共查询到20条相似文献,搜索用时 31 毫秒
1.
Highly Active and Stable Graphene Tubes Decorated with FeCoNi Alloy Nanoparticles via a Template‐Free Graphitization for Bifunctional Oxygen Reduction and Evolution
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shiva Gupta Liang Qiao Shuai Zhao Hui Xu Ye Lin Surya V. Devaguptapu Xianliang Wang Mark T. Swihart Gang Wu 《Liver Transplantation》2016,6(22)
Development of highly active and stable bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts from earth‐abundant elements remains a grand challenge for highly demanded reversible fuel cells and metal–air batteries. Carbon catalysts have many advantages over others due to their low cost, excellent electrical conductivity, high surface area, and easy functionalization. However, they typically cannot withstand the highly oxidative OER environment. Here, a new class of bifunctional electrocatalyst is reported, consisting of ultralarge sized nitrogen doped graphene tubes (N‐GTs) (>500 nm) decorated with FeCoNi alloy particles. These tubes are prepared from an inexpensive precursor, dicyandiamide, via a template‐free graphitization process. The ORR/OER activity and the stability of these graphene tube catalysts depend strongly on the transition metal precursors. The best performing FeCoNi‐derived N‐GT catalyst exhibits excellent ORR and OER activity along with adequate electrochemical durability over a wide potential window (0–1.9 V) in alkaline media. The measured OER current is solely due to desirable O2 evolution, rather than carbon oxidation. Extensive electrochemical and physical characterization indicated that high graphitization degree, thicker tube walls, proper nitrogen doping, and presence of FeCoNi alloy particles are vital for high bifunctional activity and electrochemical durability of tubular carbon catalysts. 相似文献
2.
Electronic and Defective Engineering of Electrospun CaMnO3 Nanotubes for Enhanced Oxygen Electrocatalysis in Rechargeable Zinc–Air Batteries
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shengjie Peng Xiaopeng Han Linlin Li Shulei Chou Dongxiao Ji Huangjiao Huang Yonghua Du Jian Liu Seeram Ramakrishna 《Liver Transplantation》2018,8(22)
Rational design and massive production of bifunctional catalysts with superior oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities are essential for developing metal–air batteries and fuel cells. Herein, controllable large‐scale synthesis of sulfur‐doped CaMnO3 nanotubes is demonstrated via an electrospinning technique followed by calcination and sulfurization treatment. The sulfur doping can not only replace oxygen atoms to increase intrinsic electrical conductivity but also introduce abundant oxygen vacancies to provide enough catalytically active sites, which is further demonstrated by density functional theory calculation. The resulting sulfur‐modified CaMnO3 (CMO/S) exhibits better electrocatalytic activity for ORR and OER in alkaline solution with higher stability performance than the pristine CMO. These results highlight the importance of sulfur treatment as a facile yet effective strategy to improve the ORR and OER catalytic activity of the pristine CaMnO3. As a proof‐of‐concept, a rechargeable Zn–air battery using the bifunctional catalyst exhibits a small charge–discharge voltage polarization, and long cycling life. Furthermore, a solid‐state flexible and rechargeable Zn–air battery gives superior discharge–charge performance and remarkable stability. Therefore, the CMO/S nanotubes might be a promising replacement to the Pt‐based electrocatalysts for metal–air batteries and fuel cells. 相似文献
3.
Post Iron Decoration of Mesoporous Nitrogen‐Doped Carbon Spheres for Efficient Electrochemical Oxygen Reduction
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Zhuang Liu Fei Sun Lin Gu Gen Chen Tongtong Shang Jing Liu Zaiyuan Le Xianyang Li Hao Bin Wu Yunfeng Lu 《Liver Transplantation》2017,7(22)
Iron–nitrogen–carbon (Fe–N–C) catalysts are considered as the most promising nonprecious metal catalysts for oxygen reduction reactions (ORRs). Their synthesis generally involves complex pyrolysis reactions at high temperature, making it difficult to optimize their composition, pore structure, and active sites. This study reports a simple synthesis strategy by reacting preformed nitrogen‐doped carbon scaffolds with iron pentacarbonyl, a liquid precursor that can effectively form active sites with the nitrogen sites, enabling more effective control of the catalyst. The resultant catalyst possesses a well‐defined mesoporous structure, a high surface area, and optimized active sites. The catalysts exhibit high ORR activity comparable to that of Pt/C catalyst (40% Pt loading) in alkaline media, with excellent stability and methanol tolerance. The synthetic strategy can be extended to synthesize other metal–N–C catalysts. 相似文献
4.
