Marcel Pourbaix (Figure 1) was a Belgian chemist (born in Russia) who greatly contributed to studies on corrosion. His biggest achievement is the derivation of potential-pH diagrams, better known as “Pourbaix Diagrams” (Figure 2a). Pourbaix Diagrams are thermodynamic charts constructed using the Nernst equation. They visualize the relationship between possible redox states of a system, bounded by lines representing the reactions between them under thermodynamic equilibrium. The Pourbaix diagrams can be read much like phase diagrams. In 1963, Pourbaix produced “Atlas of Electrochemical Equilibria in Aqueous Solutions” (Figure 2b), which contains potential-pH diagrams for all elements known at the time. Pourbaix and his collaborators began preparing the work in the early 1950s and continued the diagram updates over many years.
{"title":"Electrochemical contributions: Marcel Pourbaix (1904–1998)","authors":"Evgeny Katz","doi":"10.1002/elsa.202200015","DOIUrl":"10.1002/elsa.202200015","url":null,"abstract":"<p>Marcel Pourbaix (Figure 1) was a Belgian chemist (born in Russia) who greatly contributed to studies on corrosion. His biggest achievement is the derivation of potential-pH diagrams, better known as “Pourbaix Diagrams” (Figure 2a). Pourbaix Diagrams are thermodynamic charts constructed using the Nernst equation. They visualize the relationship between possible redox states of a system, bounded by lines representing the reactions between them under thermodynamic equilibrium. The Pourbaix diagrams can be read much like phase diagrams. In 1963, Pourbaix produced “Atlas of Electrochemical Equilibria in Aqueous Solutions” (Figure 2b), which contains potential-pH diagrams for all elements known at the time. Pourbaix and his collaborators began preparing the work in the early 1950s and continued the diagram updates over many years.</p><p>The author declares no conflict of interest.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202200015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47528882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel Winkler, Teja Stüwe, Daniel Werner, Christoph Griesser, Christoph Thurner, David Stock, Julia Kunze-Liebhäuser, Engelbert Portenkirchner
NaTi2(PO4)3 (NTP) and Na0.44MnO2 (NMO), and their derivatives, have emerged as the most promising materials for aqueous Na-ion batteries. For both, NTP and NMO, avoiding the evolution of hydrogen and oxygen is found to be mandatory in order to mitigate material dissolution. Intriguingly, however, no direct determination of the hydrogen and oxygen evolution reactions (HER and OER) has yet been carried out. Using differential electrochemical mass spectrometry (DEMS) we directly identify the onset potentials for the HER and OER. Surprisingly, the potential window is found to be significantly smaller than suggested by commonly employed cyclic voltammetry measurements. CO2 evolution, upon decomposition of carbon black, is observed at an onset potential of 1.61 VRHE, which is 0.25 V more cathodic than the OER for the NMO electrode. Our results show that the state-of-the-art carbon additive plays a crucial role in the stability of the positive NMO electrode in the ion battery.
{"title":"What is limiting the potential window in aqueous sodium-ion batteries? Online study of the hydrogen-, oxygen- and CO2-evolution reactions at NaTi2(PO4)3 and Na0.44MnO2 electrodes","authors":"Daniel Winkler, Teja Stüwe, Daniel Werner, Christoph Griesser, Christoph Thurner, David Stock, Julia Kunze-Liebhäuser, Engelbert Portenkirchner","doi":"10.1002/elsa.202200012","DOIUrl":"10.1002/elsa.202200012","url":null,"abstract":"<p>NaTi<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> (NTP) and Na<sub>0.44</sub>MnO<sub>2</sub> (NMO), and their derivatives, have emerged as the most promising materials for aqueous Na-ion batteries. For both, NTP and NMO, avoiding the evolution of hydrogen and oxygen is found to be mandatory in order to mitigate material dissolution. Intriguingly, however, no direct determination of the hydrogen and oxygen evolution reactions (HER and OER) has yet been carried out. Using differential electrochemical mass spectrometry (DEMS) we directly identify the onset potentials for the HER and OER. Surprisingly, the potential window is found to be significantly smaller than suggested by commonly employed cyclic voltammetry measurements. CO<sub>2</sub> evolution, upon decomposition of carbon black, is observed at an onset potential of 1.61 V<sub>RHE</sub>, which is 0.25 V more cathodic than the OER for the NMO electrode. Our results show that the state-of-the-art carbon additive plays a crucial role in the stability of the positive NMO electrode in the ion battery.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202200012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51125079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The presently increasing global population demands increased food production. Consequently, phosphate – an indispensable fertilizer component – will be needed in ever greater amounts. Current levels of mining of phosphate's most important constituent element, phosphorus (P), are unsustainable, and P rock is predicted to soon be completely depleted. Because P is a non-renewable resource, techniques to recover and reuse waste phosphate are necessary. Large amounts of unused phosphate exist in both municipal and agricultural wastewater streams, as well as in sewage sludge. Approaches to recovering phosphate from these sources fall into three main categories: biological, chemical, and electrochemical. Biological phosphate