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Graphitic, porous carbons for catalysts with increased stability in the proton exchange membrane fuel cell

用于提高质子交换膜燃料电池稳定性的催化剂的石墨多孔碳

基本信息

批准号：
284032131
负责人：
Professor Dr.-Ing. Bastian Etzold
金额：
--
依托单位：
Lehrstuhl für Power-to-X-Technologien
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/284032131?language=en
关键词：
Graphitic porous carbons catalysts increased

项目摘要

The proton exchange membrane fuel cell (PEMFC) is believed to be of great importance for a successful usage of sustainable energy, because it enables the conversion of sustainably produced hydrogen into electricity. Challenges for this technology are mainly increasing activity and stability of the electrocatalyst. This key component usually consists of a catalyst support based on carbon materials on which the active metal (e.g. platinum) is dispersed. In the last years the activity of these catalysts could be considerably increased by optimizing the structure of the active component, for instance in the form of metal alloys like PtNi. The stability of the catalyst is mainly limited by the carbon support. Employing non-carbon support materials can mitigate some of the disadvantages carbon supports inherit, e.g. the low stability against oxidation. Yet these materials give rise to other drawbacks like a poor electrical conductivity. Recently an extraordinary stability was reported when employing porous hollow graphitic spheres as electrocatalyst support. Reason for the stability is seen in the combination of inner porosity, mesopores with size similar to the dispersed platinum particles and the graphitic structure of the carbon material. In contrast to the typically used carbon black containing outer porosity these novel supports seem to 'trap' the active metal inside the pores. This shows that the stability of carbon supports can be increased to a satisfying level. In this proposal the described findings shall be applied to develop new mesoporous, graphitic carbon supports with inner porosity for stable PEMFC catalysts. The development will base on Carbide Derived Carbons (CDC) that are obtained by the reactive extraction of carbides, while crucial parameters like pore structure and degree of graphitization can be adjusted by the choice of carbide precursor and extraction temperature. The resulting carbon is very pure and the material properties can be obtained with a high reproducibility. Preliminary work showed that mesoporous and graphitic carbons are obtained at extraction temperatures above 1200 °C, which shall be employed within the project to vary the degree of graphitization and pore sizes of CDC based carbon supports. Furthermore a method for the deposition of platinum on these supports shall be developed, which result in homogeneous dispersion of the metal within the pore system. After Subsequently, the platinum clusters will be sintered to the size of the pores to allow for 'trapping'. The resulting catalysts will be tested regarding their activity and stability for the Oxygen Reduction Reaction with half-cell measurements. Further insights will be obtained by characterization of the pristine and used electrocatalysts with IL-TEM. In external cooperation optimized materials resulting will be studied in single stack fuel cell experiments for their long-term stability under realistic conditions.

质子交换膜燃料电池（PEMFC）被认为对于可持续能源的成功利用非常重要，因为它能够将可持续生产的氢气转化为电力。该技术面临的挑战主要是提高电催化剂的活性和稳定性。该关键部件通常由基于碳材料的催化剂载体组成，其上分散有活性金属（例如铂）。在过去的几年中，通过优化活性成分的结构（例如 PtNi 等金属合金的形式），可以显着提高这些催化剂的活性。催化剂的稳定性主要受碳载体的限制。采用非碳支撑材料可以减轻碳支撑所继承的一些缺点，例如抗氧化稳定性低。然而这些材料还存在其他缺点，例如导电性差。最近报道了当使用多孔空心石墨球作为电催化剂载体时具有非凡的稳定性。稳定性的原因在于内部孔隙率、尺寸与分散的铂颗粒相似的中孔以及碳材料的石墨结构的组合。与通常使用的含有外部孔隙的炭黑相比，这些新型载体似乎将活性金属“捕获”在孔隙内。这表明碳载体的稳定性可以提高到令人满意的水平。在该提案中，所描述的发现应应用于开发具有内部孔隙的新型介孔石墨碳载体，以用于稳定的质子交换膜燃料电池催化剂。该开发将基于通过碳化物反应萃取获得的碳化物衍生碳（CDC），而孔结构和石墨化程度等关键参数可以通过选择碳化物前体和萃取温度来调整。所得碳非常纯净，并且可以以高再现性获得材料性能。初步工作表明，在高于 1200 °C 的萃取温度下可以获得介孔碳和石墨碳，该项目将采用该温度来改变基于 CDC 的碳载体的石墨化程度和孔径。此外，应开发一种在这些载体上沉积铂的方法，从而使金属均匀分散在孔隙系统内。随后，铂簇将被烧结至孔径大小以允许“捕获”。将通过半电池测量来测试所得催化剂的氧还原反应活性和稳定性。通过使用 IL-TEM 对原始和使用过的电催化剂进行表征，可以获得进一步的见解。在外部合作中，优化后的材料将在单堆燃料电池实验中研究其在实际条件下的长期稳定性。