Electron Divergence of Cu δ- and Pd δ+ in Cu 3 Pd Alloy-Based Heterojunctions Boosts Concerted C≡C Bond Binding and the Volmer Step for Alkynol Semihydrogenation.

Electrocatalytic semihydrogenation of alkynols presents a sustainable alternative to conventional thermal methodologies for the high-value production of alkenols. The design of efficient catalysts with superior catalytic and energy efficiency for semihydrogenation poses a significant challenge. Here, we present the application of an electron-divergent Cu 3 Pd alloy-based heterojunction in promoting the electrocatalytic semihydrogenation of alkynols to alkenols using water as the proton source. The tunable electron divergence of Cu δ- and Pd δ+ , modulated by rectifying contact with nitrogen-rich carbons, enables the concerted binding of active H species from the Volmer step of water dissociation and the C≡C bond of alkynols on Pd δ+ sites. Simultaneously, the pronounced electron divergence of Cu 3 Pd facilitates the universal adsorption of OH species from the Volmer step and alkynols on the Cu δ- sites. The electron-divergent dual-center substantially boosts water dissociation and inhibition of completing hydrogen evolution to give a turnover frequency of 2412 h -1 , outperforming the reported electrocatalysts' value of 7.3. Moreover, the continuous production of alkenols at industrial-related current density (-200 mA cm -2 ) over the efficient and durable Cu 3 Pd-based electrolyzer could achieve a cathodic energy efficiency of 45 mol kW·h -1 , 1.7 times the bench-marked reactors, promising great potential for sustainable industrial synthesis.