Apically Dominant Mechanism for Improving Catalytic Activities of N‐Doped Carbon Nanotube Arrays in Rechargeable Zinc–Air Battery
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wenhan Niu Srimanta Pakhira Kyle Marcus Zhao Li Jose L. Mendoza‐Cortes Yang Yang 《Liver Transplantation》2018,8(20)
The oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in zinc–air batteries (ZABs) require highly efficient, cost‐effective, and stable electrocatalysts as alternatives to high cost and low poison resistant platinum group metals (PGM) catalysts. Although nitrogen‐doped carbon nanotube (NCNT) arrays are now capable of catalyzing ORR efficiently, their hydrophobic surface and base‐growth mode are found to limit the catalytic performance in the practical ZABs. Here, the concept of an apically dominant mechanism in improving the catalytic performance of NCNT by precisely encapsulating CoNi nanoparticles (NPs) within the apical domain of NCNT on the Ni foam (denoted as CoNi@NCNT/NF) is demonstrated. The CoNi@NCNT/NF exhibits a more excellent catalytic performance toward both ORR and OER than that of traditional NCNT derived from the base‐growth method. The ZAB coin cell using CoNi@NCNT/NF as an air electrode shows a peak power density of 127 mW cm?2 with an energy density of 845 Wh kgZn?1 and rechargeability over 90 h, which outperforms the performance of PGM catalysts. Density functional theory calculations reveal that the ORR catalytic performance of the CoNi@NCNT/NF is mainly attributed to the synergetic contributions from NCNT and the apical active sites on NCNT near to CoNi NPs. 相似文献
5.
Bimetallic Zeolitic Imidazolite Framework Derived Carbon Nanotubes Embedded with Co Nanoparticles for Efficient Bifunctional Oxygen Electrocatalyst
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yinle Li Baoming Jia Yanzhong Fan Kelong Zhu Guangqin Li Cheng‐Yong Su 《Liver Transplantation》2018,8(9)
Bifunctional oxygen catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with high activities and low‐cost are of prime importance and challenging in the development of fuel cells and rechargeable metal–air batteries. This study reports a porous carbon nanomaterial loaded with cobalt nanoparticles (Co@NC‐x/y) derived from pyrolysis of a Co/Zn bimetallic zeolitic imidazolite framework, which exhibits incredibly high activity as bifunctional oxygen catalysts. For instance, the optimal catalyst of Co@NC‐3/1 has the interconnected framework structure between porous carbon and embedded carbon nanotubes, which shows the superb ORR activity with onset potential of ≈1.15 V and half‐wave potential of ≈0.93 V. Moreover, it presents high OER activity that can be further enhanced to over commercial RuO2 by P‐doped with overpotentials of 1.57 V versus reversible hydrogen electrode at 10 mA cm?2 and long‐term stability for 2000 circles and a Tafel slope of 85 mV dec?1. Significantly, the nanomaterial demonstrates better catalytic performance and durability than Pt/C for ORR and commercial RuO2 and IrO2 for OER. These findings suggest the importance of a synergistic effect of graphitic carbon, nanotubes, exposed Co–Nx active sites, and interconnected framework structure of various carbons for bifunctional oxygen electrocatalysts. 相似文献
6.
Polydopamine‐Inspired,Dual Heteroatom‐Doped Carbon Nanotubes for Highly Efficient Overall Water Splitting
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Konggang Qu Yao Zheng Yan Jiao Xianxi Zhang Sheng Dai Shi‐Zhang Qiao 《Liver Transplantation》2017,7(9)
Overall water splitting involved hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are critical for renewable energy conversion and storage. Heteroatom‐doped carbon materials have been extensively employed as efficient electrocatalysts for independent HER or OER processes, while those as the bifunctional catalysts for simultaneously generating H2 and O2 by splitting water have been seldom reported. Inspired by the unparalleled virtues of polydopamine, the authors devise the facile synthesis of nitrogen and sulfur dual‐doped carbon nanotubes with in situ, homogenous and high concentration sulfur doping. The newly developed dual‐doped electrocatalysts display superb bifunctional catalytic activities for both HER and OER in alkaline solutions, outperforming all other reported carbon counterparts. Experimental characterizations confirm that the excellent performance is attributed to the multiple doping together with efficient mass and charge transfer, while theoretical computations reveal the promotion effect of secondary sulfur dopant to enhance the spin density of dual‐doped samples and consequently to form highly electroactive sites for both HER and OER. 相似文献
7.
