An Organic Molecular Mimetic Metal‐Free Heterogeneous Catalyst for Electrocatalytic Alkyne Semihydrogenation

Abstract

The direct construction of metal‐free catalysts on conductive substrates for electrocatalytic organic hydrogenation reactions is significant but still unexplored. Here, learning from the homogeneous molecular catalysts, an organic molecular mimetic metal‐free heterogeneous catalyst is designed and constructed in situ on a graphite flake electrode via a mild electrochemical oxidation‒reduction relay strategy. The as‐prepared –COOH‐ and –OH‐functionalized metal‐free catalyst exhibits an electrocatalytic alkyne semihydrogenation performance with a 72% Faradaic efficiency, 99% selectivity and 96% yield of the alkene product, which is comparable to that of noble metal catalysts. The removal of these oxygen‐containing groups leads to negligible activity. The experimental and calculation results reveal that the origin of the high activity can be assigned to the –COOH and –OH groups on graphite. A flow electrolytic cell delivers ten grams of hydrogenated products with 81% Faradaic efficiency. This metal‐free catalyst is also suitable for gas‐phase acetylene semihydrogenation and other electrocatalytic hydrogenation reactions.