Meng Tianjiao, Nsabimana Anaclet, Liu Zuoyi, Jia Huixian, An Siying, Wang Huan, Zhang Yufan
Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Key Laboratory of Analytical Science and Technology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei 071002, China.
Chemistry Department, College of Science and Technology, University of Rwanda, Po Box: 3900, Kigali, Rwanda.
J Colloid Interface Sci. 2020 Nov 1;579:12-20. doi: 10.1016/j.jcis.2020.06.053. Epub 2020 Jun 15.
Exploring a cheap catalyst with effective activity for oxygen reduction reaction (ORR) to replace precious metal electrocatalysts has gained tremendous attention for several decades. In this study, we designed and synthesized cobalt and nitrogen supported on mesoporous hollow carbon hemisphere (Co/N/HCHs) nanocomposites by a facile and economical approach. Semisphere-shaped mesoporous hollow carbon is self-generated using silica particles as template, followed by a pyrolysis-etching process; and exhibits high electrical conductivity and high specific surface. The unique porous structure of carbon provides significant number of the abundant defective sites and shortens the mass transfer pathway, leading to a greatly enhanced electrocatalytic activity with mainly 4e reduction. Moreover, the synergistic effects of large electrochemically active areas and good electrical conductivity, resulting from the introduction of Co and N heteroatom, are the main reason for displaying outstanding ORR activity with a high half-wave potential of 0.8 V and the electron transfer numbers of 3.89. Furthermore, an excellent long-term stability (the current density retention of 87.0%) and superb methanol tolerance in alkaline medium are achieved. Undoubtedly, this demonstrates a potential way to strategically design the non-precious metal doped carbon catalysts for wider practical applications.
几十年来，探索一种具有有效氧还原反应（ORR）活性的廉价催化剂以取代贵金属电催化剂一直备受关注。在本研究中，我们通过一种简便且经济的方法设计并合成了负载在介孔空心碳半球（Co/N/HCHs）上的钴和氮纳米复合材料。以二氧化硅颗粒为模板自生成半球形介孔空心碳，随后经过热解蚀刻过程；其具有高电导率和高比表面积。碳独特的多孔结构提供了大量丰富的缺陷位点并缩短了传质路径，从而导致主要以4e还原为主的电催化活性大大增强。此外，引入Co和N杂原子所产生的大电化学活性面积和良好电导率的协同效应，是其具有0.8 V的高半波电位和3.89的电子转移数，从而展现出优异ORR活性的主要原因。此外，在碱性介质中实现了出色的长期稳定性（电流密度保留率为87.0%）和卓越的甲醇耐受性。毫无疑问，这展示了一种从战略上设计非贵金属掺杂碳催化剂以实现更广泛实际应用的潜在方法。
