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Graphene Electrolyte Interfaces
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Book Synopsis Graphene–Electrolyte Interfaces by : Hualin Zhan
Download or read book Graphene–Electrolyte Interfaces written by Hualin Zhan and published by CRC Press. This book was released on 2020-04-07 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene–electrolyte systems are commonly found in cutting-edge research on electrochemistry, biotechnology, nanoelectronics, energy storage, materials engineering, and chemical engineering. The electrons in graphene intimately interact with ions from an electrolyte at the graphene–electrolyte interface, where the electrical or chemical properties of both graphene and electrolyte could be affected. The electronic behavior therefore determines the performance of applications in both Faradaic and non-Faradaic processes, which require intensive studies. This book systematically integrates the electronic theory and experimental techniques for both graphene and electrolytes. The theoretical sections detail the classical and quantum description of electron transport in graphene and the modern models for charges in electrolytes. The experimental sections compile common techniques for graphene growth/characterization and electrochemistry. Based on this knowledge, the final chapter reviews a few applications of graphene–electrolyte systems in biosensing, neural recording, and enhanced electronic devices, in order to inspire future developments. This multidisciplinary book is ideal for a wide audience, including physicists, chemists, biologists, electrical engineers, materials engineers, and chemical engineers.
Book Synopsis Surface-specific Vibrational Spectroscopy of the Graphene Electrode/aqueous Electrolyte Interface by : Yongkang Wang (Ph. D.)
Download or read book Surface-specific Vibrational Spectroscopy of the Graphene Electrode/aqueous Electrolyte Interface written by Yongkang Wang (Ph. D.) and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling the Behavior of the Graphene to Liquid Interfaces in an Electrolytic Liquid by : Caitlin Duffner
Download or read book Modeling the Behavior of the Graphene to Liquid Interfaces in an Electrolytic Liquid written by Caitlin Duffner and published by . This book was released on 2016 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the mechanism for charge transfer between a graphene biosensor and its electrodes within an electrolyte solution is vital to better understand the sources of electrical noise in the system. By measuring the effective resistance and capacitance of the system at different frequencies, it is possible to develop a circuit model of the system's electrical behavior. This model provides a deeper understanding of the fundamental interactions that occur in a top-gated graphene device and provides opportunities to improve a signal. To reduce noise created at the liquid to graphene interface, a buffer layer of Yttrium Oxide was applied. While the buffer layer did not work as expected, this type of experimental approach and model will provide deeper understanding of the electrical noise.
Download or read book Graphene Surfaces written by Karim Kakaei and published by Academic Press. This book was released on 2018-10-09 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene Surfaces: Particles and Catalysts focuses on the surface chemistry and modification of graphene and its derivatives from a theoretical and electrochemical point-of-view. It provides a comprehensive overview of their electronic structure, synthesis, properties and general applications in catalysis science, including their relevance in alcohols and their derivatives oxidation, oxygen reduction, hydrogen evolution, energy storage, corrosion protection and supercapacitors. The book also covers emerging research on graphene chemistry and its impact. Chemical engineers, materials scientists, electrochemists and engineers will find information that will answer their most pressing questions on the surface aspects of graphene and its effect on catalysis. Serves as a time-saving reference for researchers, graduated students and chemical engineers Equips the reader with catalysis knowledge for practical applications Discusses the physical and electrochemical properties of graphene Provides the most important applications of graphene in electrochemical systems Highlights both experimental and theoretical aspects of graphene
Book Synopsis Graphene Field-Effect Transistors by : Omar Azzaroni
Download or read book Graphene Field-Effect Transistors written by Omar Azzaroni and published by John Wiley & Sons. This book was released on 2023-10-16 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene Field-Effect Transistors In-depth resource on making and using graphene field effect transistors for point-of-care diagnostic devices Graphene Field-Effect Transistors focuses on the design, fabrication, characterization, and applications of graphene field effect transistors, summarizing the state-of-the-art in the field and putting forward new ideas regarding future research directions and potential applications. After a review of the unique electronic properties of graphene and the production of graphene and graphene oxide, the main part of the book is devoted to the fabrication of graphene field effect transistors and their sensing applications. Graphene Field-Effect Transistors includes information on: Electronic properties of graphene, production of graphene oxide and reduced graphene oxide, and graphene functionalization Fundamentals and fabrication of graphene field effect transistors, and nanomaterial/graphene nanostructure-based field-effect transistors Graphene field-effect transistors integrated with microfluidic platforms and flexible graphene field-effect transistors Graphene field-effect transistors for diagnostics applications, and DNA biosensors and immunosensors based on graphene field-effect transistors Graphene field-effect transistors for targeting cancer molecules, brain activity recording, bacterial detection, and detection of smell and taste Providing both fundamentals of the technology and an in-depth overview of using graphene field effect transistors for fabricating bioelectronic devices that can be applied for point-of-care diagnostics, Graphene Field-Effect Transistors is an essential reference for materials scientists, engineering scientists, laboratory medics, and biotechnologists.
