Electrocatalytic Hydrogenation of Alkynes

Electrocatalytic hydrogenation of alkynes has emerged as a sustainable route to convert carbon–carbon triple bonds into alkenes under ambient conditions. By harnessing protons and electrons from water electrolysis, this approach circumvents the need for high-pressure hydrogen gas and reduces energy consumption. Advances in catalyst design—spanning nanoscale copper, palladium alloys and earth-abundant metal chalcogenides—have focused on optimising the adsorption of alkynes and hydrogen intermediates, suppressing competing hydrogen evolution and directing semihydrogenation towards alkenes with high selectivity. The development of structured electrodes, alloy compositions and local environment engineering has enabled significant improvements in Faradaic efficiency, current density and stereoselectivity. Such progress underpins applications in polymer-grade ethylene production, alkenol manufacture and selective synthesis of functionalised Z-alkenes, illustrating the global relevance of this technology for cleaner chemical manufacturing.

Research from Nature Portfolio

Recent studies have demonstrated that hierarchically nanoporous copper–gold alloys achieve quantitative semihydrogenation of terminal alkynes with complete alkene selectivity and Faradaic efficiencies exceeding 90% over a wide potential window. In situ spectroscopy and theoretical modelling reveal that gold tuning of copper’s electronic structure inhibits hydrogen evolution, weakens alkene binding and, in conjunction with the nanopore-induced electric field, enriches cation concentration to accelerate proton transfer. Complementary work shows that concave-surface carbon-supported copper electrodes enrich acetylene locally, enabling direct conversion of low-grade acetylene streams into polymer-grade ethylene with over 90% Faradaic efficiency at industrially relevant current densities. In addition, electrocatalytic semihydrogenation of alkynols using electrochemically derived copper nanoarrays under ambient conditions yields alkenols at continuous rates exceeding 150 g g⁻¹ h⁻¹ with selectivities above 95%, highlighting adaptability to diverse alkynic substrates.

Electrocatalytic Hydrogenation of Alkynes publication trend

The graph below shows the total number of articles in electrocatalytic hydrogenation of alkynes across all publications each year (not limited to Nature Index journals).

Technical terms

Faradaic efficiency: Proportion of electrical charge that drives the intended electrochemical conversion, expressed as a percentage of total charge passed.

Semihydrogenation: Selective addition of one equivalent of hydrogen to an alkyne, yielding an alkene without further reduction to an alkane.

Overpotential: Excess potential beyond the thermodynamic requirement needed to sustain an electrochemical reaction at a given current density.

Zero-gap electrolyser: Cell design minimising distance between electrodes and membrane to reduce electrical resistance and support high current densities.

Nanoporous architecture: Catalyst structure featuring interconnected pores at the nanometre scale to enhance surface area, mass transport and local electric fields.

References

1. Alloying and confinement effects on hierarchically nanoporous CuAu for efficient electrocatalytic semi-hydrogenation of terminal alkynes. Nature Communications (2024).
2. Ethylene electrosynthesis from low-concentrated acetylene via concave-surface enriched reactant and improved mass transfer. Nature Communications (2024).
3. Highly selective electrocatalytic alkynol semi-hydrogenation for continuous production of alkenols. Nature Communications (2023).
4. Electrochemical Proton Reduction over Nickel Foam for Z‐Stereoselective Semihydrogenation/deuteration of Functionalized Alkynes. ChemSusChem (2021).
5. Opening the pathway towards a scalable electrochemical semi-hydrogenation of alkynols via earth-abundant metal chalcogenides. Chemical Science (2022).