Performance and stability of Pd–Pt–Ni nanoalloy electrocatalysts in proton exchange membrane fuel cells
Performance and stability of Pd–Pt–Ni nanoalloy electrocatalysts in proton exchange membrane fuel cells
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DOI：
10.1016/j.jpowsour.2011.01.026
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发表时间：
2011-05
影响因子：
9.2
通讯作者：
Juan Zhao;K. Jarvis;P. Ferreira;A. Manthiram
中科院分区：
文献类型：
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作者：
Juan Zhao;K. Jarvis;P. Ferreira;A. Manthiram
采用多元醇还原法制备了Pd-Pt-Ni纳米合金催化剂，并对该催化剂在质子交换膜燃料电池（PEMFC）中的氧还原反应（ORR）进行了表征。发现用Pd-Pt-Ni催化剂制造的膜电极组件（MEA）的性能在整个电流密度范围内随着在PEMFC中的操作时间而连续增加，直到其变得与商业Pt的性能相当。Pd-Pt-Ni催化剂的Pt基质量活度超过商品Pt的2倍，其长期使用寿命在200 h内与商品Pt相当。通过能量色散谱（EDS）和X射线光电子能谱（XPS）的组成表征表明，由富Pd核和富Pt壳组成的脱合金活性催化剂相，在测试条件下通过Pd和Ni的溶解形成。纳米颗粒的表面催化活性可以通过表面和核心组分之间的晶格失配引起的应变效应来改变。的MEA横截面的透射电子显微镜（TEM）观察表明，Pd离子移动到Nafion膜，甚至到阳极侧和再沉积的氢交叉还原。富Pd的PdPt颗粒的沉积主要在膜的中心和沿着阴极/膜界面形成带。另一方面，Ni离子与Nafion膜中的质子进行离子交换。
Pd–Pt–Ni nanoalloy catalysts have been synthesized by a polyol reduction method and characterized for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). The performance of the membrane-electrode assembly (MEA) fabricated with the Pd–Pt–Ni catalysts is found to increase continuously in the entire current density range with the operation time in the PEMFC until it becomes comparable to that of commercial Pt. The Pt-based mass activity of Pd–Pt–Ni exceeds that of commercial Pt by a factor of 2, and its long-term durability is comparable to that of commercial Pt within the 200h of operation. Compositional characterizations by energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) suggest a dealloyed active catalyst phase consisting of Pd-rich core and Pt-rich shell, formed by dissolution of Pd and Ni under the testing conditions. The surface catalytic activity of nanoparticles can be modified by the strain effect caused by lattice mismatch between the surface and core components. Transmission electron microscopy (TEM) observation of the MEA cross-section reveals that the Pd ions move into the Nafion membrane and even to the anode side and redeposit on reduction by hydrogen crossover. The deposition of Pd-rich PdPt particles mainly forms a band at the center of the membrane and along the cathode/membrane interface. On the other hand, the Ni ions ion-exchange with the protons in the Nafion membrane.