Fully exposed cobalt nanoclusters anchored on nitrogen-doped carbon synthesized by a host-guest strategy for semi-hydrogenation of phenylacetylene

Abstract

Atomically dispersed nanocluster catalysts with fully available metal active sites can maximize atom utilization efficiency and deliver unique catalytic performance relative to nanoparticle and single-atom counterparts. Herein, we report a host–guest strategy by synergizing metal-support interaction and spatial confinement effect to access fully exposed cobalt nanoclusters over nitrogen-doped carbon as a highly active, selective, and reusable catalyst (Co loading of 1.6 wt%) for semi-hydrogenation of phenylacetylene. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and CO-absorbed diffuse reflectance infrared Fourier transform spectroscopy collectively confirm the cobalt nanoclusters were loosely bonded and randomly dispersed over the nitrogen-doped carbon support. This catalyst, with a full metal availability to the reactants, shows an exceptional catalytic activity (turnover frequency of 3132 h−1) and selectivity (92%) in the semi-hydrogenation of phenylacetylene (1 atm H2@60 °C), superior to most of the previously reported catalysts. In addition, this catalyst exhibits a wide substrate scope and broad functional-group tolerance. This work may provide an avenue for the design and facile synthesis of fully exposed metal catalysts with high activity.