DOCSLIB.ORG

Regulating Kinetics and Thermodynamics of Electrochemical Nitrogen Reduction with Metal Single-Atom Catalysts in a Pressurized Electrolyser

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Regulating Kinetics and Thermodynamics of Electrochemical Nitrogen Reduction with Metal Single-Atom Catalysts in a Pressurized Electrolyser Regulating kinetics and thermodynamics of electrochemical nitrogen reduction with metal single-atom catalysts in a pressurized electrolyser Haiyuan Zoua,b, Weifeng Ronga, Shuting Weia, Yongfei Jic,1, and Lele Duana,d,1 aDepartment of Chemistry, Southern University of Science and Technology, 518055 Shenzhen, Guangdong, China; bSchool of Chemistry and Chemical Engineering, Harbin Institute of Technology, 150001 Harbin, China; cSchool of Chemistry and Chemical Engineering, Guangzhou University, 510006 Guangzhou, China; and dShenzhen Grubbs Institute, Southern University of Science and Technology, 518055 Shenzhen, Guangdong, China Edited by Alexis T. Bell, University of California, Berkeley, CA, and approved October 8, 2020 (received for review July 17, 2020) Using renewable electricity to synthesize ammonia from nitrogen practical requirements. On the other hand, the improvement of the paves a sustainable route to making value-added chemicals but yet thermodynamic driving force for ammonia production, such as requires further advances in electrocatalyst development and device regulating electrochemical reaction conditions, may offer equally integration. By engineering both electrocatalyst and electrolyzer to positive effects to efficiently promote the N2 reduction process and simultaneously regulate chemical kinetics and thermodynamic driving suppress the unwanted side reactions (22). Conventionally, explo- forces of the electrocatalytic nitrogen reduction reaction (ENRR), we ration of the innovation of electrocatalysts or electrochemical cell report herein stereoconfinement-induced densely populated metal devices has always been undergone independently, despite their single atoms (Rh, Ru, Co) on graphdiyne (GDY) matrix (formulated indivisible interconnection nature. Indeed, the ENRR advance- asMSA/GDY)andrealizedaboostedENRRactivityinapressurized ments toward the envisioned practical applications depend very reaction system. Remarkably, under the pressurized environment, the hydrogen evolution reaction of M SA/GDY was effectively suppressed much on the cooperative development of both electrocatalysts and and the desired ENRR activity was strongly amplificated. As a result, electrochemical cell devices (23). − + → = the pressurized ENRR activity of Rh SA/GDY at 55 atm exhibited a Given that the reductive N2 adsorption (N2 +e +H *N −1 −2 record-high NH3 formation rate of 74.15 μgh ·cm , a Faraday effi- NH) is usually regarded as the potential limiting step, novel metal −2 ciency of 20.36%, and a NH3 partial current of 0.35 mA cm single-atom catalysts (SACs, e.g., Ru, Rh, Co) with a favorable at −0.20 V versus reversible hydrogen electrode, which, respectively, ENRR kinetics guarantee a great promise to circumvent the N2 displayed 7.3-, 4.9-, and 9.2-fold enhancements compared with those activation energy barrier (24–27). These catalysts, on the other obtained under ambient conditions. Furthermore, a time-independent hand, also suffer vigorous competition from HER and low content 15 ammonia yield rate using purified N2 confirmed the concrete am- of metal loading (28–30). Encouragingly, the most recent research monia electroproduction. Theoretical calculations reveal that the driv- work demonstrated that the system-level regulation of the pres- ing force for the formation of end-on N2*onRhSA/GDYincreasedby surized electrocatalytic environment could affect the chemical 9.62 kJ/mol under the pressurized conditions, facilitating the ENRR equilibrium of the ammonia production reaction and meanwhile process. We envisage that the cooperative regulations of catalysts endow tangible HER suppression (31). It thus warrants research and electrochemical devices open up the possibilities for industrially efforts to query whether the integration of SACs with pressurized viable electrochemical ammonia production. electrochemical environments will lever synergies between kinetics single-atom catalysts | graphdiyne | pressurized electrocatalysis | nitrogen reduction reaction Significance mmonia is essential for human propagation and thriving (1, The present-day industrial ammonia synthesis is overreliance on – A2). Today’s global ammonia production is excessively de- the Haber Bosch process, yet consumes more than 1% of the