Hasil untuk "Industrial electrochemistry"

Marie Grundmann, Justus Kümper, Sonja D. Mürtz et al.

Electrocatalytic reductive amination (ECRA) offers a sustainable approach for the synthesis of primary amines by replacing stoichiometric reducing agents with electrons and using water as both solvent and proton source. This atom‐efficient strategy minimizes waste, avoids hazardous reagents, and eliminates the need for hydrogen handling. The coupling of ECRA with biomass‐derived substrates underscores the overall sustainability potential of this synthesis approach. However, current ECRA systems are limited by low substrate conversion, poor Faradaic efficiencies, competing side reactions, and high overpotentials. In this work, we overcome these limitations by developing a highly efficient electrocatalytic system for the reductive amination of biomass‐derived levulinic acid as a model reaction. To this end, we use a simple two‐electrode setup operated under galvanostatic conditions combined with the addition of ppm‐amounts of lead as a catalytic additive. We achieve complete substrate conversion, Faradaic efficiencies of up to 70%, and product selectivities exceeding 98%. These findings demonstrate the potential of ECRA as a practical approach for efficient and sustainable primary amine synthesis.

Epiphane Zingbe, Damgou Mani Kongnine, Bienvenu M. Agbomahena et al.

In a plant microbial fuel cell (P-MFC), the plant provides the fuel in the form of exudates secreted by the roots, which are oxidised by electroactive bacteria. The immature plant is hampered by low energy yields. Several factors may explain this situation, including the low open-circuit voltage of the plant cell. This is a function of the development of the biofilm formed by the electroactive bacteria on the surface of the anode, in relation to the availability of the exudates produced by the roots. In order to exploit the fertilising role of biochars, a plant cell was developed from <i>C. citratus</i> and grown in a medium to which 5% by mass of coconut shell biochar had been added. Its effect was studied as well as the distance between the electrodes. The potential of Cymbopogon citratus was also evaluated. Three samples without biochar, with inter-electrode distances of 2, 5 and 7 cm, respectively, identified as SCS2, SCS5 and SCS7, and three with the addition of 5 % biochar, with the same inter-electrode distance values, identified as S2, S5 and S7, were prepared. Open-circuit voltage (OCV) measurements were taken at 6 a.m., 1 p.m. and 8 p.m. The results showed that all the samples had high open-circuit voltage values at 1 p.m. Samples containing 5% biochar had open-circuit voltages increased by 16 %, 8.94% and 5.78%, respectively, for inter-electrode distances of 2, 5 and 7 cm compared with those containing no biochar. Furthermore, the highest open-circuit voltage values were obtained for all samples with <i>C. citratus</i> at an inter-electrode distance of 5 cm. The maximum power output of the PMFC with <i>C. citratus</i> in this study was 75.8 mW/m², which is much higher than the power output of PMFCs in recent studies.

Tamal Krishna Paul, Md. Shohan Parvez, Chowdhury Mashfik Ahmed

Abstract MXenes, a group of two‐dimensional (2D) metal carbides and nitrides, have emerged as promising electrode materials for supercapacitors. This is primarily attributed to their inherent metal‐like electrical conductivity, layered structure, surface redox reactivity, and superior pseudocapacitance through surface functional groups. Owing to its promising features, this material suffers from low mechanical strength, restacking, and unprecedented oxidation. As a result, balancing the electrochemical performance becomes challenging, eventually impeding its potential applications in lightweight, flexible supercapacitor applications. Recent strategies are centered on lighter and more stable filler materials to tackle these issues. Among these, cellulose is considered one of the most effective renewable materials because of its biocompatibility, thermal stability, high surface area, and mechanical reinforcement. Moreover, nanocellulose is capable of hosting other functional materials on its reactive surfaces, ensuring better ion accessibility, and can be used as an electrolyte separator membrane. This review paper aims to provide a comprehensive overview of recent advances in the fabrication strategy, deterministic parameters for capacitive energy‐storage devices, electrochemical behavior, and the performance of MXene/cellulose‐based electrodes in its three‐dimensional aspect (1D, 2D and 3D) for supercapacitor application. Lastly, this review will outline the challenges and prospects of MXene/cellulose‐based composite electrodes in real‐life supercapacitor applications.

Claudia C. Zuluaga-Gómez, Balram Tripathi, Christian O. Plaza-Rivera et al.

