共查询到20条相似文献,搜索用时 775 毫秒
1.
Dandan Gao Rongji Liu Johannes Biskupek Ute Kaiser Yu‐Fei Song Carsten Streb 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(14):4692-4696
Electrocatalytic water splitting into H2 and O2 is a key technology for carbon‐neutral energy. Here, we report a modular materials design leading to noble metal‐free composite electrocatalysts, which combine high electrical conductivity, high OER and HER reactivity and high durability. The scalable bottom‐up fabrication allows the stable deposition of mixed metal oxide nanostructures with different functionalities on copper foam electrodes. The composite catalyst shows sustained OER and HER activity in 0.1 m aqueous KOH over prolonged periods (t>10 h) at low overpotentials (OER: ≈300 mV; HER: ≈100 mV) and high faradaic efficiencies (OER: ≈100 %, HER: ≈98 %). The new synthetic concept will enable the development of multifunctional, mixed metal oxide composites as high‐performance electrocatalysts for challenging energy conversion and storage reactions. 相似文献
2.
Nitrogen and Phosphorus Dual‐Doped Hierarchical Porous Carbon Foams as Efficient Metal‐Free Electrocatalysts for Oxygen Reduction Reactions 下载免费PDF全文
Dr. Hongliang Jiang Prof. Yihua Zhu Dr. Qian Feng Dr. Yunhe Su Prof. Xiaoling Yang Prof. Chunzhong Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):3106-3112
Despite tremendous progress in developing doped carbocatalysts for the oxygen reduction reaction (ORR), the ORR activity of current metal‐free carbocatalysts is still inferior to that of conventional Pt/C catalysts, especially in acidic media and neutral solution. Moreover, it also remains a challenge to develop an effective and scalable method for the synthesis of metal‐free carbocatalysts. Herein, we have developed nitrogen and phosphorus dual‐doped hierarchical porous carbon foams (HP‐NPCs) as efficient metal‐free electrocatalysts for ORR. The HP‐NPCs were prepared for the first time by copyrolyzing nitrogen‐ and phosphorus‐containing precursors and poly(vinyl alcohol)/polystyrene (PVA/PS) hydrogel composites as in situ templates. Remarkably, the resulting HP‐NPCs possess controllable nitrogen and phosphorus content, high surface area, and a hierarchical interconnected macro‐/mesoporous structure. In studying the effects of the HP‐NPCs on the ORR, we found that the as‐prepared HP‐NPC materials exhibited not only excellent catalytic activity for ORR in basic, neutral, and acidic media, but also much better tolerance for methanol oxidation and much higher stability than the commercial, state‐of‐the‐art Pt/C catalysts. Because of all these outstanding features, it is expected that the HP‐NPC material will be a very suitable catalyst for next‐generation fuel cells and lithium–air batteries. In addition, the novel synthetic method described here might be extended to the preparation of many other kinds of hierarchical porous carbon materials or porous carbon that contains metal oxide for wide applications including energy storage, catalysis, and electrocatalysis. 相似文献
3.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(27):7877-7881
Cobalt‐based nanomaterials have been intensively explored as promising noble‐metal‐free oxygen evolution reaction (OER) electrocatalysts. Herein, we report phase‐selective syntheses of novel hierarchical CoTe2 and CoTe nanofleeces for efficient OER catalysts. The CoTe2 nanofleeces exhibited excellent electrocatalytic activity and stablity for OER in alkaline media. The CoTe2 catalyst exhibited superior OER activity compared to the CoTe catalyst, which is comparable to the state‐of‐the‐art RuO2 catalyst. Density functional theory calculations showed that the binding strength and lateral interaction of the reaction intermediates on CoTe2 and CoTe are essential for determining the overpotential required under different conditions. This study provides valuable insights for the rational design of noble‐metal‐free OER catalysts with high performance and low cost by use of Co‐based chalcogenides. 相似文献
4.
