Nguyen Trung Kien, Haruki Yara, Masanobu Chiku, E. Higuchi, Hiroshi Inoue
PtxRh1−x (x = 0.76, 0.54, and 0.27) solid solutions were prepared by arc-melting. For these solid solutions, the lattice constant was linearly related to the Pt content. The surface compositions of the solid solutions determined by X-ray photoelectron spectroscopy were quite similar to their bulk compositions estimated by energy dispersive X-ray spectroscopy. The CO-stripping voltammograms demonstrated that the onset potential of CO oxidation current density (Eonset) shifted negatively as the surface Pt content decreased, suggesting an increased CO-poisoning resistance. Linear sweep voltammograms of the solid solution electrodes in an Ar-saturated (1 M ethanol + 0.1 M HClO4) solution exhibited that the onset potentials of ethanol oxidation reaction (EOR) current for all solid solution electrodes were lower than of a Pt electrode, and Pt0.54Rh0.46 gave the highest specific activity (SA) of 312 μA·cm−2, which was about 1.8 and 2.5 times higher than the SAs of Pt and Rh, respectively. In situ infrared reflection-absorption spectra exhibited that the Pt0.54Rh0.46 electrode had the bands due to the linear-bonded CO on Pt and bridge-bonded CO on Rh as EOR intermediates around 0.2 V vs. the reversible hydrogen electrode, but the band due to the linear-bonded CO on Rh was not observed even at 0.6 V, suggesting that the existence of the adjacent Pt-Rh sites and the preferential formation of bridge-bonded CO on Rh accelerated the C-C bond cleavage and improved the EOR activity.
通过电弧熔化法制备了 PtxRh1-x（x = 0.76、0.54 和 0.27）固溶体。这些固溶体的晶格常数与铂含量成线性关系。用 X 射线光电子能谱测定的固溶体表面成分与用能量色散 X 射线能谱估计的体积成分非常相似。一氧化碳剥离伏安图表明，一氧化碳氧化电流密度的起始电位（Eonset）随着表面铂含量的降低而负移，这表明一氧化碳中毒电阻增加。固溶体电极在 Ar 饱和（1 M 乙醇 + 0.1 M HClO4）溶液中的线性扫描伏安图显示，所有固溶体电极的乙醇氧化反应（EOR）电流起始电位均低于铂电极，其中 Pt0.54Rh0.46 的比活度（SA）最高，为 312 μA-cm-2，分别是 Pt 和 Rh 比活度的 1.8 倍和 2.5 倍。原位红外反射吸收光谱显示，与可逆氢电极相比，Pt0.54Rh0.46 电极在 0.2 V 左右出现了铂上线性键合 CO 和 Rh 上桥键合 CO 作为 EOR 中间产物产生的带，但即使在 0.6 V 时也没有观察到 Rh 上线性键合 CO 产生的带，这表明相邻 Pt-Rh 位点的存在和 Rh 上桥键合 CO 的优先形成加速了 C-C 键的裂解，提高了 EOR 活性。
{"title":"Effect of Surface Composition on Electrochemical Oxidation Reaction of Carbon Monoxide and Ethanol of PtxRh1−x Solid Solution Electrodes","authors":"Nguyen Trung Kien, Haruki Yara, Masanobu Chiku, E. Higuchi, Hiroshi Inoue","doi":"10.1155/2023/2386013","DOIUrl":"https://doi.org/10.1155/2023/2386013","url":null,"abstract":"PtxRh1−x (x = 0.76, 0.54, and 0.27) solid solutions were prepared by arc-melting. For these solid solutions, the lattice constant was linearly related to the Pt content. The surface compositions of the solid solutions determined by X-ray photoelectron spectroscopy were quite similar to their bulk compositions estimated by energy dispersive X-ray spectroscopy. The CO-stripping voltammograms demonstrated that the onset potential of CO oxidation current density (Eonset) shifted negatively as the surface Pt content decreased, suggesting an increased CO-poisoning resistance. Linear sweep voltammograms of the solid solution electrodes in an Ar-saturated (1 M ethanol + 0.1 M HClO4) solution exhibited that the onset potentials of ethanol oxidation reaction (EOR) current for all solid solution electrodes were lower than of a Pt electrode, and Pt0.54Rh0.46 gave the highest specific activity (SA) of 312 μA·cm−2, which was about 1.8 and 2.5 times higher than the SAs of Pt and Rh, respectively. In situ infrared reflection-absorption spectra exhibited that the Pt0.54Rh0.46 electrode had the bands due to the linear-bonded CO on Pt and bridge-bonded CO on Rh as EOR intermediates around 0.2 V vs. the reversible hydrogen electrode, but the band due to the linear-bonded CO on Rh was not observed even at 0.6 V, suggesting that the existence of the adjacent Pt-Rh sites and the preferential formation of bridge-bonded CO on Rh accelerated the C-C bond cleavage and improved the EOR activity.