Journal of Energy Chemistry ›› 2023, Vol. 85 ›› Issue (10): 267-275.DOI: 10.1016/j.jechem.2023.06.024

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Self-supported ultrathin NiCo layered double hydroxides nanosheets electrode for efficient electrosynthesis of formate

Haoyuan Chia, Jianlong Lina, Siyu Kuanga, Minglu Lia, Hai Liua, Qun Fana, Tianxiang Yana, Sheng Zhanga,b, Xinbin Maa,b   

  1. aKey Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Centre of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
    bHaihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, China
  • Received:2023-04-13 Revised:2023-06-06 Accepted:2023-06-20 Online:2023-10-15 Published:2023-11-06
  • Contact: *E-mail address: sheng.zhang@tju.edu.cn (S. Zhang).

Abstract: Electrochemical CO2 reduction into energy-carrying compounds, such as formate, is of great importance for carbon neutrality, which however suffers from high electrical energy input and liquid products crossover. Herein, we fabricated self-supported ultrathin NiCo layered double hydroxides (LDHs) electrodes as anode for methanol electrooxidation to achieve a high formate production rate (5.89 mmol h-1 cm-2) coupled with CO2 electro-reduction at the cathode. A total formate faradic efficiency of both anode for methanol oxidation and cathode for CO2 reduction can reach up to 188% driven by a low cell potential of only 2.06 V at 100 mA cm-2 in membrane-electrode assembly (MEA). Physical characterizations demonstrated that Ni3+ species, formed on the electrochemical oxidation of Ni-containing hydroxide, acted as catalytically active species for the oxidation of methanol to formate. Furthermore, DFT calculations revealed that ultrathin LDHs were beneficial for the formation of Ni3+ in hydroxides and introducing oxygen vacancy in NiCo-LDH could decrease the energy barrier of the rate-determining step for methanol oxidation. This work presents a promising approach for fabricating advanced electrodes towards electrocatalytic reactions.

Key words: CO2 reduction, Methanol oxidation reaction, Formate, Layered double hydroxides, Oxygen vacancies