In this study, we are reporting the impact of the incorporation of ferroelectric nanoparticles (FNPs), such as BaTiO₃ (BTO), BiFeO₃ (BFO), Bi₄NdTi₃Fe_0.7Ni_0.3O₁₅ (BNTFN), and Bi₄NdTi₃Fe_0.5Co_0.5O₁₅ (BNTFC), as well as the mass loading of sulfur to fabricated solvent-free sulfur/holey graphene-carbon black/polyvinylidene fluoride (S/FNPs/CBhG/PVDF) composite electrodes to achieve high areal capacity for lithium-sulfur (Li-S) batteries. The dry-press method was adopted to fabricate composite cathodes. The hG, a conductive and lightweight scaffold derived from graphene, served as a matrix to host sulfur and FNPs for the fabrication of solvent-free composites. Raman spectra confirmed the dominant hG framework for all the composites, with strong D, G, and 2D bands. The surface morphology of the fabricated cathode system showed a homogeneous distribution of FNPs throughout the composites, confirmed by the EDAX spectra. The observed Li⁺ ion diffusion coefficient for the composite cathode started at 2.17 × 10⁻¹⁶ cm²/s (S₂₅(CBhG)₆₅PVDF₁₀) and reached up to the highest value (4.15 × 10⁻¹⁵ cm²/s) for S₂₅BNTFC₅(CBhG)₆₀PVDF₁₀. The best discharge capacity values for the S₂₅(CBhG)₆₅PVDF₁₀ and S₂₅BNTFC₅(CBhG)₆₀PVDF₁₀ composites started at 1123 mAh/g_s and 1509 mAh/g_s and dropped to 612 mAh/g_s and 572 mAh/g_s, respectively, after 100 cycles; similar behavior was exhibited by the other composites that were among the best. These are better values than those previously reported in the literature. The incorporation of ferroelectric nanoparticles in the cathodes of Li-S batteries reduced the rapid formation of polysulfides due to their internal electric fields. The areal capacity for the S₂₅(CBhG)₆₅PVDF₁₀ composites was 4.84 mAh/cm² with a mass loading of 4.31 mg_s/cm², while that for the S₂₅BNTFC₅(CBhG)₆₀PVDF₁₀ composites was 6.74 mAh/cm² with a mass loading of 4.46 mg_s/cm². It was confirmed that effective FNP incorporation within the S cathode improves the cycling response and stability of cathodes, enabling the high performance of Li-S batteries.

Minjie Lai, Dongying Zhang, Fenghua Chen et al.

Quinone organic materials are promising electrodes for the next lithium-ion batteries (LIBs) owing to their versatile molecular designs, high theoretical capacity, flexibility, sustainability, and environmental friendliness. However, quinone organic electrode materials can easily dissolve in organic electrolytes during the cycling process, which leads to the decay of capacity and poor cycling stability. Here, two metal-organic frames (MOFs), one-dimensional (1D) linear structural anthraquinone-2,3-dicarboxylate zinc coordination polymer (ZnAQDC) and two-dimensional (2D) structural anthraquinone-2,3-dicarboxylate manganese coordination polymer (MnAQDC), are synthesized by using anthraquinone 2,3-dicarboxylic acid, zinc acetate, and manganese acetate in a simple hydrothermal reaction. The formed 1D and 2D structures facilitate the insertion and extraction of lithium ions in and from carbonyl groups of anthraquinone. When MnAQDC is used as cathodes for LIBs, MnAQDC electrodes show an initial discharge capacity of ~63 mAh g⁻¹ at 50 mA g⁻¹. After 200 cycles, the MnAQDC electrode still maintains the specific capacity of ~45 mA h g⁻¹, which exhibits good cycle stability. the ZnAQDC electrode displays a initial discharge capacity of ~85 mA h g⁻¹ at 50 mA g⁻¹, and retains the specific capacity of ~40 mA h g⁻¹ after 200 cycles, showing moderate cyclic performance. The lithium-inserted mechanism shows that lithium ions are inserted and extracted in and from the carbonyl groups, and the valences of the Zn and Mn ions in the two MOFs do not change, and coordination metals do not contribute capacities for the two MOFs electrodes. The strategy of designing and synthesizing MOFs with 1D and 2D structures provides guidance for suppressing the dissolution and improving the electrochemical performance of quinone electrode materials.

Kannan Ramaiyan, Lok-kun Tsui, Eric L. Brosha et al.