pendent on the Haber–Bosch method, which converts nitrogen global energy supply along with gigatonne greenhouse-gas and hydrogen to ammonia at high temperature (300–500 °C) and emission per year. Electrochemical nitrogen reduction reaction pressure (200–300 atm) (3). So far, this century-old strategy has (ENRR) offers a sustainable path to produce ammonia under mild contributed vastly annual productions, yet significantly exacer- conditions, while its efficiency achieved by far is fairly low, which bating the global energy consumption and greenhouse-gas emis- requires the development of both catalysts and electrolyzers. sion. Electrocatalytic N reduction reaction (ENRR) to synthesize Here, by the cooperation of densely populated metal single atoms 2 on graphdiyne substrate with the pressurized electrocatalytic ammonia from nitrogen and water under mild conditions repre- system, the kinetics and the thermodynamic driving force of ENRR sents a viable alternative that strategically transforms the energy- are effectively regulated, leadingtoarecord-highammoniayield intensive sector toward sustainability, while its efficiency achieved rate. This work motivates the technological and material coevo- so far is fairly low (4–8). lution for the ENRR toward its envisioned application. The primary hurdle obstructing the ENRR lies in issues such as the inherent inertness of N2, the high-energy barrier of N2 Author contributions: L.D. designed research; H.Z., W.R., and Y.J. performed research; activation, multiple electron–proton transfers, the low solubility H.Z., W.R., S.W., and L.D. analyzed data; and H.Z., Y.J., and L.D. wrote the paper. of N2 in aqueous solutions and competing hydrogen evolution The authors declare no competing interest. – reaction (HER), etc. (9 12). On the basis of these premises, This article is a PNAS Direct Submission. strategies are highlighted to modulate the kinetics and thermo- This open access article is distributed under Creative Commons Attribution License 4.0 dynamic equilibrium of the progress, thus steering the reaction (CC BY). – toward the production of ammonia while mitigating HER (13 16). 1To whom correspondence may be addressed. Email: [email protected] or From a kinetic perspective, many catalyst-centric approaches, such [email protected]. as introducing alloy, defects, doping, and strain, etc., have been This article contains supporting information online at https://www.pnas.org/lookup/suppl/ explored to improve nitrogen reduction performance (17–21). The doi:10.1073/pnas.2015108117/-/DCSupplemental. overall ENRR efficiency, however, is still insufficient to meet the First published November 10, 2020. 29462–29468 | PNAS | November 24, 2020 | vol. 117 | no. 47 www.pnas.org/cgi/doi/10.1073/pnas.2015108117 Downloaded by guest on September 24, 2021 and thermodynamic driving forces and be the game-changer for corresponding metals to be 13.22, 15.31, and 12.08 wt % for Rh, the ENRR. Ru, and Co, respectively. In principle, this simple one-pot synthetic Herein, we showcase that SACs-catalyzed N2 reduction in a method can be generally extended to prepare other metal single- pressurized system is an effective design principle to enhance atom catalysts by exchanging the metal precursors with proper both the chemical kinetics and thermodynamic process, leading oxidation power. to the amplified ENRR activity with simultaneously retarded To uncover the chemical states and atomic coordination en- HER. The deployed SACs contain Ru, Rh, and Co atoms fea- vironment of M SA/GDY, X-ray photoelectron spectroscopy tured with densely populated active sites and stabilized on (XPS) and synchrotron-based X-ray absorption spectroscopy graphdiyne (GDY) support (referred to as M SA/GDY; M = Rh, (XAS) were performed. As shown in SI Appendix, Fig. S3, rep- Ru, and Co); these electrocatalysts were prepared by a facile and resentative XPS survey spectra show two major characteristic mild method via stereoconfinement of metal atoms on the GDY peaks of C 1s and O 1s at 284.6 and 532 eV, respectively. The framework. Through extensive ENRR test using adequately core-level XPS spectra of Rh 3d and Ru 3p can be deconvoluted 0 cleaned N2, we found that the as-prepared M SA/GDY electro- into spin-orbit peaks, corresponding to the Rh at around 307.5 catalysts render prominently enhanced ammonia electroproduction and 312.2 eV, Ru0 at 461.8 and 483.7 eV (Fig. 2 A and B) (39, with obvious HER inhibition at the pressurized electrocatalytic 40). The reduced valence state of the metal center suggests that system, suggesting positive cooperation between SAC and the the reductive elimination process indeed occurs as expected, pressurized environment. Remarkably, a record-high ammonia yield − − providing the driving force for the GDY formation and metal rate of 74.15 μgh 1·cm 2, a Faraday efficiency (FE) of 20.36%, and −2 deposition. It is important to point out that the high-resolution aNH3 partial current density of 0.35 mA cm were achieved for Co 2p profile mainly comprises Co2+ at around 780.5 and 796.4 Rh SA/GDY at 55 atm of N2, which shows 7.3-, 4.9-, and 9.2-fold eV, which arises from the easy oxidation of Co atoms (Fig. 2C) enhancement in comparison with those obtained in ambient con- (41). Furthermore, the X-ray absorption
