Electrochemical properties of vertically aligned graphenes: tailoring heterogeneous electron transfer through manipulation of the carbon microstructure.
Electrochemical properties of vertically aligned graphenes: tailoring heterogeneous electron transfer through manipulation of the carbon microstructure.
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DOI：
10.1039/d0na00587h
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发表时间：
2020-11-11
影响因子：
4.7
通讯作者：
中科院分区：
文献类型：
--
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报道了不同形貌（微结构）的垂直排列石墨烯（VG）的电化学响应。使用外层氧化还原探针Ru（NH3）62+/3+（RuHex）和N，N，N′，N′-四甲基对苯二胺（TMPD）分析电化学性质，通过伴随的物理化学表征（拉曼、TEM、SEM、AFM和XPS）对性能进行去卷积。VG电极使用电子回旋共振化学气相沉积（ECR-CVD）方法制造，产生具有一系列不同高度、间距和边缘平面样位点/缺陷（支撑在下面的SiO2/Si上）的垂直石墨烯。我们将这些新型VG配置的电化学反应性/响应与包括其结构的边缘平面位点（%-边缘）的水平相关联，并计算相应的非均相电子转移（HET）速率k 0。具有更多凝聚层堆叠（因此暴露的边缘平面位点的更大的全局覆盖率）的更高的VG结构被示出表现出改进的HET动力学，支持边缘平面位点是碳材料中电子转移的主要来源的主张。测量的k 0 eff约为。4.00× 10−3 cm s−1（对应于1.00%的活性边缘平面样位点/缺陷的暴露表面覆盖率（% θ边缘））对于最高和最紧密堆叠的VG样品是明显的，反之亦然，其中具有大的相互排列的石墨烯间距和小的薄片高度的VG电极仅表现出0.08%的θedge和k 0 eff值在ca处慢一个数量级。3.05× 10−4 cm s−1。提供了具有常规CVD（水平）生长的石墨烯和高度有序的热解石墨（HOPG的EPPG）的边缘平面的对照实验，证明了新型VG电极表现出约100%的导电性。k 0比水平CVD石墨烯快3倍。EPPG表现出最快的HET动力学，表现出约。k 0比最佳VG大2倍。这些结果对于2D碳电化学和材料科学家领域的工作人员具有重要意义，提供了碳基电极的宏观电化学响应取决于边缘平面含量的证据，并表明可以采用一系列结构配置来定制性能和应用。研究表明，垂直排列的石墨烯电极的结构直接影响微观结构活性边缘平面位点密度方面的非均相电子转移动力学，其中更大的边缘含量导致有利的电化学行为。
The electrochemical response of different morphologies (microstructures) of vertically aligned graphene (VG) configurations is reported. Electrochemical properties are analysed using the outer-sphere redox probes Ru(NH3)62+/3+ (RuHex) and N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), with performances de-convoluted via accompanying physicochemical characterisation (Raman, TEM, SEM, AFM and XPS). The VG electrodes are fabricated using an electron cyclotron resonance chemical vapour deposition (ECR-CVD) methodology, creating vertical graphene with a range of differing heights, spacing and edge plane like-sites/defects (supported upon underlying SiO2/Si). We correlate the electrochemical reactivity/response of these novel VG configurations with the level of edge plane sites (%-edge) comprising their structure and calculate corresponding heterogeneous electron transfer (HET) rates, k0. Taller VG structures with more condensed layer stacking (hence a larger global coverage of exposed edge plane sites) are shown to exhibit improved HET kinetics, supporting the claims that edge plane sites are the predominant source of electron transfer in carbon materials. A measured k0eff of ca. 4.00 × 10−3 cm s−1 (corresponding to an exposed surface coverage of active edge plane like-sites/defects (% θedge) of 1.00%) was evident for the tallest and most closely stacked VG sample, with the inverse case true, where a VG electrode possessing large inter-aligned-graphene spacing and small flake heights exhibited only 0.08% of % θedge and a k0eff value one order of magnitude slower at ca. 3.05 × 10−4 cm s−1. Control experiments are provided with conventional CVD (horizontal) grown graphene and the edge plane of highly ordered pyrolytic graphite (EPPG of HOPG), demonstrating that the novel VG electrodes exhibit ca. 3× faster k0 than horizontal CVD graphene. EPPG exhibited the fastest HET kinetics, exhibiting ca. 2× larger k0 than the best VG. These results are of significance to those working in the field of 2D-carbon electrochemistry and materials scientists, providing evidence that the macroscale electrochemical response of carbon-based electrodes is dependent on the edge plane content and showing that a range of structural configurations can be employed for tailored properties and applications. The structure of vertically aligned graphene electrodes is shown to directly affect heterogeneous electron transfer kinetics in terms of the density of active edge plane sites of the microstructure, where greater edge content results in favourable electrochemical behaviour.
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影响因子：
3.5
作者：
Brownson DAC;Smith GC;Banks CE
通讯作者：
Banks CE
DOI：
10.3390/bios8020053
发表时间：
2018-06-08
期刊：
Biosensors
影响因子：
--
作者：
García-Miranda Ferrari A;Foster CW;Kelly PJ;Brownson DAC;Banks CE
通讯作者：
Banks CE
影响因子：
6.4
作者：
Cui, Dongdong;Li, Hongji;Yang, Baohe
通讯作者：
Yang, Baohe
影响因子：
6.7
作者：
Brownson, Dale A. C.;Varey, Sarah A.;Banks, Craig E.
通讯作者：
Banks, Craig E.
影响因子：
2.7
作者：
Dettori, Riccardo;Cadelano, Emiliano;Colombo, Luciano
通讯作者：
Colombo, Luciano