Yuwen Li Mengting Lu Panpan He Yuhang Wu Jiawen Wang Danni Chen Hui Xu Junkuo Gao Juming Yao 《化学:亚洲杂志》2019,14(9):1590-1594
Non‐noble metal‐based metal–organic framework (MOF)‐derived electrocatalysts have recently attracted great interest in the oxygen evolution reaction (OER). Here we report a facile synthesis of nickel‐based bimetallic electrocatalysts derived from 2D nanosheet‐assembled nanoflower‐like MOFs. The optimized morphologies and large Brunauer–Emmett–Teller (BET) surface area endow FeNi@CNF with efficient OER performance, where the aligned nanosheets can expose abundant active sites and benefit electron transfer. The complex nanoflower morphologies together with the synergistic effects between two metals attributed to the OER activity of the Ni‐based bimetallic catalysts. The optimized FeNi@CNF afforded an overpotential of 356 mV at a current density of 10 mA cm?2 with a Tafel slope of 62.6 mV dec?1, and also exhibited superior durability with only slightly degradation after 24 hours of continuous operation. The results may inspire the use of complex nanosheet‐assembled nanostructures to explore highly active catalysts for various applications. 相似文献
5.
Weiren Cheng Xue Feng Lu Deyan Luan Xiong Wen Lou 《Angewandte Chemie (International ed. in English)》2020,59(41):18234-18239
Developing noble‐metal‐free bifunctional oxygen electrocatalysts is of great significance for energy conversion and storage systems. Herein, we have developed a transformation method for growing NiMn‐based bimetal–organic framework (NiMn‐MOF) nanosheets on multi‐channel carbon fibers (MCCF) as a bifunctional oxygen electrocatalyst. Owing to the desired components and architecture, the MCCF/NiMn‐MOFs manifest comparable electrocatalytic performance towards oxygen reduction reaction (ORR) with the commercial Pt/C electrocatalyst and superior performance towards oxygen evolution reaction (OER) to the benchmark RuO2 electrocatalyst. X‐ray absorption fine structure (XAFS) spectroscopy and density functional theory (DFT) calculations reveal that the strong synergetic effect of adjacent Ni and Mn nodes within MCCF/NiMn‐MOFs effectively promotes the thermodynamic formation of key *O and *OOH intermediates over active NiO6 centers towards fast ORR and OER kinetics. 相似文献
6.
Zhao Zhang Xiaopeng Li Cheng Zhong Naiqin Zhao Yida Deng Xiaopeng Han Wenbin Hu 《Angewandte Chemie (International ed. in English)》2020,59(18):7245-7250
The fabrication of metal‐supported hybrid structures with enhanced properties typically requires external energy input, such as pyrolysis, photolysis, and electrodeposition. In this study, silver‐nanoparticle‐decorated transition‐metal hydroxide (TMH) composites were synthesized by an approach based on a spontaneous redox reaction (SRR) at room temperature. The SRR between silver ions and TMH provides a simple and facile route to establish effective and stable heterostructures that can enhance the oxygen evolution reaction (OER) activity. Ag@Co(OH)x grown on carbon cloth exhibits outstanding OER activity and durability, even superior to IrO2 and many previously reported OER electrocatalysts. Experimental and theoretical analysis demonstrates that the strong electronic interaction between Ag and Co(OH)2 activates the silver clusters as catalytically OER active sites, effectively optimizing the binding energies with reacted intermediates and facilitating the OER kinetics. 相似文献
7.
Dr. Chuangang Hu Prof. Liming Dai 《Angewandte Chemie (International ed. in English)》2016,55(39):11736-11758
Besides their use in fuel cells for energy conversion through the oxygen reduction reaction (ORR), carbon‐based metal‐free catalysts have also been demonstrated to be promising alternatives to noble‐metal/metal oxide catalysts for the oxygen evolution reaction (OER) in metal–air batteries for energy storage and for the splitting of water to produce hydrogen fuels through the hydrogen evolution reaction (HER). This Review focuses on recent progress in the development of carbon‐based metal‐free catalysts for the OER and HER, along with challenges and perspectives in the emerging field of metal‐free electrocatalysis. 相似文献
8.