Surface‐Modified Porous Carbon Nitride Composites as Highly Efficient Electrocatalyst for Zn‐Air Batteries
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wenhan Niu Zhao Li Kyle Marcus Le Zhou Yilun Li Ruquan Ye Kun Liang Yang Yang 《Liver Transplantation》2018,8(1)
Porous carbon nitride (PCN) composites are fabricated using a top‐down strategy, followed by additions of graphene and CoSx nanoparticles. This subsequently enhances conductivity and catalytic activity of PCN (abbreviated as CoSx@PCN/rGO) and is achieved by one‐step sulfuration of PCN/graphene oxides (GO) composite materials. As a result, the as‐prepared CoSx@PCN/rGO catalysts display excellent activity and stability toward both oxygen evolution and reduction reactions, surpassing electrocatalytic performance shown by state‐of‐the‐art Pt, RuO2 and other carbon nitrides. Remarkably, the CoSx@PCN/rGO bifunctional activity allows for applications in zinc‐air batteries, which show better rechargeability than Pt/C. The enhanced catalytic performance of CoSx@PCN/rGO can primarily be attributed to the highly porous morphology and sufficiently exposed active sites that are favorable for electrocatalytic reactions. 相似文献
8.
Yuanzhi Zhu Joshua Sokolowski Xiancheng Song Yanghua He Yi Mei Gang Wu 《Liver Transplantation》2020,10(11)
Carbon‐based heteroatom‐coordinated single‐atom catalysts (SACs) are promising candidates for energy‐related electrocatalysts because of their low‐cost, tunable catalytic activity/selectivity, and relatively homogeneous morphologies. Unique interactions between single metal sites and their surrounding coordination environments play a significant role in modulating the electronic structure of the metal centers, leading to unusual scaling relationships, new reaction mechanisms, and improved catalytic performance. This review summarizes recent advancements in engineering of the local coordination environment of SACs for improved electrocatalytic performance for several crucial energy‐convention electrochemical reactions: oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, CO2 reduction reaction, and nitrogen reduction reaction. Various engineering strategies including heteroatom‐doping, changing the location of SACs on their support, introducing external ligands, and constructing dual metal sites are comprehensively discussed. The controllable synthetic methods and the activity enhancement mechanism of state‐of‐the‐art SACs are also highlighted. Recent achievements in the electronic modification of SACs will provide an understanding of the structure–activity relationship for the rational design of advanced electrocatalysts. 相似文献
9.
Mengran Wang Yuan Li Jing Fang Cesar J. Villa Yaobin Xu Shiqiang Hao Jie Li Yexiang Liu Chris Wolverton Xinqi Chen Vinayak P. Dravid Yanqing Lai 《Liver Transplantation》2020,10(3)
Carbon dots have been recognized as one of the most promising candidates for the oxygen reduction reaction (ORR) in alkaline media. However, the desired ORR performance in metal–air batteries is often limited by the moderate electrocatalytic activity and the lack of a method to realize good dispersion. To address these issues, herein a biomass‐deriving method is reported to achieve the in situ phosphorus doping (P‐doping) of carbon dots and their simultaneous decoration onto graphene matrix. The resultant product, namely P‐doped carbon dot/graphene (P‐CD/G) nanocomposites, can reach an ultrahigh P‐doping level for carbon nanomaterials. The P‐CD/G nanocomposites are found to exhibit excellent ORR activity, which is highly comparable to the commercial Pt/C catalysts. When used as the cathode materials for a primary liquid Al–air battery, the device shows an impressive power density of 157.3 mW cm?2 (comparing to 151.5 mW cm?2 of a similar Pt/C battery). Finally, an all‐solid‐state flexible Al–air battery is designed and fabricated based on our new nanocomposites. The device exhibits a stable discharge voltage of ≈1.2 V upon different bending states. This study introduces a unique biomass‐derived material system to replace the noble metal catalysts for future portable and wearable electronic devices. 相似文献
10.
