物理化学学报 >> 2019, Vol. 35 >> Issue (12): 1404-1411.doi: 10.3866/PKU.WHXB201905030

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泡沫铜基底原位生长的铜基导电金属有机框架作为双功能电催化剂

张楚风,陈哲伟,连跃彬,陈宇杰,李沁,顾银冬,陆永涛,邓昭,彭扬*()   

  • 收稿日期:2019-05-06 录用日期:2019-06-04 发布日期:2019-06-10
  • 通讯作者: 彭扬 E-mail:ypeng@suda.edu.cn
  • 基金资助:
    国家自然科学基金(21701118);国家自然科学基金(21805201);江苏省自然科学基金(BK20161209);江苏省自然科学基金(BK20160323);江苏省自然科学基金(BK20170341);中国博士后科学基金(2017M611899);中国博士后科学基金(2018T110544);苏州市产业技术创新专项(前瞻性应用研究)(SYG201748)

Copper-based Conductive Metal Organic Framework In-situ Grown on Copper Foam as a Bifunctional Electrocatalyst

Chufeng ZHANG,Zhewei CHEN,Yuebin LIAN,Yujie CHEN,Qin LI,Yindong GU,Yongtao LU,Zhao DENG,Yang PENG*()   

  • Received:2019-05-06 Accepted:2019-06-04 Published:2019-06-10
  • Contact: Yang PENG E-mail:ypeng@suda.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21701118);The project was supported by the National Natural Science Foundation of China(21805201);the Natural Science Foundation of Jiangsu Province, China(BK20161209);the Natural Science Foundation of Jiangsu Province, China(BK20160323);the Natural Science Foundation of Jiangsu Province, China(BK20170341);the Postdoctoral Science Foundation of China(2017M611899);the Postdoctoral Science Foundation of China(2018T110544);the Key Technology Initiative of Suzhou Municipal Science and Technology Bureau, China(SYG201748)

摘要:

以泡沫铜为基底生长氢氧化铜纳米线,通过原位转化合成二维导电金属有机框架(MOF)材料Cu3HITP2 (HITP = 2, 3, 6, 7, 10, 11-六氨基三亚苯)作为双功能催化剂,可直接用作析氧及氧还原反应的工作电极,而无需使用额外的基底或粘合剂,且无需后续热处理。研究发现以氢氧化铜纳米线为模板的Cu3HITP2表现出了更大的电化学比表面积,这种新型的电极可在碱性溶液(0.1和1.0 mol·L-1 KOH)中可以稳定运行,析氧反应中在电流密度达到10 mA·cm-2时的过电位仅为1.53 V,超越了商业二氧化钌的催化性能。此外,该催化剂在氧还原反应中的半波电位达到0.75 V,优于大多数MOF材料。

关键词: 二维导电MOF, 析氧反应, 氧还原反应, 原位转化

Abstract:

With the increasing energy demands for electronic equipment, numerous studies have been conducted to achieve higher energy conversion and develop storage devices such as metal-air batteries, water splitting devices, and fuel cells. All these devices are related to the oxygen evolution reaction (OER) and/or oxygen reduction reaction (ORR). Currently, platinum group metals (PGMs) or their oxides are the most active electrocatalysts for OER and ORR. However, the high cost and scarcity of these noble metals hinder their widespread application. Therefore, the development of a low-cost electrocatalyst that exhibits catalytic performance comparable to or better than that of PGMs is essential.

Metal-organic frameworks (MOFs) are a new class of porous materials constructed from metal ions and organic linkers. MOF materials have diverse metal centers. In addition, organic ligands containing various heteroatoms can change the microenvironment of these metal centers. Moreover, the size, morphology, and porosity of MOF materials can be precisely tuned. These advantages of MOF are beneficial for electrocatalytic reactions. However, MOF is generally considered to be a poor electrocatalyst and is rarely used in the field of electrocatalysis because of its low electrical conductivity. To increase the electrical conductivity of MOF, high-temperature calcination or hybridization with conductive supports is necessary. However, high-temperature calcination may sacrifice the intrinsic molecular metal active sites of MOFs, whereas hybridization with conductive supports may block their inherent micropores. The development of MOF materials with high electrical conductivity is vital for electrocatalysis.

Herein, we report a two-dimensional conductive MOF based on copper foam growth (Cu3HITP2/CF, where HITP = 2, 3, 6, 7, 10, 11-hexaaminotriphenylene hexahydrochloride, CF = copper foam), which has high electrical conductivity and excellent catalytic stability and can be used as a bi-functional electrocatalyst in OER and ORR. In addition, this catalyst does not require heat treatment or the addition of a conductive agent. We first electroplated needle-shaped Cu(OH)2 nanowires onto the surface of a blank copper foam, and then immersed it in a solution of HITP to convert it into Cu3HITP2 at 65 ℃. To confirm its physicochemical properties, the as-synthesized Cu3HITP2/CF was characterized and analyzed by X-ray diffraction, infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The morphology was characterized by scanning and transmission electron microscopy. The as-synthesized Cu3HITP2/CF maintained a two-dimensional needle-like morphology during the reaction and could be stably operated in an alkaline solution. The overpotential at 10 mA·cm-2 in the OER was only 1.53 V, and the current density did not decrease significantly after 24 h. The Faraday efficiency was as high as 96.84%, and only 1.57% of the by-product H2O2 was produced. In addition, during the ORR, the half-wave potential of Cu3HITP2/CF reached 0.75 V and its activity did not decrease significantly after 2000 cycles of voltammetric scanning. Moreover, its electron transfer number was 3.85, with 5.7% H2O2 generation. Comparative experiments with powder Cu3HITP2 showed that Cu3HITP2 grown on copper foam had a larger electrochemical specific surface area and exhibited superior OER and ORR properties, which was due to its two-dimensional needle-like morphology. In general, this study not only provides a method for in-situ growth of MOF materials on copper foam but also provides new ideas for developing two-dimensional conductive MOF materials in the field of electrocatalysis.

Key words: 2D conductive MOF, Oxygen evolution reaction, Oxygen reduction reaction, In-situ conversion

MSC2000: 

  • O646