Zehtab Yazdi Alireza, Fei Huilong, Ye Ruquan, Wang Gunuk, Tour James, Sundararaj Uttandaraman
†Polymer Processing Group, Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive, NW, Calgary, Alberta T2N1N4, Canada.
ACS Appl Mater Interfaces. 2015 Apr 15;7(14):7786-94. doi: 10.1021/acsami.5b01067. Epub 2015 Apr 6.
Bamboo structured nitrogen doped multiwalled carbon nanotubes have been helically unzipped, and nitrogen doped graphene oxide nanoribbons (CNx-GONRs) with a multifaceted microstructure have been obtained. CNx-GONRs have then been codoped with nitrogen and boron by simultaneous thermal annealing in ammonia and boron oxide atmospheres, respectively. The effects of the codoping time and temperature on the concentration of the dopants and their functional groups have been extensively investigated. X-ray photoelectron spectroscopy results indicate that pyridinic and BC3 are the main nitrogen and boron functional groups, respectively, in the codoped samples. The oxygen reduction reaction (ORR) properties of the samples have been measured in an alkaline electrolyte and compared with the state-of-the-art Pt/C (20%) electrocatalyst. The results show that the nitrogen/boron codoped graphene nanoribbons with helically unzipped structures (CNx/CBx-GNRs) can compete with the Pt/C (20%) electrocatalyst in all of the key ORR properties: onset potential, exchange current density, four electron pathway selectivity, kinetic current density, and stability. The development of such graphene nanoribbon-based electrocatalyst could be a harbinger of precious metal-free carbon-based nanomaterials for ORR applications.
竹节状氮掺杂多壁碳纳米管已被螺旋展开，从而获得了具有多面微观结构的氮掺杂氧化石墨烯纳米带（CNx-GONRs）。然后，分别在氨气氛和氧化硼气氛中通过同步热退火对CNx-GONRs进行氮和硼的共掺杂。广泛研究了共掺杂时间和温度对掺杂剂浓度及其官能团的影响。X射线光电子能谱结果表明，在共掺杂样品中，吡啶型氮和BC3分别是主要的氮和硼官能团。在碱性电解质中测量了样品的氧还原反应（ORR）性能，并与最先进的Pt/C（20%）电催化剂进行了比较。结果表明，具有螺旋展开结构的氮/硼共掺杂石墨烯纳米带（CNx/CBx-GNRs）在所有关键的ORR性能方面都能与Pt/C（20%）电催化剂相媲美：起始电位、交换电流密度、四电子途径选择性、动力学电流密度和稳定性。这种基于石墨烯纳米带的电催化剂的开发可能预示着用于ORR应用的无贵金属碳基纳米材料的出现。