Efforts to create a sustainable hydrogen economy are gaining momentum as governments all over the world are investing in hydrogen production, storage, distribution, and delivery technologies to develop a hydrogen infrastructure. This involves transporting hydrogen in gaseous or liquid form or using carrier gases such as methane, ammonia, or mixtures of methane and hydrogen. Hydrogen is a colorless, odorless gas and can easily leak into the atmosphere leading to economic loss and safety concerns. Therefore, deployment of robust low-cost sensors for various scenarios involving hydrogen is of paramount importance. Here, we review some recent developments in hydrogen sensors for applications such as leak detection, safety, process monitoring in production, transport and use scenarios. The status of methane and ammonia sensors is covered due to their important role in hydrogen production and transportation using existing natural gas and ammonia infrastructure. This review further provides an overview of existing commercial hydrogen sensors and also addresses the potential for hydrogen as an interferent gas for currently used sensors. This review can help developers and users make informed decisions about how to drive hydrogen sensor technology forward and to incorporate hydrogen sensors into the various hydrogen deployment projects in the coming decade.

Noelia A. Palacios, María L. Vera, Victoria Flexer

Cong Zhou, Jing Liu, Weiwei Zhuo

In this work, an electrochemical sensor of Gonadotropin-releasing hormone (GnRH) agonists was proposed by deposition of the conductive nanocomposite of Ag and graphene oxide on glassy carbon electrode (Ag-GO/GCE) and electropolymerization of poly(L-Serine) on nanocomposite (p-L-serine/Ag-GO/GCE). Because of excellent conductivity between Ag nanoparticles and graphene oxide nansheets, and synergic catalytic effect of Ag-GO nanocomposite and the conducting polymer, the developed GnRH sensor provides a highly porous surface and a larger effective surface area, which facilitates electron transfer and promotes the electro-catalytic performance. p-L-serine/Ag-GO/GCE exhibited good electro-catalytic and selectivity with a sensitivity of 0.74036 μA/μgml-1, a linear range of 1 to 15×107 μg/ml, and a low detection limit of 20 pg/ml (S/N = 3). Moreover, the p-L-serine/Ag-GO/GCE was successfully applied for the determination of GnRH in real blood serum of patients aged 40-50 years old who administrated GnRH for treatment of uterine fibroids and the obtained RSD≤4.20% was demonstrated to good accuracy of p-L-serine/Ag-GO/GCE for the determination of GnRH in patient blood serum and in clinical applications.

Steffen Oswald

Li-based batteries are a key element in reaching a sustainable energy economy in the near future. The understanding of the very complex electrochemical processes is necessary for the optimization of their performance. X-ray photoelectron spectroscopy (XPS) is an accepted method used to improve understanding around the chemical processes at the electrode surfaces. Nevertheless, its application is limited because the surfaces under investigation are mostly rough and inhomogeneous. Local elemental analysis, such as Auger electron spectroscopy (AES), could assist XPS to gain more insight into the chemical processes at the surfaces. In this paper, some challenges in using electron spectroscopy are discussed, such as binding energy (BE) referencing for the quantitative study of chemical shifts, gas atmospheric influences, or beam damage (including both AE and XP spectroscopy). Carefully prepared and surface-modified metallic lithium material is used as model surface, considering that Li is the key element for most battery applications.

Rasha Rahman Poolakkandy, Mini Mol Menamparambath

Abstract Diagnosis of brain disorders is an extremely confronting task for the medical community and hence, the recognition and detection of pertinent biomarkers for neurological disorders is a crucial phase. Electrochemical techniques with transition metal oxide (TMOs) modified electrodes have emerged as a promising technique for the detection of neurotransmitters, which act as potent biomarkers. This review has tried to sum up the recent advancements made in the TMOs modified non‐enzymatic electrochemical detection of important neurotransmitters in the last two decades. A comprehensive description of these neurotransmitters along with their biochemistry and impact on the human body is also provided. A short description of the future perspectives of the electrochemical detection of neurotransmitters is given highlighting the wearable sensors for the in vivo detection.

Qianqian Ji, Xi Xu, Xuehua Liu et al.

Partial substitution of lanthanum with strontium yields lanthanum strontium manganite (La1-xSrxMnO3, 0 < x < 1). In this work, lanthanum strontium manganite catalysts with x = 0, 0.2, 0.4, 0.6 and 0.8 are synthesized and characterized, and their catalytic properties for the oxygen reduction reaction (ORR) are studied both experimentally and theoretically. It is found that the catalyst with x = 0.6 (La0.4Sr0.6MnO3) displays the highest ORR activity. To further improve the catalytic performance of this catalyst, porous La0.4Sr0.6MnO3 is prepared using carbon spheres as pore-forming templates. The results show that use of a moderate amount of carbon spheres helps to improve the ORR activity.

Pattarachai Srimuk, Lei Wang, Öznil Budak et al.