Load more

Recommended publications
  • Optimum Alkaline Electrolyzer-Proton Exchange Membrane Fuel Cell Coupling in a Residential Solar Stand-Alone Power System
    International Scholarly Research Network ISRN Renewable Energy Volume 2011, Article ID 953434, 13 pages doi:10.5402/2011/953434 Research Article Optimum Alkaline Electrolyzer-Proton Exchange Membrane Fuel Cell Coupling in a Residential Solar Stand-Alone Power System Hany A. Khater, Amr A. Abdelraouf, and Mohamed H. Beshr Department of Mechanical Power Engineering, Faculty of Engineering, Cairo University, P.O. Box 12211, Giza, Egypt Correspondence should be addressed to Mohamed H. Beshr, [email protected] Received 22 July 2011; Accepted 4 September 2011 Academic Editors: K. Kaygusuz and A. Stoppato Copyright © 2011 Hany A. Khater et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Modeling of an alkaline electrolyzer and a proton exchange membrane fuel cell (PEMFC) is presented. Also, a parametric study is performed for both components in order to determine the effect of variable operating conditions on their performance. The aim of this study is to determine the optimum operating conditions when the electrolyzer and the PEMFC are coupled together as part of a residential solar powered stand-alone power system comprising photovoltaic (PV) arrays, an alkaline electrolyzer, storage tanks, a secondary battery, and a PEMFC. The optimum conditions are determined based on an economic study which is performed to determine the cost of electricity (COE) produced from this system so as to determine the lowest possible COE. All of the calculations are performed using a computer code developed by using MATLAB. The code is designed so that any user can easily change the data concerning the location of the system or the working parameters of any of the system’s components to estimate the performance of a modified system.
    [Show full text]
  • EFFECT of TEMPERATURE on PERFORMANCE of ADVANCED ALKALINE ELECTROLYZER Mohamad Azuan1,,Nor Zaihar Yahaya2,*,Amelia Melinda2,Muhammad Wasif Umar2 1,2Dept
    Sci.Int.(Lahor),31(5),757-762,2019 ISSN 1013-5316;CODEN: SINTE 8 757 EFFECT OF TEMPERATURE ON PERFORMANCE OF ADVANCED ALKALINE ELECTROLYZER Mohamad Azuan1,,Nor Zaihar Yahaya2,*,Amelia Melinda2,Muhammad Wasif Umar2 1,2Dept. of Electrical & Electronic Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia For correspondence; Tel. + (60)175514728, E-mail: [email protected] For correspondence; Tel. + (60)125363696, E-mail: [email protected] ABSTRACT: Water electrolysis is one of the most widely used techniques for hydrogen production whereas alkaline electrolyzer is the most commercially available technology in industry. Conventionally, the industrial electrolyzers normally produce around 70 % efficiency. This low efficiency is due to high power dissipation in electrolysis process. In an ideal water electrolysis, the cell voltage is equal to the minimum reversible voltage which is 1.23 V for chemical reaction to take place in electrolysis process. However, this cell voltage is much higher in industrial electrolysis cells. This excess voltage is caused by the over voltage potential which increases the electrical impedance of an electrolysis cell causing a fraction of the applied energy to be wasted as heat while allowing the electric current passes through it. This paper aims to study the effect of temperature towards the I-U curve, over-voltage potentials, hydrogen flow rate and energy efficiency of an advanced alkaline electrolyzer. The simulation model is carried out at five different temperature levels varying between 20⁰ C and 100⁰ C. All related equations to the electrochemical reaction are modelled and simulated in MATLAB/Simulink. The results have shown that the temperature does not have an effect on the hydrogen flow rate but instead have a significant effect on the I-U curve, over voltage potentials and energy efficiency.