Tiva Sharifi Eduardo Gracia‐Espino Anran Chen Guangzhi Hu Thomas Wgberg 《Liver Transplantation》2020,10(11)
The oxygen reduction reaction (ORR) is of great importance in energy‐converting processes such as fuel cells and in metal–air batteries and is vital to facilitate the transition toward a nonfossil dependent society. The ORR has been associated with expensive noble metal catalysts that facilitate the O2 adsorption, dissociation, and subsequent electron transfer. Single‐ or few‐atom motifs based on earth‐abundant transition metals, such as Fe, Co, and Mo, combined with nonmetallic elements, such as P, S, and N, embedded in a carbon‐based matrix represent one of the most promising alternatives. Often these are referred to as single atom catalysts; however, the coordination number of the metal atom as well as the type and nearest neighbor configuration has a strong influence on the function of the active sites, and a more adequate term to describe them is metal‐coordinated motifs. Despite intense research, their function and catalytic mechanism still puzzle researchers. They are not molecular systems with discrete energy states; neither can they fully be described by theories that are adapted for heterogeneous bulk catalysts. Here, recent results on single‐ and few‐atom electrocatalyst motifs are reviewed with an emphasis on reports discussing the function and the mechanism of the active sites. 相似文献
11.
Tran Van Tam Sung Gu Kang Mun Ho Kim Seung Geol Lee Seung Hyun Hur Jin Suk Chung Won Mook Choi 《Liver Transplantation》2019,9(26)
Herein, a facile, one‐step hydrothermal route to synthesize novel all‐carbon‐based composites composed of B‐doped graphene quantum dots anchored on a graphene hydrogel (GH‐BGQD) is demonstrated. The obtained GH‐BGQD material has a unique 3D architecture with high porosity and large specific surface area, exhibiting abundant catalytic active sites of B‐GQDs as well as enhanced electrolyte mass transport and ion diffusion. Therefore, the prepared GH‐BGQD composites exhibit a superior trifunctional electrocatalytic activity toward the oxygen reduction reaction, oxygen evolution reaction, and hydrogen evolution reaction with excellent long‐term stability and durability comparable to those of commercial Pt/C and Ir/C catalysts. A flexible solid‐state Zn–air battery using a GH‐BGQD air electrode achieves an open‐circuit voltage of 1.40 V, a stable discharge voltage of 1.23 V for 100 h, a specific capacity of 687 mAh g?1, and a peak power density of 112 mW cm?2. Also, a water electrolysis cell using GH‐BGQD electrodes delivers a current density of 10 mA cm?2 at cell voltage of 1.61 V, with remarkable stability during 70 h of operation. Finally, the trifunctional GH‐BGQD catalyst is employed for water electrolysis cell powered by the prepared Zn–air batteries, providing a new strategy for the carbon‐based multifunctional electrocatalysts for electrochemical energy devices. 相似文献
12.
In Situ Exfoliating and Generating Active Sites on Graphene Nanosheets Strongly Coupled with Carbon Fiber toward Self‐Standing Bifunctional Cathode for Rechargeable Zn–Air Batteries
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Chao Hang Jian Zhang Jiawei Zhu Wenqiang Li Zongkui Kou Yunhui Huang 《Liver Transplantation》2018,8(16)
The self‐standing electrode nanomaterials with highly effective bifunctional electrocatalysis for oxygen reduction and evolution reactions (ORR/OER) are important for practical applications in metal–air batteries. Herein, a defect‐enriched and pyridinic‐N (PN) dominated bifunctional electrocatalyst with novel core–shell architecture (DN‐CP@G) is successfully fabricated by in situ exfoliating graphene from carbon paper followed by high temperature ammonia treatment. Benefitting from its strongly coupled core–shell structure, abundant defective sites and high‐content PN dopants, the DN‐CP@G displays an excellent electrocatalytic (ORR and OER) activity and stability in alkaline media, which are comparable to commercial Pt/C and Ir/C catalysts. The experiment, and theoretical calculations demonstrate that the electrocatalytic activities of carbon materials strongly depend on their defective sites and PN dopants. By directly using DN‐CP@G as a self‐standing electrode, the assembled zinc–air battery demonstrates a high discharge performance and outstanding long‐term cycle stability with at least 250 cycles, which is much superior to the mixed Pt/C and Ir/C electrodes. Remarkably, the DN‐CP@G based all‐solid‐state battery also reveals a good discharge and cycle performance. A facile and cost‐efficient approach to prepare highly effective bifunctional self‐standing electrode is provided by in situ generation of active sites on carbon support for metal–air batteries. 相似文献
13.
