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Homonuclear Dual-Atom Cobalt Sites for Enhanced Selective Hydrogenation
DOI:10.1002/anie.2095526.png)
Abstract
En 中文
Single-atom catalysts based on non-noble metals have demonstrated remarkable selectivity in selective hydrogenation. However, their electron-deficient metal sites and the absence of adjacent metal sites often limit their hydrogenation activity. In this study, a homonuclear dual-atom cobalt site catalyst (Co-DAC) containing Co─Co bonds was synthesized by adsorbing a Co2-complex onto ZIF-8 through a simple impregnation–pyrolysis process. The intrinsic activity of Co-DAC in selective hydrogenation, including nitroarene hydrogenation to arylamines and alkyne semi-hydrogenation to alkenes, was then investigated. The turnover frequency of Co-DAC was 431 h−1 in nitrobenzene hydrogenation and 1665 h−1 in phenylacetylene semi-hydrogenation. These values were 6.8-fold and 17.5-fold higher than those of the single-atom catalyst, respectively. Moreover, it demonstrated broad substrate scope in these two reactions. Mechanistic studies revealed that the Co─Co dual-atomic sites enhanced the adsorption capacity for nitro groups. Simultaneously, due to the electron coupling between Co─Co atom pairs, the electron density on the Co atoms increased. This facilitated the activation of H2 and the desorption of aniline from the Co sites. Furthermore, the Co─Co sites enabled the homolytic cleavage of H2 with a lower activation energy barrier. Therefore, Co-DAC exhibited significantly improved catalytic performance in selective hydrogenation.
Keywords:
alkyne hydrogenation
dual-atom site catalysts
heterogeneous catalysis
nitroarene hydrogenation
Journal
IF:
16.9
Papers:
5.6W
Citations:
53.0W