    [Show full text]
  • Emilia Motoasca Avinash Kumar Agarwal Hilde Breesch Editors Energy Sustainability in Built and Urban Environments Energy, Environment, and Sustainability
    Energy, Environment, and Sustainability Series Editors: Avinash Kumar Agarwal · Ashok Pandey Emilia Motoasca Avinash Kumar Agarwal Hilde Breesch Editors Energy Sustainability in Built and Urban Environments Energy, Environment, and Sustainability Series editors Avinash Kumar Agarwal, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh, India Ashok Pandey, Distinguished Scientist, CSIR-Indian Institute of Toxicology Research, Lucknow, Uttar Pradesh, India This books series publishes cutting edge monographs and professional books focused on all aspects of energy and environmental sustainability, especially as it relates to energy concerns. The Series is published in partnership with the International Society for Energy, Environment, and Sustainability. The books in these series are editor or authored by top researchers and professional across the globe. The series aims at publishing state-of-the-art research and development in areas including, but not limited to: • Renewable Energy • Alternative Fuels • Engines and Locomotives • Combustion and Propulsion • Fossil Fuels • Carbon Capture • Control and Automation for Energy • Environmental Pollution • Waste Management • Transportation Sustainability More information about this series at http://www.springer.com/series/15901 Emilia Motoasca • Avinash Kumar Agarwal Hilde Breesch Editors Energy Sustainability in Built and Urban Environments 123 Editors Emilia Motoasca Hilde Breesch Department of Electrical Engineering Department of Civil Engineering KU Leuven (Catholic University Leuven) KU Leuven (Catholic University Leuven) Ghent, Belgium Ghent, Belgium Avinash Kumar Agarwal Department of Mechanical Engineering Indian Institute of Technology Kanpur Kanpur, Uttar Pradesh, India ISSN 2522-8366 ISSN 2522-8374 (electronic) Energy, Environment, and Sustainability ISBN 978-981-13-3283-8 ISBN 978-981-13-3284-5 (eBook) https://doi.org/10.1007/978-981-13-3284-5 Library of Congress Control Number: 2018961716 © Springer Nature Singapore Pte Ltd.
    [Show full text]
  • Electroreduction of Carbon Monoxide to Liquid Fuel on Oxide-Derived Nanocrystalline Copper
    LETTER doi:10.1038/nature13249 Electroreduction of carbon monoxide to liquid fuel on oxide-derived nanocrystalline copper Christina W. Li1, Jim Ciston2 & Matthew W. Kanan1 The electrochemical conversion of CO and H O into liquid fuel z z { {z { 2 2 2CO 3H2O 4e ?CH3CO2 3HO is ideal for high-density renewable energy storage and could pro- ð2Þ E~0:50 V versus RHE vide an incentive for CO2 capture. However, efficient electrocata- lysts for reducing CO and its derivatives into a desirable fuel1–3 are 2 By comparing OD-Cu to electrodes comprised of commercial Cu nano- not available at present. Although many catalysts4–11 can reduce CO 2 particles, we show that CO reduction activity is not a consequence of to carbon monoxide (CO), liquid fuel synthesis requires that CO is re- 1 nanocrystallite size or morphology; instead, we propose that grain boun- duced further, using H OasaH source. Copper (Cu) is the only known 2 daries participate in the catalysis. material with an appreciable CO electroreduction activity, but in bulk OD-Cu electrodes were prepared by annealing polycrystalline Cu form its efficiency and selectivity for liquid fuel are far too low for prac- foil in air at 500 C to grow a thick Cu O layer on the surface and sub- tical use. In particular, H O reduction to H outcompetes CO reduc- u 2 2 2 sequently reducing this oxide to form Cu0 nanocrystallites. We used tion on Cu electrodes unless extreme overpotentials are applied, at which two reduction methods to vary the properties of the material.
