Title: Electrosynthesis and Microanalysis in Thin Layer: An Electrochemical Pipette for Rapid Electrolysis and Mechanistic Study of Electrochemical Reactions
Abstract Electrochemistry represents unique approaches for the promotion and mechanistic study of chemical reactions and has garnered increasing attention in different areas of chemistry. This expansion necessitates the enhancement of the traditional electrochemical cells that are intrinsically constrained by mass transport limitations. Herein, we present an approach for designing an electrochemical cell by limiting the reaction chamber to a thin layer of solution, comparable to the thickness of the diffusion layer. This thin layer electrode (TLE) provides a modular platform to bypass the constraints of traditional electrolysis cells and perform electrolysis reactions in the timescale of electroanalytical techniques. The utility of the TLE for electrosynthetic applications benchmarked using NHPI‐mediated electrochemical C−H functionalization. The application of microscale electrolysis for the study of drug metabolites was showcased by elucidating the oxidation pathways of the paracetamol drug. Moreover, hosting a microelectrode in the TLE, was shown to enable real‐time probing of the profiles of redox‐active components of these rapid electrosynthesis reactions. more »« less
Punchihewa, Buwanila T.; Khalafi, Lida; Rafiee, Mohammad
(, Current Opinion in Electrochemistry)
Compton Richard G
(Ed.)
Thin-layer electrochemistry deals with electrochemical reactions in a confined solution comparable to the thickness of the diffusion layer. It gives immediate access to the electrode surface for performing rapid electrolysis reactions. The aim of this article is to highlight the seminal studies and some recent updates on thin-layer electrochemistry in three sub-sections: a) batch-type thin-layer electrodes (TLEs) and their principles, b) optically transparent TLEs for in situ spectral observation of the electrode reaction, and c) thin layer flow microreactors focusing on paired electrochemical reactions.
Park, Beom-Kyeong; Scipioni, Roberto; Zhang, Qian; Cox, Dalton; Voorhees, Peter W.; Barnett, Scott A.
(, Journal of Materials Chemistry A)
Solid oxide cells (SOCs) have important applications as fuel cells and electrolyzers. The application for storage of renewable electricity is also becoming increasingly relevant; however, it is difficult to meet stringent area-specific resistance (ASR) and long-term stability targets needed to achieve required efficiency and cost. Here we show a new SOC that utilizes a very thin Gd-doped ceria (GDC)/yttria-stabilized zirconia (YSZ) bi-layer electrolyte, Ni–YSZ cell support with enhanced porosity, and electrode surface modification using PrO x and GDC nanocatalysts to achieve unprecedented low ASR values < 0.1 Ω cm 2 , fuel cell power density ∼3 W cm −2 , and electrolysis current density ∼4 A cm −2 at 800 °C. Besides this exceptionally high performance, fuel cell and electrolysis life tests suggest very promising stability in fuel cell and steam electrolysis modes. Electrochemical impedance spectroscopy analysis done using a novel impedance subtraction method shows how rate-limiting electrode processes are impacted by the new SOC materials and design.
Franke, Mareena_C; Weix, Daniel_J
(, Israel Journal of Chemistry)
Abstract Nickel‐catalyzed cross‐electrophile coupling (XEC) is an efficient method to form carbon‐carbon bonds and has become an important tool for building complex molecules. While XEC has most often used stoichiometric metal reductants, these transformations can also be driven electrochemically. Electrochemical XEC (eXEC) is attractive because it can increase the greenness of XEC and this potential has resulted in numerous advances in recent years. The focus of this review is on electrochemical, Ni‐catalyzed carbon‐carbon bond forming reactions reported since 2010 and is categorized by the type of anodic half reaction: sacrificial anode, sacrificial reductant, and convergent paired electrolysis. The key developments are highlighted and the need for more scalable options is discussed.
Wu, Tiandi; Moeller, Kevin D.
(, Angewandte Chemie International Edition)
Abstract Paired electrochemical reactions allow the optimization of both atom and energy economy of oxidation and reduction reactions. While many paired electrochemical reactions take advantage of perfectly matched reactions at the anode and cathode, this matching of substrates is not necessary. In constant current electrolysis, the potential at both electrodes adjusts to the substrates in solution. In principle, any oxidation reaction can be paired with any reduction reaction. Various oxidation reactions conducted on the anodic side of the electrolysis were paired with the generation and use of hydrogen gas at the cathode, showing the generality of the anodic process in a paired electrolysis and how the auxiliary reaction required for the oxidation could be used to generate a substrate for a non‐electrolysis reaction. This is combined with variations on the cathodic side of the electrolysis to complete the picture and illustrate how oxidation and reduction reactions can be combined.
