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Kundu J, Kwon T, Lee K, Choi S. Exploration of metal-free 2D electrocatalysts toward the oxygen electroreduction. EXPLORATION (BEIJING, CHINA) 2024; 4:20220174. [PMID: 39175883 PMCID: PMC11335471 DOI: 10.1002/exp.20220174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/21/2023] [Indexed: 08/24/2024]
Abstract
The advancement of economical and readily available electrocatalysts for the oxygen reduction reaction (ORR) holds paramount importance in the advancement of fuel cells and metal-air batteries. Recently, 2D non-metallic materials have obtained substantial attention as viable alternatives for ORR catalysts due to their manifold advantages, encompassing low cost, ample availability, substantial surface-to-volume ratio, high conductivity, exceptional durability, and competitive activity. The augmented ORR performances observed in metal-free 2D materials typically arise from heteroatom doping, defects, or the formation of heterostructures. Here, the authors delve into the realm of electrocatalysts for the ORR, pivoting around metal-free 2D materials. Initially, the merits of metal-free 2D materials are explored and the reaction mechanism of the ORR is dissected. Subsequently, a comprehensive survey of diverse metal-free 2D materials is presented, tracing their evolutionary journey from fundamental concepts to pragmatic applications in the context of ORR. Substantial importance is given on the exploration of various strategies for enhancing metal-free 2D materials and assessing their impact on inherent material performance, including electronic properties. Finally, the challenges and future prospects that lie ahead for metal-free 2D materials are underscored, as they aspire to serve as efficient ORR electrocatalysts.
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Affiliation(s)
- Joyjit Kundu
- Department of Chemistry and Green‐Nano Materials Research CenterKyungpook National UniversityDaeguRepublic of Korea
| | - Taehyun Kwon
- Department of Chemistry and Research Institute of Basic SciencesIncheon National UniversityIncheonRepublic of Korea
| | - Kwangyeol Lee
- Department of Chemistry and Research Institute for Natural SciencesKorea UniversitySeoulRepublic of Korea
| | - Sang‐Il Choi
- Department of Chemistry and Green‐Nano Materials Research CenterKyungpook National UniversityDaeguRepublic of Korea
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Mirshokraee SA, Muhyuddin M, Orsilli J, Berretti E, Lavacchi A, Lo Vecchio C, Baglio V, Viscardi R, Zaffora A, Di Franco F, Santamaria M, Olivi L, Pollastri S, Santoro C. Mono-, bi- and tri-metallic Fe-based platinum group metal-free electrocatalysts derived from phthalocyanine for oxygen reduction reaction in alkaline media. NANOSCALE 2024. [PMID: 38488880 DOI: 10.1039/d4nr00575a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
In this manuscript, a comprehensive study is presented on Fe-based electrocatalysts with mono, bi, and tri-metallic compositions, emphasizing the influence of processing-structure correlations on the electrocatalytic activity for the oxygen reduction reaction (ORR) in the alkaline medium. These electrocatalysts were synthesized through the mixing of transition metal phthalocyanines (TM-Pc) with conductive carbon support, followed by controlled thermal treatment at specific temperatures (600 °C and 900 °C). An extensive analysis was conducted, employing various techniques, including X-ray Absorption Spectroscopy (XAS), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD), providing valuable insights into the structural characteristics of the synthesized nanoparticles. Importantly, an increase in the Fe-Pc weight percentage from 10% to 30% enhanced the ORR activity, although not proportionally. Furthermore, a comparative analysis between mono, bi, and tri-metallic samples subjected to different functionalization temperatures highlighted the superior electrocatalytic activity of electrocatalysts functionalized at 600 °C, particularly Fe 600 and Fe-Ni-Cu 600. These electrocatalysts featured Eon values of 0.96 V vs. RHE and E1/2 values of 0.9 V vs. RHE, with the added benefit of reduced anionic peroxide production. The potential of these Fe-based electrocatalysts to enhance ORR efficiency is underscored by this research, contributing to the development of more effective and sustainable electrocatalysts for energy conversion technologies.
