Fabrication and functionalization of a pure non-noble metal catalyst showing activity and time stability for large scale applications

燃料电池（FC）是利用阴极电极侧的氧（来自空气）的还原和阳极侧的氢燃料的氧化来发电的电化学装置。整个电化学反应的产物是电子流和水。聚合物电解质膜燃料电池（PEM-FC）现在被强烈地认为是运输部门以及便携式微电子设备中的移动的能源。除了聚合物电解质，PEM-FC中的一个关键元素是催化剂，使两个电极上的化学反应成为可能。更重要的是，氧还原反应（ORR）需要相对大量的催化剂以使反应以足够大的速率进行以产生所需的电力。目前使用的催化剂是纳米颗粒形状的铂（Pt），这是一种非常昂贵的贵金属，供应相对有限，使得PEM-FC替代品相对于内燃机没有竞争力。该项目使用一种非贵金属，即铁（Fe），使用氮官能团在原子水平上分散在热等离子体反应器中生成的称为石墨烯纳米片（GNF）的新载体上。这种分散模拟了我们血液血红素结构的化学组织。这种新的GNF载体和制造方法的意义在于三个方面：（a）N/Fe-GNF第一次显示出在PEM-FC环境中在100小时的测试期间在时间上稳定的催化剂;（B）所达到的氮官能度的水平，其对于总电流和功率是重要的（活动），达到了前所未有的价值，比任何其他碳支持达到的创纪录的高价值翻了一番;（c）使用热等离子体反应器的制造方法能够实现产品的纯度和工艺的简单性，其可以容易地集成到燃料电池的大规模生产中。

Fuel cells (FC) are electrochemical devices for the generation of electricity using the reduction of oxygen (from air) on the cathode electrode side, and the oxidation of hydrogen fuel on the anode side. The resulting products of the full electrochemical reaction are the electron current and water. Polymer electrolyte membrane fuel cells (PEM-FC) are now strongly considered as a mobile energy source in the transportation sector as well as portable microelectronic devices. Besides the polymer electrolyte, one key element in the PEM-FC is the catalyst enabling the chemical reactions on both electrodes. More importantly, the oxygen reduction reaction (ORR) requires a relatively large amount of catalyst for the reaction to proceed at a rate large enough to generate the required electrical power. The catalyst used presently is platinum (Pt) in the shape of nanoparticles, a very expensive noble metal with relatively limited supply making the PEM-FC alternative uncompetitive with respect to internal combustion engines. This project uses a non-noble metal, namely iron (Fe), dispersed at the atomic level using nitrogen functionalities on a new support called graphene nanoflakes (GNF) generated in a thermal plasma reactor. This dispersion mimics the chemical organization of our blood heme structure. The interest of this new GNF support and method of fabrication is threefold: (a) the N/Fe-GNF showed for the first time a catalyst that is stable in time in the PEM-FC environment during tests of 100 hours; (b) the level of nitrogen functionalities attained which is important for the total current and power (the activity), reaches values that were never attained before, doubling the record high values attained by any other carbon support; (c) the method of fabrication using a thermal plasma reactor enables purity of the product and simplicity of a process that can easily be integrated in a large scale production of the fuel cells.