In this study, the successful coupling of a 3D printed electrochemical flow cell and online multi-element analysis by ICP-OES is presented. The feasibility of the coupled method is investigated on the ...basis of hot-dip coated steel sheet dissolution in diluted HCl (20%). At first a qualitative evaluation of the electrochemical and element information of the coated steel substrate and relating the results to a glow-discharge optical emission spectroscopy (GDOES) measurement is done. After the qualitative evaluation, the quantitative limits are assessed by validating the linearity, repeatability and reproducibility. Comparing the results to the standard method of bulk analysis shows that the method generates reliable results. In addition the method offers the opportunity of fully automated analysis not just limited to the sample preparation.
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•Fabrication of an electrochemical flow cell by 3D printing.•An electrochemical flow cell was coupled with an ICP-OES.•Dissolution of coated steel sheet.•Depth profile by FC-ICP-OES of coated steel.•Quantitative analysis of hot-dip coated steel.
A study of the electrochemical oxidation of catechol (CA) in the presence of 2-thenoyltrifluoroacetone (TTFA) shows that the electrochemically generated ortho benzoquinone can react with TTFA to form ...a new derivative of 2-thenoyltrifluoroacetone (TCA) as a final product. Conventional electrosynthesis methods including controlled-potential and constant-current methods in both divided and undivided cells have been used for the synthesis of TCA. In addition, a new approach using an electrolyte-free flow cell has been used for the synthesis of TCA and its results have been compared with those obtained from conventional electrosynthesis methods. The results show that the flow method (89% yield) is superior to the batch methods. The proposed method is a one-pot catalyst-free approach with the ability to synthesize the product with high yield and purity which does not require the use of toxic reagents and solvents.
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•Electrochemical synthesis of a new derivative of 2-thenoyltrifluoroacetone.•Controlled-potential synthesis.•Galvanostatic synthesis.•Single-pass electrochemical flow method.•Mechanistic studies.
Electrocatalytic partial oxygen reduction has been considered a more sustainable approach to the synthesis of hydrogen peroxide (H2O2), as compared with current industrial anthraquinone processes. ...One key research need is to explore low-cost active electrocatalysts. Here, we report a facile, solvent-free method to synthesize a metal-free nitrogen-doped ordered mesoporous carbon (N-OMC) by in situ transforming of glycine (carbon and nitrogen precursors) in the mesoporous SiO2 template (KIT-6) followed by subsequent thermal treatment at different temperatures. Among all samples, the catalyst treated at 800 °C (N-OMC-800), the nitrogen-rich carbon, exhibits outstanding structural properties and porosity, showing the dominant formation of pyrrolic-N and graphitic-N. With combined improved structural properties with the optimal ratio of N-pyrrolic/N-graphitic, P/G carbon provided an outstanding electrocatalytic activity, promoting H2O2 with high selectivity and production rate in alkaline mediums. The N-OMC-800 can achieve a faradaic efficiency (FE) of ∼100% to H2O2 at (0.6 VRHE to 0.4 VRHE) in a H-cell containing 0.1 M KOH. Furthermore, its bulk H2O2 electrosynthesis in our self-designed flow cell confirmed its practical capability by showing a remarkable H2O2 production rate of 9.43 mol gcat–1 h–1 at 0.35 VRHE and maintaining nearly 100% FE at the cathode potential of 0.6 VRHE for 12 h without any degradation.
Understanding of less-noble-metal (M) dissolution from Pt-alloy-based oxygen reduction reaction (ORR) electrocatalysts, as well its interaction with Pt surface, is crucial for maximizing their ...performance. In pursuing this goal, two ORR electrocatalystsa benchmark Pt–Co/C and an in-house designed Pt–Cu/C materialsare investigated. Both are characterized with a range of standard techniques, such as X-ray diffraction (XRD), transmission electron microscopy (TEM) combined with energy dispersive spectroscopy (EDX) and thin film-rotating disc electrode (TF-RDE) measurements. A special focus is put on combining the latter with a highly sensitive electrochemical flow cell (EFC) online connected to inductively coupled plasma mass spectrometry (ICP-MS) measurements. A combination of standard and novel techniques provides unprecedented insights into the dissolution behavior and dynamics of metals, as well as their subsequent surface interactions and effects on the electrochemical performance. A special focus is devoted to the significance of electrocatalyst activation protocols and their effects on metal dissolution. Distinct differences in the behavior of Pt–Cu and Pt–Co alloys are revealed, which will help develop proper protocols for practical implementation of Pt-alloy electrocatalysts.