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139271740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, solid polymer electrolytes (SPEs) are based on methylcellulose (MC) used as a polymer host and sodium iodide (NaI) as a dopant. The SPE films are developed using different contents of ethyl carbonate (EC) as a plasticizer to enhance their properties via a solution casting method. The surface morphology of SPE films is shown using polarized optical microscopy (POM), which indicates the existence of amorphous patches due to the plasticizing effect of EC. The creation of a complex between MC, NaI, and EC was confirmed by Fourier transform infrared (FTIR) spectra. A tiny amount of EC applied to the MC-NaI polymer salt matrix increases the number of charge carriers and improves ionic conductivity. The ionic conductivity of the generated polymer electrolytes is examined using electrochemical impedance spectroscopy (EIS). The high-ion conducting PE of 5.06 × 10−3 S·cm−1 was found with the mixture MC + 50 wt% NaI + 10 wt% EC (room temperature). The linear speed voltammetry (LSV) test shows that the optimized polymer electrolyte can withstand decomposition up to 2.5 V. The optimized sample transmission numbers were calculated using a TNM (transference number measurement) approach, and the results show that 99% of the ions contribute to the conductivity, compared to only 1% of the electrons. A solid-state electrical double-layer capacitor (EDLC) was fabricated using the highest ion-conductive polymer electrolyte and graphene oxide (GO)-based electrodes. The galvanostatic charge-discharge (GCD) technique was performed, and the GCD graph shows the behavior of an ideal capacitor with a less Faradic process and a low ESR value. The GO-based cell’s columbic efficiency is 100%, and the system delivers the charge for a long duration. The EDLC cell demonstrates outstanding cyclability. The specific capacitance of the EDLC cell incorporated with MC + 50 wt. % NaI + 10 wt. % EC was found to be 154.66 F/g.
{"title":"Development and Characterization of a New Solid Polymer Electrolyte for Supercapacitor Device","authors":"Theodore Azemtsop Manfo","doi":"10.1155/2023/4825624","DOIUrl":"https://doi.org/10.1155/2023/4825624","url":null,"abstract":"In this study, solid polymer electrolytes (SPEs) are based on methylcellulose (MC) used as a polymer host and sodium iodide (NaI) as a dopant. The SPE films are developed using different contents of ethyl carbonate (EC) as a plasticizer to enhance their properties via a solution casting method. The surface morphology of SPE films is shown using polarized optical microscopy (POM), which indicates the existence of amorphous patches due to the plasticizing effect of EC. The creation of a complex between MC, NaI, and EC was confirmed by Fourier transform infrared (FTIR) spectra. A tiny amount of EC applied to the MC-NaI polymer salt matrix increases the number of charge carriers and improves ionic conductivity. The ionic conductivity of the generated polymer electrolytes is examined using electrochemical impedance spectroscopy (EIS). The high-ion conducting PE of 5.06 × 10−3 S·cm−1 was found with the mixture MC + 50 wt% NaI + 10 wt% EC (room temperature). The linear speed voltammetry (LSV) test shows that the optimized polymer electrolyte can withstand decomposition up to 2.5 V. The optimized sample transmission numbers were calculated using a TNM (transference number measurement) approach, and the results show that 99% of the ions contribute to the conductivity, compared to only 1% of the electrons. A solid-state electrical double-layer capacitor (EDLC) was fabricated using the highest ion-conductive polymer electrolyte and graphene oxide (GO)-based electrodes. The galvanostatic charge-discharge (GCD) technique was performed, and the GCD graph shows the behavior of an ideal capacitor with a less Faradic process and a low ESR value. The GO-based cell’s columbic efficiency is 100%, and the system delivers the charge for a long duration. The EDLC cell demonstrates outstanding cyclability. The specific capacitance of the EDLC cell incorporated with MC + 50 wt. % NaI + 10 wt. % EC was found to be 154.66 F/g.