    [Show full text]
  • Improving the Efficiency of PEM Electrolyzers Through Membrane
    energies Article Improving the Efficiency of PEM Electrolyzers through Membrane-Specific Pressure Optimization Fabian Scheepers 1,* , Markus Stähler 1, Andrea Stähler 1, Edward Rauls 1 , Martin Müller 1, Marcelo Carmo 1 and Werner Lehnert 1,2 1 Forschungszentrum Juelich GmbH, Institute of Energy and Climate Research, IEK-14, Electrochemical Process Engineering, 52425 Juelich, Germany; [email protected] (M.S.); [email protected] (A.S.); [email protected] (E.R.); [email protected] (M.M.); [email protected] (M.C.); [email protected] (W.L.) 2 Faculty of Mechanical Engineering, RWTH Aachen University, 52072 Aachen, Germany * Correspondence: [email protected]; Tel.: +49-2461-61-2177 Received: 20 December 2019; Accepted: 23 January 2020; Published: 1 February 2020 Abstract: Hydrogen produced in a polymer electrolyte membrane (PEM) electrolyzer must be stored under high pressure. It is discussed whether the gas should be compressed in subsequent gas compressors or by the electrolyzer. While gas compressor stages can be reduced in the case of electrochemical compression, safety problems arise for thin membranes due to the undesired permeation of hydrogen across the membrane to the oxygen side, forming an explosive gas. In this study, a PEM system is modeled to evaluate the membrane-specific total system efficiency. The optimum efficiency is given depending on the external heat requirement, permeation, cell pressure, current density, and membrane thickness. It shows that the heat requirement and hydrogen permeation dominate the maximum efficiency below 1.6 V, while, above, the cell polarization is decisive. In addition, a pressure-optimized cell operation is introduced by which the optimum cathode pressure is set as a function of current density and membrane thickness.
    [Show full text]
  • T~-:'Al of 10 Paces Only May Be Xeroxed
    T~-:'AL OF 10 PACES ONLY MAY BE XEROXED DYNAMIC MODELING, SIMULATION AND CONTROL OF A SMALL WIND-FUEL CELL HYBRID ENERGY SYSTEM FOR STAND-ALONE APPLICATIONS by ©Mohammad Jahangir Alam Khan A thesis submitted to the School of Graduate Studies in partial fulfillment of the requirements for the degree of Master of Engineering Faculty of Engineering and Applied Science Memorial University of Newfoundland June 2004 St. John's Newfoundland Canada Library and Bibliotheque et 1+1 Archives Canada Archives Canada Published Heritage Direction du Branch Patrimoine de !'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A ON4 Ottawa ON K1A ON4 Canada Canada Your file Votre reference ISBN: 0-494-02350-3 Our file Notre reference ISBN: 0-494-02350-3 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library permettant a Ia Bibliotheque et Archives and Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I' Internet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans loan, distribute and sell theses le monde, a des fins commerciales ou autres, worldwide, for commercial or non­ sur support microforme, papier, electronique commercial purposes, in microform, et/ou autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve Ia propriete du droit d'auteur ownership and moral rights in et des droits moraux qui protege cette these. this thesis. Neither the thesis Ni Ia these ni des extraits substantiels de nor substantial extracts from it celle-ci ne doivent etre imprimes ou autrement may be printed or otherwise reproduits sans son autorisation.
    [Show full text]
  • Efficiency – Electrolysis White Paper
    Efficiency – Electrolysis White paper siemens-energy.com/electrolyzer White paper l Efficiency – Electrolysis Dr.l Philipp Lettenmeier Electrolysis In 1800, the two English scientists William Nicholson and Anthony Carlisle discovered direct current electrolysis, thereby establishing electrochemistry as a new scientific field. For a long time, electrolysis was the dominant tech- nology for the industrial generation of hydrogen. However, the increasing use of natural gas largely displaced this technology with the more cost-effective steam reforming. Now, over 200 years later, the splitting of water with elec- trical current is experiencing a renaissance. This is because this technology provides the possibility of converting and storing regenerative electric power in the form of hydrogen as a chemical energy source. In this process, traditional alkaline electrolysis is supplemented by the modern tech- nology of polymer electrolyte membrane (PEM) electrolysis. This is based on a publication by Russell et al. in 1973.1 The high reaction rate and the high power density make PEM electrolysis interesting with the use of fluctuating renew- able energy. The efficiency of the electrolysis systems is critical both technically and economically for electrochemical hydrogen generation using renewable energy.2 Hydrogen generation costs are primarily dominated by the relatively high power costs in addition to operating hours and amortization of the plant. From a technical standpoint, these costs can only be reduced by increasing overall efficiency. Efficiency is not just efficiency The following document is intended to illustrate for the The efficiency of two processes can reader what has to be taken into account when specifying only be compared if all of the reference or comparing efficiency levels for electrolysis systems.