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•Innovative electrochemical approach to oxidative degradation studies.•Electrochemical oxidation is comparable to peroxide mediated oxidation.•Monitoring two degradation mechanisms in ...one experiment.
This article demonstrates the potential of electrochemical oxidation as an alternative approach to studying the effect of oxidation on active pharmaceutical ingredients. The performance and the outcomes of the electrochemical approach are compared to those of the more common approaches such as peroxide mediated, radical, or metal ion oxidation. The effect of oxidation on abacavir and the effect of the solvent were studied. Electrochemical oxidation was performed using an electrochemical flow cell in static mode, with a glassy carbon electrode (working potential 1.3 V) and a boron-doped diamond electrode (working potential 2.5 V) used as the working electrodes. The glassy carbon electrode was used to monitor the oxidative degradation by electron transfer mechanism and boron-doped diamond electrode was used to monitor the degradation by electron transfer and radical mechanism. The largest amounts of degradation products formed by electrochemical oxidation were observed in a cosolvent consisting of 0.5 M aqueous ammonium acetate pH 7.0 with MeOH (1:9; v/v) in 5 h, 10.6 % and 7.1 % of degradation products were formed on glassy carbon electrode and boron-doped diamond electrode, respectively. Peroxide mediated oxidation in 0.3 % hydrogen peroxide for 72 h at ambient temperature yielded the most degradation products, i.e., 8.7 %, in cosolvent consisting of 0.5 M ammonium acetate, pH 7.0, with MeOH (1:1; v/v). The third approach was radical oxidation using AIBN as a radical initiator at a concentration of 20 mol % at 50 °C for 7 days. The most degradation products, i.e., 34.2 %, formed by radical oxidation were observed in pure MeOH. The last approach tested was oxidation using metal ions. A 1.0 mmol/l FeCl3 solution was used and the oxidation took place for 7 days at 50 °C. During the metal ion oxidation, the most degradation products, i.e., 25.7 % were formed in pure MeOH.
A concentric thin layer cell accommodating a non-standard 0.2 mm diameter pencil graphite disposable working electrode is described. The cell was installed into HPLC manifold as an electrochemical ...detector. Trouble-free operation in mobile phases containing both low and high content of organic solvents is demonstrated by HPLC analyses of phenolic acids and tocopherol isomers. The data obtained from HPLC separation of model mixtures of gentisic, caffeic and dihydrocaffeic acids show a remarkable electrolytic efficiency exceeding 80% at 200, and 50% at 500 μL min−1, while for gentisic acid the limit of detection (LOD) was 0.4 nmol L−1 at 20 microliter sample loading (8 fmol on-column). Similar performances were found in non-aqueous mobile phase, where a LOD of 0.8 nmol L−1 was achieved for delta-tocopherol. The developed flow-through detector is designed to allow easy replacement of pencil graphite working electrode in a highly reproducible manner. The relative standard deviation for the HPLC analysis of tocopherol isomers was of 5.3% (n = 3, C = 500 nmol L−1). The combination of simple construction, excellent electrochemical performance and hydrodynamics identical to that of commercial UV-VIS HPLC detector suggests that the proposed device is a viable low-cost alternative to commercially available electrochemical detectors.
In this work, an improved in-situ EPR hydrodynamic electrochemical cell design is constructed and validated. The created platform enables the fast and accurate screening of new electrocatalytic ...materials, providing insights into their effects on radical products of a reaction. Furthermore, it is essential that the reaction kinetics are not influenced by the set-up and that mass transfer can be controlled. Our modular design allows for fast and easy replacement of parts and adjustments to electrodes in order to unravel the catalysts' influence on radical formation. The proximity of the pseudo-reference electrode to the working electrode in combination with the flow and electrode positioning allows for good potential control. The POM housing allows easy manipulation of the channel and excludes the use of sealing agents.
