ACS electrochemistry最新文献

{"title":"Electrochemical Investigation of Enzyme Kinetics with an Unmediated, Unmodified Platinum Microelectrode: The Case of Glucose Oxidase.","authors":"Connor Davis, Ashildur Fridriksdottir, Omar Alkhairi, Lior Sepunaru","doi":"10.1021/acselectrochem.5c00139","DOIUrl":"10.1021/acselectrochem.5c00139","url":null,"abstract":"<p><p>We present a simple analytical method for studying the physical parameters governing redox-active enzyme kinetics using microscale electrodes. With the enzyme freely diffusing in solution, the interaction with its natural substrates produces a linearly increasing current corresponding to the reaction rate and the intrinsic thermodynamic properties of the enzyme. We show that external complications, such as artificial mediators or enzyme surface immobilization, can be avoided by using an unmediated, unmodified platinum microelectrode and that control over the dominating kinetic process can be readily achieved by changing the enzyme and (co)substrate concentrations. This is achieved using the glucose oxidase (GOx)/glucose system to compare with standard practice UV-Vis techniques, including the pH dependence of the enzyme activity. We illustrate how this straightforward chronoamperometric measurement is influenced by changes to reaction conditions commonly employed in enzyme investigations, including enzyme and oxygen concentrations as well as pH and the presence of chloride. Our method emphasizes that interpreting a simple increasing slope to analyze enzyme behavior requires ensuring adherence to initial rate assumptions, empirical observation of the current-concentration relationship, and insight from using the ping-pong framework. This enables a discussion of the bounds for evoking the commonly used Michaelis-Menten rate framework as well as the existing constraints of spectroscopy, contrasted with microscale voltammetry.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12306184/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144755560","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":"Vinylogous Electrochemical Carboxylation of Dienones.","authors":"Catia Nicoletti, Elena Tacchi, Noemi Trovato, Manuel Orlandi, Luca Dell'Amico, Abdirisak Ahmed Isse, Marco Fantin, Andrea Sartorel","doi":"10.1021/acselectrochem.5c00078","DOIUrl":"10.1021/acselectrochem.5c00078","url":null,"abstract":"<p><p>Among the reconversion strategies of carbon dioxide, its electrochemical fixation as a C1 synthon onto organic scaffolds (electrochemical carboxylation) displays an enormous synthetic potential and is thus receiving increasing attention. Examples of electrochemical carboxylation are reported via the activation of C-X (X = halide or pseudo-halide), C-H, or C-C bonds, or of unsaturated systems comprising CC, CN, and CO bonds. In this work, we report the electrochemical carboxylation of dienones, achieving the synthesis of 6-oxo-carboxylic acid derivatives in useful yields up to 56%. We show that electrochemical reduction of dienones drives their umpolung reactivity as nucleophiles toward carbon dioxide, promoting a δ-selective electrochemical carboxylation. The electrochemical reactivity was expanded to polyconjugated carboxylic derivatives such as α,β,γ,δ-unsaturated esters, thioesters, and amides. This work provides to the best of our knowledge the first example of vinylogous electrochemical reactivity in extended conjugated carbonyls involving carbon dioxide as the partner reactant. The reactivity and regioselectivity are rationalized through a mechanistic investigation that integrates cyclic voltammetry analysis and DFT calculations: this supports the reactivity with the CO₂ electrophile of nucleophilic doubly reduced species of the parent compound, preferentially occurring at the vinylogous position. The role of CO₂ in this process is also discussed. Considering the large synthetic versatility of carboxylic acids, our new protocol may become a useful tool for accessing novel synthons in drug design and general scientific development. We believe that these results will provide a guide for future studies on CO₂ fixation.