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136014491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, various-sized nitrogen-doped carbon nanotubes (NCNTs) were fabricated by varying the concentration of chlorine in the feed. The diameter of the NCNTs was found to influence the sensing ability of the nanomaterials when coated onto the glassy carbon electrode (GCE) and used for the detection of catechol (CC) and resorcinol (RS). Larger diameter NCNTs (denoted NCNTs (2 : 1)) were produced when a low concentration of chlorine was added into the acetonitrile feed, whereas smaller diameter NCNTs (denoted NCNTs (1 : 2)) were produced when a large concentration of chlorine was added. This investigation revealed that the addition of controllable amounts of chlorine during the fabrication of NCNTs led to the creation of nanostructures with different properties. The greatest current response which was evidenced by an enhanced anodic peak of CC and RS was obtained when GCE was coated with NCNTs (2 : 1), and this was attributed to their large diameter and high graphitic nature which facilitated electron transfer as evidenced by scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analysis. A linear response was obtained when varying the concentration of both CC and RS, with the limits of detection of about 0.059 μM (CC) and 0.034 μM (RS) (3S/M) obtained.
{"title":"Size-Dependent Chlorinated Nitrogen-Doped Carbon Nanotubes: Their Use as Electrochemical Detectors for Catechol and Resorcinol","authors":"W. K. Maboya, Mologadi Nkiyasi Rantho","doi":"10.1155/2023/7977453","DOIUrl":"https://doi.org/10.1155/2023/7977453","url":null,"abstract":"In this study, various-sized nitrogen-doped carbon nanotubes (NCNTs) were fabricated by varying the concentration of chlorine in the feed. The diameter of the NCNTs was found to influence the sensing ability of the nanomaterials when coated onto the glassy carbon electrode (GCE) and used for the detection of catechol (CC) and resorcinol (RS). Larger diameter NCNTs (denoted NCNTs (2 : 1)) were produced when a low concentration of chlorine was added into the acetonitrile feed, whereas smaller diameter NCNTs (denoted NCNTs (1 : 2)) were produced when a large concentration of chlorine was added. This investigation revealed that the addition of controllable amounts of chlorine during the fabrication of NCNTs led to the creation of nanostructures with different properties. The greatest current response which was evidenced by an enhanced anodic peak of CC and RS was obtained when GCE was coated with NCNTs (2 : 1), and this was attributed to their large diameter and high graphitic nature which facilitated electron transfer as evidenced by scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analysis. A linear response was obtained when varying the concentration of both CC and RS, with the limits of detection of about 0.059 μM (CC) and 0.034 μM (RS) (3S/M) obtained.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46768474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Mohsin, Luca Schneider, Zheng Yu, Wenqing Cai, C. Ziebert
NaMnPO4 and NaFePO4, polyanion cathode materials, exist in two different phases maricite/natrophilite and maricite/olivine, respectively. Both natrophilite NaMnPO4 and olivine NaFePO4 are electrochemically active and possess a one-dimensional tunnel for sodium-ion migration; however, these two phases are thermodynamically unstable. Therefore, they can be synthesized through an electrochemical route. On the contrary, maricite (m)-NaMnPO4 and maricite (m)-NaFePO4 are thermodynamically stable forms but have a huge activation energy of their diffusion pathways for sodium extraction and insertion in the crystal structure, which hinders electrochemical reactions. Therefore, the electrochemical behaviour of commercial m-NaMnPO4 and m-NaFePO4 has been studied to find a way for enabling them electrochemically. Ball milling and thermal/mechanical carbon coating are employed to reduce the particle size to enhance the electrochemical performance and shorten the diffusion pathway. Moreover, ball milling leads to defects and partial phase transformation. The electrochemical performance of milled-coated NaMnPO4 and NaFePO4 has been thoroughly investigated and compared. The phase transition of NaFePO4 is revealed by a differential scanning calorimeter. As a result, the achievable capacities of both cathode materials are significantly enhanced up to ∼50 mAh.g−1 via the particle size reduction as well as by carbon coating. However, the side reactions and agglomeration problems in such materials need to be minimized and must be considered to enable them for applications.
