Electrochemical oxidation behavior of titanium nitride based electrocatalysts under PEM fuel cell conditions
Electrochemical oxidation behavior of titanium nitride based electrocatalysts under PEM fuel cell conditions
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DOI：
10.1016/j.electacta.2010.08.035
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发表时间：
2010-12-01
影响因子：
6.6
通讯作者：
Haldar, Pradeep
中科院分区：
文献类型：
--
作者：
Avasarala, Bharat;Haldar, Pradeep
氮化钛（TiN）作为一种低温质子交换膜燃料电池的有前途的材料而备受关注。由于其高导电性和抗氧化性，TiN有作为一种耐用的电催化剂材料的潜力。利用电化学和光谱技术，在质子交换膜燃料电池条件下研究了TiN纳米粒子（NP）的电化学氧化特性，并与传统的炭黑载体进行了比较。观察到由于TiN NP的惰性性质以及其表面存在天然氧化物/氮氧化物层，它的电化学氧化速率明显低于炭黑。根据电化学条件中使用的温度和酸性介质的不同，开路电位（OCP）曲线显示覆盖层溶解在酸性溶液中，导致暴露的氮化物表面钝化。结果表明，TiN NP在测试条件下表现出钝化行为。XPS表征进一步支持了溶解的观点，并表明表面被O - H基团钝化，降低了TiN NP的导电性。在质子交换膜燃料电池条件下测试了Pt/TiN电催化剂的长期稳定性，并且在不同温度下测量的电化学表面积的趋势与所提出的钝化模型相符。© 2010 Elsevier Ltd版权所有
Titanium nitride (TIN) is attracting attention as a promising material for low temperature proton exchange membrane fuel cells With its high electrical conductivity and resistance to oxidation TIN has a potential to act as a durable electrocatalyst material Using electrochemical and spectroscopic techniques the electrochemical oxidation properties of TIN nanoparticles (NP) are studied under PEM fuel cell conditions and compared with conventional carbon black supports It is observed that TIN NP has a significantly lower rate of electrochemical oxidation than carbon black due to its inert nature and the presence of a native oxide/oxynande layer on its surface Depending on the temperature and the acidic media used in the electrochemical conditions the open circuit potential (OCP) curves shows the overlayer dissolved in the acidic solution leading to the passivation of the exposed nitride surface It is shown that TIN NP displays passive behavior under the tested conditions The XPS characterization further supports the dissolution argument and shows that the surface becomes passivated with the O-H groups reducing the electrical conductivity of TIN NP The long-term stability of the Pt/TiN electrocatalysts is tested under PEM fuel cell conditions and the trends of the measured electrochemical surface area at different temperatures is shown to agree with the proposed passivation model (C) 2010 Elsevier Ltd All rights reserved