Book Synopsis Graphene Network Scaffolded Flexible Electrodes—From Lithium to Sodium Ion Batteries by : Dongliang Chao
Download or read book Graphene Network Scaffolded Flexible Electrodes—From Lithium to Sodium Ion Batteries written by Dongliang Chao and published by Springer. This book was released on 2018-12-11 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on deformable and wearable electronics has promoted an increasing demand for next-generation power sources with high energy/power density that are low cost, lightweight, thin and flexible. One key challenge in flexible electrochemical energy storage devices is the development of reliable electrodes using open-framework materials with robust structures and high performance. Based on an exploration of 3D porous graphene as a flexible substrate, this book constructs free-standing, binder-free, 3D array electrodes for use in batteries, and demonstrates the reasons for the research transformation from Li to Na batteries. It incorporates the first principles of computational investigation and in situ XRD, Raman observations to systematically reveal the working mechanism of the electrodes and structure evolution during ion insertion/extraction. These encouraging results and proposed mechanisms may accelerate further development of high rate batteries using smart nanoengineering of the electrode materials, which make “Na ion battery could be better than Li ion battery” possible.
Book Synopsis The Handbook of Graphene Electrochemistry by : Dale A. C. Brownson
Download or read book The Handbook of Graphene Electrochemistry written by Dale A. C. Brownson and published by Springer. This book was released on 2014-05-21 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene has grasped the attention of academia and industry world-wide due its unique structure and reported advantageous properties. This was reflected via the 2010 Nobel Prize in Physics being awarded for groundbreaking experiments regarding the two-dimensional material graphene. One particular area in which graphene has been extensively explored is electrochemistry where it is potentially the world’s thinnest electrode material. Graphene has been widely reported to perform beneficially over existing electrode materials when used within energy production or storage devices and when utilised to fabricate electrochemical sensors. This book charts the history of graphene, depicting how it has made an impact in the field of electrochemistry and how scientists are trying to unravel its unique properties, which has, surprisingly led to its fall from grace in some areas. A fundamental introduction into Graphene Electrochemistry is given, through which readers can acquire the tools required to effectively explain and interpret the vast array of graphene literature. The readers is provided with the appropriate insights required to be able to design and implement diligent electrochemical experiments when utilising graphene as an electrode material.
