催化学报 ›› 2016, Vol. 37 ›› Issue (1): 43-53.DOI: 10.1016/S1872-2067(15)60878-6

• 新型多孔催化材料专栏 • 上一篇    下一篇

用于燃料电池阳极的有序介孔碳负载的双功能Pt-M(M=Ru,Fe,Mo)电催化剂

洪锦德a, 刘子豪a,b, 维拉库玛a, 吴培豪a, 刘端祺a, 刘尚斌a,c   

  1. a “中央”研究院原子与分子科学研究所, 台湾台北10617;
    b “国立”台湾科技大学化学工程系, 台湾台北10607;
    c “国立”台湾师范大学化学系, 台湾台北10617
  • 收稿日期:2015-03-30 修回日期:2015-04-27 出版日期:2015-12-26 发布日期:2015-12-26
  • 通讯作者: 刘端祺, 刘尚斌
  • 作者简介:刘端祺, 刘尚斌
  • 基金资助:

    台湾科技支撑项目(NSC98-2113-M-001-017-MY3, NSC101-2113-M-001-020-MY3).

Ordered mesoporous carbon supported bifunctional PtM (M = Ru, Fe, Mo) electrocatalysts for a fuel cell anode

Chin-Te Hunga, Zih-Hao Lioua,b, Pitchaimani Veerakumara, Pei-Hao Wua, Tuan-Chi Liua, Shang-Bin Liua,c   

  1. a Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan, China;
    b Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, China;
    c Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan, China
  • Received:2015-03-30 Revised:2015-04-27 Online:2015-12-26 Published:2015-12-26
  • Supported by:

    This work was supported by the Ministry of Science and Technology (NSC98-2113-M-001-017-MY3, NSC101-2113-M-001-020-MY3), Taiwan, China.

摘要:

质子交换膜燃料电池(PEMFCs)不仅采用可再生的和环境友好的能源(如氢气和甲醇)作为燃料,而且转换效率高,因此被认为是潜在的能量转换设备.目前PEMFCs大多采用活性炭负载的贵金属作为其阴极和阳极的电催化剂,因此制造成本高,限制了它的实际应用.燃料电池电催化剂研发的一个紧迫的任务就是避免使用采用贵金属.直接甲醇燃料电池(DMFCs)阳极上进行的甲醇氧化反应(MOR)通常采用活性炭或多孔碳材料负载的Pt基双功能催化剂.在此基础上复合第二贵金属(如Ru)可改善其结构、电子和表面化学性质,表现出较高的稳定性和抗CO中毒性能,因而在MOR中具有优异的电催化活性.然而,在DMFCs长期运行期间,该Pt-Ru/C阳极催化剂大多出现严重的金属Ru溶解流失,以及燃料甲醇透过聚电解质膜的现象.因此,进一步提高Pt-Ru/C电催化剂的稳定性成为当务之急.另外,考虑到膜电极的成本和PEMFCs的整体效率,在保持较好MOR活性的前提下,减少贵金属用量或采用非贵金属,甚至不用金属,进一步降低其成本也尤为重要,这也将十分有利于基础研究和实际的工业应用.
采用软模板或硬模板法制得的有序介孔碳(OMCs)因具有高的比表面积、可调的中孔尺寸和表面官能团性质而广受关注,已经应用于催化剂载体,吸附剂,传感器和电极材料等领域.OMCs可负载Pt制成电催化剂而用于DMFCs/PEMFCs中.本课题组前期以介孔氧化硅SBA-15为硬模板剂,糠醇和三甲苯为初始碳源,Pt和Ru的乙酰丙酮化物为金属前驱体和次级碳源,采用一步法直接制备了OMC负载的高分散、高稳定性的单Pt和Pt-Ru双金属纳米粒子,在MOR中表现出优异的电催化活性和较高的稳定性性能,超过常用的商用催化剂,显示出较大的应用潜力.因此,本文采用类似的方法将高度分散的PtM(M = Ru, Fe, Mo)合金纳米粒子沉积于OMCs上,从而制得PtM-OMC(M = Ru, Fe, Mo)催化剂;同时采用N2物理吸附、X射线衍射、透射电镜、X射线吸收近边结构、扩展X射线吸收精细结构谱等手段对其结构组成、形貌和织构等物化性质进行了表征.结果表明,合金化的PtM纳米粒子的平均粒径约2-3nm,且高度分散于OMC载体孔道内.另外,PtM纳米粒子中第二金属M(Ru, Fe, Mo)大多以还原态形式存在,形成了典型的核(Pt)-壳(M)结构.循环伏安法测量结果表明,在MOR反应中,所制PtM-OMC电极表现出较高的电催化活性和抗CO中毒性能,超过典型的活性炭负载的Pt-Ru催化剂.
尤其值得一提的是,Pt-Fe-OMC催化剂不但具有非常高的稳定性,优越的抗CO性能,而且其催化MOR反应活性与PtRu-OMC的相当,因而具有更低的生产成本,所以Pt-Fe-OMC催化剂在DMFCs阳极电催化剂具有很大的应用前景.

关键词: 有序介孔碳, 铂基电催化剂, 甲醇氧化反应, X射线吸收光谱, 核-壳合金纳米粒子, 一氧化碳溶出伏安法, 燃料电池

Abstract:

The deposition onto an ordered mesoporous carbon (OMC) support of well dispersed PtM (M = Ru, Fe, Mo) alloy nanoparticles (NPs) were synthesized by a direct replication method using SBA-15 as the hard template, furfuryl alcohol and trimethylbeneze as the primary carbon sources, and metal acetylacetonate as the alloying metal precursor and secondary carbon source. The physicochemical properties of the PtM-OMC catalysts were characterized by N2 adsorption-desorption, X-ray diffraction, transmission electron microscopy, X-ray absorption near edge structure, and extended X-ray absorption fine structure. The alloy PtM NPs have an average size of 2-3 nm and were well dispersed in the pore channels of the OMC support. The second metal (M) in the PtM NPs was mostly in the reduced state, and formed a typical core (Pt)-shell (M) structure. Cyclic voltammetry measurements showed that these PtM-OMC electrodes had excellent electrocatalytic activities and tolerance to CO poisoning during the methanol oxidation reaction, which surpassed those of typical activated carbon-supported PtRu catalysts. In particular, the PtFe-OMC catalyst, which exhibited the best performance, can be a practical anodic electrocatalyst in direct methanol fuel cells due to its superior stability, excellent CO tolerance, and low production cost.

Key words: Ordered mesoporous carbon, Platinum-based electrocatalysts, Methanol oxidation reaction, X-ray absorption spectroscopy, Core-shell alloy nanoparticles, Carbon monoxide-stripping voltammetry, Fuel cells