Mesoporous Cu Nanoplates with Exposed Cu⁺ Sites for Efficient Electrocatalytic Transfer Semi-Hydrogenation of Alkynes

Electrocatalytic transfer alkyne semi-hydrogenation with H₂O as hydrogen source is industrially promising for selective electrosynthesis of high value-added alkenes while inhibiting byproduct alkanes. Although great achievements, their development has remarkably restricted by designing atomically sophisticated electrocatalysts. Here, we reported single-crystalline mesoporous copper nanoplates (meso-Cu PLs) as a robust yet highly efficient electrocatalyst for selective alkene electrosynthesis from transfer semi-hydrogenation reaction of alkyne in H₂O. Anisotropic meso-Cu PLs were prepared through a facile epitaxial growth strategy with functional C₂₂H₄₅N(CH₃)₂-C₃H₆-SH as concurrent mesopore-forming and structure-controlled surfactant. Different to nonporous Cu counterparts with flat surface, meso-Cu PLs with spherical mesopores exposed abundant Cu⁺ sites, which not only stabilized active H* radicals from electrocatalytic H₂O splitting without coupling into molecular H₂ but also accelerated kinetically the desorption of semi-hydrogenated alkenes. With 4-aminophenylacetylene (4-AP) as the substrate, anisotropic meso-Cu PLs delivered superior electrocatalytic transfer semi-hydrogenation performance with up to 99 % of 4-aminostyrene selectivity and 100 % of 4-AP conversion as well as good cycle stability. Meanwhile, meso-Cu PLs were electrocatalytically applicable for transfer semi-hydrogenation of various alkynes. This work thus paved an alternative paradigm for designing robust mesoporous metal electrocatalysts with structurally functional metal sites applied in the selective electrosynthesis of industrially value-added chemicals in H₂O.