•Electrocatalyst research does sometimes not discriminate between reaction mechanisms.•This setup can provide valuable insights in a radical reaction mechanism.•Modularity, potential control and hydrodynamics provide advantages herein.•The design is validated electrochemically and by EPR spectroscopy.
Electrochemical machining (ECM) is one of the key techniques for fabricating structures on difficult-to-cut materials. It has a potential in the domain of high-end manufacturing because there is no ...post-process heat affected layer or surface stress. This study attempted to utilize a scanning micro electrochemical flow cell (SMEFC) as a method of ECM, which can confine the electrolyte beneath a hollow electrode with the help of a suction head. This method is capable of concentrating the electrolyte on a relatively small region in a controllable way. Without electrolyte splashing, it enables a lower consumption of the electrolyte, an easier integration with other methods and better safety for the operators. An test rig with desirable repeatability has been proposed and the accompanying on-line monitoring system has also been presented. A multi-physics model has been developed to theoretically study the machining process in a SMEFC. The electric field, the flow field and the temperature during the electrochemical dissolution have been analyzed in details. Finally, experiments have been conducted to examine the effects of a series of parameters on the cavity formation process by SMEFC. The microstructures on the machined surface have also been compared and analyzed to reveal the heterogeneous phenomenon. The machining results have shown that the cavity shape and the localization derived via SMEFC can be modulated by several parameters.
Integrated Flow-Cell Arrays (FCAs) represent a combination of integrated liquid cooling and on-chip power generation, converting chemical energy of the flowing electrolyte solutions to electrical ...energy. The FCA technology provides a promising way to address both heat removal and power delivery issues in 3D Multiprocessor Systems-on-Chips (MPSoCs). In this paper we motivate the benefits of FCA in 3D MPSoCs via a qualitative analysis and explore the capabilities of the proposed technology using our extended PowerCool simulator. PowerCool is a tool that performs combined compact thermal and electrochemical simulation of 3D MPSoCs with inter-tier FCA-based cooling and power generation. We validate our electrochemical model against experimental data obtained using a micro-scale FCA, and extend PowerCool with a compact thermal model (3D-ICE) and subthreshold leakage estimation. We show the sensitivity of the FCA cooling and power generation on the design-time (FCA geometry) and run-time (fluid inlet temperature, flow rate) parameters. Our results show that we can optimize the FCA to keep maximum chip temperature below 95 °C for an average chip power consumption of 50 W/cm 2 while generating up to 3.6 W per cm 2 of chip area.
•A 3D FEM model is proposed to simulate the channel generation by scanning micro electrochemical flow cell and jet-ECM.•The key to the simulation model is the introduction of the (virtual) thin ...electrolyte layer.•Validation from the experiments and literature is conducted.
In this research, a three-dimensional (3D) finite element method (FEM) model based on Faraday’s law and moving mesh technique is proposed to simulate the channel machining process in Scanning Micro Electrochemical Flow Cell (SMEFC) and jet electrochemical machining (jet-ECM). The scarcity of available FEM models for the channel fabrication by electrochemical machining (ECM) with confined electrolyte is identified through a brief review of ECM simulation with moving electrode. The detailed information on the model establishment is then presented, including the fundamental principle, the way to construct the geometrical model of the moving electrolyte droplet during the machining process, the boundary settings and some key assumptions. Thanks to the introduction of the virtual electrolyte layer and the moving mesh technique, confined machining of channels by SMEFC can be simulated. In the experimental validation phase, species of the electrolyte (NaNO3 and NaCl), the dimension of the hollow electrodes and the electrochemical equivalent of the workpiece, the machining voltages and feed rates are compared in terms of the channel cross-sectional profiles and errors. The flow field and heat transfer still need to be considered in order to simulate the case with NaNO3 electrolyte in the future. This proposed 3D simulation model can improve the understanding and applicability of channel machining by SMEFC, since the current density distribution and the change of workpiece shape can be calculated simultaneously. With some modifications, this method can be as well extended to the channel machining by jet-ECM. Two case studies of micro scale and meso scale jet-ECM are simulated respectively. The proposed simulation method is a potential way to understand and improve the channel machining process by ECM with confined electrolyte.
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