Electrochemical science advances最新文献

{"title":"Role of solvation model on the stability of oxygenates on Pt(111): A comparison between microsolvation, extended bilayer, and extended metal/water interface","authors":"Giovanni Di Liberto,&nbsp;Livia Giordano","doi":"10.1002/elsa.202100204","DOIUrl":"10.1002/elsa.202100204","url":null,"abstract":"<p>The activity of catalysts is mainly dictated by the adsorption strength of reaction intermediates at their surfaces. For electrocatalysts in solution, the adsorption strength is not only determined by the intrinsic properties of catalysts and reactants, but also by the solvation energy of reaction intermediates, which is difficult to capture with theoretical methods. Here, we report the impact of different explicit solvation approaches in estimating the stability of oxygenates on the (111) surface of platinum, widely used in oxygen electrocatalysis. We simulate the adsorption of OH, O, and OOH intermediates, relevant for oxygen reduction and oxygen evolution reactions, on Pt(111) with different solvation environments. We apply the static water bilayer model, typically adopted to calculate solvation energies on Pt(111) in computational studies. We then study the trend of solvation energies under different microsolvation environments, by adsorbing the intermediates in presence of an increasing number of water molecules. Last, we use a dynamic approach based on ab-initio molecular dynamics (AIMD) to account for dynamic effects. Our results indicate that the stabilities of oxygenates approach those of the water bilayer when the number of molecules increases from zero to three, but the free energies are affected in a not trivial way by the morphology and size of the water cluster, due to the increased complexity and configurational space. Moreover, static methods imply overcorrected free energies. The adoption of a molecular dynamics approach, based on single-run AIMD simulation of the Pt(111)/H₂O interface, allows retrieval estimates close to the experimental observation, including dynamic effects, and is highly transferrable. These results suggest that i) when using a microsolvation scheme, it is recommended to include a few water molecules, up to three to resemble the picture of the static bilayer model; ii) dynamic effects are important and can be included with a single-run AIMD scheme.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202100204","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42389593","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}

{"title":"Electrochemical contributions: William W. Jacques (1855–1932)","authors":"Evgeny Katz","doi":"10.1002/elsa.202300004","DOIUrl":"10.1002/elsa.202300004","url":null,"abstract":"<p>William W. Jacques was an American electrical engineer and chemist who designed in 1896 a very unusual fuel cell operated on solid (coal) fuel named by him a “carbon battery”. While the majority of fuel cells utilize gas (usually H₂) or liquid (e.g., ethanol) fuel, the “carbon battery” designed by Jacques was based on a carbon electrode operated as the fuel.</p><p>The battery consisted of 100 cells connected in series (Figure 1a) and placed on top of a furnace that kept the electrolyte temperature between 400–500°C (Figure 1b). The produced electrical output was 16 A at 90 V. Based on the experimental results, Jacques claimed ca. 82% efficiency for his carbon battery, but careful analysis considering the heat energy used in the furnace and the energy used to pump air (O₂ was an oxidizer) resulted in a much lower battery efficiency of ca. 8%.</p><p>Later research demonstrated that the current generated by his battery was not obtained through electrochemical reaction as suggested by Jacques, but rather through the thermoelectric effect. Several subsequent researchers have stated that Jacques's was the last notable attempt to derive electricity directly from coal.</p><p>The author declares that he has no conflict of interest.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202300004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46477241","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}