{"title":"Enabling the Electrochemical Performance of Maricite-NaMnPO4 and Maricite-NaFePO4 Cathode Materials in Sodium-Ion Batteries","authors":"I. Mohsin, Luca Schneider, Zheng Yu, Wenqing Cai, C. Ziebert","doi":"10.1155/2023/6054452","DOIUrl":"https://doi.org/10.1155/2023/6054452","url":null,"abstract":"NaMnPO4 and NaFePO4, polyanion cathode materials, exist in two different phases maricite/natrophilite and maricite/olivine, respectively. Both natrophilite NaMnPO4 and olivine NaFePO4 are electrochemically active and possess a one-dimensional tunnel for sodium-ion migration; however, these two phases are thermodynamically unstable. Therefore, they can be synthesized through an electrochemical route. On the contrary, maricite (m)-NaMnPO4 and maricite (m)-NaFePO4 are thermodynamically stable forms but have a huge activation energy of their diffusion pathways for sodium extraction and insertion in the crystal structure, which hinders electrochemical reactions. Therefore, the electrochemical behaviour of commercial m-NaMnPO4 and m-NaFePO4 has been studied to find a way for enabling them electrochemically. Ball milling and thermal/mechanical carbon coating are employed to reduce the particle size to enhance the electrochemical performance and shorten the diffusion pathway. Moreover, ball milling leads to defects and partial phase transformation. The electrochemical performance of milled-coated NaMnPO4 and NaFePO4 has been thoroughly investigated and compared. The phase transition of NaFePO4 is revealed by a differential scanning calorimeter. As a result, the achievable capacities of both cathode materials are significantly enhanced up to ∼50 mAh.g−1 via the particle size reduction as well as by carbon coating. However, the side reactions and agglomeration problems in such materials need to be minimized and must be considered to enable them for applications.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43967025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anabolic-androgenic steroids (AASs), a class of compounds frequently misused by competitors and unfortunately by the general population, have lately attracted international attention. Thus, extraordinary demands for developing low cost, precise, rapid, and facile protocols for detection and/or determination of AAS have arisen. Hence, the current strategy explores for the first time the redox features of 21-hydroxypregn-4-ene-3, 20-dione, namely, 11-desoxycorticosterone (DCS) AA drug steroid at a glassy-carbon electrode (GCE) in a wide pH range (pH 2.0–10.0) by adsorptive differential pulse-anodic stripping voltammetry (DP- ASV) and cyclic voltammetry (CV). At pH 2, DP-ASV and CV at the optimized pH 2–3 displayed an irreversible anodic peak at 0.4 V versus Ag/AgCl electrode. The dependency of the anodic peak current of the CV at 0.4 V at various concentrations and scan rate of the DCS drug was characteristic of an electrode-coupled electron transfer of EE type mechanism. At the optimized parameters, the proposed strategy allowed quantification of DCS in the concentration range 2.5 -13.19 nM (0.83-4.36 ng mL−1) with satisfactory limits of detection (LOD) and quantization (LOQ) of 9.3 × 10−1 nM (3.1 × 10−1 ng mL−1) and 3.1 nM (1.02 ng mL−1), respectively. A relative standard deviation (RSD) of ±3.93% (n = 5) at 4.0 ng mL−1 DCS was achieved. The established probe was fruitfully employed and validated for trace determination of DCS residues in environmental water. The interference of several common diverse species on DCS sensing was insignificant revealing good selectivity. The established probe exhibited good sensitivity, selectivity, precision, and accuracy, short analytical time, and low cost compared with the reported methods, for DCS determination.