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Affiliation(s)
- Seyed Ariana Mirshokraee
- Department of Materials Science, University of Milano-Bicocca, U5, Via Roberto Cozzi, 55, 20125, Milan, MI, Italy.
| | - Mohsin Muhyuddin
- Department of Materials Science, University of Milano-Bicocca, U5, Via Roberto Cozzi, 55, 20125, Milan, MI, Italy.
| | - Jacopo Orsilli
- Department of Materials Science, University of Milano-Bicocca, U5, Via Roberto Cozzi, 55, 20125, Milan, MI, Italy.
| | - Enrico Berretti
- Istituto di Chimica Dei Composti OrganoMetallici (ICCOM), Consiglio Nazionale Delle Ricerche (CNR), Via Madonna Del Piano 10, 50019 Sesto Fiorentino, Firenze, Italy
| | - Alessandro Lavacchi
- Istituto di Chimica Dei Composti OrganoMetallici (ICCOM), Consiglio Nazionale Delle Ricerche (CNR), Via Madonna Del Piano 10, 50019 Sesto Fiorentino, Firenze, Italy
| | - Carmelo Lo Vecchio
- Istituto di Tecnologie Avanzate per l'Energia "Nicola Giordano" (ITAE), Consiglio Nazionale delle Ricerche (CNR), Via Salita S. Lucia sopra Contesse 5, Messina, 98126, Italy
| | - Vincenzo Baglio
- Istituto di Tecnologie Avanzate per l'Energia "Nicola Giordano" (ITAE), Consiglio Nazionale delle Ricerche (CNR), Via Salita S. Lucia sopra Contesse 5, Messina, 98126, Italy
| | - Rosanna Viscardi
- Casaccia Research Center, ENEA, Santa Maria di Galeria, 00123, Rome, Italy
| | - Andrea Zaffora
- Department of Engineering, University of Palermo, Viale delle Scienze, 90128, Palermo, Italy
| | - Francesco Di Franco
- Department of Engineering, University of Palermo, Viale delle Scienze, 90128, Palermo, Italy
| | - Monica Santamaria
- Department of Engineering, University of Palermo, Viale delle Scienze, 90128, Palermo, Italy
| | - Luca Olivi
- Elettra-Sincrotrone Trieste, Area Science Park, Basovizza, Trieste, Italy
| | - Simone Pollastri
- Elettra-Sincrotrone Trieste, Area Science Park, Basovizza, Trieste, Italy
- Department of Physics, Computer Science and Mathematics, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Carlo Santoro
- Department of Materials Science, University of Milano-Bicocca, U5, Via Roberto Cozzi, 55, 20125, Milan, MI, Italy.
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Afaq M, Shahid M, Ahmad I, Yousaf S, Alazmi A, Mahmoud MHH, El Azab IH, Warsi MF. Large-scale sonochemical fabrication of a Co 3O 4-CoFe 2O 4@MWCNT bifunctional electrocatalyst for enhanced OER/HER performances. RSC Adv 2023; 13:19046-19057. [PMID: 37362336 PMCID: PMC10286564 DOI: 10.1039/d3ra03117a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 06/10/2023] [Indexed: 06/28/2023] Open
Abstract
Herein, we have prepared a mixed-phase Co3O4-CoFe2O4@MWCNT nanocomposite through a cheap, large-scale, and facile ultrasonication route followed by annealing. The structural, morphological, and functional group analyses of the synthesized catalysts were performed by employing various characterization approaches such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The resultant samples were tested for bifunctional electrocatalytic activity through various electrochemical techniques: cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The prepared Co3O4-CoFe2O4@MWCNT nanocomposite achieved a very high current density of 100 mA cm-2 at a lower (290 mV and 342 mV) overpotential (vs. RHE) and a smaller (166 mV dec-1 and 138 mV dec-1) Tafel slope in the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, compared to Co3O4-CoFe2O4. The excellent electrochemical activity of the as-prepared electrocatalyst was attributed to the uniform incorporation of Co3O4-CoFe2O4 over MWCNTs which provides high redox active sites, a greater surface area, better conductivity, and faster charge mobility. Furthermore, the enhanced electrochemical active surface, low charge-transfer resistance (Rct), and higher exchange current density (J0) of the Co3O4-CoFe2O4@MWCNT ternary composite are attributed to its superior behavior as a bifunctional electrocatalyst. Conclusively, this study demonstrates a novel and large-scale synthesis approach for bifunctional electrocatalysts with a high aspect ratio and abundance of active sites for high-potential energy applications.