recovery has seen some plant-scale use, but significant drawbacks including the complication of operation have prevented it from becoming widespread. The most common method of phosphate recovery, chemical phosphate recovery, has been applied at scale with success due to the stability and reliability of the process. However, disadvantages such as the exorbitant amounts of alkali dosing required to maintain the high pH necessary for phosphate precipitation leave room for improvement. In recent years, electrochemical phosphate recovery has gained traction because of its potential to overcome the weaknesses of traditional chemical approaches by utilizing water electrolysis to induce a high pH without the need for an added base. But before plant-scale electrochemical methods can be considered economically viable, the steep energy requirements of water electrolysis must be mitigated through the development of improved electrocatalysts or circumvented through the discovery and application of new electrochemical processes to generate hydroxyl ions needed to induce a high pH. In this review, the three broad categories of phosphate recovery techniques are discussed and an outlook on the future of electrocatalysis for phosphate recovery is presented. Particularly, the requirements for improved and Earth-abundant electrocatalysts are considered alongside a critical discussion of the possibility of a decentralized network of onsite wastewater treatment facilities powered by renewable electricity.
{"title":"Perspective on the electrochemical recovery of phosphate from wastewater streams","authors":"Nicholas A. Snyder, Carlos G. Morales-Guio","doi":"10.1002/elsa.202200010","DOIUrl":"10.1002/elsa.202200010","url":null,"abstract":"<p>The presently increasing global population demands increased food production. Consequently, phosphate – an indispensable fertilizer component – will be needed in ever greater amounts. Current levels of mining of phosphate's most important constituent element, phosphorus (P), are unsustainable, and P rock is predicted to soon be completely depleted. Because P is a non-renewable resource, techniques to recover and reuse waste phosphate are necessary. Large amounts of unused phosphate exist in both municipal and agricultural wastewater streams, as well as in sewage sludge. Approaches to recovering phosphate from these sources fall into three main categories: biological, chemical, and electrochemical. Biological phosphate recovery has seen some plant-scale use, but significant drawbacks including the complication of operation have prevented it from becoming widespread. The most common method of phosphate recovery, chemical phosphate recovery, has been applied at scale with success due to the stability and reliability of the process. However, disadvantages such as the exorbitant amounts of alkali dosing required to maintain the high pH necessary for phosphate precipitation leave room for improvement. In recent years, electrochemical phosphate recovery has gained traction because of its potential to overcome the weaknesses of traditional chemical approaches by utilizing water electrolysis to induce a high pH without the need for an added base. But before plant-scale electrochemical methods can be considered economically viable, the steep energy requirements of water electrolysis must be mitigated through the development of improved electrocatalysts or circumvented through the discovery and application of new electrochemical processes to generate hydroxyl ions needed to induce a high pH. In this review, the three broad categories of phosphate recovery techniques are discussed and an outlook on the future of electrocatalysis for phosphate recovery is presented. Particularly, the requirements for improved and Earth-abundant electrocatalysts are considered alongside a critical discussion of the possibility of a decentralized network of onsite wastewater treatment facilities powered by renewable electricity.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202200010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42489018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Quinn Carvalho, Sophia R. S. Jones, Ashley E. Berninghaus, Richard F. Hilliard, Tyler S. Radniecki, Kelsey A. Stoerzinger
The electrochemical nitrate reduction reaction (NO3RR) has the potential for distributed water treatment and renewable chemical synthesis. Cu is an active monometallic electrocatalyst for the NO3RR in acidic and alkaline electrolytes, where activity is limited by the reduction of adsorbed nitrate to nitrite. Oxygen-vacancy forming metal-oxide supports provide sites for N-O bond activation in thermal reduction, impacting product distribution as well. Here we compare the electrochemical NO3RR activity of Cu deposited on two metal-oxide supports (cerium dioxide [Cu/CeO2-δ] and fluorine-doped tin dioxide [Cu/FTO]) to a Cu foil benchmark. Considering activity in phosphate-buffered neutral media, nitrate and adsorbed hydrogen compete for surface sites under NO3RR conditions. The less-cathodic overpotential on Cu/CeO2-δ compared to Cu/FTO is attributed to stronger nitrate adsorption, similar to thermal nitrate reduction. Utilization of CeO2-δ as an electrocatalyst support slightly shifting product distribution toward more oxidized products, either by enhancing nitrate affinity or by a more dynamic process involving the formation and healing of oxygen vacancies (𝑣O••). These results suggest supporting catalysts on metal oxides may enhance activity by promoting the adsorption of anionic reactants on cathodic electrocatalysts.