合成代谢雄性激素（AASs）是一类经常被竞争对手滥用的化合物，不幸的是被普通人群滥用，最近引起了国际关注。因此，对开发用于检测和/或测定AAS的低成本、精确、快速和简便的方案提出了非凡的要求。因此，目前的策略首次通过吸附微分脉冲阳极溶出伏安法（DP-ASV）和循环伏安法（CV）在宽pH范围（pH 2.0–10.0）的玻碳电极（GCE）上探索了21-羟基孕甾-4-烯-3，20-二酮，即11-脱氧皮质酮（DCS）AA药物类固醇的氧化还原特征。在pH 2时，DP-ASV和CV在优化pH 2–3时在0.4处显示出不可逆的阳极峰 V相对于Ag/AgCl电极。CV在0.4时的阳极峰值电流的依赖性 V在DCS药物的不同浓度和扫描速率下是EE型机制的电极耦合电子转移的特征。在优化参数下，所提出的策略允许对浓度范围为2.5-13.19的DCS进行量化 nM（0.83-4.36 ng mL−1），检测限（LOD）和定量限（LOQ）为9.3 × 10−1 nM（3.1 × 10−1 ng mL−1）和3.1 nM（1.02 ng mL−1）。相对标准偏差（RSD）为±3.93%（n = 5） 4.0 ng 达到mL−1 DCS。所建立的探针用于环境水中DCS残留的痕量测定，效果良好。几种常见的不同物种对DCS传感的干扰不显著，显示出良好的选择性。与已报道的DCS测定方法相比，所建立的探针具有良好的灵敏度、选择性、精密度和准确性，分析时间短，成本低。
{"title":"Electrooxidation and Development of a Highly Sensitive Electrochemical Probe for Trace Determination of the Steroid 11-Desoxycorticosterone Drug Residues in Water","authors":"W. T. Alsaggaf, M. El-Shahawi","doi":"10.1155/2022/2074908","DOIUrl":"https://doi.org/10.1155/2022/2074908","url":null,"abstract":"Anabolic-androgenic steroids (AASs), a class of compounds frequently misused by competitors and unfortunately by the general population, have lately attracted international attention. Thus, extraordinary demands for developing low cost, precise, rapid, and facile protocols for detection and/or determination of AAS have arisen. Hence, the current strategy explores for the first time the redox features of 21-hydroxypregn-4-ene-3, 20-dione, namely, 11-desoxycorticosterone (DCS) AA drug steroid at a glassy-carbon electrode (GCE) in a wide pH range (pH 2.0–10.0) by adsorptive differential pulse-anodic stripping voltammetry (DP- ASV) and cyclic voltammetry (CV). At pH 2, DP-ASV and CV at the optimized pH 2–3 displayed an irreversible anodic peak at 0.4 V versus Ag/AgCl electrode. The dependency of the anodic peak current of the CV at 0.4 V at various concentrations and scan rate of the DCS drug was characteristic of an electrode-coupled electron transfer of EE type mechanism. At the optimized parameters, the proposed strategy allowed quantification of DCS in the concentration range 2.5 -13.19 nM (0.83-4.36 ng mL−1) with satisfactory limits of detection (LOD) and quantization (LOQ) of 9.3 × 10−1 nM (3.1 × 10−1 ng mL−1) and 3.1 nM (1.02 ng mL−1), respectively. A relative standard deviation (RSD) of ±3.93% (n = 5) at 4.0 ng mL−1 DCS was achieved. The established probe was fruitfully employed and validated for trace determination of DCS residues in environmental water. The interference of several common diverse species on DCS sensing was insignificant revealing good selectivity. The established probe exhibited good sensitivity, selectivity, precision, and accuracy, short analytical time, and low cost compared with the reported methods, for DCS determination.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2022-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48371827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Alshareef, M. Orif, E. A. Al-Harbi, M. El-Shahawi
The current strategy reports a highly sensitive and selective square wave-cathodic stripping voltammetric protocol for malathion determination. The established method was based on the controlled adsorptive accumulation of malathion in the presence of Cu2+ ions in an aqueous solution of pH 2 onto the hanging mercury dropping electrode (HMDE) and measuring the resulting cathodic peak current of the adsorbed species at −0.42 V versus Ag/AgCl electrode. The low limits of detection (LOD) and quantification (LOQ) of malathion of the assay were estimated to be 3.1 × 10−10 and 1.03 × 10−9 M with a linear dynamic range of 1.03×10−9 – 2.0 × 10−7 M, respectively. The method was satisfactorily applied and validated for malathion determination in environmental samples. The experimental Student texp and Fexp values did not exceed the tabulated ttab (2.78) and Ftab (6.39) at 95% (P = 0.05) confidence (n = 5), confirming the precision and independence on the matrix. The developed sensing platform for the detection of malathion shows superior performance to conventional electrochemical methods. The proposed sensor offered simple, economical, reproducible, and applicable approach for the determination of malathion in environmental samples.
