Internal lattice oxygen sites invert product selectivity in electrocatalytic alkyne hydrogenation over copper catalysts

Copper-based catalysts exhibit excellent performance of electrocatalytic alkynes hydrogenation, especially for the selective alkynes hydrogenation toward alkenes. However, the selective electrocatalytic alkynes hydrogenation toward alkanes is hard to achieve over copper-based catalysts because electron-rich Cu⁰ sites are unable to adsorb and activate nucleophilic alkenes. Herein, we report a metallic copper catalyst containing internal lattice oxygen atoms for steering the selectivity of alkynes hydrogenation toward alkanes. Internal lattice oxygen atoms protect Cu^δ+ sites from being reduced during electrocatalytic alkynes hydrogenation so that alkenes intermediates can continually be adsorbed and converted to alkanes on stable Cu^δ+ sites. Due to the synergy between Cu⁰ and Cu^δ+ sites, metallic copper electrocatalyst containing internal lattice oxygen atoms shows an excellent selectivity for selective alkynes hydrogenation toward alkanes (2-methyl-3-butan-2-ol selectivity of 94.9%). This work opens a avenue for steering the selective alkynes hydrogenation, and more importantly, it fills in a gap on the selective electrocatalytic alkynes hydrogenation toward alkanes over copper-based catalysts.