物理化学学报 >> 2021, Vol. 37 >> Issue (9): 2008017.doi: 10.3866/PKU.WHXB202008017

所属专题: 燃料电池

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金属卟啉修饰的多孔聚苯胺基氧还原电催化剂

韩洪仨, 王彦青, 张云龙, 丛媛媛, 秦嘉琪, 高蕊, 柴春晓, 宋玉江()   

  • 收稿日期:2020-08-06 录用日期:2020-09-02 发布日期:2020-09-04
  • 通讯作者: 宋玉江 E-mail:yjsong@dlut.edu.cn
  • 作者简介:Yujiang Song, Email: yjsong@dlut.edu.cn; Tel.: +86-411-84986485
  • 基金资助:
    国家重点研发计划(2019YFB1504501);中央高校基本科研业务费专项资金(DUT19ZD208);中央高校基本科研业务费专项资金(DUT20ZD208);大连市科技创新基金(2020JJ25CY003);中央引导地方科技发展专项资金(2020JH6/10500021)

Oxygen Reduction Reaction Electrocatalysts Derived from Metalloporphyrin-Modified Meso-/Macroporous Polyaniline

Hongsa Han, Yanqing Wang, Yunlong Zhang, Yuanyuan Cong, Jiaqi Qin, Rui Gao, Chunxiao Chai, Yujiang Song()   

  • Received:2020-08-06 Accepted:2020-09-02 Published:2020-09-04
  • Contact: Yujiang Song E-mail:yjsong@dlut.edu.cn
  • Supported by:
    the National Key Research & Development Program of China(2019YFB1504501);the Fundamental Research Funds for the Central Universities(DUT19ZD208);the Fundamental Research Funds for the Central Universities(DUT20ZD208);the Science & Technology Innovation Fund of Dalian(2020JJ25CY003);the Special Funds for Guiding Local Scientific and Technological Development by the Central Government(2020JH6/10500021)

摘要:

碳基非金属氧还原(ORR)电催化剂的研究近年来发展迅速,通过掺入杂原子等方法虽获得了一定的ORR活性,但仍需进一步提高。以此类电催化剂为基体,引入更多的活性位点,有可能获得更好的ORR活性。本文首先以带负电荷的SiO2纳米球通过静电作用吸附带正电荷的质子化苯胺分子,再通过聚合反应实现聚苯胺(PANI)对SiO2纳米球的包覆,之后将四甲氧基苯基铁卟啉(FeP)沉积在PANI表面,经高温热解,并去除SiO2模板,得到了一种新型的多孔ORR电催化剂。在0.1 mol·L-1 KOH水溶液中,电催化剂的ORR半波电位达0.843 V (vs.可逆氢电极(RHE)),优于文献报道的大部分碳基非金属ORR电催化剂,与商业Pt/C相近。显著提高的ORR活性可能源于孔结构(平均孔径18 nm,孔容1.1 cm3·g-1)、高比表面积(687.5 m2·g-1)和高氮含量(6.4%)。在加速耐久性测试中,电催化剂的ORR半波电位衰减25 mV,与其它碳基非金属ORR电催化剂相当,且远优于商业Pt/C (衰减74 mV)。另外,电催化剂应用于氢氧根交换膜燃料电池(HEMFC)时的单池峰值功率密度达42 mW·cm-2

关键词: 金属卟啉, 聚苯胺, 模板, 多孔材料, 氧还原反应

Abstract:

Oxygen reduction reaction (ORR) largely governs the overall performance of fuel cells. Commercial Pt/C has long been employed as the state-of-the-art electrocatalyst for ORR. The scarcity and high price of Pt, however, have restrained the broad application of fuel cells. Thus, it is crucial to substitute commercial Pt/C with non-precious metal or metal-free electrocatalysts. Among them, heteroatom-doped metal-free electrocatalysts (DMFEs) are promising candidates. Heteroatom doping can modify the electron distribution of carbon materials, generating active sites suitable for the adsorption and reduction of oxygen. Despite significant progress in recent years, high-performance DMFEs remain rare. It is possible to obtain improved ORR activity by the introduction of more active sites to DMFEs, in combination with a large specific surface area. Since Jasinski reported cobalt phthalocyanine is active for ORR more than half a century ago (Nature 1964, 201, 1212), tremendous investigations on metallomacrocycles as ORR electrocatalysts have been carried out. Nevertheless, few studies have further enriched the active sites of DMFEs by adding metallomacrocycles. Herein, we attempt to introduce metallomacrocycles to DMFEs, and to use templates to fabricate porous nanostructures with high specific surface areas. By controlling pH, positively charged aniline monomers can be adsorbed on the negatively charged surface of SiO2 nanospheres via electrostatic interactions. After in situ polymerization of aniline monomers, a polyaniline (PANI) coated SiO2 (SiO2@PANI) composite was formed. To introduce more active components, Fe tetrakis(4-methoxyphenyl) porphyrin (FeP) was deposited on the surface of SiO2@PANI by rotary evaporation method. After pyrolysis and removal of the template, FeP-modified porous PANI-based electrocatalysts were synthesized. Remarkably, the resultant 40%FeP/PANI-18-700 electrocatalysts demonstrate a high ORR activity, in terms of a half-wave potential (E1/2) of 0.843 V (vs. reversible hydrogen electrode (RHE)) in 0.1 mol·L-1 KOH aqueous solution, which is better than that of most DMFEs, and comparable to that of commercial Pt/C. The improvement of the ORR activity likely originates from the abundant pore structure (18 nm average pore diameter, pore volume of 1.1 cm3·g-1), large surface area (687.5 m2·g-1), and high N content (6.4%). Only 25 mV degradation of E1/2 was observed for 40%FeP/PANI-18-700 during the accelerated durability test, in contrast to a 74 mV negative shift of E1/2 for commercial Pt/C. Additionally, a hydroxide exchange membrane fuel cell (HEMFC) fabricated with 40%FeP/PANI-18-700 as the cathode approaches a peak power density of 42 mW·cm-2. The results exhibit 40%FeP/PANI-18-700 may have potential applications in HEMFCs. Our strategy highlights a new avenue for the design and synthesis of non-precious metal electrocatalysts toward ORR in alkaline media.

Key words: Metalloporphyrin, Polyaniline, Template, Porous material, Oxygen reduction reaction

MSC2000: 

  • O646