China
Africa
Explore chapters and articles related to this topic
Fundamentals of Semiconductor Photoelectrochemistry
Published in Anirban Das, Gyandshwar Kumar Rao, Kasinath Ojha, Photoelectrochemical Generation of Fuels, 2023
Mamta Devi Sharma, Mrinmoyee Basu
part of the electrode, i.e., half-cell can be considered like equation 2.8. Here the electrode is dipped in an electrolyte solution and an equilibrium is established between the oxidant and the reductant due to the exchange of electrons for the process. The measured potential of the half-cell is the electrode potential, and in standard conditions, it is named as standard electrode potential.
Electrochemical Methods
Published in Jerome Greyson, Carbon, Nitrogen, and Sulfur Pollutants and Their Determination in Air and Water, 2020
With some reflection it becomes evident, however, that single electrode potentials have no meaning independent of a partner electrode system, because electrical measurements can only be made of differences of potential between electrodes. To accomodate the problem, the hydrogen half cell reaction has been selected as a reference system. That is, its standard potential (E0H) has been defined to be equal to zero. Then, when the concentration of the H+ ions (or HCl) is made equal to one molar (activity = 1) and the hydrogen gas pressure is fixed at one atmosphere (activity = 1) in its cell reaction, its total potential also becomes zero, as reference to Eq. 8.4 illustrates. That specific configuration, which is called the Standard Hydrogen Electrode (SHE), is the configuration to which all other half-cell reactions are referred.
Controlled Electrochemical Deposition for Materials Synthesis
Published in Mu Naushad, Saravanan Rajendran, Abdullah M. Al-Enizi, New Technologies for Electrochemical Applications, 2020
T. Sivaranjani, T. A. Revathy, A. Stephen
The electrolytic cell reaction is studied in two separate sets of reactions. The cathode is merely a half-cell in the whole setup where the reduction takes place and vice versa, i.e., oxidation takes place at the anode. The deposition potential and deposition rate of the same metal differs when a different type of electrolytic bath is employed. In a galvanostatic setup, where the cell is controlled by current, the electrode potential is the potential drop observed in the electrode–electrolyte interface. This potential drop is defined as galvanostatic potential difference, which cannot be measured experimentally since this is not constant and changes from time to time. When a suitable electrolyte and appropriate electrode is chosen, the electrode–electrolyte interface controls the whole electrodeposition process. When a solute (e.g., salt “MA”) is added to the electrolyte, the ions will dissociate into M+ and Ā. The electrolyte is in liquid phase and the substrate (electrode) is in solid phase. When exchange of M+ ions from solution to the substrate happens, the reduction phenomenon will occur at the cathode by the addition of electrons produced by the negative charge of the cathode. This step in electrodeposition is not as simple as we think. At the electrode surface, which is in a solid and liquid heterogeneous phase, the behavior of the double layer has local variations, which possibly affects the deposition kinetics and hence the overall reaction might be altered.
Effect of fly ash and red mud on strength and electrochemical properties of seawater mixed concrete
Published in European Journal of Environmental and Civil Engineering, 2023
Arpit Goyal, Sukhdeo R. Karade
From the findings of the investigations, it can be concluded that it is feasible to use replace 100% freshwater with SW as mixing and curing water for reinforced concrete construction by using FA as cement replacement. The mix with 100% SW and 40% replacement of OPC with FA was identified as the novel mix with compressive and tensile strength close to the traditional concrete at 90 days and even providing enhanced corrosion protection than the traditional concrete. This was confirmed by steel/concrete/electrode half-cell potential and corrosion rate monitoring. Considering the complete replacement of freshwater with abundantly available SW and replacement of 40% OPC with industrial waste satisfies the conditions of sustainable development. Even RM can be used in the mix to impart pigmentation for aesthetic purposes. However, full corrosion mechanism needs to be further studied for the conformity.
A new neutron depth profiling spectrometer at the JCNS for a focused neutron beam
Published in Radiation Effects and Defects in Solids, 2020
E. Vezhlev, A. Ioffe, S. Mattauch, S. Staringer, V. Ossovyi, Ch. Felder, E. Hüger, J. Vacik, I. Tomandl, V. Hnatowicz, C. Chen, P.H.L. Notten, Th. Brückel
The next step in exploring the capabilities of the new spectrometer were the measurements of thin-film Li-ion battery samples in their as-deposited state. Thin-film half cell battery samples of different thicknesses – comprising single electrode film and electrode/electrolyte films were deposited on silicon substrates by metal-organic chemical vapor deposition method (MOCVD). Spectra collected for 90 min from and films are shown in Figure 12. The example of unfolded spectrum for the thickest sample is shown in Figure 13. All samples in this section were deposited with the natural abundance (not exceeding ) of neutron-absorbing isotope Li.
Biodegradation mechanisms of selective laser-melted Mg–xAl–Zn alloy: grain size and intermetallic phase
Published in Virtual and Physical Prototyping, 2018
Cijun Shuai, Chongxian He, Pei Feng, Wang Guo, Chengde Gao, Ping Wu, Youwen Yang, Shizhen Bin
For the electrochemical tests, all the samples were mounted in epoxy resin with only an exposed area of 0.25 cm2. Before the electrochemical measurement, the mounted alloy was ground to 1500 grit successively by silicon carbide papers, then degreased with ethanol and washed with distilled water, then finally dried in warm flown air. The electrolyte was simulated body fluid (SBF) which was prepared according to Kokubo and Takadama (2006). An electrochemical workstation (CHI604D, Chenhua, Shanghai, China) was employed in a three-electrode configuration with 450 mL electrolyte for obtaining the half-cell characterisation of the experiment alloys. In this study, the mounted alloy SLMed ZK30-xAl act as the working electrode. Meanwhile, a saturated calomel electrode (SCE) and a platinum electrode were used as the reference electrode and the counter electrode, respectively. The potential dynamic polarisation curves were done with the sweep rate of 0.5 mV s−1 and were repeated five times for each sample at 37°C. The SLMed ZK30-xAl was firstly immersed in electrolyte to obtain the open circuit potential. Afterwards, the Tafel extrapolation was used to derive the corrosion current densities (Shi et al.2010).