Highly stable platinum electrocatalysts for oxygen reduction formed using supercritical fluid impregnation
Highly stable platinum electrocatalysts for oxygen reduction formed using supercritical fluid impregnation
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DOI：
10.1016/j.jpowsour.2009.10.097
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发表时间：
2010-05
影响因子：
9.2
通讯作者：
S. Ang;D. Walsh
中科院分区：
文献类型：
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作者：
S. Ang;D. Walsh
采用超临界浸渍法制备了一种用于酸性介质中氧还原反应（ORR）的碳载铂电催化剂。采用伏安法和显微分析法研究了该催化剂的催化性能和电化学稳定性。这些分析结果与使用传统湿化学方法（用NaBH4在水溶液中还原h2ptcl6）形成的Pt/C催化剂得到的结果进行了比较。超临界浸渍法将炭黑（Vulcan XC72R）用（1,5-环二烯）二甲基铂（II） PtMe2COD在超临界二氧化碳（scCO2）中以1200p / s的速度浸渍。i和40°C。减压后，通过热分解吸附的PtMe2COD形成碳负载的Pt纳米颗粒。进行了加速稳定性测试，发现电催化剂的形态发生了变化，在湿化学法形成的Pt/C中，这种变化更为明显。电化学分析还表明，湿化学生成的Pt/C在电位循环后失去了相当大比例的电化学表面积，而scco2生成的Pt/C则没有。此外，在scco2中形成的Pt/C在很大程度上保留了其电催化活性。使用scco 2加工形成的电催化剂的稳定性表明，这种方法可能比目前可用的方法更有希望制造更稳定的燃料电池阴极。
A carbon-supported platinum electrocatalyst for the oxygen reduction reaction (ORR) in acidic medium was synthesised using supercritical fluid impregnation. The catalytic performance and electrochemical stability of this catalyst were studied using voltammetric and microscopic analysis. The results from these analyses were compared with those obtained using a Pt/C catalyst formed using a traditional wet chemical method (reduction of H2PtCl6in aqueous solution using NaBH4). In the supercritical impregnation method, carbon black (Vulcan XC72R) was impregnated with (1,5-cyclooctadiene)dimethyl platinum(II), PtMe2COD, in supercritical carbon dioxide (scCO2) at 1200p.s.i and 40°C. After depressurisation, carbon-supported Pt nanoparticles were formed by thermally decomposing the adsorbed PtMe2COD. An accelerated stability test was performed, which revealed morphological changes in the electrocatalysts, which were significantly more pronounced in the Pt/C formed using the wet chemical method. Electrochemical analysis also showed that the Pt/C formed using wet chemistry lost a significant proportion of its electrochemical surface area after potential cycling, whereas that formed using scCO2did not. Furthermore, the Pt/C formed in scCO2retained its electrocatalytic activity to a significantly larger extent. The stability of the electrocatalysts formed using scCO2processing suggests that this approach may be promising for the fabrication of more stable fuel cell cathodes than are currently available.