Synthesis of Nanoporous Carbon–Cobalt‐Oxide Hybrid Electrocatalysts by Thermal Conversion of Metal–Organic Frameworks 下载免费PDF全文
Dr. Watcharop Chaikittisilp Dr. Nagy L. Torad Dr. Cuiling Li Dr. Masataka Imura Dr. Norihiro Suzuki Dr. Shinsuke Ishihara Prof. Dr. Katsuhiko Ariga Prof. Dr. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(15):4217-4221
Nanoporous carbon–cobalt‐oxide hybrid materials are prepared by a simple, two‐step, thermal conversion of a cobalt‐based metal–organic framework (zeolitic imidazolate framework‐9, ZIF‐9). ZIF‐9 is carbonized in an inert atmosphere to form nanoporous carbon–metallic‐cobalt materials, followed by the subsequent thermal oxidation in air, yielding nanoporous carbon–cobalt‐oxide hybrids. The resulting hybrid materials are evaluated as electrocatalysts for the oxygen‐reduction reaction (ORR) and the oxygen‐evolution reaction (OER) in a KOH electrolyte solution. The hybrid materials exhibit similar catalytic activity in the ORR to the benchmark, commercial, Pt/carbon black catalyst, and show better catalytic activity for the OER than the Pt‐based catalyst. 相似文献
9.
Co@Co3O4 Encapsulated in Carbon Nanotube‐Grafted Nitrogen‐Doped Carbon Polyhedra as an Advanced Bifunctional Oxygen Electrode 下载免费PDF全文
Dr. Arshad Aijaz Dr. Justus Masa M. Sc. Christoph Rösler Dr. Wei Xia M. Sc. Philipp Weide M. Sc. Alexander J. R. Botz Prof. Dr. Roland A. Fischer Prof. Dr. Wolfgang Schuhmann Prof. Dr. Martin Muhler 《Angewandte Chemie (International ed. in English)》2016,55(12):4087-4091
Efficient reversible oxygen electrodes for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are vitally important for various energy conversion devices, such as regenerative fuel cells and metal–air batteries. However, realization of such electrodes is impeded by insufficient activity and instability of electrocatalysts for both water splitting and oxygen reduction. We report highly active bifunctional electrocatalysts for oxygen electrodes comprising core–shell Co@Co3O4 nanoparticles embedded in CNT‐grafted N‐doped carbon‐polyhedra obtained by the pyrolysis of cobalt metal–organic framework (ZIF‐67) in a reductive H2 atmosphere and subsequent controlled oxidative calcination. The catalysts afford 0.85 V reversible overvoltage in 0.1 m KOH, surpassing Pt/C, IrO2, and RuO2 and thus ranking them among one of the best non‐precious‐metal electrocatalysts for reversible oxygen electrodes. 相似文献
10.
《中国化学快报》2020,31(9):2230-2234
Tailored design and synthesis of high-quality electrocatalysts is vital for the advancement of oxygen evolution reaction (OER). Herein, we report a powerful puffing method to fabricate hierarchical porous N-doped carbon with numerous embedded Ni nanoparticles. Interestingly, during the puffing and annealing process, rice precursor with N and Ni sources can be in-situ converted into Ni-embedded N-doped porous carbon (N-PC/Ni) composite. The obtained N-PC/Ni composite possesses a cross-linked porous architecture containing conductive carbon backbone and active Ni nanoparticles electrocatalysts for OER. The pore formation in N-PC/Ni composite is also proposed because of carbothermic reduction. The N-PC/Ni composite is fully studied as electrocatalysts for OER. Due to increased active surface area, enhanced electronic conductivity and reactivity, the designed N-PC/Ni composite exhibits superior OER performance with a low Tafel slope (∼88 mV/dec) and a low overpotential as well as excellent long-term stability in alkaline solution. Our proposed rational design strategy may provide a new way to construct other advanced metal/heteroatom-doped composites for widespread application in electrocatalysis. 相似文献
11.