Highly Efficient Oxygen Reduction Reaction Activity of Graphitic Tube Encapsulating Nitrided CoxFey Alloy
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Siraj Sultan Jitendra N. Tiwari Jue‐Hyuk Jang Ahmad M. Harzandi Foad Salehnia Sung Jong Yoo Kwang S. Kim 《Liver Transplantation》2018,8(25)
Nonprecious metals are promising catalysts to avoid the sluggish oxygen reduction reaction (ORR) in next‐generation regenerative fuel cells or metal–air batteries. Therefore, development of nonprecious metal catalysts for ORR is highly desirable. Herein, precise tuning of the atomic ratio of Fe and Co encapsulated in melamine‐derived nitrogen‐rich graphitic tube (NGT) is reported. The Co1.08Fe3.34 hybrid with metal? nitrogen bonds ( 1 : Co1.08Fe3.34@NGT) shows remarkable ORR catalytic activities (80 mV higher in onset potential and 50 mV higher in half‐wave potential than those of state‐of‐the‐art commercial Pt/C catalysts), high current density, and stability. In acidic solution, 1 also shows compatible performance to commercial Pt/C in terms of ORR activity, current density, stability, and methanol tolerance. The high ORR activity is ascribed to the co‐existence of Fe? N, Co? N, and sufficient metallic FeCo alloys which favor faster electron movement and better adsorption of oxygen molecules on the catalyst surface. In the alkaline anion exchange membrane fuel cell setup, this cell delivers the power density of 117 mW cm?2, demonstrating its potential use for energy conversion and storage applications. 相似文献
14.
Engineering Catalytic Active Sites on Cobalt Oxide Surface for Enhanced Oxygen Electrocatalysis
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Xiaopeng Han Guowei He Yu He Jinfeng Zhang Xuerong Zheng Lanlan Li Cheng Zhong Wenbin Hu Yida Deng Tian‐Yi Ma 《Liver Transplantation》2018,8(10)
Tuning the catalytic active sites plays a crucial role in developing low cost and highly durable oxygen electrode catalysts with precious metal‐competitive activity. In an attempt to engineer the active sites in Co3O4 spinel for oxygen electrocatalysis in alkaline electrolyte, herein, controllable synthesis of surface‐tailored Co3O4 nanocrystals including nanocube (NC), nanotruncated octahedron (NTO), and nanopolyhedron (NP) anchored on nitrogen‐doped reduced graphene oxide (N‐rGO), through a facile and template‐free hydrothermal strategy, is provided. The as‐synthesized Co3O4 NC, NTO, and NP nanostructures are predominantly enclosed by {001}, {001} + {111}, and {112} crystal planes, which expose different surface atomic configurations of Co2+ and Co3+ active sites. Electrochemical results indicate that the unusual {112} plane enclosed Co3O4 NP on rGO with abundant Co3+ sites exhibit superior bifunctional activity for oxygen reduction and evolution reactions, as well as enhanced metal–air battery performance in comparison with other counterparts. Experimental and theoretical simulation studies demonstrate that the surface atomic arrangement of Co2+/Co3+ active sites, especially the existence of octahedrally coordinated Co3+ sites, optimizes the adsorption, activation, and desorption features of oxygen species. This work paves the way to obtain highly active, durable, and cost‐effective electrocatalysts for practical clean energy devices through regulating the surface atomic configuration and catalytic active sites. 相似文献
15.
