Graphene Encapsulated Ni@N/C Catalyst for Highly Selec- tive Semi-hydrogenation of Terminal Alkynes

Abstract

Although precious transition metals such as palladium, platinum, and iridium have been widely used in hydro- genation reactions, the earth-abundant transition metal-catalyzed highly selective semi-hydrogenation of alkynes, especially terminal alkynes to terminal alkenes remains challenging and poor developed. We demonstrate herein that excellent selective, cost-effective semi-hydrogenation of terminal alkynes can be realized via novel none precious graphene encapsulated Ni@N/C catalyst. The precise regulation of the graphene layer for the encapsulated nano-catalyst Ni@N/C can avoid metal leaching and increase catalytic stability significantly. Nitrogen has strong interaction with Ni nanoparticles, which regulate the activity of Ni towards selective semi-hydrogenation of terminal alkynes. The substrate having un-functionalized as well as functionalized substituents, challenging hydrogenation sensitive functional groups (olefins, ketones), were semi-hydrogenated with excellent conversion (up to 99%) and selectivity (up to 99%).