Atomically Dispersed Co and Cu on N-Doped Carbon for Reactions Involving C–H Activation
Jiahan Xie, James D. Kammert, Nicholas Kaylor, Jonathan W. Zheng, Eunjin Choi, Hien N. Pham, Xiahan Sang, Eli Stavitski, Klaus Attenkofer, Raymond R. Unocic, Abhaya K. Datye, Robert J. Davis
文献索引：10.1021/acscatal.8b00141
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摘要
Atomically dispersed Co(II) cations coordinated to nitrogen in a carbon matrix (Co-N-C) catalyze oxidative dehydrogenation of benzyl alcohol in water with a specific activity approaching that of supported Pt nanoparticles. Whereas Cu(II) cations in N-doped carbon also catalyze the reaction, they are about an order of magnitude less active compared with Co(II) cations. Results from X-ray absorption spectroscopy suggest that oxygen is also bound to N-coordinated Co(II) sites but that it can be partially removed by H2 treatments at 523–750 K. The N-coordinated Co(II) sites remained cationic in H2 up to 750 K, and these stable sites were demonstrated to be active for propane dehydrogenation. In situ characterization of Cu(II) in N-doped carbon revealed that reduction of the metal in H2 started at about 473 K, indicating a much lower thermal stability of Cu(II) in H2 relative to Co(II). The demonstrated high catalytic activity and thermal stability of Co-N-C in reducing environments suggests that this material may have broad utility in a variety of catalytic transformations.