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

燃料电池（FC）是一种利用阴极侧氧气（来自空气）的还原和阳极侧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流和水。聚合物电解质膜燃料电池（PEM-FC）目前被广泛认为是一种移动能源，在交通运输领域以及便携式微电子设备中都有应用。除了聚合物电解质外，PEM-FC的一个关键元素是催化剂，它可以在两个电极上进行化学反应。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度进行，以产生所需的电能。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替代品与内燃机相比没有竞争力。该项目使用一种非贵金属，即铁（Fe），在原子水平上分散，利用氮的功能，在热等离子体反应器中生成的一种名为石墨烯纳米片（GNF）的新载体上。这种分散物模仿了我们血液血红素结构的化学组织。这种新的GNF载体和制造方法的兴趣在于三个方面：(a) N/Fe-GNF在100小时的测试中首次显示出在PEM-FC环境中稳定的催化剂；(b)对总电流和功率（活度）很重要的氮功能达到了以前从未达到的值，比任何其他碳支持所达到的最高记录值翻了一番；(c)使用热等离子体反应器的制造方法使产品纯度高，工艺简单，易于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.