Muhammad Arsalan Ghausi Dr. Jiafang Xie Prof. Qiaohong Li Xueyuan Wang Rui Yang Prof. Maoxiang Wu Prof. Yaobing Wang Prof. Liming Dai 《Angewandte Chemie (International ed. in English)》2018,57(40):13135-13139
Photo/electrochemical CO2 splitting is impeded by the low cost‐effective catalysts for key reactions: CO2 reduction (CDRR) and water oxidation. A porous silicon and nitrogen co‐doped carbon (SiNC) nanomaterial by a facile pyrolyzation was developed as a metal‐free bifunctional electrocatalyst. CO2‐to‐CO and oxygen evolution (OER) partial current density under neutral conditions were enhanced by two orders of magnitude in the Tafel regime on SiNC relative to single‐doped comparisons beyond their specific area gap. The photovoltaic‐driven CO2 splitting device with SiNC electrodes imitating photosynthesis yielded an overall solar‐to‐chemical efficiency of advanced 12.5 % (by multiplying energy efficiency of CO2 splitting cell and photovoltaic device) at only 650 mV overpotential. Mechanism studies suggested the elastic electron structure of ?Si(O)?C?N? unit in SiNC as the highly active site for CDRR and OER simultaneously by lowering the free energy of CDRR and OER intermediates adsorption. 相似文献
12.
Metal‐Nitrogen‐doped Porous Carbons Derived from Metal‐Containing Ionic Liquids for Oxygen Reduction Reaction 下载免费PDF全文
Cancan Wang Dr. Jiangna Guo Dr. Dan Xu Juewen Zhang Muzi Chen Prof. Feng Yan 《化学:亚洲杂志》2018,13(8):1029-1037
This study describes a self‐doping and additive‐free strategy for the synthesis of metal‐nitrogen‐doped porous carbon materials (CMs) via carbonizing well‐tailored precursors, metal‐containing ionic liquids (M‐ILs). The organic skeleton in M‐ILs serves as both carbon and nitrogen sources, while metal ions acts as porogen and metallic dopants. A high nitrogen content, appropriate content of metallic species and hierarchical porosity synergistically endow the resultant CMs (MIBA‐M‐T) as effective electrocatalysts for the oxygen reduction reaction (ORR). MIBA‐Fe‐900 with a high specific surface area of 1567 m2 g?1 exhibits an activity similar to that of Pt/C catalyst, a higher tolerance to methanol than Pt/C, and long‐term durability. This work supplies a simple and convenient route for the preparation of metal‐containing carbon electrocatalysts. 相似文献
13.
Biswarup Chakraborty Shweta Kalra Rodrigo Beltrn‐Suito Chittaranjan Das Tim Hellmann Prashanth W. Menezes Matthias Driess 《化学:亚洲杂志》2020,15(6):852-859
In the urge of designing noble metal‐free and sustainable electrocatalysts for oxygen evolution reaction (OER), herein, a mineral Digenite Cu9S5 has been prepared from a molecular copper(I) precursor, [{(PyHS)2CuI(PyHS)}2](OTf)2 ( 1 ), and utilized as an anode material in electrocatalytic OER for the first time. A hot injection of 1 yielded a pure phase and highly crystalline Cu9S5, which was then electrophoretically deposited (EPD) on a highly conducting nickel foam (NF) substrate. When assessed as an electrode for OER, the Cu9S5/NF displayed an overpotential of merely 298±3 mV at a current density of 10 mA cm?2 in alkaline media. The overpotential recorded here supersedes the value obtained for the best reported Cu‐based as well as the benchmark precious‐metal‐based RuO2 and IrO2 electrocatalysts. In addition, the choronoamperometric OER indicated the superior stability of Cu9S5/NF, rendering its suitability as the sustainable anode material for practical feasibility. The excellent catalytic activity of Cu9S5 can be attributed to the formation of a crystalline CuO overlayer on the conductive Cu9S5 that behaves as active species to facilitate OER. This study delivers a distinct molecular precursor approach to produce highly active copper‐based catalysts that could be used as an efficient and durable OER electro(pre)catalysts relying on non‐precious metals. 相似文献
14.