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 8","pages":"1443-1451"},"PeriodicalIF":0.0,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12337805/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144839725","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":"Approach to Evaluating Reorganization Energies of Interfacial Electrochemical Reactions.","authors":"Karnamohit Ranka, Sijia Ke, Chenqi Fan, Jeffrey B Neaton, Peter Agbo, Frances A Houle","doi":"10.1021/acselectrochem.5c00158","DOIUrl":"10.1021/acselectrochem.5c00158","url":null,"abstract":"<p><p>Reaction rate coefficients for electron-transfer processes at the electrode-electrolyte interface are commonly estimated by using the Butler-Volmer equation, but their values are inaccurate beyond a few tenths of volts of overpotential. The Marcus-Hush-Chidsey (MHC) formalism yields correct asymptotic behavior of the rate coefficients vs applied overpotential but has complex dependencies on the redox system's intrinsic parameters, which can be difficult to model or measure. In this work, we bridge the two kinetics formalisms to estimate the reorganization energy, one of the important parameters for the MHC formalism, and investigate its dependence on other intrinsic parameters such as activation barriers, electronic coupling strength, and the density of states of the electrode surface. We examine the sensitivity of the reorganization energy to these parameters, establish some general relationships for accurately predicting rate coefficients using the MHC formalism over a wide range of applied overpotentials, and compare this approach to calculating MHC rate constants with other empirical approaches for the mechanisms of CO₂ reduction on different metal electrode surfaces.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 9","pages":"1766-1775"},"PeriodicalIF":0.0,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12415831/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145031658","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 Droplet Sculpturing of Short Carbon Fiber Nanotip Electrodes for Neurotransmitter Detection.","authors":"Yuanmo Wang, Pankaj Gupta, Ajay Pradhan, Raphaël Trouillon, Jörg Hanrieder, Henrik Zetterberg, Ann-Sofie Cans","doi":"10.1021/acselectrochem.5c00135","DOIUrl":"10.1021/acselectrochem.5c00135","url":null,"abstract":"<p><p>Carbon fiber nanotip electrodes (CFNEs) are crucial for electrochemical recordings of neurotransmission release in confined spaces, such as synapses and intracellular measurements. However, fabricating CFNEs with small surface area to minimize noise remains challenging due to inconsistent tip size control, low reproducibility, and low fabrication success rate. Here, we present a reliable, user-friendly method with high reproducibility and success rate for precise CFNE fabrication using microscopy-guided electrochemical etching of cylindrical carbon fiber microelectrodes in a potassium hydroxide droplet. The electrode positioning at the droplet's liquid-air interface determines the etched region, while manually applied time- and amplitude-controlled voltage pulses regulate material removal. Hence, real-time adjustments to electrode positioning and incremental voltage pulses enable precise sculpturing, akin to woodcarving with a knife. Using this method, we demonstrate successful fabrication of short (10 μm) CFNEs with tip diameters of 100 nm, with excellent electrochemical properties and sculptured into cone- and needle-shaped electrodes. Employing these CFNEs for low-noise amperometric dopamine (DA) detection from individual 200 nm DA-loaded liposomes, combined with <i>in silico</i> simulations, revealed that electrode shape influences detection efficiency based on vesicle size. These findings highlight the critical role of electrode geometry in vesicle-based electroanalysis.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 9","pages":"1698-1709"},"PeriodicalIF":0.0,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12415824/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145031308","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":"Challenges in the Theory and Atomistic Simulation of Metal Electrodeposition.","authors":"Shayantan Chaudhuri, Reinhard J Maurer","doi":"10.1021/acselectrochem.4c00102","DOIUrl":"10.1021/acselectrochem.4c00102","url":null,"abstract":"<p><p>Electrodeposition is a fundamental process in electrochemistry and has applications in numerous industries, such as corrosion protection, decorative finishing, energy storage, catalysis, and electronics. While there is a long history of electrodeposition use, its application for controlled nanostructure growth is limited. The establishment of an atomic-scale understanding of the electrodeposition process and dynamics is crucial to enable the controlled fabrication of metal nanoparticles and other nanostructures. Significant advancements in molecular simulation capabilities and the electronic structure theory of electrified solid-liquid interfaces bring theory closer to realistic applications, but a gap remains between applications, a theoretical understanding of dynamics, and atomistic simulation. In this Review, we briefly summarize the current state-of-the-art computational techniques available for the simulation of electrodeposition and electrochemical growth on surfaces and identify the remaining open challenges.