    [Show full text]
  • Synthesis of Ammonia Directly from Air and Water at Ambient Temperature and SUBJECT AREAS: SYNTHESIS Pressure INORGANIC CHEMISTRY Rong Lan1, John T
    Synthesis of ammonia directly from air and water at ambient temperature and SUBJECT AREAS: SYNTHESIS pressure INORGANIC CHEMISTRY Rong Lan1, John T. S. Irvine2 & Shanwen Tao1 ELECTROCHEMISTRY MATERIALS CHEMISTRY 1Department of Chemical and Process Engineering, University of Strathclyde, Glasgow G1 1XJ, UK, 2School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, UK. Received 28 August 2012 The N;N bond (225 kcal mol21) in dinitrogen is one of the strongest bonds in chemistry therefore artificial Accepted synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only 19 October 2012 bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N2 separation and H2 production Published stages. A maximum ammonia production rate of 1.14 3 1025 mol m22 s21 has been achieved when a voltage 29 January 2013 of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future. Correspondence and requests for materials should be addressed to iven the need to feed a growing world population whilst simultaneously reducing global carbon emis- S.T. (shanwen.tao@ sions, it is desired to break the link between industrial production of agricultural fertilisers based on strath.ac.uk) G ammonia and the use of fossil fuels.
    [Show full text]
  • For Operation in Liquid Metal Electrode Solid Oxide Fuel Cells A
    A Rotating Electrolyte Disc (RED) for Operation in Liquid Metal Electrode Solid Oxide Fuel Cells A. Toleuova1,2, V. Yufit3, S. Simons1,4, W. C. Maskell1,3, D. J. L. Brett1 1Electrochemical Innovation Lab, University College London, London WC1E 7JE, UK 2School of Engineering, Nazarbayev University, 53 Kabanbay Batyr Ave, Astana, Kazakhstan, 010000 3Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK 4UCL School of Energy and Resources, 220 Victoria Square, Adelaide, Australia A novel solid oxide fuel cell with liquid metal anode (LMA SOFC) has been recently proposed as an alternative to conventional solid oxide fuel cells. LMA SOFC allows operation on a variety of carbonaceous fuels – gaseous or solid, while remaining tolerant towards fuel contaminants [1]. The liquid metal electrode resides in a layer between the fuel and solid electrolyte. During current flow oxygen ions migrate though the solid electrolyte (yttria- stabilised zirconia) to the liquid metal anode. At the interface between the electrolyte and the liquid metal the O2- ions react electrochemically with the metal, generating metal oxide which in turn reacts with the fuel, producing water (hydrogen as fuel) and/or carbon dioxide (carbon or hydrocarbon as fuel). With respect to reported earlier uncertainties in performance limitation of LMA SOFC [2] greater understanding of the electrochemical reactions, redox, and transport processes within liquid metal electrodes is needed. This study discusses the development of a technique to enable the determination of the parameters controlling mass transport of dissolved oxygen (and other gases) and oxidised species including metal oxide in the liquid metal; the technique also provides the possibility of the investigation of heterogeneous and homogeneous reaction kinetics as well as the influence of electrode contaminants.
    [Show full text]
  • Improvement of Electrochemical Reduction of CO2 Using
    Received: March 17, 2020 Electrochemistry Accepted: June 21, 2020 Published online: August 18, 2020 The Electrochemical Society of Japan https://doi.org/10.5796/electrochemistry.20-00037 Article Electrochemistry, 88(5), 451–456 (2020) Improvement of Electrochemical Reduction of CO2 Using the Potential-Pulse Polarization Method Toshi OGUMAa,* and Kazuhisa AZUMIb a Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita 13, Nishi 8, Kitaku, Sapporo, Hokkaido 060-8628, Japan b Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kitaku, Sapporo, Hokkaido 060-8628, Japan * Corresponding author: [email protected] ABSTRACT Electrochemical conversion of CO2 gas emitted to the atmosphere to useful chemicals has been expected to suppress the global greenhouse effect and to conserve the natural resources. For the electrochemical reduction of CO2 on an Ag electrode, the effect of the −3 addition of 1-ethyl-3-methylimidazolium ethyl sulfate (EMISE) ionic liquid to the aqueous solution of 0.1 mol dm K2CO3, and the effect of the polarization methods, i.e., the potentiostatic polarization and the potential-pulse polarization, on the reduction efficiency were investigated. From the gas chromatography measurement, CO as the main product of CO2 reduction and H2 as a by-product of water decomposition were obtained. Faraday efficiency of CO formation obtained by the potential-pulse polarization was considerably higher than that obtained by the potentiostatic polarization. The addition of EMISE could add further improvement in the efficiency of CO formation higher than 70%. Such improvement provided by the potential-pulse polarization method and the addition of EMISE was interpreted by the depletion and recovery of the reactants on the electrode in the pulse cycle and promotion of CO2 molecular formation − from HCO3 ions in the dense adsorption layer of EMIM cations on the electrode surface.