{"title":"Role of oxide support in electrocatalytic nitrate reduction on Cu","authors":"O. Quinn Carvalho, Sophia R. S. Jones, Ashley E. Berninghaus, Richard F. Hilliard, Tyler S. Radniecki, Kelsey A. Stoerzinger","doi":"10.1002/elsa.202100201","DOIUrl":"10.1002/elsa.202100201","url":null,"abstract":"<p>The electrochemical nitrate reduction reaction (NO<sub>3</sub>RR) has the potential for distributed water treatment and renewable chemical synthesis. Cu is an active monometallic electrocatalyst for the NO<sub>3</sub>RR in acidic and alkaline electrolytes, where activity is limited by the reduction of adsorbed nitrate to nitrite. Oxygen-vacancy forming metal-oxide supports provide sites for N-O bond activation in thermal reduction, impacting product distribution as well. Here we compare the electrochemical NO<sub>3</sub>RR activity of Cu deposited on two metal-oxide supports (cerium dioxide [Cu/CeO<sub>2-δ</sub>] and fluorine-doped tin dioxide [Cu/FTO]) to a Cu foil benchmark. Considering activity in phosphate-buffered neutral media, nitrate and adsorbed hydrogen compete for surface sites under NO<sub>3</sub>RR conditions. The less-cathodic overpotential on Cu/CeO<sub>2-δ</sub> compared to Cu/FTO is attributed to stronger nitrate adsorption, similar to thermal nitrate reduction. Utilization of CeO<sub>2-δ</sub> as an electrocatalyst support slightly shifting product distribution toward more oxidized products, either by enhancing nitrate affinity or by a more dynamic process involving the formation and healing of oxygen vacancies (𝑣<sub>O</sub><sup>••</sup>). These results suggest supporting catalysts on metal oxides may enhance activity by promoting the adsorption of anionic reactants on cathodic electrocatalysts.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202100201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46044562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite numerous experimental and theoretical studies devoted to the oxygen evolution reaction (OER), the mechanism of the OER on transition metal oxides remains controversial. This is in part owing to the ambiguity of electrochemical parameters of the mechanism such as the Tafel slope and reaction orders. We took the most commonly assumed adsorbate mechanism and calculated the Tafel slopes and reaction orders with respect to pH based on microkinetic analysis using the steady-state approximation. The analysis was performed for an ideal electrocatalyst without scaling of the intermediates as well as for one on the top of a volcano relation and one on each leg of the volcano relation which exhibits scaling of the intermediates. For these four cases, the number of possible Tafel slopes strongly depends on surface coverage. Furthermore, the Tafel slope becomes pH-dependent when the coverage of intermediates changes with pH. These insights complicate the identification of a rate-limiting step by a single Tafel slope at a single pH. Yet, simulations of reaction orders complementary to Tafel slopes can solve some ambiguities to distinguish between possible rate-limiting steps. The most insightful information can be obtained from the low overpotential region of the Tafel plot. The simulations in this work provide clear guidelines to experimentalists for the identification of the limiting steps in the adsorbate mechanism using the observed values of the Tafel slope and reaction order in pH-dependent studies.
