Fuel Cell System and Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China.
Nanoscale. 2018 Mar 8;10(10):4872-4881. doi: 10.1039/c7nr09452c.
Herein, a novel non-platinum core-shell catalyst, namely, IrNi@PdIr/C was prepared via a galvanic replacement reaction; it exhibits enhanced hydrogen oxidation activity and excellent stability under alkaline conditions. Electrochemical experiments demonstrated that the mass and specific activities at 50 mV of IrNi@PdIr/C are 2.1 and 2.2 times that of commercial Pt/C in 0.1 M KOH at 298 K, respectively. Moreover, accelerated degradation tests have shown that the electrochemically active surface area (ECSA) of IrNi@PdIr/C reduces by only 5.1%, which is almost 4 times less than that of commercial Pt/C and the mass activity at 50 mV of IrNi@PdIr/C after 2000 potential cycles is still 1.8 times higher than that of aged Pt/C. XRD and XPS analysis suggest that the enhanced HOR activity is attributed to the weakening of the hydrogen binding to the PdIr overlayers induced by the IrNi core. The better stability to potential cycling can be associated with the PdIr shell, which inhibits oxide formation. These results suggest that IrNi@PdIr/C is a promising non-platinum anode catalyst for alkaline anion exchange membrane fuel cells.
在此，通过电置换反应制备了一种新型的非铂核壳催化剂 IrNi@PdIr/C；它在碱性条件下表现出增强的氢氧化活性和优异的稳定性。电化学实验表明，在 298 K 下，在 0.1 M KOH 中，IrNi@PdIr/C 的质量和 50 mV 下的比活性分别是商业 Pt/C 的 2.1 倍和 2.2 倍。此外，加速降解测试表明，IrNi@PdIr/C 的电化学活性表面积（ECSA）仅减少了 5.1%，几乎是商业 Pt/C 的 4 倍，并且在 2000 个电位循环后，IrNi@PdIr/C 在 50 mV 的质量活性仍比老化的 Pt/C 高 1.8 倍。XRD 和 XPS 分析表明，增强的 HOR 活性归因于 IrNi 核引起的 PdIr 覆盖层对氢结合的减弱。更好的耐电位循环稳定性与 PdIr 壳有关，它抑制了氧化物的形成。这些结果表明，IrNi@PdIr/C 是一种很有前途的碱性阴离子交换膜燃料电池非铂阳极催化剂。