Book Synopsis The Handbook of Graphene Electrochemistry by : Robert D. Crapnell
Download or read book The Handbook of Graphene Electrochemistry written by Robert D. Crapnell and published by Springer Nature. This book was released on with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Liquid Cell Electron Microscopy by : Frances M. Ross
Download or read book Liquid Cell Electron Microscopy written by Frances M. Ross and published by Cambridge University Press. This book was released on 2017 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2.6.2 Electrodes for Electrochemistry
Book Synopsis Characterization of the Electrical Properties of Interfaces by Impedance Spectroscopy for Clean Energy Devices by : Edmund Mills
Download or read book Characterization of the Electrical Properties of Interfaces by Impedance Spectroscopy for Clean Energy Devices written by Edmund Mills and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interfaces offer unique electrical properties different than those of homogeneous phases, and as a result play key roles in electronic and electrochemical devices. It is essential to understand the electrical properties of interfaces in order to design better devices to solve the problems encountered by humanity. In this dissertation, the electrical properties of interfaces within three types of electronic and electrochemical devices are studied – solid oxide fuel cells (SOFCs), supercapacitors (SCs), and graphene barristors. SOFCs are energy conversion devices that efficiently convert chemical energy (fuel) into electrical energy. A central area of research in this field is the reduction of SOFC operation temperature, which requires the discovery and development of electrolyte materials with higher ionic conductivities at lower temperatures. One route to accomplishing this goal is through the inclusion of a dense network of solid-solid interfaces with high ionic conductivity into the electrolyte. First, a better understanding of interfacial ionic conductivity is needed. Nanocrystalline yttia-stabilized zirconia thin films were studied to gain understanding of the ionic conductivity of film-substrate interfaces in the presence of grain boundaries. It was found that Mg diffused from the substrate into the grain boundary cores, nearly eliminating the grain boundary resistance. These results show the potential and complexity of interfacial engineering for superior electrolyte materials. Supercapacitors are an energy storage device well suited to applications that require high power density. They store energy in the form of electrical double layers at the solid-liquid interfaces between the electrode and electrolyte. An important issue for supercapacitors is the relation between device performance and charge/discharge rate; the capacity decays at higher operating rates. Due to the need for high electrode-electrolyte surface area, highly porous electrodes are used. This leading to variance in the accessibility of pore surfaces to electrolyte ions, which leads to a rate-dependence of the available power and energy density. We show that Peukert’s constant, widely applied to the evaluation of the rate-dependent performance of batteries, also allows the straightforward evaluation of the rate-performance of supercapacitors. A novel method for determining Peukert’s constant using impedance spectroscopy is presented. Furthermore, relationships between the pseudocapacitance and porosity and Peukert’s constant are established. Lastly, graphene barristors are a novel type of transistor with simple fabrication and excellent performance, which take advantage of graphene’s unique electrical properties. In a graphene barristor, current passes across a graphene/semiconductor interface. At the interface, a Schottky barrier is formed with a height and resistance that can be modulated with the application of an external electric field, through the change in work function of graphene. In the work presented in this dissertation, impedance spectroscopy is used to investigate the electrical properties of the graphene/semiconductor interface in a high-performance ZnO/graphene thin film barristor. It is found that conduction across the interface is mediated by an electron tunneling process. This leads to consistent device properties over a wide temperature range.
Book Synopsis Graphene Bioelectronics by : Ashutosh Tiwari
Download or read book Graphene Bioelectronics written by Ashutosh Tiwari and published by Elsevier. This book was released on 2017-11-22 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene Bioelectronics covers the expending field of graphene biomaterials, a wide span of biotechnological breakthroughs, opportunities, possibilities and challenges. It is the first book that focuses entirely on graphene bioelectronics, covering the miniaturization of bioelectrode materials, bioelectrode interfaces, high-throughput biosensing platforms, and systemic approaches for the development of electrochemical biosensors and bioelectronics for biomedical and energy applications. The book also showcases key applications, including advanced security, forensics and environmental monitoring. Thus, the evolution of these scientific areas demands innovations in crosscutting disciplines, starting from fabrication to application. This book is an important reference resource for researchers and technologists in graphene bioelectronics—particularly those working in the area of harvest energy biotechnology—employing state-of-the-art bioelectrode materials techniques. Offers a comprehensive overview of state-of-art research on graphene bioelectronics and their potential applications Provides innovative fabrication strategies and utilization methodologies, which are frequently adopted in the graphene bioelectronics community Shows how graphene can be used to make more effective energy harvesting devices