Structural Design Principle of Small‐Molecule Organic Semiconductors for Metal‐Free,Visible‐Light‐Promoted Photocatalysis 下载免费PDF全文
Lei Wang Wei Huang Run Li Dr. Dominik Gehrig Prof. Paul W. M. Blom Prof. Katharina Landfester Dr. Kai A. I. Zhang 《Angewandte Chemie (International ed. in English)》2016,55(33):9783-9787
Herein, we report on the structural design principle of small‐molecule organic semiconductors as metal‐free, pure organic and visible light‐active photocatalysts. Two series of electron‐donor and acceptor‐type organic semiconductor molecules were synthesized to meet crucial requirements, such as 1) absorption range in the visible region, 2) sufficient photoredox potential, and 3) long lifetime of photogenerated excitons. The photocatalytic activity was demonstrated in the intermolecular C?H functionalization of electron‐rich heteroaromates with malonate derivatives. A mechanistic study of the light‐induced electron transport between the organic photocatalyst, substrate, and the sacrificial agent are described. With their tunable absorption range and defined energy‐band structure, the small‐molecule organic semiconductors could offer a new class of metal‐free and visible light‐active photocatalysts for chemical reactions. 相似文献
15.
Chengyu Xing Yurui Xue Bolong Huang Huidi Yu Lan Hui Yan Fang Yuxin Liu Yingjie Zhao Zhibo Li Yuliang Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(39):14035-14041
A highly efficient bifunctional metal‐free catalyst was prepared by growth of three‐dimensional porous fluorographdiyne networks on carbon cloth (p‐FGDY/CC). Our experiments and density functional theory (DFT) calculations show the 3D p‐FGDY/CC network is highly active and it is a high potential metal‐free catalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), as well as overall water splitting (OWS) under both acidic and alkaline conditions. The experimental and theoretical results show very good consistency; for example, in the HER process, p‐FGDY/CC exhibits small overpotentials of 82 and 92 mV to achieve 10 mA cm?2 under alkaline and acidic conditions, respectively. This ensures an even higher selectivity for the adsorption/desorption of various O/H intermediate species. The essential key promotion accomplishes a bifunctional H2O redox performance application under pH‐universal electrochemical conditions. 相似文献
16.
Pomegranate‐Inspired Design of Highly Active and Durable Bifunctional Electrocatalysts for Rechargeable Metal–Air Batteries 下载免费PDF全文
Dr. Ge Li Dr. Xiaolei Wang Jing Fu Dr. Jingde Li Moon Gyu Park Dr. Yining Zhang Gregory Lui Prof. Zhongwei Chen 《Angewandte Chemie (International ed. in English)》2016,55(16):4977-4982
Rational design of highly active and durable electrocatalysts for oxygen reactions is critical for rechargeable metal–air batteries. Herein, we report the design and development of composite electrocatalysts based on transition metal oxide nanocrystals embedded in a nitrogen‐doped, partially graphitized carbon framework. Benefiting from the unique pomegranate‐like architecture, the composite catalysts possess abundant active sites, strong synergetic coupling, enhanced electron transfer, and high efficiencies in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The Co3O4‐based composite electrocatalyst exhibited a high half‐wave potential of 0.842 V for ORR, and a low overpotential of only 450 mV at the current density of 10 mA cm?2 for OER. A single‐cell zinc–air battery was also fabricated with superior durability, holding great promise in the practical implementation of rechargeable metal–air batteries. 相似文献
17.
Jianing Guo Dr. Chun‐Yu Lin Prof. Zhenhai Xia Prof. Zhonghua Xiang 《Angewandte Chemie (International ed. in English)》2018,57(38):12567-12572
Highly efficient electrocatalysts derived from metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) for oxygen reduction reaction (ORR) have been developed. However, the subsequent pyrolysis is often needed owing to their poor intrinsic electrical conductivity, leading to undesirable structure changes and destruction of the original fine structure. Now, hybrid electrocatalysts were formed by self‐assembling pristine covalent organic polymer (COP) with reduced graphene oxide (rGO). The electrical conductivity of the hybridized COP/rGO materials is increased by more than seven orders of magnitude (from 3.06×10?9 to 2.56×10?1 S m?1) compared with pure COPs. The ORR activities of the hybrid are enhanced significantly by the synergetic effect between highly active COP and highly conductive rGO. This COP/rGO hybrid catalyst exhibited a remarkable positive half‐wave (150 mV). 相似文献
18.