Abstract Pairing the electrocatalytic hydrogenation (ECH) reaction with different anodic reactions holds great promise for producing value‐added chemicals driven by renewable energy sources. Replacing the sluggish water oxidation with a bio‐based upgrading reaction can reduce the overall energy cost and allows for the simultaneous generation of high‐value products at both electrodes. Herein, we developed a membrane‐electrode assembly (MEA)‐based electrolysis system for the conversion of 5‐(hydroxymethyl)furfural (HMF) to bis(hydroxymethyl)furan (BHMF) and 2,5‐furandicarboxylic acid (FDCA). With (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO)‐mediated electrochemical oxidation (ECO) of HMF at the anode, the unique zero‐gap configuration enabled a minimal cell voltage of 1.5 V at 10 mA, which was stable during a 24‐hour period of continuous electrolysis, resulting in a combined faradaic efficiency (FE) as high as 139 % to BHMF and FDCA. High FE was also obtained in a pH‐asymmetric mediator‐free configuration, in which the ECO was carried out in 0.1 M KOH with an electrodeposited NiFe oxide catalyst and a bipolar membrane. Taking advantage of the low cell resistance of the MEA‐based system, we also explored ECH of HMF at high current density (280 mA cm−2), in which a FE of 24 % towards BHMF was achieved. The co‐generated H2was supplied into a batch reactor in tandem for the catalytic hydrogenation of furfural or benzaldehyde under ambient conditions, resulting in an additional 7.3 % of indirect FE in a single‐pass operation. The co‐electrolysis of bio‐derived molecules and the tandem electrocatalytic‐catalytic process provide sustainable avenues towards distributed, flexible, and energy‐efficient routes for the synthesis of valuable chemicals.
Punchihewa, Buwanila T., Minda, Vidit, Gutheil, William G., and Rafiee, Mohammad. Electrosynthesis and Microanalysis in Thin Layer: An Electrochemical Pipette for Rapid Electrolysis and Mechanistic Study of Electrochemical Reactions. Angewandte Chemie International Edition 62.44 Web. doi:10.1002/anie.202312048.
Punchihewa, Buwanila T., Minda, Vidit, Gutheil, William G., & Rafiee, Mohammad. Electrosynthesis and Microanalysis in Thin Layer: An Electrochemical Pipette for Rapid Electrolysis and Mechanistic Study of Electrochemical Reactions. Angewandte Chemie International Edition, 62 (44). https://doi.org/10.1002/anie.202312048
Punchihewa, Buwanila T., Minda, Vidit, Gutheil, William G., and Rafiee, Mohammad.
"Electrosynthesis and Microanalysis in Thin Layer: An Electrochemical Pipette for Rapid Electrolysis and Mechanistic Study of Electrochemical Reactions". Angewandte Chemie International Edition 62 (44). Country unknown/Code not available: Wiley Blackwell (John Wiley & Sons). https://doi.org/10.1002/anie.202312048.https://par.nsf.gov/biblio/10469860.
@article{osti_10469860,
place = {Country unknown/Code not available},
title = {Electrosynthesis and Microanalysis in Thin Layer: An Electrochemical Pipette for Rapid Electrolysis and Mechanistic Study of Electrochemical Reactions},
url = {https://par.nsf.gov/biblio/10469860},
DOI = {10.1002/anie.202312048},
abstractNote = {Abstract Electrochemistry represents unique approaches for the promotion and mechanistic study of chemical reactions and has garnered increasing attention in different areas of chemistry. This expansion necessitates the enhancement of the traditional electrochemical cells that are intrinsically constrained by mass transport limitations. Herein, we present an approach for designing an electrochemical cell by limiting the reaction chamber to a thin layer of solution, comparable to the thickness of the diffusion layer. This thin layer electrode (TLE) provides a modular platform to bypass the constraints of traditional electrolysis cells and perform electrolysis reactions in the timescale of electroanalytical techniques. The utility of the TLE for electrosynthetic applications benchmarked using NHPI‐mediated electrochemical C−H functionalization. The application of microscale electrolysis for the study of drug metabolites was showcased by elucidating the oxidation pathways of the paracetamol drug. Moreover, hosting a microelectrode in the TLE, was shown to enable real‐time probing of the profiles of redox‐active components of these rapid electrosynthesis reactions.},
journal = {Angewandte Chemie International Edition},
volume = {62},
number = {44},
publisher = {Wiley Blackwell (John Wiley & Sons)},
author = {Punchihewa, Buwanila T. and Minda, Vidit and Gutheil, William G. and Rafiee, Mohammad},
}
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