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Affiliation(s)
- Muhammad Afaq
- Institute of Chemistry, Baghdad-ul-Jadeed Campus, The Islamia University of Bahawalpur Bahawalpur 63100 Pakistan
| | - Muhammad Shahid
- Department of Chemistry, College of Science, University of Hafr Al Batin P.O. Box 1803 Hafr Al Batin Saudi Arabia
| | - Iqbal Ahmad
- Department of Chemistry, Allama Iqbal Open University Islamabad 44000 Pakistan
| | - Sheraz Yousaf
- Institute of Chemistry, Baghdad-ul-Jadeed Campus, The Islamia University of Bahawalpur Bahawalpur 63100 Pakistan
| | - Amira Alazmi
- Department of Science and Technology, University Colleges at Nairiyah, University of Hafr Al Batin Nairiyah 31981 Saudi Arabia
| | - M H H Mahmoud
- Department of Chemistry, College of Science, Taif University Taif 21944 Saudi Arabia
| | - Islam H El Azab
- Department of Food Science and Nutrition, College of Science, Taif University P.O. Box 11099 Taif 21944 Saudi Arabia
| | - Muhammad Farooq Warsi
- Institute of Chemistry, Baghdad-ul-Jadeed Campus, The Islamia University of Bahawalpur Bahawalpur 63100 Pakistan
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Wang B, Gu C, Jiao Y, Gao Y, Liu X, Guo J, Qian T. Novel preparation of red fluorescent carbon dots for tetracycline sensing and its application in trace determination. Talanta 2023; 253:123975. [PMID: 36228555 DOI: 10.1016/j.talanta.2022.123975] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/22/2022] [Accepted: 09/25/2022] [Indexed: 11/23/2022]
Abstract
The controllable design of red-emitting carbon dots and further exploration of their application in the trace determination of environmental pollutants remains a tremendous challenge. Herein, the novel strategy for red fluorescent carbon dots (R-CDs) with a higher quantum yield of 58.9% was proposed by doping small-molecule urea into the bio-dye of resazurin for the first time, which can retain the luminophore of precursors and exhibit exceptional optical, advantageous reversibility and outstanding photostability. Importantly, the R-CDs exhibit a remarkable fluorescence reduction towards tetracyclines (TCs) accompanied by a noticeable color change of R-CDs solution from red to yellow, which can realize the trace detection of TCs at strelatively low levels, including tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC). The linear range of TC, CTC, and OTC are 3-40 μM, 4-50 μM, and 2-50 μM, and the corresponding detection limits are 38.5 nM, 64.6 nM, and 45.4 nM, respectively (S/N = 3). Furthermore, the R-CDs demonstrate sensitivity to the physiological pH in the linear range of 4.0-5.0 and 5.0-6.2 with a pKa of 5.61. As a multifunctional fluorescent sensor, R-CDs can provide a new perspective for the preparation of long-wavelength CDs, and further realize the trace determination of environmental pollutants.
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Affiliation(s)
- Bingyan Wang
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, 030600, China
| | - Changxin Gu
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, 030600, China
| | - Yuan Jiao
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, 030600, China
| | - Yifang Gao
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, 030600, China
| | - Xiaona Liu
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, 030600, China
| | - Junmei Guo
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, 030600, China
| | - Tianwei Qian
- College of Environmental Science and Engineering, Taiyuan University of Technology, Jinzhong, 030600, China.
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Deshmukh MA, Park SJ, Thorat HN, Bodkhe GA, Ramanavicius A, Ramanavicius S, Shirsat MD, Ha TJ. Advanced Energy Materials: Current Trends and Challenges in Electro- and Photo-Catalysts for H2O Splitting. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.11.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Díaz-Duran AK, Iadarola-Pérez G, Halac EB, Roncaroli F. Trifunctional Catalysts for Overall Water Splitting and Oxygen Reduction Reaction Derived from Co,Ni MOFs. Top Catal 2022. [DOI: 10.1007/s11244-022-01611-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Wang T, Ola O, Dapaah MF, Lu Y, Niu Q, Cheng L, Wang N, Zhu Y. Preparation and Characterization of Multi-Doped Porous Carbon Nanofibers from Carbonization in Different Atmospheres and Their Oxygen Electrocatalytic Properties Research. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:832. [PMID: 35269320 PMCID: PMC8912686 DOI: 10.3390/nano12050832] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 12/24/2022]
Abstract
Recently, electrocatalysts for oxygen reduction reaction (ORR) as well as oxygen evolution reaction (OER) hinged on electrospun nanofiber composites have attracted wide research attention. Transition metal elements and heteroatomic doping are important methods used to enhance their catalytic performances. Lately, the construction of electrocatalysts based on metal-organic framework (MOF) electrospun nanofibers has become a research hotspot. In this work, nickel-cobalt zeolitic imidazolate frameworks with different molar ratios (NixCoy-ZIFs) were synthesized in an aqueous solution, followed by NixCoy-ZIFs/polyacrylonitrile (PAN) electrospun nanofiber precursors, which were prepared by a simple electrospinning method. Bimetal (Ni-Co) porous carbon nanofiber catalysts doped with nitrogen, oxygen, and sulfur elements were obtained at high-temperature carbonization treatment in different atmospheres (argon (Ar), Air, and hydrogen sulfide (H2S)), respectively. The morphological properties, structures, and composition were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Moreover, the specific surface area of materials and their pore size distribution was characterized by Brunauer-Emmett-Teller (BET). Linear sweep voltammetry curves investigated catalyst performances towards oxygen reduction and evolution reactions. Importantly, Ni1Co2-ZIFs/PAN-Ar yielded the best ORR activity, whereas Ni1Co1-ZIFs/PAN-Air exhibited the best OER performance. This work provides significant guidance for the preparation and characterization of multi-doped porous carbon nanofibers carbonized in different atmospheres.
