Regulating Second-Shell Coordination in Cobalt Single-Atom Catalysts toward Highly Selective Hydrogenation
Yunxia Duan, Yongming Xia, Yuxuan Ling, Shijie Zhou, Xuehui Liu, Yinghui Lan, Xiong Yin, Yusen Yang, Xiaoying Yan, Minghui Liang, Song Hong, Lipeng Zhang, Leyu Wang
Abstract
Manipulating the local coordination environment of central metal atoms in single-atom catalysts (SACs) is a powerful strategy to exploit efficient SACs with optimal electronic structures for various applications. Herein, Co-SACs featured by Co single atoms with coordinating S atoms in the second shell dispersed in a nitrogen-doped carbon matrix have been developed toward the selective hydrogenation of halo-nitrobenzene. The location of the S atom in the model Co-SAC is verified through synchrotron-based X-ray absorption spectroscopy and theoretical calculations. The resultant Co-SACs containing second-coordination shell S atoms demonstrate excellent activity and outstanding durability for selective hydrogenation, superior to most precious metal-based catalysts. In situ characterizations and theoretical results verify that high activity and selectivity are attributed to the advantageous formation of the Co–O bond between p -chloronitrobenzene and Co atom at Co 1 N 4 –S moieties and the lower free energy and energy barriers of the reaction. Our findings unveil the correlation between the performance and second-shell coordination atom of SACs.