Book Synopsis Nanoscale Characterization of Electrolyte Diffusion, Interface Morphology Disruption and Surface Dynamics of Polymer Melt Films Adsorbed on Graphene by : Feipeng Yang
Download or read book Nanoscale Characterization of Electrolyte Diffusion, Interface Morphology Disruption and Surface Dynamics of Polymer Melt Films Adsorbed on Graphene written by Feipeng Yang and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant efforts have been made to understand corrosion since it is important both scientifically and technologically, as the direct cost resulting from corrosion and its prevention has become a non-negligible portion of the gross domestic product. While considerable effort has been made to understand the macroscopic corrosion behavior and empirical knowledge of effective corrosion mitigation strategies is available, a nanoscale description of corrosion processes is still lacking. This dissertation describes efforts to establish a fundamental understanding of the corrosion process at the coating/metal interface on the nanoscale. The dissertation is divided into three parts. In the first part, a nanoscale depiction of the influence of ions on the diffusion of water is garnered from the analysis of X-ray and neutron reflectivity (XR/NR) and electrochemical impedance spectroscopy (EIS) data since metal, water and oxygen are three key ingredients in corrosion and ions play an important part in accelerating corrosion. The diffusion of water or electrolyte in thin polymeric films in different directions, parallel to the film or perpendicular to it, was distinguished. XR/NR measurements were used to probe the diffusion parallel to the film using a customized diffusion cell and that rate was found to be orders of magnitude larger than the diffusion rate in bulk epoxy. In contrast, when EIS data were analyzed using equivalent electrical circuit (EEC) model fitting, the penetration (diffusion perpendicular to the film) rate was found to be orders of magnitude smaller than the diffusion rate in bulk epoxy. Consistent results from XR, NR and EIS showed that the diffusion rates of electrolyte in both the lateral and perpendicular directions are lower than those of water (H2O/D2O), and that the higher the ion concentration, the lower the rate of diffusion. Reflectivity measurements probing at small (nm) length scales and also comparatively short times (hours) complement the widespread use of EIS and provide a means of quantitatively investigating phenomena that occur rapidly as a first step in the metallic substrate corrosion. The second part of this dissertation provides a detailed description of the changes in an epoxy/aluminum interface morphology that occur upon exposure of the interface to water or electrolytes, with information derived from X-ray off-specular scattering and atomic force microscopy (AFM). The interface is quantitatively described using a self-affine model of a randomly rough interface based on height difference correlation function with parameters of roughness, jaggedness, and correlation length. "Rocking curve" measurements show the interface becomes more rough, the texture becomes more jagged and the correlation length becomes smaller. Different electrolytes (NaCl and NaI aqueous solutions) have similar effects on the disruption of the interface morphology, and H2O is less disruptive to the interface as compared to the two electrolytes. In the last part of this dissertation, the surface fluctuations of polystyrene (PS) melt films adsorbed on graphene are compared to the surface fluctuations on films adsorbed on single crystal silicon wafers. The surface fluctuations on polymer thin films have received intense interest since surface fluctuations influence important interfacial properties such as wetting, adhesion, and tribology. Additionally, for sufficiently thin films the surface fluctuations also reflect realities of the chain adsorption and organization at the interface with the substrate and those features of films should be important for dictating the resistance to water or electrolyte incursion at a substrate/film or matrix/filler interface. For 8Rg thick entangled linear polystyrene (PS) films on silicon (8Rg PS/Si) the surface fluctuations can be described using a hydrodynamic continuum theory (HCT), which assumes the thin film viscosity is equivalent to the bulk viscosity throughout its entire depth. For 131000 g/mol linear PS, when the thickness of the film is less than 4Rg, the surface fluctuations show confinement effects and the fluctuations are slowed. The surface fluctuations for an 8Rg thick PS film on graphene (8Rg PS/Graphene) are three orders of magnitude slower than those on 8Rg PS/Si. The 170°C data from the 3Rg PS/Si, 8Rg PS/Si and 8Rg PS/Graphene samples collapse on a universal curve using a two-layer model with a 75 nm (ca. 7Rg) thick highly viscous layer on graphene and a 14 nm (ca. 1.5Rg) thick highly viscous layer on silicon. The layer left after a rinsing and drying procedure reflects a 2.4 times thicker strongly adsorbed layer on graphene compared to that on silicon. Thus the effect of adsorption of melt PS chains on graphene on dynamics of the chains near the graphene is far more profound than the effect of adsorption of PS chains on silicon. This remarkable slowing of material near the polymer/graphene interface could have important implications for the performance of other graphene containing composites and coating systems when the polymer is able to interact as strongly with graphene as does PS.