Xiaogang Fu Na Li Bohua Ren Gaopeng Jiang Yanru Liu Fathy M. Hassan Dong Su Jianbing Zhu Lin Yang Zhengyu Bai Zachary P. Cano Aiping Yu Zhongwei Chen 《Liver Transplantation》2019,9(11)
Transition metal atoms with corresponding nitrogen coordination are widely proposed as catalytic centers for the oxygen reduction reaction (ORR) in metal–nitrogen–carbon (M–N–C) catalysts. Here, an effective strategy that can tailor Fe–N–C catalysts to simultaneously enrich the number of active sites while boosting their intrinsic activity and utilization is reported. This is achieved by edge engineering of FeN4 sites via a simple ammonium chloride salt‐assisted approach, where a high fraction of FeN4 sites are preferentially generated and hosted in a graphene‐like porous scaffold. Theoretical calculations reveal that the FeN4 moieties with adjacent pore defects are likely to be more active than the nondefective configuration. Coupled with the facilitated accessibility of active sites, this prepared catalyst, when applied in a practical H2–air proton exchange membrane fuel cell, delivers a remarkable peak power density of 0.43 W cm?2, ranking it as one of the most active M–N–C catalysts reported to date. This work provides a new avenue for boosting ORR activity by edge manipulation of FeN4 sites. 相似文献
16.
Atomic Modulation of FeCo–Nitrogen–Carbon Bifunctional Oxygen Electrodes for Rechargeable and Flexible All‐Solid‐State Zinc–Air Battery
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Chang‐Yuan Su Hui Cheng Wei Li Zhao‐Qing Liu Nan Li Zhufeng Hou Fu‐Quan Bai Hong‐Xing Zhang Tian‐Yi Ma 《Liver Transplantation》2017,7(13)
Rational design and exploration of robust and low‐cost bifunctional oxygen reduction/evolution electrocatalysts are greatly desired for metal–air batteries. Herein, a novel high‐performance oxygen electrode catalyst is developed based on bimetal FeCo nanoparticles encapsulated in in situ grown nitrogen‐doped graphitic carbon nanotubes with bamboo‐like structure. The obtained catalyst exhibits a positive half‐wave potential of 0.92 V (vs the reversible hydrogen electrode, RHE) for oxygen reduction reaction, and a low operating potential of 1.73 V to achieve a 10 mA cm?2 current density for oxygen evolution reaction. The reversible oxygen electrode index is 0.81 V, surpassing that of most highly active bifunctional catalysts reported to date. By combining experimental and simulation studies, a strong synergetic coupling between FeCo alloy and N‐doped carbon nanotubes is proposed in producing a favorable local coordination environment and electronic structure, which affords the pyridinic N‐rich catalyst surface promoting the reversible oxygen reactions. Impressively, the assembled zinc–air batteries using liquid electrolytes and the all‐solid‐state batteries with the synthesized bifunctional catalyst as the air electrode demonstrate superior charging–discharging performance, long lifetime, and high flexibility, holding great potential in practical implementation of new‐generation powerful rechargeable batteries with portable or even wearable characteristic. 相似文献
17.
Siraj Sultan Jitendra N. Tiwari Aditya Narayan Singh Shynggys Zhumagali Miran Ha Chang Woo Myung Pandiarajan Thangavel Kwang S. Kim 《Liver Transplantation》2019,9(22)
The sustainable and scalable production of hydrogen through hydrogen evolution reaction (HER) and oxygen through oxygen evolution reaction (OER) in water splitting demands efficient and robust electrocatalysts. Currently, state‐of‐the‐art electrocatalysts of Pt and IrO2/RuO2 exhibit the benchmark catalytic activity toward HER and OER, respectively. However, expanding their practical application is hindered by their exorbitant price and scarcity. Therefore, the development of alternative effective electrocatalysts for water splitting is crucial. In the last few decades, substantial effort has been devoted to the development of alternative HER/OER and water splitting catalysts based on various transition metals (including Fe, Co, Ni, Mo, and atomic Pt) which show promising catalytic activities and durability. In this review, after a brief introduction and basic mechanism of HER/OER, the authors systematically discuss the recent progress in design, synthesis, and application of single atom and cluster‐based HER/OER and water splitting catalysts. Moreover, the crucial factors that can tune the activity of catalysts toward HER/OER and water splitting such as morphology, crystal defects, hybridization of metals with nonmetals, heteroatom doping, alloying, and formation of metals inside graphitic layered materials are discussed. Finally, the existing challenges and future perspectives for improving the performance of electrocatalysts for water splitting are addressed. 相似文献
18.
