Remarkably High Heterogeneous Electron Transfer Activity of Carbon-Nanotube-Supported Reduced Graphene Oxide

Mao, Xianwen; Guo, Fei; Yan, Esther H.; Hatton, T. Alan

doi:10.1021/acs.chemmater.6b03024

Cited by 17 publications

(16 citation statements)

References 78 publications

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“…The high activity of the defect enriched activated carbon for HER endows it to be the most promising metal‐free substitute for the commercial Pt/C catalyst . Additionally, the heterogeneous electron transfer rate of DG is proved much faster than that of the prefect graphene through evaluating the FcMeOH electrochemical oxidation–reduction reaction,[39b] which may be attributed to the high density of π electronic states of DG …”

Section: Defective Nanocarbons For Hermentioning

confidence: 99%

Activity Origins in Nanocarbons for the Electrocatalytic Hydrogen Evolution Reaction

Zhang

Jia

Yan

et al. 2018

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Sustainable hydrogen production is an essential prerequisite for realizing the future hydrogen economy. The electrocatalytic hydrogen evolution reaction (HER), as the cornerstone of exploring the mechanism of water electrolysis, has attracted extensive interest in the past decades. Carbon-based materials with significant merits such as abundance, low cost, high conductivity, and tunable molecular structures, are considered as promising candidates for replacing the commercial noble metal electrocatalysts. To date, activity origins of these carbon-based electrocatalysts are mainly attributed to the dopants (e.g., N, B, P or S), whereas the contribution of intrinsic/induced carbon defects has recently been a hot research topic. In this Review, besides the development of heteroatoms doping strategies, the latest studies on defective carbon-based materials for HER electrocatalysis are summarized, especially for various approaches to prepare defective carbons and the detailed introduction regarding the defect catalysis mechanism. Finally, an outlook into the development of future defective carbon-based HER electrocatalysts is presented.

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Section: Defective Nanocarbons For Hermentioning

confidence: 99%

Activity Origins in Nanocarbons for the Electrocatalytic Hydrogen Evolution Reaction

Zhang

Jia

Yan

et al. 2018

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“…Electrochemical impedance measurements were performed in a three-electrode system that consists of i) a flat-surface working electrode (either glassy carbon electrode with a diameter of 3.0 mm, or Au electrode with 99.95% purity and a diameter of 3.0 mm), ii) a Ag/Ag + reference electrode made of a silver wire, 10 mM AgBF , the respective ionic liquid inside a glass tube with a porous CoralPor™ tip, and iii) a platinum gauze auxiliary electrode (90/10 platinum/iridium alloy, 50.0 mm height, 38.0 mm diameter). The heterogeneous electron transfer kinetics on the selected electrode were measured by sampled current voltammetry (SCV)47 using an electrolyte solution consisting of 1 mM Ru(NH 3 )6 3+/2+ and 1.0 M KCl. Details of electrochemical characterizations are presented in Supplementary Note 3.…”

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confidence: 99%

Self-assembled nanostructures in ionic liquids facilitate charge storage at electrified interfaces