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Affiliation(s)
- Tao Wang
- Key Laboratory of Modern Agriculture Equipment and Technology, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China; (T.W.); (Y.L.)
| | - Oluwafunmilola Ola
- Advanced Materials Research Group, University of Nottingham, Nottingham NG7 2RD, UK;
| | - Malcom Frimpong Dapaah
- Institute of Environmental Health and Ecological Security, School of the Environment and SafetyEngineering, Jiangsu University, Zhenjiang 212013, China; (M.F.D.); (L.C.)
| | - Yuhao Lu
- Key Laboratory of Modern Agriculture Equipment and Technology, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China; (T.W.); (Y.L.)
| | - Qijian Niu
- Key Laboratory of Modern Agriculture Equipment and Technology, School of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China; (T.W.); (Y.L.)
| | - Liang Cheng
- Institute of Environmental Health and Ecological Security, School of the Environment and SafetyEngineering, Jiangsu University, Zhenjiang 212013, China; (M.F.D.); (L.C.)
| | - Nannan Wang
- Guangxi Institute for Fullerene Technology, Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, School of Resources Environment and Materials, University of Guangxi, Nanning 530000, China;
| | - Yanqiu Zhu
- Guangxi Institute for Fullerene Technology, Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, School of Resources Environment and Materials, University of Guangxi, Nanning 530000, China;
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Centi G, Perathoner S. Nanocarbon for Energy Material Applications: N 2 Reduction Reaction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2007055. [PMID: 33682312 DOI: 10.1002/smll.202007055] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/28/2020] [Indexed: 06/12/2023]
Abstract
Nanocarbons are an important class of energy materials and one relevant application is for the nitrogen reduction reaction, i.e., the direct synthesis of NH3 from N2 and H2 O via photo- and electrocatalytic approaches. Ammonia is also a valuable energy or hydrogen vector. This perspective paper analyses developments in the field, limiting discussion to nanocarbon-based electrodes. These aspects are discussed: i) active sites related to charge density differences on C atoms associated to defects/strains, ii) doping with heteroatoms, iii) introduction of isolated metal ions, iv) creation and in situ dynamics of metal oxide(hydroxide)/nanocarbon boundaries, and v) nanocarbon characteristics to control the interface. Discussion is focused on the performances and mechanistic aspects. Aim is not a systematic state-of-the-art report but to highlight the need to use a different perspective in studying this challenging reaction by using selected papers. Notwithstanding the large differences in the proposed nature of the active sites, fall all within a restricted range of performances, far from the targets. A holistic approach is emphasized to make a breakthrough advance.