{"title":"Electrochemical contributions: John Edward Brough Randles (1912–1998)","authors":"Evgeny Katz","doi":"10.1002/elsa.202300005","DOIUrl":"10.1002/elsa.202300005","url":null,"abstract":"&lt;p&gt;John Edward Brough Randles (Figure 1) was an English electrochemist who made important contributions to the theoretical background of polarography, cyclic voltammetry, and electrochemical impedance spectroscopy. Many modern techniques of electrochemistry are descended from his work, including cyclic voltammetry, anodic stripping voltammetry, and various types of hydrodynamic voltammetry. The Randles-Ševčík equation applied on linear sweep voltammetry and cyclic voltammetry, and the Randles equivalent circuit used in the modeling of impedance spectra are named after him.&lt;/p&gt;&lt;p&gt;The earliest electrochemical work of Randles performed with an oscillopolarograph (cathode ray polarograph) resulted in the development of linear sweep voltammetry.&lt;sup&gt;[&lt;/sup&gt;&lt;span&gt;&lt;sup&gt;1, 2&lt;/sup&gt;&lt;/span&gt;&lt;sup&gt;]&lt;/sup&gt; In addition to the experimental work, Randles solved a theoretical problem for expressing the current for diffusion-controlled electrochemical reactions by applying an ingenious graphical method.&lt;sup&gt;[&lt;/sup&gt;&lt;span&gt;&lt;sup&gt;3&lt;/sup&gt;&lt;/span&gt;&lt;sup&gt;]&lt;/sup&gt;&lt;/p&gt;&lt;p&gt;Another important contribution of Randles to electrochemistry was in the theoretical analysis of Faraday impedance spectra published in 1947.&lt;sup&gt;[&lt;/sup&gt;&lt;span&gt;&lt;sup&gt;4&lt;/sup&gt;&lt;/span&gt;&lt;sup&gt;]&lt;/sup&gt; The Randles equivalent circuit has been applied to the analysis of the impedance spectra including interfacial electron transfer (Faradaic component), capacitance and diffusion contributions to the impedance. It became the most frequently used theoretical treatment of impedance spectra. It should be noted that similar results were obtained by Russian scientists Dolin and Erschler in 1940, but the papers published in the Russian language have not been seen by the electrochemical community.&lt;/p&gt;&lt;p&gt;The Randles equivalent circuit (Figure 2) is one of the simplest and most common circuit models of electrochemical impedance. It includes a solution resistance, a double-layer capacitor, and a charge transfer or polarization resistance. While the Randles equivalent circuit is frequently sufficient for modeling simple electrochemical systems, it can be used as a starting point for more sophisticated models, for example, based on more resistances and capacitances organized in parallel or in a sequence.&lt;/p&gt;&lt;p&gt;It should be noted that John Randles was not only working on solving theoretical problems in electrochemistry, but he was a very good experimentalist. As an example of his experimental work, the Volta potential difference between a mercury droplet and an electrolyte solution measured by Randles can be mentioned.&lt;sup&gt;[&lt;/sup&gt;&lt;span&gt;&lt;sup&gt;5&lt;/sup&gt;&lt;/span&gt;&lt;sup&gt;]&lt;/sup&gt; Notably, the great Russian electrochemist Alexander Frumkin had failed to obtain a stable and reproducible result for this kind of measurement.&lt;/p&gt;&lt;p&gt;Randles published relatively few papers, but many of them are of great importance and his theoretical treatments of electrochemical systems have been included in all electrochemistry textbooks.&lt;/p&gt;&lt;p&gt;The author declares that he ha","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202300005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49027984","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}

{"title":"Electrochemical contributions: Hans Wenking (1923–2007)","authors":"Evgeny Katz","doi":"10.1002/elsa.202300003","DOIUrl":"10.1002/elsa.202300003","url":null,"abstract":"&lt;p&gt;Hans Wenking (Figure 1) was a German electrical engineer, physicist and inventor who devoted his lifetime to the development of electronic equipment for chemistry and physics, particularly constructing the first potentiostats, which became major parts of modern electrochemical instruments. He was the first who described the basic principles of potentiostats.&lt;/p&gt;&lt;p&gt;In 1952, Hans Wenking constructed an electronic amplifier for controlling an oscilloscope using a mirror galvanometer with the signals recorded on photographic paper. This amplifier was later used as a core of a new potentiostat with only a power supplier added. This potentiostat, being an important instrument for electrochemical investigations, was designed by Wenking during his work at the Max Plank Institute in Göttingen, Germany. At that time Hans Wenking was working in a group with Professor Karl Friedrich Bonhoeffer where he was appointed to develop a potentiostat that was needed for electrochemical experiments, particularly, for studying corrosion.&lt;/p&gt;&lt;p&gt;Until 1957, Wenking's potentiostat was manufactured only for the internal use of the Max Planck Institute in Göttingen. Later Hans Wenking together with Gerhard Bank established “Elektronische Werkstatt Göttingen” to commercialize the potentiostats. From 1959, the company operated under the name “Gerhard Bank Electronik”. Wenking designed the instruments as a freelance, but the brand “Wenking potentiostat” (Figure 2) soon became a famous trademark. The consequence of the potentiostat development was a rush in the development of electrochemical science. The phenomena of metal passivity could be better explained, including mechanisms of oxide layer formation, and far beyond the materials science. The potentiostat became a standard instrument for most electrochemical investigations, particularly for electroanalytical measurements.&lt;/p&gt;&lt;p&gt;Independent of Wenking's work, similar instruments were designed by other companies. Tacussel was one of those companies which came to a similar design as Wenking's potentiostats and started manufacturing potentiostats in France. In the USA, Wenking's potentiostats were leading on the market and became standard instruments in electrochemical labs.&lt;/p&gt;&lt;p&gt;Wenking has never published his results in scientific papers. On the other hand, Wenking never concealed the technical details of his instruments. The circuits and layouts designed by him were included in the operation manuals for the instruments, and even in some manuals, a detailed theoretical treatise was given. Wenking's instruments were always state-of-the-art and electrochemists of the 1950s–70s used them for many different applications.&lt;/p&gt;&lt;p&gt;In the 1920s–50s many polarographic and later voltammetric (e.g., cyclic voltammetry) measurements were performed using a two-electrode configuration composed of a dropping mercury electrode or any other small working electrode and a counter electrode, also serving as a reference. The two-electrode conf","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202300003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46568525","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}