{"title":"Calculation of the Tafel slope and reaction order of the oxygen evolution reaction between pH 12 and pH 14 for the adsorbate mechanism","authors":"Denis Antipin, Marcel Risch","doi":"10.1002/elsa.202100213","DOIUrl":"https://doi.org/10.1002/elsa.202100213","url":null,"abstract":"<p>Despite numerous experimental and theoretical studies devoted to the oxygen evolution reaction (OER), the mechanism of the OER on transition metal oxides remains controversial. This is in part owing to the ambiguity of electrochemical parameters of the mechanism such as the Tafel slope and reaction orders. We took the most commonly assumed adsorbate mechanism and calculated the Tafel slopes and reaction orders with respect to pH based on microkinetic analysis using the steady-state approximation. The analysis was performed for an ideal electrocatalyst without scaling of the intermediates as well as for one on the top of a volcano relation and one on each leg of the volcano relation which exhibits scaling of the intermediates. For these four cases, the number of possible Tafel slopes strongly depends on surface coverage. Furthermore, the Tafel slope becomes pH-dependent when the coverage of intermediates changes with pH. These insights complicate the identification of a rate-limiting step by a single Tafel slope at a single pH. Yet, simulations of reaction orders complementary to Tafel slopes can solve some ambiguities to distinguish between possible rate-limiting steps. The most insightful information can be obtained from the low overpotential region of the Tafel plot. The simulations in this work provide clear guidelines to experimentalists for the identification of the limiting steps in the adsorbate mechanism using the observed values of the Tafel slope and reaction order in pH-dependent studies.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202100213","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138558228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<p>The young journal <i>Electrochemical Science Advances</i> copublished by Wiley-VCH and Chemistry Europe has had a great start. Its constitution reflects the increasing interest in electrochemical research and development. Its content is therefore devoted not only to fundamental research in electrochemistry but (importantly) to consequential applications like generation and storage of electricity, photovoltaics, corrosion, electrochemical sensors, analysers, electrochromism, (photo)electrocatalysis, electrosynthesis, photo- and spectroelectrochemistry, molecular electronics, and alternative electrodes etc.</p><p>The beginning of electrochemistry is dated about three centuries back, and its development is connected with the names like Luigi Galvani (1737–1798), Alessandro Volta (1745–1827), Humphry Davy (1778-1829), John F. Daniell (1790–1845), Michael Faraday (1791–1867), and many others. In the 19th century, electrochemistry was rather a part of physics connected with the general studies of electricity—at first its generation (Volta, Daniell), then its combination with biology (Galvani), later electrolyses and metal electrodeposition (Faraday), surface effects, and conductivity of electrolytes etc.</p><p>The current collection of this new journal is symbolically devoted to the <i>100th anniversary of polarography</i> invented at the Charles University, Prague, by <i>Jaroslav Heyrovský</i> (Nobel Prize 1959). In February 1922, the first polarographic curve was recorded, where for the first time, the electrochemical current was plotted against potential (i-E curve) offering simultaneously qualitative as well as quantitative analytical data. Therefore, the year 1922 is considered as the true <i>start of modern electrochemistry</i> as a part of chemical sciences. The instrument itself—<i>polarograph</i>—was at that time the first fully automatic analytical device where after filling the cell, connecting electrodes, setting the conditions (scan rate, initial and final potential, sensitivity, drop size etc.) and switching ON the instrument, the whole experiment including photographic recording was running automatically.</p><p>After the initial applications in electroanalysis, the development continued toward organic electrosynthesis, redox characterization of new molecules, and investigation of the relationship between their structure and chemical properties. Because electrochemistry, as an alternative to the classic thermal redox chemistry, uses “pure” electrons generated or accepted by an electrode for reduction and oxidation reactions, respectively, it represents an approach and tool suitable for all branches of chemistry.</p><p>Although currently electrochemistry goes through enormous and fascinating development both in fundamental research and in applied sciences, still, the original polarography that means voltammetry utilizing mercury drop as the working electrode (today mostly computer-controlled) has and will have its permanent position amo
