物理化学学报 >> 2020, Vol. 36 >> Issue (9): 1912049.doi: 10.3866/PKU.WHXB201912049

所属专题: 精准纳米合成

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具有优异甲醇耐受性的Rh掺杂PdCu有序金属间化合物纳米粒子增强氧还原电催化

李蒙刚1,2, 夏仲泓2, 黄雅荣1, 陶璐2, 晁玉广2, 尹坤2, 杨文秀2, 杨微微1,*(), 于永生1,*(), 郭少军2,3,*()   

  1. 1 哈尔滨工业大学化工与化学学院,新能源转化与储存关键材料技术工信部重点实验室,哈尔滨 150001
    2 北京大学工学院材料科学与工程系,北京 100871
    3 北京大学工学院工程科学与新兴技术高精尖中心,北京 100871
  • 收稿日期:2019-12-19 录用日期:2020-02-26 发布日期:2020-03-06
  • 通讯作者: 杨微微,于永生,郭少军 E-mail:yangww@hit.edu.cn;ysyu@hit.edu.cn;guosj@pku.edu.cn
  • 基金资助:
    北京市自然科学基金(JQ18005);国家重点基础研究发展计划(2016YFB0100201);国家自然科学基金(51671003);国家自然科学基金(21802003);国家自然科学基金(51571072);国家自然科学基金(51871078);中国博士后基金(2018M631239)

Rh-Doped PdCu Ordered Intermetallics for Enhanced Oxygen Reduction Electrocatalysis with Superior Methanol Tolerance

Menggang Li1,2, Zhonghong Xia2, Yarong Huang1, Lu Tao2, Yuguang Chao2, Kun Yin2, Wenxiu Yang2, Weiwei Yang1,*(), Yongsheng Yu1,*(), Shaojun Guo2,3,*()   

  1. 1 MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China
    2 Department of Materials Science & Engineering, College of Engineering, Peking University, Beijing 100871, P. R. China
    3 BIC-ESAT, College of Engineering, Peking University, Beijing 100871, P. R. China
  • Received:2019-12-19 Accepted:2020-02-26 Published:2020-03-06
  • Contact: Weiwei Yang,Yongsheng Yu,Shaojun Guo E-mail:yangww@hit.edu.cn;ysyu@hit.edu.cn;guosj@pku.edu.cn
  • Supported by:
    the Beijing Natural Science Foundation, China(JQ18005);the National Key R & D Program of China(2016YFB0100201);the National Natural Science Foundation of China(51671003);the National Natural Science Foundation of China(21802003);the National Natural Science Foundation of China(51571072);the National Natural Science Foundation of China(51871078);the China Postdoctoral Science Foundation(2018M631239)

摘要:

由于阴极催化剂有限的活性和耐久性以及甲醇渗透到阴极所导致的催化剂中毒问题,直接甲醇燃料电池(DMFCs)仍面临严峻的挑战。本文报道了一类新型的具有有序金属间结构的Rh掺杂PdCu纳米颗粒用于提高阴极氧还原反应(ORR)的活性、耐久性和甲醇耐受性。通过结合Rh原子掺杂以及有序金属间结构两者的优点,在碱性条件下,Rh掺杂PdCu金属间化合物催化剂在0.9 V电位下对氧还原质量活性相比商业Pt/C提高7.4倍。这种独特的结构还使其表现出出色的ORR耐久性,在连续20000个循环后的半波电位和质量活性几乎不变。此外,在苛刻的中毒环境下,仍可以保持Rh掺杂PdCu金属间化合物电催化剂高的氧还原催化活性。

关键词: Rh掺杂, 有序金属间化合物, 纳米颗粒, 氧还原, 甲醇耐受性

Abstract:

Direct methanol fuel cells (DMFCs), as one of the important energy conversion devices, are of great interest in the fields of energy, catalysis and materials. However, the application of DMFCs is presently challenged because of the limited activity and durability of cathode catalysts as well as the poisoning issues caused by methanol permeation to the cathode during operation. Herein, we report a new class of Rh-doped PdCu nanoparticles (NPs) with ordered intermetallic structure for enhancing the activity and durability of the cathode for oxygen reduction reaction (ORR) and achieving superior methanol tolerance. The disordered Rh-doped PdCu NPs can be prepared via a simple wet-chemical method, followed by annealing to convert it to ordered phases. The results of transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), power X-ray diffraction (PXRD) analysis and high resolution TEM (HRTEM) successfully demonstrate the formation of near-spherical NPs with an average size of 6.5 ± 0.5 nm and the conversion of the phase structure. The complete phase transition temperatures of Rh-doped PdCu NPs and PdCu are 500 and 400 ℃, respectively. The molar ratio of Rh/Pd/Cu in the as-synthesized Rh-doped PdCu NPs is 5/48/47. Benefitting from Rh doping and the presence of the ordered intermetallic structure, the Rh-doped PdCu intermetallic electrocatalyst achieves the maximum ORR mass activity of 0.96 A·mg-1 at 0.9 V versus reversible hydrogen electrode (RHE) under alkaline conditions—a 7.4-fold enhancement compared to the commercial Pt/C catalyst. For different electrocatalysts, the ORR activities follow the sequence, ordered Rh-doped PdCu intermetallics > ordered PdCu intermetallics > disordered Rh-doped PdCu NPs > disordered PdCu NPs > commercial Pt/C catalyst. In addition, the distinct structure endows the Rh-doped PdCu intermetallics with highly stable ORR durability with unaltered half-wave potential (E1/2) and mass activity after continuous 20000 cycles, which are higher than those of other electrocatalysts. Furthermore, the E1/2 of the Rh-doped PdCu intermetallics decreases by only 5 mV after adding 0.5 mol·L-1 methanol to the electrolyte, while the commercial Pt/C catalyst negatively shifts by 235 mV and a distinct oxidation peak can be observed. The results indicate that the ORR activity of the Rh-doped PdCu intermetallic electrocatalyst can be well maintained even in the presence of poisoning environment. Our results have demonstrated that Rh-doped PdCu NPs with ordered intermetallic structures is a potential electrocatalyst toward the next-generation high-performance DMFCs.

Key words: Rh doping, Ordered intermetallics, Nanoparticle, Oxygen reduction, Methanol tolerance

MSC2000: 

  • O646