Single Atomic Cu-N2 Catalytic Sites for Highly Active and Selective Hydroxylation of Benzene to Phenol

Ting Zhang; Xiaowa Nie; Weiwei Yu; Xinwen Guo; Chunshan Song; Rui Si; Yuefeng Liu; Zhongkui Zhao

doi:10.1016/j.isci.2019.11.010

Single Atomic Cu-N₂ Catalytic Sites for Highly Active and Selective Hydroxylation of Benzene to Phenol

iScience. 2019 Dec 20:22:97-108. doi: 10.1016/j.isci.2019.11.010. Epub 2019 Nov 8.

Authors

Ting Zhang¹, Xiaowa Nie¹, Weiwei Yu¹, Xinwen Guo¹, Chunshan Song², Rui Si³, Yuefeng Liu⁴, Zhongkui Zhao⁵

Affiliations

¹ State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
² State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China; EMS Energy Institute PSU-DUT Joint Center for Energy Research and Department of Energy & Mineral Engineering and Chemical Engineering, Pennsylvania State University, University Park, PA 16802, USA.
³ Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, P. R. China. Electronic address: sirui@sinap.ac.cn.
⁴ Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China. Electronic address: yuefeng.liu@dicp.ac.cn.
⁵ State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China. Electronic address: zkzhao@dlut.edu.cn.

Abstract

Searching for an efficient single-atom catalyst for benzene hydroxylation to phenol is of critical importance, but it still remains a challenge. Herein, a single-atom catalyst with unique Cu-N₂ moieties (Cu₁-N₂/HCNS) was prepared and confirmed by HAADF-STEM and EXAFS. Turnover number (TON) over Cu₁-N₂/HCNS (6,935) is 3.4 times of Cu₁-N₃/HCNS (2,034) under the same reaction conditions, and both exhibit much higher phenol selectivity (close to 99%) and stability compared with Cu nanoparticles and nanoclusters. Experiments and DFT calculations reveal that atomically dispersed Cu species are active sites for benzene hydroxylation to phenol, and the Cu-N₂ is more active than Cu-N₃ owing to its much lower energy barrier concerning the activation of H₂O₂ led by its unique coordination state of local atomic structure. We envision that this work opens a new window for modulating coordination environments of single metallic atoms in catalysis design.

Keywords: Catalysis; Materials Synthesis; Nanomaterials.