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In proton exchange membrane fuel cells,cost,performance and durability are important issues that are need to be resolved before commercialization. The main reason for fuel cell performance degradation during operation is the loss of electrochemical surface area during long-term aging or transient. These losses mainly come from the degradation of the catalyst metal and the corrosion of the carbon support. This is a continuous and irreversible process that will greatly shorten the service life of the fuel cell. In order to explore this problem,20%(mass fraction)Pt/C catalyst is prepared based on carbon carrier etched by sulfuric acid. The morphology characterization test shows that it is uniformly dispersed and uniform in particle size,which is considered as an excellent material for long-term oxygen reduction (ORR) stability test. Next,the ORR stability test method with different cyclic voltammetry (CV) cycles is used to observe its performance degradation,and a series of physical characterizations,e. g. transmission electron microscopy(TEM),high-resolution electron microscopy(HRTEM),X-ray photoelectron spectroscopy(XPS)and Raman spectroscopy (Raman),are used to further intuitively analyzed the attenuation mechanism. It is reported that the reasons for the degradation of the stability of Pt/C catalysts are mainly from the dissolution,agglomeration,oxidation and migration of Pt particles and the corrosion of carbon supports. This study elucidates the source of the impact on the stability of fuel cells during operation,and provides a reference for designing high-stability commercial ORR catalysts. © 2022, Science Press (China). All rights reserved. 相似文献
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氨在人类的生产生活中起着重要的作用,但目前工业上合成氨广泛采用的Haber-Bosch法耗能大,且污染严重。 而N2电还原反应(ENRR)被认为是一种有效的替代方法,由于N2的键能较高,目前仍然缺乏高活性的催化剂。 在这里,通过简单的浸渍法和氧化还原法制备了多价态的MnOx/C催化剂,该催化剂具有较高的氮还原反应活性(氨产率达到7.8 μgNH3/(h·mgcat),法拉第效率高达9.2%) 。进一步研究表明,多价态MnOx/C催化剂具有高氮还原反应活性的主要原因是不同价态的Mn离子(Mn2+、Mn3+、Mn4+)之间存在协同效应。 相似文献
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