Cysteamine-modified Pd sites in covalent organic framework for efficient electrocatalytic semi-hydrogenation of terminal alkynes

Abstract

Achieving selective alkyne hydrogenation under mild conditions is highly appealing. In this work, cysteamine-modified Pd-based COF (denoted as Pd-TpBpy/Cys COF) was prepared and used as a heterogeneous redox mediator for electrocatalytic semi-hydrogenation of terminal alkynes with H₂O as a sustainable hydrogen source. Notably, Pd-TpBpy/Cys COF could enable the reaction to proceed at a more positive potential and enhance catalytic selectivity, which was superior to that of the unmodified Pd-based COF. Mechanistic investigation indicated that the in-situ generated H* by H₂O electrolysis was the key point and the semi-hydrogenation reaction might proceed through a H*_ads addition pathway. In addition, good recycles showed their promising applications.