of water and the Gibbs free energy for H* formation. The finite element method shows high-curvature structured catalyst concentrates K+ by enhancing electric field at the tips, accelerating more H* formation from water electrolysis via sulfur anion-hydrated cation networks, and promoting alkyne transformations. So, self-supported Pd nanotips with sulfur modifiers are developed for electrochemical alkyne semihydrogenation with up to 97% conversion yield, 96% selectivity, 75% FE, and a reaction rate of 465.6 mmol m-2 hour-1. Wide potential window and time irrelevance for high alkene selectivity, good universality, and easy access to deuterated alkenes highlight the promising potential.

Field-induced reagent concentration and sulfur adsorption enable efficient electrocatalytic semihydrogenation of alkynes