Park Gil-Ryeong, Jo Seung Geun, Varyambath Anuraj, Kim Jeonghyun, Lee Jung Woo
Department of Materials Science and Engineering, Pusan National University, Busan 46241, Korea.
Department of Electronic Convergence Engineering, Kwangwoon University, Seoul 01899, Korea.
Nanomaterials (Basel). 2021 Oct 15;11(10):2727. doi: 10.3390/nano11102727.
It is imperative to design an inexpensive, active, and durable electrocatalyst in oxygen reduction reaction (ORR) to replace carbon black supported Pt (Pt/CB). In this work, we synthesized PdRu nanoparticles on nitrogen-doped reduced graphene oxide (PdRu NPs/NrGO) by a facile microwave-assisted method. Nitrogen atoms were introduced into the graphene by thermal reduction with NH gas and several nitrogen atoms, such as pyrrolic, graphitic, and pyridinic N, found by X-ray photoelectron spectroscopy. Pyridinic nitrogen atoms acted as efficient particle anchoring sites, making strong bonding with PdRu NPs. Additionally, carbon atoms bonding with pyridinic N facilitated the adsorption of O as Lewis bases. The uniformly distributed ~2.4 nm of PdRu NPs on the NrGO was confirmed by transmission electron microscopy. The optimal composition between Pd and Ru is 4.7:1, reaching -6.33 mA/cm at 0.3 V for the best ORR activity among all measured catalysts. Furthermore, accelerated degradation test by electrochemical measurements proved its high durability, maintaining its initial current density up to 98.3% at 0.3 V and 93.7% at 0.75 V, whereas other catalysts remained below 90% at all potentials. These outcomes are considered that the doped nitrogen atoms bond with the NPs stably, and their electron-rich states facilitate the interaction with the reactants on the surface. In conclusion, the catalyst can be applied to the fuel cell system, overcoming the high cost, activity, and durability issues.
设计一种用于氧还原反应（ORR）的廉价、活性高且耐用的电催化剂以取代炭黑负载的铂（Pt/CB）势在必行。在这项工作中，我们通过简便的微波辅助方法在氮掺杂还原氧化石墨烯（PdRu NPs/NrGO）上合成了钯钌纳米颗粒。通过用NH气体热还原将氮原子引入石墨烯中，并用X射线光电子能谱发现了几种氮原子，如吡咯型、石墨型和吡啶型N。吡啶型氮原子作为有效的颗粒锚定位点，与PdRu NPs形成强键。此外，与吡啶型N键合的碳原子促进了O作为路易斯碱的吸附。通过透射电子显微镜证实了PdRu NPs在NrGO上均匀分布，粒径约为2.4 nm。Pd和Ru之间的最佳组成是4.7:1，在0.3 V时达到-6.33 mA/cm，在所有测量的催化剂中具有最佳的ORR活性。此外，通过电化学测量进行的加速降解测试证明了其高耐久性，在0.3 V时保持其初始电流密度高达98.3%，在0.75 V时保持93.7%，而其他催化剂在所有电位下均低于90%。这些结果被认为是掺杂的氮原子与纳米颗粒稳定键合，并且它们的富电子状态促进了与表面反应物的相互作用。总之，该催化剂可应用于燃料电池系统，克服了高成本、活性和耐久性问题。
