Chinese Journal of Catalysis ›› 2024, Vol. 57: 68-79.DOI: 10.1016/S1872-2067(23)64585-1

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Integration of theory prediction and experimental electrooxidation of glycerol on NiCo2O4 nanosheets

Yan Duana,c,1, Mifeng Xueb,1, Bin Liua, Man Zhanga, Yuchen Wanga, Baojun Wangb, Riguang Zhangb,*(), Kai Yana,*()   

  1. aGuangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
    bState Key Laboratory of Clean and Efficient Coal Utilization, College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
    cSchool of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China
  • Received:2023-11-01 Accepted:2023-12-20 Online:2024-02-18 Published:2024-02-10
  • Contact: * E-mail: zhangriguang@tyut.edu.cn (R. Zhang), yank9@mail.sysu.edu.cn (K. Yan).
  • About author:1 Contributed to this work equally.
  • Supported by:
    National Key R&D Program of China(2023YFC3905804);Scientific and Technological Planning Project of Guangzhou(202206010145);National Natural Science Foundation of China(22078374);National Natural Science Foundation of China(22378434);Science and Technology Planning Project of Guangdong Province, China(2021B1212040008);Guangdong Laboratory for Lingnan Modern Agriculture Project(NT2021010)

Abstract:

Electrocatalytic refinery of low-value biomass-based glycerol into value-added chemicals formic acid (FA) is an attractive alternative to traditional thermochemical refineries. However, constructing non-precious catalysts with abundant active hydroxyl (OH*) is the main obstacle to the electrocatalytic glycerol oxidation reaction (EGOR). Herein, we combine density functional theory (DFT) and experiments to investigate EGOR over the finely constructed NiCo2O4 nanosheets. DFT results firstly indicate that the NiCo2O4 nanosheets exhibit the highly hydroxylated (311)-OH* surface with the lowest Gibbs free energy, which significantly improves the electrochemical reaction kinetics and can achieve desirable FA yield by adjusting the adsorption energy of the adsorption intermediate. Following the theoretical prediction, ultrathin NiCo2O4 nanosheets (~1.70 nm) are fabricated by a facile electrodeposition method with sufficient OH* on the surface. The charge-transfer resistance of NiCo2O4 nanosheets in EGOR is only 0.94 Ω and the anode power consumption can be reduced by up to 320 mV at 10 mA cm-2, keeping the high glycerol conversion (89%) and FA selectivity (70%) during the 120-h stability test. DFT calculations and experimental tools (e.g., multi-potential step experiments, operational electrochemical impedance spectroscopy) confirm that OH* in-situ generated on the thin nanosheets structure is essential in facilitating charge transfer between catalysts and adsorbed molecules to enhance C-C bond cleavage. This work offers a guideline for the rational design of robust catalysts for the selective upgrading of biomass-derived chemicals.

Key words: Density functional theory prediction, active hydroxyl, Electrochemical oxidation, Glycerol, NiCo2O4 nanosheets