{"title":"Editorial overview: Porous electrodes for energy applications","authors":"Ulrike Krewer,&nbsp;Thomas Turek","doi":"10.1002/elsa.202300001","DOIUrl":"10.1002/elsa.202300001","url":null,"abstract":"<p>Porous electrodes are essential and high-performance components, which determine the performance of batteries, fuel cells, electrolysis cells, and further electrochemical devices. Improving their performance is a complex endeavor as the situation inside the electrodes is hard to grasp and control. This special collection brings together a series of valuable contributions regarding advanced experimental investigations and modeling studies of porous electrodes used in electrochemical devices for energy applications.</p><p>Porous electrodes should provide a sufficiently large surface area for the catalyzed reactions. Very often, the solid porous structure consists of several materials with very different functions such as catalytic activity and electronic or ionic conductivity. The pore system of these electrodes must be optimally designed for the transport of the various reacting species through diffusion, migration, and convection. Moreover, the presence of different phases (liquid electrolytes, gases) in the porous solid matrix of the electrodes leads to an extremely high complexity of the occurring processes. Obviously, there is a great need for improved experimental techniques for the determination of transport parameters and the precise characterization of the porous electrode structures. Based on this information, the development of detailed physicochemically based electrode models will allow for an optimal design of the porous electrodes with even better performance of energy-related electrochemical devices.</p><p>The overall 11 contributions in this collection cover different electrochemical applications such as lithium-ion batteries, carbon dioxide electrolysis, fuel cells, supercapacitors, and solar cells. In addition to experimental studies devoted to the characterization of the pore system and the determination of important performance parameters, improved models for electrodes and cells are another focus of this special issue. As guest editors appointed by <i>Electrochemical Science Advances</i>, we would like to thank all authors for their valuable contributions, the reviewers for their thoughtful comments, and the publisher Brian P. Johnson for his kind support. We do hope that this special collection on porous electrodes will provide some useful insights for the future development of improved technologies for energy storage and conversion.</p><p>The authors declare no conflict of interest.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.202300001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44528610","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}

{"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}

{"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,&nbsp;Teja Stüwe,&nbsp;Daniel Werner,&nbsp;Christoph Griesser,&nbsp;Christoph Thurner,&nbsp;David Stock,&nbsp;Julia Kunze-Liebhäuser,&nbsp;Engelbert Portenkirchner","doi":"10.1002/elsa.202200012","DOIUrl":"10.1002/elsa.202200012","url":null,"abstract":"<p>NaTi₂(PO₄)₃ (NTP) and Na_0.44MnO₂ (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 V_RHE, 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}

{"title":"Perspective on the electrochemical recovery of phosphate from wastewater streams","authors":"Nicholas A. Snyder,&nbsp;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}

{"title":"Role of oxide support in electrocatalytic nitrate reduction on Cu","authors":"O. Quinn Carvalho,&nbsp;Sophia R. S. Jones,&nbsp;Ashley E. Berninghaus,&nbsp;Richard F. Hilliard,&nbsp;Tyler S. Radniecki,&nbsp;Kelsey A. Stoerzinger","doi":"10.1002/elsa.202100201","DOIUrl":"10.1002/elsa.202100201","url":null,"abstract":"<p>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/CeO_2-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/CeO_2-δ compared to Cu/FTO is attributed to stronger nitrate adsorption, similar to thermal nitrate reduction. Utilization of CeO_2-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 (𝑣_O^••). 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}

{"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,&nbsp;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}