Revealing the Active Species for Aerobic Alcohol Oxidation by Using Uniform Supported Palladium Catalysts

Pingyu Xin; Jia Li; Yu Xiong; Xi Wu; Juncai Dong; Wenxing Chen; Yu Wang; Lin Gu; Jun Luo; Hongpan Rong; Chen Chen; Qing Peng; Dingsheng Wang; Yadong Li

doi:10.1002/anie.201801103

Revealing the Active Species for Aerobic Alcohol Oxidation by Using Uniform Supported Palladium Catalysts

Angew Chem Int Ed Engl. 2018 Apr 16;57(17):4642-4646. doi: 10.1002/anie.201801103. Epub 2018 Mar 24.

Authors

Pingyu Xin¹, Jia Li², Yu Xiong^{1

3}, Xi Wu², Juncai Dong⁴, Wenxing Chen¹, Yu Wang⁵, Lin Gu⁶, Jun Luo⁷, Hongpan Rong¹, Chen Chen¹, Qing Peng¹, Dingsheng Wang¹, Yadong Li¹

Affiliations

¹ Department of Chemistry, Tsinghua University, Beijing, 100084, China.
² Institute of Advanced Materials, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China.
³ College of Chemistry and Chemical Engineering, Central South University, Hunan, 410083, China.
⁴ Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, China.
⁵ Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai, 100049, China.
⁶ Institute of Physics, Chinese Academy of Science, Beijing, 100190, China.
⁷ Center for Electron Microscopy, Tianjin University of Technology, Tianjin, 300384, China.

PMID: 29464839
DOI: 10.1002/anie.201801103

Abstract

The active species in supported metal catalysts are elusive to identify, and large quantities of inert species can cause significant waste. Herein, using a stoichiometrically precise synthetic method, we prepare atomically dispersed palladium-cerium oxide (Pd₁ /CeO₂ ) and hexapalladium cluster-cerium oxide (Pd₆ /CeO₂ ), as confirmed by spherical-aberration-corrected transmission electron microscopy and X-ray absorption fine structure spectroscopy. For aerobic alcohol oxidation, Pd₁ /CeO₂ shows extremely high catalytic activity with a TOF of 6739 h^-1 and satisfactory selectivity (almost 100 % for benzaldehyde), while Pd₆ /CeO₂ is inactive, indicating that the true active species are single Pd atoms. Theoretical simulations reveal that the bulkier Pd₆ clusters hinder the interactions between hydroxy groups and the CeO₂ surface, thus suppressing synergy of Pd-Ce perimeter.

Keywords: aerobic oxidation; benzyl alcohol; palladium clusters; single atom catalysts; supported catalysts.

Publication types

Research Support, Non-U.S. Gov't