Su Yunhe, Zhu Yihua, Jiang Hongliang, Shen Jianhua, Yang Xiaoling, Zou Wenjian, Chen Jianding, Li Chunzhong
Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
Nanoscale. 2014 Dec 21;6(24):15080-9. doi: 10.1039/c4nr04357j. Epub 2014 Nov 5.
Cobalt based catalysts are promising bifunctional electrocatalysts for both oxygen reduction and oxygen evolution reactions (ORR and OER) in unitized regenerative fuel cells (URFCs) operating with alkaline electrolytes. Here we report a hybrid composite of cobalt nanoparticles embedded in nitrogen-doped carbon (Co/N-C) via a solvothermal carbonization strategy. With the synergistic effect arising from the N-doped carbon and cobalt nanoparticles in the composite, the Co/N-C hybrid catalyst exhibits highly efficient bifunctional catalytic activity and excellent stability toward both ORR and OER. The ΔE (oxygen electrode activity parameter for judging the overall electrocatalytic activity of a bifunctional electrocatalyst) value for Co/N-C is 0.859 V, which is smaller than those of Pt/C and most of the non-precious metal catalysts in previous studies. Furthermore, the Co/N-C composite also shows better bifunctional catalytic activity than its oxidative counterparts, which could be attributed to the high specific surface area and the efficient charge transfer ability of the composite, as well as the good synergistic effect between N-doped carbon and the Co nanoparticles in the Co/N-C composite.
钴基催化剂是用于在碱性电解质中运行的一体化再生燃料电池（URFC）中氧还原和析氧反应（ORR和OER）的有前景的双功能电催化剂。在此，我们报道了一种通过溶剂热碳化策略嵌入氮掺杂碳中的钴纳米颗粒的混合复合材料（Co/N-C）。由于复合材料中氮掺杂碳和钴纳米颗粒产生的协同效应，Co/N-C混合催化剂对ORR和OER均表现出高效的双功能催化活性和优异的稳定性。Co/N-C的ΔE（用于判断双功能电催化剂整体电催化活性的氧电极活性参数）值为0.859 V，小于先前研究中Pt/C和大多数非贵金属催化剂的值。此外，Co/N-C复合材料还显示出比其氧化对应物更好的双功能催化活性，这可归因于复合材料的高比表面积和有效的电荷转移能力，以及Co/N-C复合材料中氮掺杂碳与钴纳米颗粒之间良好的协同效应。
