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Smart Wireless Nanosensor Systems for Human Healthcare
Published in Suresh Kaushik, Vijay Soni, Efstathia Skotti, Nanosensors for Futuristic Smart and Intelligent Healthcare Systems, 2022
Voltammetric methods measure current response as a result of applied potential. The potential can be varied step by step or continuously between a working and reference electrode. Three electrodes—working, auxiliary/counter, and reference (Figure 1d)—are mostly used in voltammetric aptasensors for accurate and stable application of potentials and the current measurement (Manurung et al. 2012). Cyclic voltammetry (CV) and pulse voltammetry (e.g., Differential Pulse Voltammetry) are two commonly used voltammetric techniques. Cyclic voltammetry technique involves varying the applied potential in forward and reverse directions at the working electrode and measuring the current. The resulting current is plotted against the applied potential to produce a CV graph. Contrarily, the DPV uses a series of potential pulses of fixed amplitude which is superimposed on a slowly changing base potential and measures current at two points for each pulse just before the application of the pulse and at the end of the pulse (Bertrand 1998).
Use of Vertically Aligned Carbon Nanotubes for Electrochemical Double-Layer Capacitors
Published in James E. Morris, Krzysztof Iniewski, Nanoelectronic Device Applications Handbook, 2017
Adrianus I. Aria, Mélanie Guittet, Morteza Gharib
Cyclic voltammetry is a very common and widely used electrochemical characterization technique, because of its ability and effectiveness to quickly observe an electrochemical behavior over a wide potential range. It is basically a cyclic measurement of potential-dependent current when the potential is varied linearly across the potential window at a constant scan rate. Since, in principle, capacitors are free from Faradaic redox reactions, the plot of current versus potential (called voltammogram) of ideal capacitors is perfectly rectangular. The gravimetric specific capacitance (CG) of an ideal capacitor is given by the following relation:() CG=I(dV/dt)m
Electrochemical Techniques
Published in Jagriti Narang, Chandra Shekhar Pundir, Biosensors, 2017
Jagriti Narang, Nitesh Malhotra, Chandra Shekhar Pundir
Cyclic voltammetry is a versatile electrochemical technique that helps in getting information about an analyte by measuring current as a function of the applied potential. It allows investigation of the mechanism of the redox process and the transport properties of a system in solution. In this system, three types of transport mechanisms are involved: (i) migration—movement of ions through the solution by electrostatic attraction to the charged electrode, (ii) convection—mechanical motion of the solution as a result of stirring or flow, and (iii) diffusion—motion of a species caused by a concentration gradient.
Development and characterization of Zn–Ni, Zn–Co and Zn–Ni–Co coatings
Published in Surface Engineering, 2020
Ramesh S. Bhat, Vinayak B. Shet
Cyclic voltammetry is used to characterize the electrochemical behaviour and kinetics of electrochemical reactions and mechanisms including the quantitative investigations. The procedure consists of varying the electrode potential in a linear manner between two confines [29]. In Zn–Ni, Zn–Co and Zn–Ni–Co bath was observed that an additive (SA) has a significant effect on the uniformity and brightness of the deposits by varying the plating conditions. Hence, the presence and absence of adding additive (SA) in the bath was tested. In the case of Zn–Ni and Zn–Co bath, absence of SA the electrochemical oxidation curve showed multiple peaks as shown in Figure 6(a,b). This corresponds to the dissolution of the metals in the alloy, via different transitional phases]. Further, when additive (SA) was added to the Zn–Ni bath, the shape of voltammogram changed significantly with one major peak at −0.69 V and one minor peak at −0.27 V corresponding to dissolution of alloys at two different phases (Figure 6(a)).
Energy storehouse and a remarkable photocatalyst: Al2S3/Cu2S/Ni17S18 thin film as supercapacitor electrode and pollutants degradation
Published in Surface Engineering, 2023
Mahwash Mahar Gul, Khuram Shahzad Ahmad
where ʃidV = area of the CV curve, m = mass of the synthesised material, Vs = scan rate, ΔV = potential window. The calculated value of specific capacitance was 595 F g−1. The impressive Cs value indicates the presence of high number of electroactive sites for the electrochemical processes to occur. The anodic peak (Ipa) was obtained at 1.31 A whereas the cathodic peak (Ipc) was detected at −1.7 A. The energy storage ability is evident from the stretched CV curve indicating its supercapacitor performance. A comparison of specific capacitance of various electrode with the present study is presented in Table 2. Cyclic voltammetry is a powerful electroanalytical technique that measures the current response of an electrochemical cell as a function of applied potential. During CV of metal sulphides, several physical and surface phenomena can occur, depending on the specific metal sulphide and experimental conditions. For e.g. the faradaic reactions. Metal sulphides can undergo electrochemical reactions, such as oxidation or reduction, at their surfaces in response to the applied potential. These reactions involve the transfer of electrons between the metal sulphide and the electrolyte solution, leading to changes in the current and potential signals observed in CV. The specific reaction mechanisms depend on the metal sulphide and the surrounding solution chemistry. In addition to Faradaic reactions, metal sulphides can also exhibit capacitive behaviour during CV. This occurs when the applied potential induces charging or discharging of the electrical double layer at the metal sulphide/electrolyte interface, leading to a capacitive current response. Furthermore, the diffusion of species in the electrolyte solution to the metal sulphide surface can also affect the CV response. Depending on the experimental conditions, mass transport can be limiting, leading to concentration gradients near the metal sulphide surface that can influence the kinetics of Faradaic reactions. Overall, the specific physical and surface phenomena occurring during CV of metal sulphides depend on a diversity of features, comprising the properties of the metal sulphide, the composition of the electrolyte solution, and the experimental parameters used for CV. In present study reduction and oxidation reactions were seen through the voltammograms as a function of applied potential. The mechanisms that govern CV are related to the fundamental principles of electrochemistry, including the flow of electrons through the circuit due to Faradaic reactions, the dispersion of electroactive species to the electrode surface, the capacitance of the electrical double layer, and the kinetics of the electrochemical reactions.