Carbon black/sulfur-doped graphene composite prepared by pyrolysis of graphene oxide with sodium polysulfide for oxygen reduction reaction
Carbon black/sulfur-doped graphene composite prepared by pyrolysis of graphene oxide with sodium polysulfide for oxygen reduction reaction
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DOI：
10.1016/j.electacta.2014.07.108
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发表时间：
2014-10
影响因子：
6.6
通讯作者：
R. K. Shervedani;Akbar Amini
中科院分区：
文献类型：
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作者：
R. K. Shervedani;Akbar Amini
以氧化石墨烯（GO）为碳源，多硫化钠为硫源，制备了硫掺杂的石墨烯纳米片（S-GN），并将制备的前驱体（S-GO）在1000 °C以下的不同温度下退火。采用场发射扫描电子显微镜（FESEM）、傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、X射线光电子能谱（XPS）和电化学方法研究了复合材料的结构和形貌特征。电化学结果表明，与GNs相比，S-GNs在碱性电解质中对氧还原反应（ORR）具有较高的催化活性。为了改善S-GNs的特性并防止颗粒团聚，通过将S-GNs-1000与炭黑（CB）混合来制备S-GNs-1000-CB。结果表明，CB颗粒插入S-GNs层间起到间隔层的作用，阻止了S-GNs在干燥过程中的重新堆积，从而促进了O2分子在S-GNs中的扩散，提高了ORR速率. S-GNs-1000-CB复合材料在碱性溶液中表现出优异的电催化活性。我们的研究结果表明，S-GNs-1000-CB是一种合适的催化剂，在碱性溶液中的ORR，并可能是一个很好的候选人，为实现这一目标的昂贵的铂基催化剂的替代品。
Sulfur doped graphene nanosheets (S-GNs) are synthesized by using graphene oxide (GO) as carbon source and sodium polysulfide as sulfur source, and then, annealing the prepared precursors (S-GO) at different temperatures up to 1000 °C. The structure and morphological characteristics of the fabricated composites are investigated by Field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical methods. Electrochemical results show that S-GNs has high catalytic activity toward oxygen reduction reaction (ORR) in an alkaline electrolyte in comparison with GNs. To improve the characteristics of S-GNs and prevent agglomeration of the particles, the S-GNs-1000-CB is fabricated by mixing the S-GNs-1000 with the carbon black (CB). The results show that CB particles inserted between S-GNs layers function as spacers and prevent the restacking of S-GNs during drying, and thus, most probably promote the diffusion of O2molecules through S-GNs and enhance the ORR rate. The S-GNs-1000-CB composites show excellent electrocatalytic activity in alkaline solutions over all the studied (catalyst) samples. Our findings demonstrate that S-GNs-1000-CB is an appropriate catalyst for ORR in alkaline solutions, and could be a good candidate for replacement of the precious Pt based catalysts for this goal.