{"title":"Editorial: 100 years of polarography","authors":"Jiří Ludvík","doi":"10.1002/elsa.202260007","DOIUrl":"10.1002/elsa.202260007","url":null,"abstract":"<p>The young journal <i>Electrochemical Science Advances</i> copublished by Wiley-VCH and Chemistry Europe has had a great start. Its constitution reflects the increasing interest in electrochemical research and development. Its content is therefore devoted not only to fundamental research in electrochemistry but (importantly) to consequential applications like generation and storage of electricity, photovoltaics, corrosion, electrochemical sensors, analysers, electrochromism, (photo)electrocatalysis, electrosynthesis, photo- and spectroelectrochemistry, molecular electronics, and alternative electrodes etc.</p><p>The beginning of electrochemistry is dated about three centuries back, and its development is connected with the names like Luigi Galvani (1737–1798), Alessandro Volta (1745–1827), Humphry Davy (1778-1829), John F. Daniell (1790–1845), Michael Faraday (1791–1867), and many others. In the 19th century, electrochemistry was rather a part of physics connected with the general studies of electricity—at first its generation (Volta, Daniell), then its combination with biology (Galvani), later electrolyses and metal electrodeposition (Faraday), surface effects, and conductivity of electrolytes etc.</p><p>The current collection of this new journal is symbolically devoted to the <i>100th anniversary of polarography</i> invented at the Charles University, Prague, by <i>Jaroslav Heyrovský</i> (Nobel Prize 1959). In February 1922, the first polarographic curve was recorded, where for the first time, the electrochemical current was plotted against potential (i-E curve) offering simultaneously qualitative as well as quantitative analytical data. Therefore, the year 1922 is considered as the true <i>start of modern electrochemistry</i> as a part of chemical sciences. The instrument itself—<i>polarograph</i>—was at that time the first fully automatic analytical device where after filling the cell, connecting electrodes, setting the conditions (scan rate, initial and final potential, sensitivity, drop size etc.) and switching ON the instrument, the whole experiment including photographic recording was running automatically.</p><p>After the initial applications in electroanalysis, the development continued toward organic electrosynthesis, redox characterization of new molecules, and investigation of the relationship between their structure and chemical properties. Because electrochemistry, as an alternative to the classic thermal redox chemistry, uses “pure” electrons generated or accepted by an electrode for reduction and oxidation reactions, respectively, it represents an approach and tool suitable for all branches of chemistry.</p><p>Although currently electrochemistry goes through enormous and fascinating development both in fundamental research and in applied sciences, still, the original polarography that means voltammetry utilizing mercury drop as the working electrode (today mostly computer-controlled) has and will have its permanent position amo","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"2 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202260007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49253495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The electrochemical study of 2-Sulfanylidene-1,3-thiazolidin-4-one (rhodanine, R) was performed on a glassy carbon working electrode by using three methods: differential pulse voltammetry (DPV), cyclic voltammetry (CV), and linear sweep voltammetry (LSV) at rotating disk electrode voltammetry (RDE). The CV, DPV, and LSV at RDE curves for R were recorded at different concentrations in 0.1 M TBAP/CH3CN. Polymeric films were formed by successive cycling at different potentials and by controlled potential electrolysis. The film formation was proved by recording the CV curves of the chemically modified electrodes (CMEs) in transfer solutions containing ferrocene in 0.1 M TBAP/CH3CN. The obtained CMEs were used for the detection of heavy metal ions. Synthetic samples of heavy metal ions (Cd (II), Pb (II), Cu (II), Hg (II)) of concentrations between 10−7 and 10−5 M were analyzed using CMEs prepared in different conditions. The most intense signal was obtained for Pb(II) ion (estimated detection limit = 10−7 M), which shows that these CMEs can be used for Pb(II) ion detection. The ability of R to form complexes with Pb(II) ion was also tested by UV-Vis spectrometry. The obtained results showed the formation of Pb(II)R2 as the most stable complex.
