Chen Xi'an, Chen Xiaohua, Xu Xin, Yang Zhi, Liu Zheng, Zhang Lijie, Xu Xiangju, Chen Ying, Huang Shaoming
College of Materials Science and Engineering, Hunan University, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Changsha 410082, P. R. China.
Nanoscale. 2014 Nov 21;6(22):13740-7. doi: 10.1039/c4nr04783d.
Chemical doping with foreign atoms is an effective approach to significantly enhance the electrochemical performance of the carbon materials. Herein, sulfur-doped three-dimensional (3D) porous reduced graphene oxide (RGO) hollow nanosphere frameworks (S-PGHS) are fabricated by directly annealing graphene oxide (GO)-encapsulated amino-modified SiO2 nanoparticles with dibenzyl disulfide (DBDS), followed by hydrofluoric acid etching. The XPS and Raman spectra confirmed that sulfur atoms were successfully introduced into the PGHS framework via covalent bonds. The as-prepared S-PGHS has been demonstrated to be an efficient metal-free electrocatalyst for oxygen reduction reaction (ORR) with the activity comparable to that of commercial Pt/C (40%) and much better methanol tolerance and durability, and to be a supercapacitor electrode material with a high specific capacitance of 343 F g(-1), good rate capability and excellent cycling stability in aqueous electrolytes. The impressive performance for ORR and supercapacitors is believed to be due to the synergistic effect caused by sulfur-doping enhancing the electrochemical activity and 3D porous hollow nanosphere framework structures facilitating ion diffusion and electronic transfer.
用外来原子进行化学掺杂是显著提高碳材料电化学性能的有效方法。在此，通过将包覆有氧化石墨烯（GO）的氨基修饰二氧化硅纳米颗粒与二苄基二硫化物（DBDS）直接退火，随后进行氢氟酸蚀刻，制备了硫掺杂的三维（3D）多孔还原氧化石墨烯（RGO）中空纳米球框架（S-PGHS）。X射线光电子能谱（XPS）和拉曼光谱证实硫原子通过共价键成功引入到PGHS框架中。所制备的S-PGHS已被证明是一种高效的无金属氧还原反应（ORR）电催化剂，其活性与商业Pt/C（40%）相当，甲醇耐受性和耐久性更好，并且是一种超级电容器电极材料，在水性电解质中具有343 F g(-1)的高比电容、良好的倍率性能和优异的循环稳定性。ORR和超级电容器的出色性能被认为是由于硫掺杂增强了电化学活性以及3D多孔中空纳米球框架结构促进了离子扩散和电子转移所产生的协同效应。