    [Show full text]
  • Supporting Info
    Electronic Supplementary Material (ESI) for Energy & Environmental Science. This journal is © The Royal Society of Chemistry 2019 Supporting Info Electrochemical conversion of a bio-derivable hydroxy acid to a drop-in oxygenate diesel fuel Jérôme Meyers,+a Joel B. Mensah,+a F. Joschka Holzhäuser,a Ahmad Omari,b Christian C. Blesken,c Till Tiso,c Stefan Palkovits,a Lars M. Blank,c Stefan Pischinger,b Regina Palkovits*a a Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany. b Lehrstuhl für Verbrennungskraftmaschinen, RWTH Aachen University, Forckenbeckstraße 4, 52074 Aachen, Germany. c Institut für Angewandte Mikrobiologie, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany. + These authors contributed equally to this work. * author of correspondence: [email protected] Table of Contents 1 Experimental section Materials HAA synthesis Composition of simulated fermentation broth Electrolysis NMR HPLC Gas chromatography Gas chromatography-mass spectrometry Determination of the product yields Determination of the fuel properties 2 Results Electrolysis in fermentative medium Proposed reaction pathway 3 Analytical data 4 References 2 1 Experimental section Materials 3-Hydroxy decanoic acid (≥95%; 007Chemicals), methanol (≥99.8%, TH-Geyer), ethanol (≥99.9%; TH-Geyer), acetonitrile (≥99.9%, Roth), ethyl heptanoate (99%, Sigma-Aldrich), heptane (≥96%, Sigma-Aldrich), potassium hydroxide (≥99.5%; Roth), tetrabutylammonium perchlorate (99%, Sigma-Aldrich), tetrabutylammonium tetrafluoroborate (99%, Sigma- Aldrich), trimethylamine (≥99.5%, Roth), 1-nonanol (98%, Sigma-Aldrich), 2-nonanol (99%, Sigma-Aldrich), 2-nonanone (≥99%, Sigma-Aldrich), nonanal (95%, Sigma-Aldrich), nonanal dimethyl acetal (>97%, TCI), methyl nonanoate (>96%, TCI) and nonane (≥99%, Honeywell) were used as purchased without any further purification.
    [Show full text]
  • Delft University of Technology Syngas Production from Electrochemical
    Delft University of Technology Syngas Production from Electrochemical Reduction of CO2: Current Status and Prospective Implementation Hernández, S.; Amin Farkhondehfal, M.; Sastre, Francesc; Makkee, Michiel; Saracco, G.; Russo, Nunzio DOI 10.1039/C7GC00398F Publication date 2017 Document Version Accepted author manuscript Published in Green Chemistry Citation (APA) Hernández, S., Amin Farkhondehfal, M., Sastre, F., Makkee, M., Saracco, G., & Russo, N. (2017). Syngas Production from Electrochemical Reduction of CO2: Current Status and Prospective Implementation. Green Chemistry. https://doi.org/10.1039/C7GC00398F Important note To cite this publication, please use the final published version (if applicable). Please check the document version above. Copyright Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons. Takedown policy Please contact us and provide details if you believe this document breaches copyrights. We will remove access to the work immediately and investigate your claim. This work is downloaded from Delft University of Technology. For technical reasons the number of authors shown on this cover page is limited to a maximum of 10. View Article Online View Journal Green Chemistry Cutting-edgeAccepted researchManuscript for a greener sustainable future This article can be cited before page numbers have been issued, to do this please use: S. Hernandez, M. A. Farkhondehfal, F. Sastre, M. Makkee, G. Saracco and N. Russo, Green Chem., 2017, DOI: 10.1039/C7GC00398F. Volume 18 Number 7 7 April 2016 Pages 1821–2242 This is an Accepted Manuscript, which has been through the Green Royal Society of Chemistry peer review process and has been Chemistry accepted for publication.
    [Show full text]