{"title":"A Highly Sensitive Electrochemical Sensor Based on Electrocatalytic Reduction Effect of Cu2+ on Trace Determination of Malathion in Soil and Other Complex Matrices","authors":"F. Alshareef, M. Orif, E. A. Al-Harbi, M. El-Shahawi","doi":"10.1155/2021/8110364","DOIUrl":"https://doi.org/10.1155/2021/8110364","url":null,"abstract":"The current strategy reports a highly sensitive and selective square wave-cathodic stripping voltammetric protocol for malathion determination. The established method was based on the controlled adsorptive accumulation of malathion in the presence of Cu2+ ions in an aqueous solution of pH 2 onto the hanging mercury dropping electrode (HMDE) and measuring the resulting cathodic peak current of the adsorbed species at −0.42 V versus Ag/AgCl electrode. The low limits of detection (LOD) and quantification (LOQ) of malathion of the assay were estimated to be 3.1 × 10−10 and 1.03 × 10−9 M with a linear dynamic range of 1.03×10−9 – 2.0 × 10−7 M, respectively. The method was satisfactorily applied and validated for malathion determination in environmental samples. The experimental Student texp and Fexp values did not exceed the tabulated ttab (2.78) and Ftab (6.39) at 95% (P = 0.05) confidence (n = 5), confirming the precision and independence on the matrix. The developed sensing platform for the detection of malathion shows superior performance to conventional electrochemical methods. The proposed sensor offered simple, economical, reproducible, and applicable approach for the determination of malathion in environmental samples.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45930004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study reports the design of the Mn3O4-Cn electrode and its use for simultaneous detection of selenium and nickel in water. The designed electrode can be used as a convenient electrochemical device for on-site testing of Se (IV) and Ni (II) levels in affected regions. The best responses are obtained with 0.1 M phosphate buffer saline (PBS) and 5 mM Fe (CN)6 as supporting electrolyte. The scan rate and the number of cyclic repetitions have a great effect on peak shape and intensity. It is seen from our study that peak intensity is directly proportional to Se (IV) and Ni (II) concentrations in the range of 5 to 250 µg/L (correlation coefficients 0.952 and 0.984) when the optimized parameters are used. The detection limit of 0.533 µg/L Se (IV) and 0.718 µg/L for Ni (VI) with a response time of 18 s for 5–250 µg/L concentration is obtained, respectively. Enhanced analytical results for different water samples establish that the proposed method is appropriate for Se (IV) and Ni (II) detection. FESEM images confirm the Mn3O4-Cn nanocomposite formation on the electrode.