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Affiliation(s)
- Gabriele Centi
- Departments ChiBioFarAm and MIFT, University of Messina and ERIC aisbl, V.le F. Stagno D'Alcontres 31, Messina, 98166, Italy
| | - Siglinda Perathoner
- Departments ChiBioFarAm and MIFT, University of Messina and ERIC aisbl, V.le F. Stagno D'Alcontres 31, Messina, 98166, Italy
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Zhao R, Chen Y, Huang S. Doping engineering on carbons as electrocatalysts for oxygen reduction reaction. FUNDAMENTAL RESEARCH 2021. [DOI: 10.1016/j.fmre.2021.06.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Mechanochemically Synthetized PAN-Based Co-N-Doped Carbon Materials as Electrocatalyst for Oxygen Evolution Reaction. NANOMATERIALS 2021; 11:nano11020290. [PMID: 33499395 PMCID: PMC7911492 DOI: 10.3390/nano11020290] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/15/2021] [Accepted: 01/20/2021] [Indexed: 11/16/2022]
Abstract
We report a new class of polyacrylonitrile (PAN)-based Co-N-doped carbon materials that can act as suitable catalyst for oxygen evolution reactions (OER). Different Co loadings were mechanochemically added into post-consumed PAN fibers. Subsequently, the samples were treated at 300 °C under air (PAN-A) or nitrogen (PAN-N) atmosphere to promote simultaneously the Co3O4 species and PAN cyclization. The resulting electrocatalysts were fully characterized and analyzed by X-ray diffraction (XRD) and photoelectron spectroscopy (XPS), transmission (TEM) and scanning electron (SEM) microscopies, as well as nitrogen porosimetry. The catalytic performance of the Co-N-doped carbon nanomaterials were tested for OER in alkaline environments. Cobalt-doped PAN-A samples showed worse OER electrocatalytic performance than their homologous PAN-N ones. The PAN-N/3% Co catalyst exhibited the lowest OER overpotential (460 mV) among all the Co-N-doped carbon nanocomposites, reaching 10 mA/cm2. This work provides in-depth insights on the electrocatalytic performance of metal-doped carbon nanomaterials for OER.
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Sideri IK, Tagmatarchis N. Noble-Metal-Free Doped Carbon Nanomaterial Electrocatalysts. Chemistry 2020; 26:15397-15415. [PMID: 32931046 DOI: 10.1002/chem.202003613] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Indexed: 11/08/2022]
Abstract
Electrocatalytic processes, such as oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CO2 RR), play key roles in various sustainable energy storage and production devices and their optimization in an ecological manner is of paramount importance for mankind. In this inclusive Review, we aspire to set the scene on doped carbon-based nanomaterials and their hybrids as precious-metal alternative electrocatalysts for these critical reactions in order for the research community not only to stay up-to-date, but also to get inspired and keep pushing forward towards their practical application in energy conversion.
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Affiliation(s)
- Ioanna K Sideri
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635, Athens, Greece
| | - Nikos Tagmatarchis
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635, Athens, Greece
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Song BY, Yao S. Optimization of Sulfurization Process of Cobalt Sulfide and Nitrogen Doped Carbon Material for Boosting the Oxygen Reduction Reaction Catalytic Activity in Alkaline Medium. Front Chem 2020; 8:314. [PMID: 32411665 PMCID: PMC7199712 DOI: 10.3389/fchem.2020.00314] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 03/30/2020] [Indexed: 11/29/2022] Open
Abstract
In order to reduce fuel cell material cost and promote its application, it is urgent to develop non-noble metal materials to replace platinum as the cathode catalysts in fuel cells. The cobalt sulfide and nitrogen co-doped carbon (S-Co-N/C) materials with metal-organic frameworks as precursors have shown good oxygen reduction reaction (ORR) catalytic activity. Benefiting from the protection of catalytic active sites by sulfur atoms, the stability and alcohol-tolerance of the S-Co-N/C catalyst can be significantly improved. In order to fully understand the effect of the sulfurization process on the properties of the material, zeolite imidazole frameworks (ZIF)-8, and ZIF-67 are used as precursors to prepare a novel material of S-Co-N/C by using a sulfurization-pyrolysis method. Another S-Co-N/C material by using a pyrolysis- sulfurization method is prepared for comparison. The effects of the sulfurization process in the preparation on the morphology, chemical structure, specific surface area, and ORR catalytic activity of the final material are investigated. The experimental results show that the surface of the S-Co-N/C material tends to be rough due to the sulfurization reaction of the metal elements. The porosity of the material is reduced to some extent due to the remaining Zn elements in the final product. Interestingly, some carbon nanotubes are found to be generated on the surface of the S-Co-N/C material because of the synergistic effect of Zn and Co on the carbon material during the pyrolysis process, which is beneficial to accelerate the adsorption of oxygen on the S-Co-N/C surface and the electron transportation during the oxygen reduction reaction. In addition, the generated CoS during the sulfurization process can further protect the Co elements from agglomeration, which can effectively increase the ORR catalytic active sites in the final material. The S-Co-N/C material prepared by the sulfurization-pyrolysis method performs a superior ORR catalytic activity to the one synthesized by the pyrolysis-sulfurization method.
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Affiliation(s)
- Bing-Ye Song
- Key Laboratory of Thermo-Fluid Science and Engineering of MOE, School of Energy & Power Engineering, Xi'an Jiaotong University, Xi'an, China
| | - Sen Yao
- Key Laboratory of New Materials and Facilities for Rural Renewable Energy of MOA, Henan Agricultural University, Zhengzhou, China
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