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 7","pages":"1014-1032"},"PeriodicalIF":0.0,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12235630/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144602697","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":"Choosing the Correct Internal Reference Redox Species for Overcoming Reference Electrode Drift in Voltammetric pH Measurements.","authors":"Nafiz B Biswas, Tania Read, Katherine J Levey, Julie V Macpherson","doi":"10.1021/acselectrochem.5c00138","DOIUrl":"10.1021/acselectrochem.5c00138","url":null,"abstract":"<p><p>Reference electrode (RE) drift is a common problem when electrodes are used for pH determination, especially over extended periods of time or in complex media. For voltammetric pH measurements, one method to mitigate against RE drift is to add a second pH insensitive redox species (the internal reference, IREF) and measure the difference in peak potential, <i>E</i> _diff, between the signal associated with the pH sensitive species, <i>E</i> _pH, and IREF, <i>E</i> _IREF. This work strategically explores how to choose the correct IREF species. For these studies, a quinone-functionalized boron doped diamond (BDD-Q) electrode is employed as the pH sensing electrode over the pH range of 4-9. To avoid errors in reporting of the real <i>E</i> _pH and <i>E</i> _IREF values, there must be a minimum separation between the two peaks. Moreover, the distance on the potential axis between a peak and that of the current response pertaining to water electrolysis must also be considered. For the BDD-Q pH electrode, an operable potential window for IREF is established and the IREF redox species, hexachloroiridate (IrCl₆ ^2-/3-), is determined to be most appropriate, showing an ∼0.08 pH error over the pH range of 4-9 and reducing to ∼0.02 pH error over the pH range of 6-8. The use of <i>E</i> _diff is further assessed via the voltammetric measurement of dissolved carbon dioxide (CO₂) in a Stow-Severinghaus arrangement over the partial pressure range of 30.4-152.0 mmHg. The <i>R</i> ² linearity of the calibration line (=0.998) is shown to be equivalent and in agreement with theory when plotting either <i>E</i> _diff or <i>E</i> _pH versus CO₂ partial pressure. This data bodes well for the use of <i>E</i> _diff as a measurement signal in Stow-Severinghaus dissolved CO₂ transcutaneous sensors, where continuous measurement of pH over several days is required.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 8","pages":"1532-1539"},"PeriodicalIF":0.0,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12337080/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144839786","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":"Diffusional Voltammetry in Finite Spaces.","authors":"Yoshua H Moore, Ben A Johnson, Nicolas Plumeré","doi":"10.1021/acselectrochem.5c00091","DOIUrl":"10.1021/acselectrochem.5c00091","url":null,"abstract":"<p><p>The pore structure is a key design parameter for optimizing electrocatalytic systems that utilize porous electrodes, necessitating characterization at scales relevant to catalysis (∼0.1-100 μm). In this Review, we examine how diffusion during faradaic processes is impacted by the electrode pore geometry, defined by the concavity/convexity of its surface curvature, and by pore size, defined by the finiteness of the diffusion domain. We briefly outline experimental considerations for correlating experimental and simulated data from porous electrodes, and then outline the current theories for modeling diffusional voltammetry at various electrodes with finite diffusion spaces (direct problem), including planar redox-active films, concave inverse opals and hollow tubes, and convex pillar arrays and particle arrays. Finally, we describe how these theoretical frameworks can be applied to characterize the electrode pore structure by analyzing experimental voltammetric current responses (inverse problem).</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 8","pages":"1258-1273"},"PeriodicalIF":0.0,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12337096/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144839789","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":"Microalgae-Based Hybrid Biophotoelectrode for Efficient Light Energy Conversion.","authors":"Caio C G Silva, Guilherme Martins, André Luís, Hernán D Rojas-Mantilla, Ana Rovisco, Rodrigo Martins, Elvira Fortunato, Inês A C Pereira, Maria V B Zanoni, Saulo S Garrido, Felipe Conzuelo","doi":"10.1021/acselectrochem.5c00053","DOIUrl":"10.1021/acselectrochem.5c00053","url":null,"abstract":"<p><p>Photosynthetic microorganisms are promising candidates for sustainable energy production in photobio-electrochemical systems. However, integrating them with electrodes is challenging due to the compartmentalized nature of photosynthetic organelles. Microalgae, in particular, have a more complex cell structure