Book Synopsis Interfaces in Energy Storage Systems by : Brett Lucht
Download or read book Interfaces in Energy Storage Systems written by Brett Lucht and published by The Electrochemical Society. This book was released on 2015-12-28 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Supercapacitor Technology by : Inamuddin
Download or read book Supercapacitor Technology written by Inamuddin and published by Materials Research Forum LLC. This book was released on 2019-11-25 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supercapacitors are most interesting in the area of rechargeable battery based energy storage because they offer an unbeatable power density, quick charge/discharge rates and prolonged lifetimes in comparison to batteries. The book covers inorganic, organic and gel-polymer electrolytes, electrodes and separators used in different types of supercapacitors; with emphasis on material synthesis, characterization, fundamental electrochemical properties and most promising applications. Keywords: Supercapacitors, Rechargeable Batteries, Organic Electrolytes, Inorganic Electrolytes, Gel Polymer based Supercapacitors, Redox Electrolytes, Starch-Based Electrolytes, Flexible Supercapacitors, Pseudocapacitors, Carbon Nanoarchitectures for Supercapacitors, Photo-Supercapacitors, Bimetal Oxides/Sulfides for Electrochemical Supercapacitors.
Book Synopsis Nanocarbon Electrochemistry by : Nianjun Yang
Download or read book Nanocarbon Electrochemistry written by Nianjun Yang and published by John Wiley & Sons. This book was released on 2020-01-07 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a comprehensive introduction to the field of nanocarbon electrochemistry The discoveries of new carbon materials such as fullerene, graphene, carbon nanotubes, graphene nanoribbon, carbon dots, and graphdiyne have triggered numerous research advances in the field of electrochemistry. This book brings together up-to-date accounts of the recent progress, developments, and achievements in the electrochemistry of different carbon materials, focusing on their unique properties and various applications. Nanocarbon Electrochemistry begins by looking at the studies of heterogeneous electron transfer at various carbon electrodes when redox-active molecules are reversibly and specifically adsorbed on the carbon electrode surface. It then covers electrochemical energy storage applications of various carbon materials, particularly the construction and performance of supercapacitors and batteries by use of graphene and related materials. Next, it concentrates on electrochemical energy conversion applications where electrocatalysis at 0D, 1D, 2D, and 3D carbon materials nanocarbon materials is highlighted. The book finishes with an examination of the contents of electrogenerated chemiluminescence and photoelectrochemical pollutant degradation by use of diamond and related carbon materials. Covers the fundamental properties of different carbon materials and their applications across a wide range of areas Provides sufficient background regarding different applications, which contributes to the understanding of specialists and non-specialists Examines nanoelectrochemistry of adsorption-coupled electron transfer at carbon electrodes; graphene and graphene related materials; diamond electrodes for the electrogenerated chemiluminescence; and more Features contributions from an international team of distinguished researchers Nanocarbon Electrochemistry is an ideal book for students, researchers, and industrial partners working on many diverse fields of electrochemistry, whether they already make frequent use of carbon electrodes in one form of another or are looking at electrodes for new applications.
Book Synopsis Handbook of Graphene, Volume 5 by : Cengiz Ozkan
Download or read book Handbook of Graphene, Volume 5 written by Cengiz Ozkan and published by John Wiley & Sons. This book was released on 2019-06-12 with total page 809 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fifth volume in a series of handbooks on graphene research and applications Graphene is a valuable nanomaterial used in technology. The Handbook of Graphene: Graphene in Energy, Healthcare, and Environmental Applications is the fifth volume in the handbook series. The book's topics include: graphene nanomaterials in energy and environment applications and graphene used as nanolubricant. Within the handbook, three-dimensional graphene materials are discussed, as are synthesis and applications in electrocatalysts and electrochemical sensors. The battery topics cover: graphene and graphene-based hybrid composites for advanced rechargeable battery electrodes; graphene-based materials for advanced lithium-ion batteries; graphene-based materials for supercapacitors and conductive additives of lithium ion batteries. The book's graphene-based sensor information addresses flexible actuators, sensors, and supercapacitors.