本研究报告了Mn3O4-Cn电极的设计及其在同时检测水中硒和镍中的应用。所设计的电极可作为一种方便的电化学装置，用于受影响地区Se（IV）和Ni（II）水平的现场测试。最佳响应为0.1 M磷酸盐缓冲盐水（PBS）和5 mM Fe（CN）6作为支撑电解质。扫描速率和循环重复次数对峰值形状和强度有很大影响。从我们的研究中可以看出，在5-250的范围内，峰值强度与Se（IV）和Ni（II）浓度成正比 µg/L（相关系数0.952和0.984）。检测限0.533 µg/L Se（IV）和0.718 µg/L的Ni（VI），响应时间为18 s代表5–250 分别获得µg/L的浓度。对不同水样的增强分析结果表明，所提出的方法适用于Se（IV）和Ni（II）的检测。FESEM图像证实了Mn3O4-Cn纳米复合材料在电极上的形成。
{"title":"Detection of Selenium and Nickel Metal Ion in Water Using Mn3O4-Cn-Modified Electrode","authors":"N. John, K. E. Abraham","doi":"10.1155/2021/6650542","DOIUrl":"https://doi.org/10.1155/2021/6650542","url":null,"abstract":"The present study reports the design of the Mn3O4-Cn electrode and its use for simultaneous detection of selenium and nickel in water. The designed electrode can be used as a convenient electrochemical device for on-site testing of Se (IV) and Ni (II) levels in affected regions. The best responses are obtained with 0.1 M phosphate buffer saline (PBS) and 5 mM Fe (CN)6 as supporting electrolyte. The scan rate and the number of cyclic repetitions have a great effect on peak shape and intensity. It is seen from our study that peak intensity is directly proportional to Se (IV) and Ni (II) concentrations in the range of 5 to 250 µg/L (correlation coefficients 0.952 and 0.984) when the optimized parameters are used. The detection limit of 0.533 µg/L Se (IV) and 0.718 µg/L for Ni (VI) with a response time of 18 s for 5–250 µg/L concentration is obtained, respectively. Enhanced analytical results for different water samples establish that the proposed method is appropriate for Se (IV) and Ni (II) detection. FESEM images confirm the Mn3O4-Cn nanocomposite formation on the electrode.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43653175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tetrakis[(benzo[d]thiazol-2-yl-thio) phthalocyaninato] gallium(III)chloride (1) and tetrakis[(benzo[d]thiazol-2ylphenoxy) phthalocyaninato] gallium(III)chloride (2) were successfully electrodeposited onto aluminium for corrosion retardation in 1.0 M hydrochloric acid solution. The aim of this study was to compare the corrosion resistance of electrodeposited metallated phthalocyanines. Scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy (EIS), and polarization confirmed the aluminium corrosion inhibition potentials of complexes 1 and 2. EIS and polarization techniques showed that complex 2 performed better than complex 1, with values from EIS measurements of 82% for 1 and 86% for 2 in 1.0 M hydrochloric acid solution. The importance of electrodeposition in industries and a dearth of research on the use of electrodeposited metallated phthalocyanines necessitated this study, and results show that coatings formed by electrodeposition of 1 and 2 onto aluminium reduced its susceptibility to corrosion attack.
{"title":"Electrodeposited Benzothiazole Phthalocyanines for Corrosion Inhibition of Aluminium in Acidic Medium","authors":"N. Nnaji, Njemuwa Nwaji, T. Nyokong","doi":"10.1155/2020/8892559","DOIUrl":"https://doi.org/10.1155/2020/8892559","url":null,"abstract":"Tetrakis[(benzo[d]thiazol-2-yl-thio) phthalocyaninato] gallium(III)chloride (1) and tetrakis[(benzo[d]thiazol-2ylphenoxy) phthalocyaninato] gallium(III)chloride (2) were successfully electrodeposited onto aluminium for corrosion retardation in 1.0 M hydrochloric acid solution. The aim of this study was to compare the corrosion resistance of electrodeposited metallated phthalocyanines. Scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy (EIS), and polarization confirmed the aluminium corrosion inhibition potentials of complexes 1 and 2. EIS and polarization techniques showed that complex 2 performed better than complex 1, with values from EIS measurements of 82% for 1 and 86% for 2 in 1.0 M hydrochloric acid solution. The importance of electrodeposition in industries and a dearth of research on the use of electrodeposited metallated phthalocyanines necessitated this study, and results show that coatings formed by electrodeposition of 1 and 2 onto aluminium reduced its susceptibility to corrosion attack.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/8892559","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43554157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Koumya, R. Idouhli, A. Oukhrib, M. Khadiri, A. Abouelfida, A. Benyaich
The corrosion of stainless steel is one of the major industries’ issues that gained wide interest among researchers. It became necessary to develop and apply eco-friendly approaches to corrosion control. This work explores the inhibitory effect of a newly synthesized amino cadalene (ACM) on the corrosion of stainless steel type 321 in sulfuric acid 1M. Particularly, the experimental study consisting of electrochemical and surface analyses was conducted in conjunction with a theoretical approach. The electrochemical results showed that ACM acted as a mixed-type corrosion inhibitor and the inhibition efficiency attained 91% at 10−3M. EIS measurements revealed that both metal charge transfer and diffusion processes are involved in the interfacial metal/solution reactions. The interfacial mechanism is thoroughly investigated; the physisorption of the protonated molecules was preceded by the formation of a negative layer due to adsorption of the solution anionic species. The experimental insights are corroborated with the quantum chemical calculations.