采用微分脉冲伏安法(DPV)、循环伏安法(CV)和旋转盘电极伏安法(RDE)线性扫描伏安法(LSV)三种方法,在玻璃碳工作电极上对 2-硫代-1,3-噻唑烷-4-酮(罗丹宁,Rhodanine,R)进行了电化学研究。在 0.1 M TBAP/CH3CN 中记录了不同浓度 R 的 CV、DPV 和 LSV 曲线。通过在不同电位下连续循环和控制电位电解,形成了聚合物薄膜。通过记录化学修饰电极(CME)在 0.1 M TBAP/CH3CN 中含有二茂铁的转移溶液中的 CV 曲线,证明了薄膜的形成。获得的 CME 用于检测重金属离子。使用在不同条件下制备的 CME 分析了浓度在 10-7 和 10-5 M 之间的重金属离子(镉 (II)、铅 (II)、铜 (II)、汞 (II))合成样品。Pb(II) 离子获得了最强烈的信号(估计检测限 = 10-7M),这表明这些 CMEs 可用于 Pb(II) 离子的检测。紫外可见光谱法还测试了 R 与铅(II)离子形成络合物的能力。结果表明,形成的 Pb(II)R2 是最稳定的络合物。
{"title":"Electrochemical and spectral studies of rhodanine in view of heavy metals determination","authors":"Ovidiu Teodor Matica, Alina Giorgiana Brotea, Eleonora-Mihaela Ungureanu, Luisa Roxana Mandoc, Liviu Birzan","doi":"10.1002/elsa.202100218","DOIUrl":"10.1002/elsa.202100218","url":null,"abstract":"<p>The electrochemical study of 2-Sulfanylidene-1,3-thiazolidin-4-one (rhodanine, <b>R</b>) was performed on a glassy carbon working electrode by using three methods: differential pulse voltammetry (DPV), cyclic voltammetry (CV), and linear sweep voltammetry (LSV) at rotating disk electrode voltammetry (RDE). The CV, DPV, and LSV at RDE curves for <b>R</b> were recorded at different concentrations in 0.1 M TBAP/CH<sub>3</sub>CN. Polymeric films were formed by successive cycling at different potentials and by controlled potential electrolysis. The film formation was proved by recording the CV curves of the chemically modified electrodes (CMEs) in transfer solutions containing ferrocene in 0.1 M TBAP/CH<sub>3</sub>CN. The obtained CMEs were used for the detection of heavy metal ions. Synthetic samples of heavy metal ions (Cd (II), Pb (II), Cu (II), Hg (II)) of concentrations between 10<sup>−7</sup> and 10<sup>−5</sup> M were analyzed using CMEs prepared in different conditions. The most intense signal was obtained for Pb(II) ion (estimated detection limit = 10<sup>−7</sup> M), which shows that these CMEs can be used for Pb(II) ion detection. The ability of <b>R</b> to form complexes with Pb(II) ion was also tested by UV-Vis spectrometry. The obtained results showed the formation of Pb(II)<b>R</b><sub>2</sub> as the most stable complex.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202100218","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43645539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigated the oxygen evolution reaction (OER) activity changes of cobalt oxide (CoOx) thin films on Ir(111) and Pt(111) substrates by repeated OER measurements in 0.1 M KOH. Atomic force microscopy and X-ray photoelectron spectroscopy analysis of the as-prepared CoOx/Ir(111) and CoOx/Pt(111) showed similar surface morphologies of the CoOx thin films and almost the same OER overpotentials, which were estimated to be around 430 mV. However, after three OER measurements, the overpotential of CoOx/Ir(111) decreased by 70 mV, whereas that of CoOx/Pt(111) increased slightly. Structural analysis showed that CoOx/Ir(111) revealed the island-like nanostructures of CoOx dispersed on Ir(111) surface, accompanied by the generation of CoOOH. In contrast, for CoOx/Pt(111), the Pt(111) substrate remains covered by the CoOx thin film. The results suggest that the interaface at CoOx (CoOOH) nano-islands and Ir(111) substrate are responsible for reducing the OER overpotential.
我们通过在 0.1 M KOH 中反复测量氧化钴(CoOx)薄膜在 Ir(111) 和 Pt(111) 基底上的氧演化反应(OER)活性变化进行了研究。对制备的 CoOx/Ir(111) 和 CoOx/Pt(111) 进行的原子力显微镜和 X 射线光电子能谱分析表明,CoOx 薄膜的表面形态相似,OER 过电位几乎相同,估计在 430 mV 左右。然而,经过三次 OER 测量后,CoOx/Ir(111) 的过电位下降了 70 mV,而 CoOx/Pt(111) 的过电位则略有上升。结构分析表明,CoOx/Ir(111)显示了分散在 Ir(111) 表面的岛状 CoOx 纳米结构,并伴随着 CoOOH 的生成。相反,对于 CoOx/Pt(111),铂(111)基底仍然被 CoOx 薄膜覆盖。结果表明,CoOx(CoOOH)纳米带和 Ir(111)基底之间的界面是降低 OER 过电位的原因。
{"title":"Surface microstructures and oxygen evolution properties of cobalt oxide deposited on Ir(111) and Pt(111) single crystal substrates","authors":"Naoto Todoroki, Hiroto Tsurumaki, Arata Shinomiya, Toshimasa Wadayama","doi":"10.1002/elsa.202200007","DOIUrl":"10.1002/elsa.202200007","url":null,"abstract":"<p>We investigated the oxygen evolution reaction (OER) activity changes of cobalt oxide (CoO<i><sub>x</sub></i>) thin films on Ir(111) and Pt(111) substrates by repeated OER measurements in 0.1 M KOH. Atomic force microscopy and X-ray photoelectron spectroscopy analysis of the as-prepared CoO<i><sub>x</sub></i>/Ir(111) and CoO<i><sub>x</sub></i>/Pt(111) showed