Chinese Journal of Chemical Engineering ›› 2021, Vol. 29 ›› Issue (3): 126-134.doi: 10.1016/j.cjche.2020.11.016

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A first-principles study of reaction mechanism over carbon decorated oxygen-deficient TiO2 supported Pd catalyst in direct synthesis of H2O2

Zihao Yao, Jinyan Zhao, Chenxia Zhao, Shengwei Deng, Guilin Zhuang, Xing Zhong, Zhongzhe Wei, Yang Li, Shibin Wang, Jianguo Wang   

  1. Institute of Industrial Catalysis, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China
  • Received:2020-09-15 Revised:2020-11-13 Online:2021-03-28 Published:2021-05-13
  • Contact: Jianguo Wang
  • Supported by:
    The authors acknowledge the financial support from the National Natural Science Foundation of China (NSFC-21625604, 91934302, and 22008211) and Zhejiang Innovation Team (2017R5203).

Abstract: The choice of support is one of the most significant components in the direct synthesis of H2O2. Aiming to improvement of activity and selectivity of H2O2 on Pd/TiO2 surface, we systematically investigated the important elementary steps on Pd/TiO2-Vo@C, Pd/TiO2-Vo, Pd/TiO2-2Vo, Pd/TiO2, and Pd/C using the first-principles calculations. The Bader charge analysis and charge density difference of O2 adsorption elucidate the relationship between the electronic distribution and chemisorption energy. The effective barrier analysis further enables to quantitatively estimate the reactivity of H2O2 and H2O. We demonstrate unambiguously that the selectivity of H2O formation is boosted as the oxygen vacancy concentration raised. Moreover, the introduction of C into a TiO2 with appropriate oxygen vacancies can slightly reduce the effective barrier for H2O2 formation and increase the effective barrier for H2O formation leading to a higher activity and selectivity of H2O2 formation. Our finding suggests that carbon-doped oxygen vacancy TiO2 supported Pd is potential alternative catalyst compared with the Pd/TiO2.

Key words: Direct synthesis of H2O2, DFT, Supported Pd-catalysts, TiO2-support, Carbon-doped, Oxygen vacancies