Pd Nanoparticles Supported on N-Doped Porous Carbon Cathodes for the Catalytic Semideuteration of Alkynes

Achieving precise control over the site-selective production of deuterium-labeled alkenes under mild conditions is highly appealing. However, it is crucial to determine how to use a green chemical process and an economical deuterium source to achieve this goal. In this paper, Pd nanoparticles supported on N-doped porous carbon (Pd0.05-NC) on the cathode for the electrocatalytic semideuteration reaction of alkynes with D2O. The reaction exhibits a high selectivity of 96% and a Faradaic efficiency (FE) of 74.9% under low voltage conditions. Mechanistic studies highlight the importance of adsorption of alkynes and the activation of D2O on the Pd0.05-NC cathode surface to achieve highly selective and efficient synthesis. The capture of key deuterium and carbon radicals confirms the existence of the reactive D species addition pathway and cross-coupling of free radicals. The gram-scale synthesis of deuterated alkenes in a continuous-flow electrolyzer and the wide range of substrates highlight their promising applications.