than cyanobacteria, leading to low electron transfer rates and compromising electrochemical communication. In this study, we propose a hybrid biophotoelectrode that integrates intact microalgae cells with a WO₃ semiconductor electrode using polydopamine for cell entrapment and charge transfer enhancement. The biophotoelectrode delivers photocurrents of up to 24 μA cm^-2 under visible light illumination with an incident light power below 6.0 mW cm^-2. The photoelectrode performance and the origin of electron flow are investigated, confirming a substantial contribution of immobilized microalgae to the overall photocurrent. We present a proof-of-concept application of the microalgae-based hybrid electrode in combination with a formate dehydrogenase biocathode for the implementation of a biophoto-electrochemical cell for the conversion of CO₂ to formate assisted by light. The system demonstrates the potential for coupling photosynthetic processes with bioelectrochemical conversion, achieving efficient and sustainable production of value-added chemicals. These findings advance our understanding of photosynthetic cell-electrode interactions in hybrid systems, offering insights for developing photobio-electrochemical devices and innovative conversion strategies for waste products.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 7","pages":"1184-1193"},"PeriodicalIF":0.0,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12235756/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144602699","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 Ammoxidation of Unprotected Glycosides.","authors":"Imke M A Bartels, Md Asmaul Hoque, J Prathap Kaniraj, Mathew R Johnson, Sebastian B Beil, Shannon S Stahl, Martin D Witte, Adriaan J Minnaard","doi":"10.1021/acselectrochem.5c00111","DOIUrl":"10.1021/acselectrochem.5c00111","url":null,"abstract":"<p><p>Cyano-sugars are useful carbohydrate building blocks. Here, we report an electrocatalytic method to oxidize the primary alcohols of unprotected glycosides to the corresponding nitrile using 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) as a mediator and ammonium tetrafluoroborate as the ammonia source. Monosaccharides and disaccharides undergo successful reactions in an acetonitrile/pyridine solvent mixture at room temperature under constant current electrolysis.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 8","pages":"1515-1522"},"PeriodicalIF":0.0,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12337100/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144839790","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":"Coated Bipolar Membranes with Improved Forward Bias Performance for Energy Harvesting from Salt-Contaminated Acid and Base.","authors":"Nadia Boulif, Kitty Nijmeijer, Zandrie Borneman","doi":"10.1021/acselectrochem.5c00052","DOIUrl":"10.1021/acselectrochem.5c00052","url":null,"abstract":"<p><p>Background sodium chloride in hydrochloric acid and sodium hydroxide solutions leads to large overpotentials when a bipolar membrane (BPM) is operated under forward bias (FB). Under FB polarization, the accumulation of salt ions at the junction hinders the transport of H⁺ and OH^- ions, thus increasing the mass transport resistance and lowering the water recombination rate. The \"ionic blockade\" phenomenon is mainly observed if the base is contaminated with Cl^- ions due to the poor OH^-/Cl^- selectivity of the BPM's anion exchange layer (AEL). This shortcoming is successfully reduced by modifying the AEL with a sub-micrometer thick poly-(benzimidazole) (PBI) coating. Ionic crosslinking between the AEL and PBI leads to a denser interface that enhances the size exclusion of Cl^- ions. Furthermore, the negative charges of deprotonated benzimidazole units at the basic operating conditions contribute to the Donnan exclusion of Cl^- ions, while the OH^- ions can still hop between the alkaline-doped free volumes of the PBI film. The enhanced OH^-/Cl^- selectivity prevents the accumulation of Cl^- ions at the junction and leads to lower overpotentials during the forward bias operation of BPMs in salt-contaminated acid and base. As a result, the PBI-coated BPM has a peak power density 1.6 times higher than that of an uncoated BPM when harvesting electrical energy from a pH gradient. The BPM modification also benefits flow battery applications, as the calculated BPM voltaic efficiency at 100 A/m² (dis)-charge current density is increased from -3.7% to 57% with the addition of the PBI coating.</p>","PeriodicalId":520400,"journal":{"name":"ACS electrochemistry","volume":"1 8","pages":"1360-1372"},"PeriodicalIF":0.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12337089/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144839787","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}