Book Synopsis The Interactions of Graphene with Ionic Solutions and Their Effects on the Differential Capacitance for Sensing Applications by : Lindsey Daniels
Download or read book The Interactions of Graphene with Ionic Solutions and Their Effects on the Differential Capacitance for Sensing Applications written by Lindsey Daniels and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nano-scale devices continue to challenge the theoretical understanding of microscopic systems. Of particular interest is the characterization of the interface electrochemistry of sensors, which operate as field effect transistors with graphene in contact with the solution. While plenty of experimental research has been conducted in regard to the viability and sensitivity of graphene-based devices, the understanding of the microscopic and macroscopic physics of these sensors has lagged, unlike any other areas of applications for graphene. Although some successful models of these sensors have been developed, relatively little theoretical work to account for the vast extent of experimental work. Typically operated in a regime of high ion concentration and high surface charge density, dielectric saturation, dielectric decrement, and ion crowding become non-negligible at the interface, complicating continuum treatments based upon the Poisson-Boltzmann equation. Modifications to the standard Poisson-Boltzmann theory are explored, with modifications due to dielectric saturation and dielectric decrement considered in tandem with a Bikerman-Friese model to account for the steric effects of ions. In the case of dielectric saturation, a model proposed by Booth is used to characterize the diffuse layer capacitance for both metallic and graphene electrodes immersed in an electrolyte. The dependence of the diffuse layer capacitance on the surface charge density of the electrode exhibits two peaks, in contrast to the experimental results. For dielectric decrement, a dielectric permittivity dependent on the concentration of positive and negative ions is used to determine the diffuse layer capacitance for both metallic and graphene electrodes. The diffuse layer capacitance shows a strong interplay between ion polarizability and steric effects, while exhibiting a single peak. A self-consistent and parameter-free method for the inclusion of a Stern layer is used in both cases, which eliminates the spurious secondary peak in the case of dielectric saturation and reduces the overall magnitude of the capacitance of the diffuse layer in both dielectric saturation and dielectric decrement. When a graphene electrode is used, the total capacitance in all modifications is dominated by V-shaped quantum capacitance of graphene at low potentials, which is a manifestation of the Dirac cone structure of the graphene $\pi$-electron bands. A broad peak develops in the total capacitance at high potentials, which is sensitive to the ion size at dielectric saturation, but is stable with dielectric decrement. In addition to the interactions of graphene with an electrolyte, considerable interest has recently been shown in studying the electric double layer that arises at the interface of doped graphene and a class of electrolytes known as ionic liquids. Ionic liquids are a class of molten ionic salts at room temperature that have low volatility and high ionic concentration, and are characterized by the overscreening and overcrowding effects in their electric double layer. A mean field model for ionic liquids is presented, which takes into account both the ion correlation and the finite ion size effects, in order to calculate the differential capacitance of the ionic liquid interface with single-layer graphene. Besides choosing ion packing fractions that give rise to the camel-shaped and bell-shaped capacitances of the diffuse layer in ionic liquids, the regimes of ``dilute electrolytes'' and asymmetric ionic liquids are considered. As in the case of electrolytes, the main effect of a graphene electrode arises due to its V-shaped quantum capacitance. As a result, the total capacitance of a graphene--ionic liquid interface exhibits a camel-shaped dependence on the total applied potential, even for large ion packing fractions and finite ion correlation lengths. While the minimum at the neutrality point in the total capacitance is``inherited" from the quantum capacitance of graphene, the two peaks that occur at applied potentials of $\sim \pm1$ V are sensitive to the presence of the ion correlation and a Stern layer, which both tend to reduce the height and flatten the peaks in the camel-shaped total capacitance. It is also determined that the largest fraction of the applied potential goes to charging the graphene electrode. When considering the sensitivity of graphene-based sensors to ion concentration and/or pH of the surrounding environment, a site binding model which allows hydrogen and hydroxyl groups to adsorb onto the surface of the device is proposed. Both a regime in which bare graphene is exposed to the electrolyte and a regime where a functionalized oxide, which contains a density of charged impurities to facilitate ion binding, is situated between graphene and the electrolyte are proposed. With regard to the dependence on ion concentration, comparisons between the model and experimental data show good agreement when the finite size of ions is included in the electrolyte. In the case of pH dependence, comparisons between the model and experimental data show excellent agreement, particularly when steric effects are included in the electrolyte. The favourable comparisons here are the first steps in developing a comprehensive model of graphene based biological and chemical sensors.