Pengzuo Chen Kun Xu Zhiwei Fang Yun Tong Junchi Wu Xiuli Lu Xu Peng Hui Ding Changzheng Wu Yi Xie 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(49):14923-14927
Designing highly efficient electrocatalysts for oxygen evolution reaction (OER) plays a key role in the development of various renewable energy storage and conversion devices. In this work, we developed metallic Co4N porous nanowire arrays directly grown on flexible substrates as highly active OER electrocatalysts for the first time. Benefiting from the collaborative advantages of metallic character, 1D porous nanowire arrays, and unique 3D electrode configuration, surface oxidation activated Co4N porous nanowire arrays/carbon cloth achieved an extremely small overpotential of 257 mV at a current density of 10 mA cm−2, and a low Tafel slope of 44 mV dec−1 in an alkaline medium, which is the best OER performance among reported Co‐based electrocatalysts to date. Moreover, in‐depth mechanistic investigations demonstrate the active phases are the metallic Co4N core inside with a thin cobalt oxides/hydroxides shell during the OER process. Our finding introduces a new concept to explore the design of high‐efficiency OER electrocatalysts. 相似文献
19.
Lin Ye Yiran Ying Dengrong Sun Zhouyang Zhang Linfeng Fei Zhenhai Wen Jinli Qiao Haitao Huang 《Angewandte Chemie (International ed. in English)》2020,59(8):3244-3251
We report a straightforward strategy to design efficient N doped porous carbon (NPC) electrocatalyst that has a high concentration of easily accessible active sites for the CO2 reduction reaction (CO2RR). The NPC with large amounts of active N (pyridinic and graphitic N) and highly porous structure is prepared by using an oxygen‐rich metal–organic framework (Zn‐MOF‐74) precursor. The amount of active N species can be tuned by optimizing the calcination temperature and time. Owing to the large pore sizes, the active sites are well exposed to electrolyte for CO2RR. The NPC exhibits superior CO2RR activity with a small onset potential of ?0.35 V and a high faradaic efficiency (FE) of 98.4 % towards CO at ?0.55 V vs. RHE, one of the highest values among NPC‐based CO2RR electrocatalysts. This work advances an effective and facile way towards highly active and cost‐effective alternatives to noble‐metal CO2RR electrocatalysts for practical applications. 相似文献
20.
Yikang Cong Shengsheng Huang Yan Mei Prof. Dr. Ting-Ting Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(64):15866-15888
Electrocatalytic water splitting has been considered as a promising strategy for the sustainable evolution of hydrogen energy and storage of intermittent electric energy. Efficient catalysts for electrocatalytic water splitting are urgently demanded to decrease the overpotentials and promote the sluggish reaction kinetics. Carbon-based composites, including heteroatom-doped carbon materials, metals/alloys@carbon composites, metal compounds@carbon composites, and atomically dispersed metal sites@carbon composites have been widely used as the catalysts due to their fascinating properties. However, these electrocatalysts are almost powdery form, and should be cast on the current collector by using the polymeric binder, which would result in the unsatisfied electrocatalytic performance. In comparison, a self-supported electrode architecture is highly attractive. Recently, self-supported metal–organic frameworks (MOFs) constructed by coordination of metal centers and organic ligands have been considered as suitable templates/precursors to construct free-standing carbon-based composites grown on conductive substrate. MOFs-derived carbon-based composites have various merits, such as the well-aligned array architecture and evenly distributed active sites, and easy functionalization with other species, which make them suitable alternatives to non-noble metal-included electrocatalysts. In this review, we intend to show the research progresses by employment of MOFs as precursors to prepare self-supported carbon-based composites. Focusing on these MOFs-derived carbon-based nanomaterials, the latest advances in their controllable synthesis, composition regulation, electrocatalytic performances in hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water splitting (OWS) are presented. Finally, the challenges and perspectives are showed for the further developments of MOFs-derived self-supported carbon-based nanomaterials in electrocatalytic reactions. 相似文献