similar surface morphologies of the CoO<i><sub>x</sub></i> thin films and almost the same OER overpotentials, which were estimated to be around 430 mV. However, after three OER measurements, the overpotential of CoO<i><sub>x</sub></i>/Ir(111) decreased by 70 mV, whereas that of CoO<i><sub>x</sub></i>/Pt(111) increased slightly. Structural analysis showed that CoO<i><sub>x</sub></i>/Ir(111) revealed the island-like nanostructures of CoO<i><sub>x</sub></i> dispersed on Ir(111) surface, accompanied by the generation of CoOOH. In contrast, for CoO<i><sub>x</sub></i>/Pt(111), the Pt(111) substrate remains covered by the CoO<i><sub>x</sub></i> thin film. The results suggest that the interaface at CoO<i><sub>x</sub></i> (CoOOH) nano-islands and Ir(111) substrate are responsible for reducing the OER overpotential.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202200007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43907437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Camila Carvalho de Almeida, Soliu O. Ganiyu, Carlos A. Martínez-Huitle, Elisama Vieira dos Santos, Katlin Ivon Barrios Eguiluz, Giancarlo Richard Salazar-Banda
Based on the existing literature, active chlorine-mediated electrochemical oxidation has been extensively studied when Cl‒ is added or Cl‒ is already present in the water matrices, as well as when Cl‒ is released from the target organic pollutants during their degradation. However, no attempts have been published concerning the fate and role of bromide (Br‒) ions released during the anodic oxidation (AO) of organobromine compounds. Therefore, the AO of bromophenol blue dye (BPB) was investigated in a parallel plate flow reactor using a boron-doped diamond (BDD) anode. The effect of the applied current on the color removal efficiency and mineralization of BPB solution was examined and compared with AO of phenol red (PR) which has a similar molecular structure to BPB (but without Br) in order to understand the role of Br heteroatoms on the mineralization of BPB. Faster and higher mineralization and discoloration were achieved when treated with BPB solution compared to PR under similar experimental conditions. This behavior was associated with the electrogeneration of BrO‒, from the heteroatom Br which is released as the bromide ion (Br‒), during the degradation of BPB. The active bromine species are formed via direct and indirect oxidation approaches which were proposed based on ion chromatography and linear scanning voltammetry analysis.
{"title":"Unprecedented formation of reactive BrO– ions and their role as mediators for organic compounds degradation: The fate of bromide ions released during the anodic oxidation of Bromophenol blue dye","authors":"Camila Carvalho de Almeida, Soliu O. Ganiyu, Carlos A. Martínez-Huitle, Elisama Vieira dos Santos, Katlin Ivon Barrios Eguiluz, Giancarlo Richard Salazar-Banda","doi":"10.1002/elsa.202100225","DOIUrl":"10.1002/elsa.202100225","url":null,"abstract":"<p>Based on the existing literature, active chlorine-mediated electrochemical oxidation has been extensively studied when Cl<sup>‒</sup> is added or Cl<sup>‒</sup> is already present in the water matrices, as well as when Cl<sup>‒</sup> is released from the target organic pollutants during their degradation. However, no attempts have been published concerning the fate and role of bromide (Br<sup>‒</sup>) ions released during the anodic oxidation (AO) of organobromine compounds. Therefore, the AO of bromophenol blue dye (BPB) was investigated in a parallel plate flow reactor using a boron-doped diamond (BDD) anode. The effect of the applied current on the color removal efficiency and mineralization of BPB solution was examined and compared with AO of phenol red (PR) which has a similar molecular structure to BPB (but without Br) in order to understand the role of Br heteroatoms on the mineralization of BPB. Faster and higher mineralization and discoloration were achieved when treated with BPB solution compared to PR under similar experimental conditions. This behavior was associated with the electrogeneration of BrO<sup>‒</sup>, from the heteroatom Br which is released as the bromide ion (Br<sup>‒</sup>), during the degradation of BPB. The active bromine species are formed via direct and indirect oxidation approaches which were proposed based on ion chromatography and linear scanning voltammetry analysis.