Recent Development of Zeolitic Imidazolate Frameworks (ZIFs) Derived Porous Carbon Based Materials as Electrocatalysts
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Development of effective, stable, and economic electrocatalysts is critical for further implementation of fuel cells, water electrolysis, and metal–air batteries in clean energy conversion technologies. As a subfamily of metal–organic frameworks (MOFs), zeolitic imidazolate frameworks (ZIFs) possess the characteristics of both MOFs and zeolites, showing highly porous structures, large surface area, and open catalytic active sites. This review presents materials design strategies for constructing improved electrocatalysts based on ZIF precursors/templates, with special emphasis on the varieties of derivatives, controllable building of active sites, the construction of macroscopic structure, and the favored electrocatalytic reactions based on these materials. These ZIF‐derived N‐doped carbon‐based composites or compounds have exhibited remarkable activity and stability for a broad electrocatalysis application, displaying great potential to replace noble‐metal‐based catalysts. The challenges and perspectives regarding ZIF‐derived electrocatalysts are also discussed for better development of ZIF‐derived electrocatalysts. 相似文献
19.
Developing earth‐abundant and active electrocatalysts for the oxygen evolution reaction (OER) as replacements for conventional noble metal catalysts is of scientific and technological importance for achieving cost‐effective and efficient conversion and storage of renewable energy. However, most of the promising candidates thus far are exclusively metal‐based catalysts, which are disadvantaged by relatively restricted electron mobility, corrosion susceptibility, and detrimental environmental influences. Herein, hierarchically porous nitrogen (N) and phosphorus (P) codoped carbon nanofibers directly grown on conductive carbon paper are prepared through an electrochemically induced polymerization process in the presence of aniline monomer and phosphonic acid. The resultant material exhibits robust stability (little activity attenuation after 12 h continuous operation) and high activity with low overpotential (310 mV at 10 mA cm?2) toward electrocatalytic oxygen production, with performance comparable to that of the precious iridium oxide (IrO2) benchmark. Experimental measurements reveal that dual doping of N and P can result in an increased active surface area and abundant active sites in comparison with the single doped and pristine carbon counterparts, and density functional theory calculations indicate that N and P dopants can coactivate the adjacent C atoms, inducing synergistically enhanced activity toward OER. 相似文献
20.
Controlling the Active Sites of Sulfur‐Doped Carbon Nanotube–Graphene Nanolobes for Highly Efficient Oxygen Evolution and Reduction Catalysis
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Abdelhamid M. El‐Sawy Islam M. Mosa Dong Su Curtis J. Guild Syed Khalid Raymond Joesten James F. Rusling Steven L. Suib 《Liver Transplantation》2016,6(5)
Controlling active sites of metal‐free catalysts is an important strategy to enhance activity of the oxygen evolution reaction (OER). Many attempts have been made to develop metal‐free catalysts, but the lack of understanding of active‐sites at the atomic‐level has slowed the design of highly active and stable metal‐free catalysts. A sequential two‐step strategy to dope sulfur into carbon nanotube–graphene nanolobes is developed. This bidoping strategy introduces stable sulfur–carbon active‐sites. Fluorescence emission of the sulfur K‐edge by X‐ray absorption near edge spectroscopy (XANES) and scanning transmission electron microscopy electron energy loss spectroscopy (STEM‐EELS) mapping and spectra confirm that increasing the incorporation of heterocyclic sulfur into the carbon ring of CNTs not only enhances OER activity with an overpotential of 350 mV at a current density of 10 mA cm?2, but also retains 100% of stability after 75 h. The bidoped sulfur carbon nanotube–graphene nanolobes behave like the state‐of‐the‐art catalysts for OER but outperform those systems in terms of turnover frequency (TOF) which is two orders of magnitude greater than (20% Ir/C) at 400 mV overpotential with very high mass activity 1000 mA cm?2 at 570 mV. Moreover, the sulfur bidoping strategy shows high catalytic activity for the oxygen reduction reaction (ORR). Stable bifunctional (ORR and OER) catalysts are low cost, and light‐weight bidoped sulfur carbon nanotubes are potential candidates for next‐generation metal‐free regenerative fuel cells. 相似文献