无机材料学报

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自支撑Bi@Cu纳米树电极高效电化学还原CO2制甲酸

施桐1,2, 甘乔炜2, 刘东2, 张莹2, 冯浩2, 李强1,2   

  1. 1. 西安交通大学 能源与动力工程学院,动力工程多相流国家重点实验室,西安 710049;
    2. 南京理工大学 能源与动力工程学院,电子设备热控制工信部重点实验室,南京 210094
  • 收稿日期:2023-12-21 修回日期:2024-01-30 出版日期:2024-02-26 网络出版日期:2024-02-26
  • 作者简介:施桐(1997-), 男, 博士研究生. E-mail: shitong@stu.xjtu.edu.cn.
  • 基金资助:
    国家自然科学基金(51888103); 江苏省前沿引领技术基础重大项目(BK20232022)

Boost Electroreduction of CO2 to Formate Using a Self-supporting Bi@Cu Nanotree Electrode

SHI Tong1,2, GAN Qiaowei2, LIU Dong2, ZHANG Ying2, FENG Hao2, LI Qiang1,2   

  1. 1. State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China;
    2. MIIT Key Laboratory of Thermal Control of Electronic Equipment, School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
  • Received:2023-12-21 Revised:2024-01-30 Published:2024-02-26 Online:2024-02-26
  • About author:SHI Tong (1997-), male, PhD candidate. E-mail: shitong@stu.xjtu.edu.cn
  • Supported by:
    National Natural Science Foundation of China (51888103); Natural Science Foundation of Jiangsu Province (BK20232022)

摘要: 利用电化学方法将CO2转化为高值化学品是实现碳中和目标的一条有效途径。制备高性能电极是实现CO2高效转化的关键一环。常规喷涂法所制电极中催化层与集流体间的不良接将严重影响了电催化活性以及稳定性。为此,本研究结合电化学沉积和离子置换反应法,提出一种原位生长的Bi@Cu纳米树自支撑电极。自支撑纳米树结构在降低界面电阻、确保空间结构稳定的同时,为反应提供了丰富的活性位点和发达的孔隙结构,从而实现CO2分子、电解液离子以及电子的协同传输并进一步促进电化学CO2转化。实验结果表明,自支撑Bi@Cu纳米树电极在电化学活性和长期运行稳定性方面表现出色。在-0.8至-1.4 V (vs. RHE)的宽工作电位窗口下,甲酸选择性均超过90%。典型地,在-1.2 V的工作电位下,该电极同时实现了高达97.9%的甲酸选择性和170.6 mA‧cm-2的电流密度。此外,该电极在-1.0 V下经过50 h持续电解,获得了超90%的平均甲酸选择性及大于110 mA‧cm-2的平均电流密度,且性能未见明显衰减,稳定性优异。

关键词: 电化学还原CO2, 甲酸, 自支撑电极, 纳米树结构, 铋纳米片。

Abstract: Electrochemical reduction of CO2 into high value-added hydrocarbon fuels and chemicals has emerged as an effective strategy to achieve carbon neutrality. In conventional electrocatalytic powder-coated electrodes fabricated by spraying method, poor contact between the electrocatalyst and substrate can severely impact the electrocatalytic activity and stability. Herein, a self-supporting nanotree electrode (Bi@Cu NTs) for efficient electroreduction CO2 to formate was proposed by combing facile electrodeposition method and galvanic replacement reaction. The advantages of self-supporting nanotree structure including: 1) minimization of the interfacial resistance and improvement of the spatial structure stability; 2) rich active sites and plentiful pore structures. The charge transfer resistant could be effectively reduced while ensuring the stability of the electrode operation. The results demonstrated that the prepared self-supporting nanotree electrode exhibited outstanding performance for CO2 conversion in both electrochemical activity and long-term operation stability. In a wide operating potential window from -0.8 to -1.4 V (vs. RHE), the proposed Bi@Cu NTs electrode presented excellent formate selectivity, where the Faradaic efficiency of CO2-to-formate (FEformate) at each operating potential was above 90%. Typically, at -1.2 V, the proposed electrode achieved a high FEformate of 97.9% and a current density of 170.6 mA·cm-2, simultaneously. Meanwhile, the self-supporting Bi@Cu NTs electrode also revealed excellent stability in a long-term operation, as evidenced by maintaining an average FEformate of more than 90% and an average current density higher than 110 mA·cm-2 over 50 h of continuous electrolysis at a controlled potential of -1.0 V without any degradation in performance.

Key words: electrochemical co2 reduction, formate, self-supporting electrode, nanotree structure, bismuth nanosheet

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