物理化学学报 >> 2023, Vol. 39 >> Issue (9): 2212057.doi: 10.3866/PKU.WHXB202212057

所属专题: 多物理场能源催化转化

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基于四硫富瓦烯的无金属共价有机框架材料用于高效电催化析氧反应

夏伟锋, 季成宇, 王锐, 裘式纶, 方千荣()   

  • 收稿日期:2022-12-30 录用日期:2023-01-31 发布日期:2023-04-03
  • 通讯作者: 方千荣 E-mail:qrfang@jlu.edu.cn

Metal-Free Tetrathiafulvalene Based Covalent Organic Framework for Efficient Oxygen Evolution Reaction

Weifeng Xia, Chengyu Ji, Rui Wang, Shilun Qiu, Qianrong Fang()   

  • Received:2022-12-30 Accepted:2023-01-31 Published:2023-04-03
  • Contact: Qianrong Fang E-mail:qrfang@jlu.edu.cn

摘要:

共价有机框架(COFs)在电催化析氧反应(OER)中的应用得到了广泛的关注。然而,大多数无金属共价有机框架(COFs)的导电性较差,不利于OER反应。四硫富瓦烯(TTF)是一种良好的电子供体,具有快速的电子转移能力,将TTF整合到共价有机框架骨架中将有助于电子的转移。在此,我们报道了一种基于四硫富瓦烯的二维无金属共价有机框架材料,JUC-630。与不含四硫富瓦烯的同类材料(Etta-Td COF)相比,JUC-630具有较低的过电位(400 mV)和塔菲尔斜率(104 mV∙dec−1)。本研究提出了合理设计功能基元的策略,这有助于大大提高COF材料的OER催化活性。

关键词: 共价有机框架, 析氧反应, 电催化, 无金属催化剂

Abstract:

Increasing global energy consumption and the depletion of traditional energy sources pose severe challenges to environmental protection and energy supply security. Electrochemical decomposition of water is a green and promising technology and is also a key technology for efficient and sustainable energy production and storage by fuel cells and metal-air batteries. The electrocatalytic oxygen evolution reaction (OER), as the anode reaction for the electrolysis of water, requires large amounts of energy owing to multielectron participation, and to the breaking of O―H bonds and formation of O―O bonds. Many precious metal catalysts are expensive, and these are responsible for secondary environmental pollution, which is detrimental for the large-scale application of the OER. Therefore, it is necessary to develop a stable, clean, and efficient electrocatalyst to improve the efficiency of the OER. The application of covalent organic frameworks (COFs) to the electrocatalytic oxygen evolution reaction (OER) has received widespread attention. However, most metal-free covalent organic frameworks (COFs) have unsuitably poor conductivity for the OER. Herein, we report a 2D metal-free tetrathiafulvalene (TTF)-based COF, termed JUC-630. To improve the conductivity of COFs, we introduced TTF, which is a good electron donor, into the COF material. At the same time, compared with its analogue without TTF (Etta-Td COF), we found that JUC-630 has a large surface area, better crystallinity, and higher stability. Furthermore, we tested their OER performance in a 1 mol∙L−1 KOH solution, and the results show that JUC-630 has a higher current density than Etta-Td COF and TTF at the same potential. For example, at a current density of 10 mA∙cm−2, the overpotential of JUC-630 was 400 mV, which was significantly lower than that of Etta-Td COF (450 mV). This overpotential is comparable to or even better than those of the widely discussed carbon and graphene materials. The lower overpotential, Tafel slope values, and smaller electrochemical impedance illustrate that the introduction of TTF monomers into the COF material results in a significantly improved OER performance for JUC-630. This study proposes a strategy for the rational design of functional motifs that can greatly improve the OER catalytic activity of COF materials. Thus, the results should help to suggest new efficient approaches for the preparation of catalysts for energy conversion from water resources.

Key words: Covalent organic frameworks, Oxygen evolution reaction, Electrocatalysis, Metal-free catalyst