et al. 2019

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Driven by the potential applications of ionic liquids (ILs) in many emerging electrochemical technologies, recent research efforts have been directed at understanding the complex ion ordering in these systems, to uncover novel energy storage mechanisms at IL/electrode interfaces. Here, we discover that surface-active ionic liquids (SAILs), which contain amphiphilic structures inducing self-assembly, exhibit enhanced charge storage performance at electrified surfaces. Unlike conventional nonamphiphilic ILs (NAILs), for which ion distribution is dominated by Coulombic interactions, SAILs exhibit significant and competing van der Waals interactions owing to the nonpolar surfactant tails, leading to unusual interfacial ion distributions. We reveal that at an intermediate degree of electrode polarization SAILs display optimal performance, because the low-charge-density alkyl tails are effectively excluded from the electrode surfaces, whereas the formation of nonpolar domains along the 2 surface suppresses undesired overscreening effects. This work represents a crucial step towards understanding the unique interfacial behavior and electrochemical properties of amphiphilic liquid systems showing long-range ordering, and offers insights into the design principles for high-energydensity electrolytes based on spontaneous self-assembly behavior. Research interest in ionic liquids (ILs) as electrolytes for energy devices stems from several unique properties such as low volatility and flammability, as well as high electrochemical stability 1-5. An understanding of the molecular-level interactions between ILs and electrified interfaces is crucial for optimization of device performance 6. For instance, interfacial IL layers at charged surfaces govern the electric double layer (EDL) structure, a key factor determining the device energy density 2,4,6,7. The EDL structure with ILs is drastically different from that in aqueous and organic electrolytes 8-10 ; the complex ion ordering in ILs exhibits many subtleties, and remains an active area of debate 11-14. Here we present the first detailed investigation into electrocapacitive characteristics and fundamental EDL structures of an emerging IL class based on surface-active agents, or surface-active ILs (SAILs) 13,15-19. Our study reveals a novel material design principle for enhancing charge storage owing to the self-assembled nanostructures in amphiphilic liquids, and introduces a class of liquids with long-range ordering, having broad implications for diverse fields, ranging from interfacial science 20,21 to energy technologies 22,23. SAILs are inherently amphiphilic, and can self-assemble into nanostructures composed of distinct polar and nonpolar domains 13,15-19. Most previous studies on the IL EDL structure and IL-based energy devices focus on non-amphiphilic ILs (NAILs) where neither ion is based on a classical surfactant structure 6,24. Whereas nanostructuring was observed under confinement for some NAILs where one of the ions, usually the cation, bears moderate to long chai...

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“…Carbon nanofibers [ 150 ], Ketjen Black [ 27 ], and CNT-supported reduced graphene oxide [ 151 ] were all used to study the DET of horseradish peroxidase, and the electrocatalytic responses for reducing H 2 O 2 were 0.6 μA mM −1 cm −2 , 4800, μA mM −1 cm −2 , and ca. 5000 μA mM −1 , respectively.…”

Section: Electrode Materials and Modificationsmentioning

confidence: 99%

“… Overview of the examples of commonly employed nanomaterials for enabling or enhancing DET electrocatalysis. Nanocarbon: carbon cryogel for PQQ-glucose dehydrogenase [ 50 ], SWCNT for FAD-glucose dehydrogenase [ 144 ]; nanometal: polyethyleneimine-stabilized Au nanoparticles for cellobiose dehydrogenase [ 153 ], mixed thiol-SAMs modified Au nanoparticles for cellobiose dehydrogenase [ 127 ]; nanocomposites: PtNPs-MWCNT and PdNPs-MWCNT for cellobiose dehydrogenase [ 154 ], CNT-supported reduced graphene oxide for horseradish peroxidase [ 151 ]. …”

Section: Electrode Materials and Modificationsmentioning

confidence: 99%

Amperometric Biosensors Based on Direct Electron Transfer Enzymes

et al. 2021

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The accurate determination of analyte concentrations with selective, fast, and robust methods is the key for process control, product analysis, environmental compliance, and medical applications. Enzyme-based biosensors meet these requirements to a high degree and can be operated with simple, cost efficient, and easy to use devices. This review focuses on enzymes capable of direct electron transfer (DET) to electrodes and also the electrode materials which can enable or enhance the DET type bioelectrocatalysis. It presents amperometric biosensors for the quantification of important medical, technical, and environmental analytes and it carves out the requirements for enzymes and electrode materials in DET-based third generation biosensors. This review critically surveys enzymes and biosensors for which DET has been reported. Single- or multi-cofactor enzymes featuring copper centers, hemes, FAD, FMN, or PQQ as prosthetic groups as well as fusion enzymes are presented. Nanomaterials, nanostructured electrodes, chemical surface modifications, and protein immobilization strategies are reviewed for their ability to support direct electrochemistry of enzymes. The combination of both biosensor elements—enzymes and electrodes—is evaluated by comparison of substrate specificity, current density, sensitivity, and the range of detection.

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Remarkably High Heterogeneous Electron Transfer Activity of Carbon-Nanotube-Supported Reduced Graphene Oxide

Cited by 17 publications

References 78 publications

Activity Origins in Nanocarbons for the Electrocatalytic Hydrogen Evolution Reaction

Activity Origins in Nanocarbons for the Electrocatalytic Hydrogen Evolution Reaction

Self-assembled nanostructures in ionic liquids facilitate charge storage at electrified interfaces

Amperometric Biosensors Based on Direct Electron Transfer Enzymes

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