Fluorine tuning of nickel phthalocyanine electrocatalysts for stable and rapid CO 2 reduction to CO

Authors:
  • HLHuan Li
    Huan Li
  • HZHongzhi Zheng
    Hongzhi Zheng
  • YYYubo Yuan
    Yubo Yuan
  • YWYuan Wang
    Yuan Wang
  • ZJZhan Jiang
    Zhan Jiang
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Abstract
Due to their high selectivity, nickel phthalocyanine (NiPc) based molecular electrocatalysts supported on carbon nanotubes have been regarded as promising candidates for electrochemical CO2-to-CO conversion. However, it lacks effective strategies to simultaneously enhance the intrinsic activity and stability of NiPc electrocatalysts. Here, we show that fluorine tuning of NiPc can address this limitation. As a bridging study, incorporating polytetrafluoroethylene (PTFE) is shown to facilitate CO desorption near active sites, thereby enhancing electrochemical stability but reducing activity due to partial site masking. Building on this insight, β-site fluorination of NiPc affords a robust electrocatalyst (NiPc–F) with enhanced intrinsic CO2-to-CO activity and durability. Microenvironment and operando studies reveal that fluorination improves CO2 adsorption and enhances CO desorption, resulting in intact Ni–N4 coordination during electrocatalysis. The optimized NiPc-F catalyst delivers stable operation at −300 milliamperes per square centimeter for 45 hours in neutral electrolytes, with CO Faradaic efficiencies over 98 percent.

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