{"title":"Synthesis, Electrochemical, Thermodynamic, and Quantum Chemical Investigations of Amino Cadalene as a Corrosion Inhibitor for Stainless Steel Type 321 in Sulfuric Acid 1M","authors":"Y. Koumya, R. Idouhli, A. Oukhrib, M. Khadiri, A. Abouelfida, A. Benyaich","doi":"10.1155/2020/5620530","DOIUrl":"https://doi.org/10.1155/2020/5620530","url":null,"abstract":"The corrosion of stainless steel is one of the major industries’ issues that gained wide interest among researchers. It became necessary to develop and apply eco-friendly approaches to corrosion control. This work explores the inhibitory effect of a newly synthesized amino cadalene (ACM) on the corrosion of stainless steel type 321 in sulfuric acid 1M. Particularly, the experimental study consisting of electrochemical and surface analyses was conducted in conjunction with a theoretical approach. The electrochemical results showed that ACM acted as a mixed-type corrosion inhibitor and the inhibition efficiency attained 91% at 10−3M. EIS measurements revealed that both metal charge transfer and diffusion processes are involved in the interfacial metal/solution reactions. The interfacial mechanism is thoroughly investigated; the physisorption of the protonated molecules was preceded by the formation of a negative layer due to adsorption of the solution anionic species. The experimental insights are corroborated with the quantum chemical calculations.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/5620530","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41368215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Four LnMnO3+δ (Ln = La, Pr, Sm, and Gd) perovskites were synthesized and characterized by powder XRD. It was shown that the perovskite lattice became more and more distorted when lowering the size of the A-site cation. The manganite-based perovskites were evaluated for the ability to electrochemically reduce oxygen and nitric oxide in the temperature range of 200 to 400°C. At the lowest temperature, the electrodes were better at reducing nitric oxide than oxygen. At higher temperatures, the activity for the reduction of oxygen and nitric oxide became similar. The activation energies for the reduction of oxygen and nitric oxide were markedly different for LaMnO3+δ and PrMnO3+δ whereas it was similar for SmMnO3+δ and GdMnO3+δ.
{"title":"Electrochemical Reduction of Oxygen and Nitric Oxide on Mn-Based Perovskites with Different A-Site Cations","authors":"K. Kammer Hansen","doi":"10.1155/2020/4013697","DOIUrl":"https://doi.org/10.1155/2020/4013697","url":null,"abstract":"Four LnMnO3+δ (Ln = La, Pr, Sm, and Gd) perovskites were synthesized and characterized by powder XRD. It was shown that the perovskite lattice became more and more distorted when lowering the size of the A-site cation. The manganite-based perovskites were evaluated for the ability to electrochemically reduce oxygen and nitric oxide in the temperature range of 200 to 400°C. At the lowest temperature, the electrodes were better at reducing nitric oxide than oxygen. At higher temperatures, the activity for the reduction of oxygen and nitric oxide became similar. The activation energies for the reduction of oxygen and nitric oxide were markedly different for LaMnO3+δ and PrMnO3+δ whereas it was similar for SmMnO3+δ and GdMnO3+δ.","PeriodicalId":13933,"journal":{"name":"International journal of electrochemistry","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2020-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/4013697","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48153202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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