Electrochemical processes enable a new generation of energy-efficient desalination technologies. While ion electrosorption via capacitive deionization is only suitable for brackish water with low molar strength, the use of Faradaic materials capable of reversible ion intercalation or conversion reactions allows energy-efficient removal of ions from seawater. However, the limited charge transfer/storage capacity of Faradaic materials indicates an upper limit for their desalination applications. Therefore, a new electrochemical concept must be explored to exceed the current state-of-the-art results and to push the desalination capacity beyond 100–200 mgNaCl/gelectrode. In this proof-of-concept work, we introduce the new concept of using metal–air battery technology for desalination. We do so by presenting performance data for zinc–air desalination (ZAD) in 600 mM NaCl. The ZAD cell provides a desalination capacity of 0.9–1.0 mgNaCl/cm2 (normalized to the membrane area; corresponding to 1300 mgNaCl/gZn) with a charge efficiency of 70% when charging/discharging the cell at 1 mA/cm2. The energy consumption of ZAD is 68–92 kJ/mol.

Gaosheng Nie, Shizhen Dai, Hangchun Deng et al.

Composites of ultrafine tin dioxide nanoparticles grown on nitrogen-doped graphene (SnO2@NG) with high pyrrolic nitrogen content are successfully prepared via a one-step method by employing graphene oxide, tin chloride, and urea as raw materials. Morphology and microstructure of SnO2@NG are characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA), revealing evenly dispersed SnO2 nanoparticles on the surface of nitrogen-doped graphene sheets and a SnO2 content of 54.23%. The SnO2@NG electrode exhibits a specific capacitance of 289.5 F/g at a current density of 0.5 A/g in 0.5 mol/L Na2SO4 solution and retains 92.85% of its initial capacitance after 2000 charge/discharge cycles. These results prove that SnO2@NG is an excellent material for high-performance supercapacitors.

Liang Huang, Yan Cao, Feng Jia et al.

With the widespread application of non-conducting tough materials, such as glass in MEMS recent years, many difficulties have arisen in the processing of these kind of material with eigen-structure characteristics. In this paper, based on the technical advantages of electrochemical discharge machining, the mechanism of tool electrode structure and process parameters for the stability of gas film, processing efficiency and forming quality is analysed, and the machining of a glass micro-array hole is accomplished by obtaining the optimal process parameters.

Kuo-Lin Huang, Shi-Jie Huang

This study focuses on the electrochemical degradation of acetaminophen (AP) in the presence of individual redox mediators. The oxidation peaks of Fe(II), Ag(I), and sulfate were detected on a Windsor boron-dopped diamond (BDD) electrode in 1 M Na2SO4. The AP degradation performance using a single mediator was in the following order: Ce(IV) (from Ce(SO4)2) > Fe(III) (from Fe(NO3)3 or FeCl3) > Co(II) (from C0Cl2) ≈ Ag(I) (from AgNO3). p-BQ due to AP degradation was observed in 1 M Na2SO4 in the presence of Ce(IV) and Fe(III), while the former exhibited more and faster p-benzoquinone (p-BQ) generation than the latter. In the presence of individual mediators in 1 M Na2SO4 or NaNO3, the performance of electrochemical AP degradation, p-BQ removal, and TOC mineralization on a Diachem BDD anode occurred in the following order: Fe(III) > Ce(IV) > Fe(II) ≈ Co(II) > Ag(I), but the performance decreased when replacing Na2SO4 with NaNO3 as the electrolyte. The Cl2/Cl- redox mediator could also enhance AP degradation and TOC mineralization. The apparent pseudo first-order rate constants for AP electrochemical degradation in these solutions ranged from 2.92×10-4-4.34x10-2 1/s. An Fe(III) dosage of 100 ppm (Fe(III)/AP mole ratio = 2.7) at 0.25 A/cm2 is suggested for this electrochemical process although Fe(III) dosage in the range of 50-500 ppm could be considered. Fe(III) has good potential for use in the elctrochemical advanced oxidation process (EAOP) to significantly improve organic pollutant degradation performance.

Yan Zhang, Yu Zhou, Zonghua Wang et al.

Exploring cheap and stable electrocatalyst for the oxygen reduction reaction (ORR) is now an important issue for the large-scale application of fuel cells. Herein, we have demonstrated a facile synthesis of Nitrogen-doped porous carbons (NPC-MILs) for oxygen reduction reaction by using an amine functionalized Al-MOFs (NH2-MIL-53(Al)) as the precursor with both nitrogen source and carbon source. NPC-MILs as metal-free electrocatalysts are demonstrated promising potential for ORR. The optimized NPC-MIL-900 (carbonized at 900 °C) exhibits a likeness four-electron process and its ORR catalytic activity can be comparable to commercial Pt/C. Furthermore, chronoamperometric measurement shows that only 13% loss at the current density is occurred after 40000 s, whereas the corresponding current density loss at the Pt/C (20wt%) is as high as 31%. Chronoamperometric responses also show the NPC-MIL-900 catalyst has higher resistance to methanol in alkaline electrolyte than Pt/C. Those indicate that the NPC-MIL-900 has potential application in fuel cells.