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202100225","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47135054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The hydrogen evolution reaction (HER), the key reaction for electrocatalytic production of hydrogen, is of fundamental importance due to its simplicity yet is very important for renewable energy. Notwithstanding, Pt is still the main catalyst for this reaction, which is not practical for the industrial deployment of this technology owing to the high cost and scarcity of Pt. The successful synthesis of high entropy alloy (HEA) nanoparticles opens a new frontier for the development of new catalysts. Herein we investigate the design of a multinary noble metal-free HER catalyst based on earth-abundant elements Co, Mo, Fe, Ni, and Cu. Using a machine learning (ML) approach in conjunction with first-principles methods, we build a model that can rapidly compute the hydrogen adsorption energy on the alloyed surfaces with high fidelity. Within the large composition space of the CoMoFeNiCu HEA, a large number of alloy combinations are shown to optimally bind hydrogen with a high probability. Further, most of these alloy compositions are found stable against dissociation into intermetallics, and hence synthesizable as a solid solution, by virtue of a large mixing entropy compared to mixing enthalpy and a small lattice mismatch between the elements. This finding is partly consistent with recent experimental results that synthesized five different CoMoFeNiCu HEA compositions. Our study underscores the significant impact that computational modeling and ML can have on developing new cost-effective electrocatalysts in the nearly-infinite materials design space of HEAs, and calls for experimental validation.
氢进化反应(HER)是电催化制氢的关键反应,因其简单性而具有根本性的重要意义,但对可再生能源却非常重要。尽管如此,铂仍是该反应的主要催化剂,但由于铂的高成本和稀缺性,该技术的工业应用并不现实。高熵合金(HEA)纳米粒子的成功合成为新型催化剂的开发开辟了新的领域。在此,我们研究了基于地球富集元素 Co、Mo、Fe、Ni 和 Cu 的不含二元贵金属的 HER 催化剂的设计。利用机器学习(ML)方法和第一原理方法,我们建立了一个模型,该模型可以快速、高保真地计算合金表面的氢吸附能。在 CoMoFeNiCu HEA 的巨大成分空间内,大量合金组合被证明能以很高的概率优化氢结合。此外,由于混合熵与混合焓相比较大,且元素间的晶格失配较小,因此发现这些合金组合中的大多数在解离成金属间化合物时是稳定的,因而可合成为固溶体。这一发现与最近合成五种不同的 CoMoFeNiCu HEA 成分的实验结果部分吻合。我们的研究强调了计算建模和 ML 对在几乎无限的 HEA 材料设计空间中开发新的经济高效的电催化剂的重要影响,并呼吁进行实验验证。
{"title":"Designing multinary noble metal-free catalyst for hydrogen evolution reaction","authors":"Wissam A. Saidi, Tarak Nandi, Timothy Yang","doi":"10.1002/elsa.202100224","DOIUrl":"10.1002/elsa.202100224","url":null,"abstract":"<p>The hydrogen evolution reaction (HER), the key reaction for electrocatalytic production of hydrogen, is of fundamental importance due to its simplicity yet is very important for renewable energy. Notwithstanding, Pt is still the main catalyst for this reaction, which is not practical for the industrial deployment of this technology owing to the high cost and scarcity of Pt. The successful synthesis of high entropy alloy (HEA) nanoparticles opens a new frontier for the development of new catalysts. Herein we investigate the design of a multinary noble metal-free HER catalyst based on earth-abundant elements Co, Mo, Fe, Ni, and Cu. Using a machine learning (ML) approach in conjunction with first-principles methods, we build a model that can rapidly compute the hydrogen adsorption energy on the alloyed surfaces with high fidelity. Within the large composition space of the CoMoFeNiCu HEA, a large number of alloy combinations are shown to optimally bind hydrogen with a high probability. Further, most of these alloy compositions are found stable against dissociation into intermetallics, and hence synthesizable as a solid solution, by virtue of a large mixing entropy compared to mixing enthalpy and a small lattice mismatch between the elements. This finding is partly consistent with recent experimental results that synthesized five different CoMoFeNiCu HEA compositions. Our study underscores the significant impact that computational modeling and ML can have on developing new cost-effective electrocatalysts in the nearly-infinite materials design space of HEAs, and calls for experimental validation.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202100224","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43228854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}