Electron Divergence of Cuδ− and Pdδ+ in Cu3Pd Alloy-Based Heterojunctions Boosts Concerted C≡C Bond Binding and the Volmer Step for Alkynol Semihydrogenation

Abstract

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 Cu₃Pd 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 Cu₃Pd 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 Cu₃Pd-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.