Hao Wu, Honglei Li, Puheng Yang et al.

To enhance the initial coulombic efficiency, cyclic stability and electronic conductivity of lithium-rich cathode material Li1.2Mn0.6Ni0.2O2, surface modification is carried out by a facile chemical oxidation polymerization method with pyrrole monomer. The comparison between bare and polypyrrole-coated samples on the structure, morphology and electrochemical properties are investigated and analyzed. Despite sacrificed a part of initial capacity, the initial coulombic efficiency, the cyclic stability and electronic conductivity have been improved.

Ya-wei Hu, Wei Wang, Huai-en Li et al.

Using a hydrothermal technique, the present study demonstrated the synthesis of a Cu metal–organic framework (Cu-MOF), [Cu(adp)(BIB)(H2O)]n (BIB = 1,4-bisimidazolebenzene; H2adp = adipic acid). Carbendazim was successfully detected by an ultra-sensitive and facile electrochemical sensor fabricated based on the [Cu(adp)(BIB)(H2O)]n-coated GCE via differential pulse voltammetry. The present study employed [Fe(CN)6]3−/4− as an electrochemical probe to investigate the electrochemical properties of our developed sensor. The charge transfer rate and electrode surface of the [Cu(adp)(BIB)(H2O)]n/GCE were both more favourable compared to those of the bare GCE. Cyclic voltammetry results suggested a desirable electrochemical performance of our developed sensor towards the detection of carbendazim. Our developed sensor was excellent towards the electrochemical oxidation of the analyte. In addition, the as-prepared electrochemical sensor showed great potential for the detection of carbendazim in water samples.

Wen Zheng, Wenshu Zhao, Wei Chen et al.

In this paper the effect of carboxyl graphene (G-COOH) on the electrochemical behavior of myoglobin (Mb) was investigated in detail. A Nafion, Mb and G-COOH modified carbon ionic liquid electrode (CILE) was constructed and applied to electrochemical biosensing. G-COOH with high conductivity and good biocompatibility could act as an electron transfer bridge for enhancing the electron transfer reactivity of Mb. In phosphate buffer solution (pH 6.0) Mb exhibited a pair of good-shape redox peaks on cyclic voltammogram with the formal peak potential (E0′) as -0.255 V (vs. SCE). Electrochemical studies of Mb were checked with electrochemical parameters calculated. Mb molecules on the electrode displayed excellent electrocatalytic reduction to trichloroacetic acid (TCA). The current showed a linear response to TCA concentrations from 5.0 to 57.0 mmol L-1 with a low detection limit (1.0 mmol L-1). The Michaelis–Menten constant (KM app) of the fabricated Mb bioelectrode for TCA was determined as 1.30 mmol L-1. Therefore the usage of G-COOH established an effective platform for direct electrochemistry of redox enzymes in the field of third-generation electrochemical sensor.

O.A. Omotosho, C.A. Loto, O.O. Ajayi et al.

Potential monitoring experiments were performed on steel rebars embedded in concrete admixed with potassium chromate, aniline and their synergetic combinations with fixed amount of sodium chloride salt partially immersed in sulphuric acid and sodium chloride solution. Two-sets of fifteen steel-rebar concrete specimens were employed for the study and potential readings were taken in accordance with ASTM C 876. Quality and consistency of the inhibitor was then estimated by the Weibull probability density distribution as an extreme value statistical modeling approach to study the efficacy and predict the most efficient inhibitor concentration in each media. The effect of the inhibitors on the compressive strengths of the test samples was also conducted. Results revealed that test sample admixed with 0.15M potassium chromate partially immersed in sulphuric acid medium exhibited the best overall performance while 0.34M aniline admixture was identified as exhibiting the best performance in the sodium chloride medium. The results also show that the admixture combination of 0.15M potassium chromate and 0.07M aniline in the sodium chloride medium produced the best result amongst the synergistic combination used. Control sample in the saline medium gave the highest increase in compressive strength (330KN) amongst all the samples considered. Also, in the NaCl medium the 0.14M aniline admixture gave the highest increase in compressive strength amongst the inhibited samples. However, the 0.41M aniline admixture gave the highest increase in compressive strength amongst all the samples considered in the H2SO4 medium.