Stability of Pt–Ni/C (1:1) and Pt/C electrocatalysts as cathode materials for polymer electrolyte fuel cells: Effect of ageing tests
Stability of Pt–Ni/C (1:1) and Pt/C electrocatalysts as cathode materials for polymer electrolyte fuel cells: Effect of ageing tests
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Pt-Ni/C (1:1) 和 Pt/C 电催化剂作为聚合物电解质燃料电池阴极材料的稳定性：老化测试的影响
DOI：
10.1016/j.jpowsour.2009.01.088
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
E. Gonzalez
中科院分区：
文献类型：
--
作者：
S. Zignani;E. Antolini;E. Gonzalez
通过用 NaBH4 还原金属前体来制备碳负载的 Pt 和 Pt-Ni (1:1) 纳米粒子。 XRD分析表明，只有少量的Ni与Pt形成合金（合金中Ni的原子分数约为0.05）。对所制备的催化剂进行计时电流分析法 (CA) 测量，以评估其氧还原反应 (ORR) 的活性。 CA测量表明所制备的含Ni催化剂的ORR活性高于纯Pt。然后，通过对这些催化剂进行耐久性测试来研究它们的稳定性，其中包括 30 小时的恒电位（CP，0.8V 与 RHE）操作或在 20mVs−1 下 0.5 至 1.0V 与 RHE 之间的重复电位循环（RPC，1000 次循环）。在 0.8V vs. RHE 下进行 CP 操作 30 小时后，观察到 Pt-Ni/C 催化剂所有非合金 Ni 的损失、Pt-Ni 合金的部分溶解以及微晶尺寸的增加。 Pt-Ni/C 催化剂的 ORR 活性几乎稳定，而 Pt/C 的 ORR 活性相对于制备的催化剂略有下降。在重复电位循环后，观察到 Pt-Ni/C 催化剂所有非合金镍和部分合金镍的损失。与 0.8V vs. RHE 下 CP 操作 30 小时的结果相反，RPC 后 Pt-Ni/C 的 ORR 活性低于制备的 Pt-Ni/C 和循环 Pt/C。这一结果可以通过 Pt-Ni/C 催化剂的 Pt 表面富集和微晶尺寸增加来解释。
Carbon supported Pt and Pt–Ni (1:1) nanoparticles were prepared by reduction of metal precursors with NaBH4. XRD analysis indicated that only a small amount of Ni alloyed with Pt (Ni atomic fraction in the alloy about 0.05). The as-prepared catalysts were submitted to chronoamperometry (CA) measurements to evaluate their activity for the oxygen reduction reaction (ORR). CA measurements showed that the ORR activity of the as-prepared Ni-containing catalyst was higher than that of pure Pt. Then, their stability was studied by submitting these catalysts to durability tests involving either 30h of constant potential (CP, 0.8V vs. RHE) operation or repetitive potential cycling (RPC, 1000 cycles) between 0.5 and 1.0V vs. RHE at 20mVs−1. After 30h of CP operation at 0.8V vs. RHE, loss of all non-alloyed Ni, partial dissolution of the Pt–Ni alloy and an increase of the crystallite size was observed for the Pt–Ni/C catalyst. The ORR activity of the Pt–Ni/C catalyst was almost stable, whereas the ORR activity of Pt/C slightly decreased with respect to the as-prepared catalyst. Loss of all non-alloyed and part of alloyed Ni was observed for the Pt–Ni/C catalyst following repetitive potential cycling. Conversely to the results of 30h of CP operation at 0.8V vs. RHE, after RPC the ORR activity of Pt–Ni/C was lower than that of both as-prepared Pt–Ni/C and cycled Pt/C. This result was explained in terms of Pt surface enrichment and crystallite size increase for the Pt–Ni/C catalyst.