Efficient Selective Oxidation of Aromatic Alkanes by Double Cobalt Active Sites over Oxygen Vacancy-rich Mesoporous Co3 O4

Yali Liu; Yuenan Zheng; Danyang Feng; Liangliang Zhang; Ling Zhang; Xiaowei Song; Zhen-An Qiao

doi:10.1002/anie.202306261

Efficient Selective Oxidation of Aromatic Alkanes by Double Cobalt Active Sites over Oxygen Vacancy-rich Mesoporous Co₃ O₄

Angew Chem Int Ed Engl. 2023 Jul 17;62(29):e202306261. doi: 10.1002/anie.202306261. Epub 2023 Jun 12.

Authors

Yali Liu^{1

2}, Yuenan Zheng^{1

3}, Danyang Feng⁴, Liangliang Zhang¹, Ling Zhang⁵, Xiaowei Song¹, Zhen-An Qiao¹

Affiliations

¹ State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin, 130012, China.
² Department of Chemical Engineering, School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan, Zhejiang, 316022, China.
³ State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, Liaoning, 116081, China.
⁴ Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education, Northeast Normal University, Jilin, 130024, China.
⁵ State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin, 130012, China.

PMID: 37222120
DOI: 10.1002/anie.202306261

Abstract

The development of efficient catalyst for selective oxidation of hydrocarbon to functional compounds remains a challenge. Herein, mesoporous Co₃ O₄ (mCo₃ O₄ -350) showed excellent catalytic activity for selective oxidation of aromatic-alkanes, especially for oxidation of ethylbenzene with a conversion of 42 % and selectivity of 90 % for acetophenone at 120 °C. Notably, mCo₃ O₄ presented a unique catalytic path of direct oxidation of aromatic-alkanes to aromatic ketones rather than the conventional stepwise oxidation to alcohols and then to ketones. Density functional theory calculations revealed that oxygen vacancies in mCo₃ O₄ activate around Co atoms, causing electronic state change from Co³⁺ _(Oh) →Co²⁺ _(Oh) . Co²⁺ _(Oh) has great attraction to ethylbenzene, and weak interaction with O₂ , which provide insufficient O₂ for gradual oxidation of phenylethanol to acetophenone. Combined with high energy barrier for forming phenylethanol, the direct oxidation path from ethylbenzene to acetophenone is kinetically favorable on mCo₃ O₄ , sharply contrasted to non-selective oxidation of ethylbenzene on commercial Co₃ O₄ .

Keywords: Heterogeneous Catalysis; Hydrocarbons Oxidation; Oxidation Route; Oxygen Vacancy.

Abstract

Grants and funding