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1.
Ordered PdCu‐Based Nanoparticles as Bifunctional Oxygen‐Reduction and Ethanol‐Oxidation Electrocatalysts 下载免费PDF全文
Kezhu Jiang Pengtang Wang Prof. Shaojun Guo Dr. Xu Zhang Dr. Xuan Shen Prof. Gang Lu Dr. Dong Su Prof. Xiaoqing Huang 《Angewandte Chemie (International ed. in English)》2016,55(31):9030-9035
The development of superior non‐platinum electrocatalysts for enhancing the electrocatalytic activity and stability for the oxygen‐reduction reaction (ORR) and liquid fuel oxidation reaction is very important for the commercialization of fuel cells, but still a great challenge. Herein, we demonstrate a new colloidal chemistry technique for making structurally ordered PdCu‐based nanoparticles (NPs) with composition control from PdCu to PdCuNi and PtCuCo. Under the dual tuning on the composition and intermetallic phase, the ordered PdCuCo NPs exhibit better activity and much enhanced stability for ORR and ethanol‐oxidation reaction (EOR) than those of disordered PdCuM NPs, the commercial Pt/C and Pd/C catalysts. The density functional theory (DFT) calculations reveal that the improved ORR activity on the PdCuM NPs stems from the catalytically active hollow sites arising from the ligand effect and the compressive strain on the Pd surface owing to the smaller atomic size of Cu, Co, and Ni. 相似文献
2.
Kassa B. Ibrahim Meng‐Che Tsai Soressa A. Chala Mulatu K. Berihun Amaha W. Kahsay Taame A. Berhe Wei‐Nien Su Bing‐Joe Hwang 《中国化学会会志》2019,66(8):829-865
Electrochemical energy storage and conversion devices play a key role in the development of clean, sustainable, and efficient energy systems to meet the sustainable growth of our society. However, challenging issues including the sluggish kinetics of oxygen electrode reactions involving the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are present, limiting the implementation of devices such as metal‐air batteries, water electrolyzers, and regenerative fuel cells. In this review, various monometallic and bimetallic transition metal oxides (TMOs) and hydroxides are summarized in terms of their application for ORR/OER, in which the merits and demerits of various precious metal and carbon‐based metal oxide materials are discussed, with requirements for better electrocatalysts and catalyst support being introduced as well. Following this, different approaches to improve catalytic activity such as the introduction of doping and defects, the manipulation of crystal facets, and the engineering of supports, compositions, and morphologies are summarized in which TMOs with improved ORR/OER catalytic activities can be synthesized, further improving the speed, stability, and polarization of electrochemical energy storage and conversion devices. Finally, perspectives into the improvement of performance and the better understanding of ORR/OER mechanisms for bifunctional electrocatalysts using in situ spectroscopic techniques and density functional theory calculations are also discussed. 相似文献
3.
Carboxylated,Fe‐Filled Multiwalled Carbon Nanotubes as Versatile Catalysts for O2 Reduction and H2 Evolution Reactions at Physiological pH 下载免费PDF全文
M. Victoria Bracamonte Dr. Michele Melchionna Dr. Antoine Stopin Angela Giulani Prof. Claudio Tavagnacco Dr. Yann Garcia Prof. Paolo Fornasiero Prof. Davide Bonifazi Prof. Maurizio Prato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(36):12769-12777
The development of new electrocatalysts for the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) at physiological pH is critical for several fields, including fuel cells and biological applications. Herein, the assembly of an electrode based on carboxyl‐functionalised hydrophilic multiwalled carbon nanotubes (MWCNTs) filled with Fe phases and their excellent performance as electrocatalysts for ORR and HER at physiological pH are reported. The encapsulated Fe dramatically enhances the catalytic activity, and the graphitic shells play a double role of efficiently mediating the electron transfer to O2 and H2O reactants and providing a cocoon that prevents uncontrolled Fe oxidation or leaching. 相似文献
4.
Bamboo‐Like Nitrogen‐Doped Carbon Nanotubes with Co Nanoparticles Encapsulated at the Tips: Uniform and Large‐Scale Synthesis and High‐Performance Electrocatalysts for Oxygen Reduction 下载免费PDF全文
Tai Cao Dingsheng Wang Jiatao Zhang Chuanbao Cao Yadong Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(40):14022-14029
In recent years, various non‐precious metal electrocatalysts for the oxygen reduction reaction (ORR) have been extensively investigated. The development of an efficient and simple method to synthesize non‐precious metal catalysts with ORR activity superior to that of Pt is extremely significant for large‐scale applications of fuel cells. Here, we develop a facile, low‐cost, and large‐scale synthesis method for uniform nitrogen‐doped (N‐doped) bamboo‐like CNTs (NBCNT) with Co nanoparticles encapsulated at the tips by annealing a mixture of cobalt acetate and melamine. The uniform NBCNT shows better ORR catalytic activity and higher stability in alkaline solutions as compared with commercial Pt/C and comparable catalytic activity to Pt/C in acidic media. NBCNTs exhibit outstanding ORR catalytic activity due to high defect density, uniform bamboo‐like structure, and the synergistic effect between the Co nanoparticles and protective graphitic layers. This facile method to synthesize catalysts, which is amenable to the large‐scale commercialization of fuel cells, will open a new avenue for the development of low‐cost and high‐performance ORR catalysts to replace Pt‐based catalysts for applications in energy conversion. 相似文献
5.
《应用有机金属化学》2017,31(10)
Iron‐ and nitrogen‐functionalized graphene (Fe‐N‐G), as well as iron‐ and nitrogen‐functionalized oxidized graphene (Fe‐N‐Gox) catalysts were synthesized as non‐noble metal electrocatalysts for oxygen reduction reaction (ORR). The physical properties of the resultant catalysts were characterized using nitrogen adsorption measurements, X‐ray diffraction, Raman and X‐ray photoelectron spectroscopies and transmission electron microscopy. Subsequently, ORR activities of the catalysts were determined electrochemically using a conventional three‐electrode cell via cyclic voltammetry with a rotating disc electrode, the results of which indicated that the synthesized catalysts had a marked electrocatalytic activity towards ORR in acid media. Among the synthesized catalysts, that functionalized using 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine as nitrogen source had the highest electrocatalytic activity with the highest onset potential (0.98 V/SHE) and limiting current density (5.12 mA cm−2). The findings are particularly important to determine a non‐precious metal catalyst for ORR activity in fuel cells. 相似文献
6.
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
7.
《中国化学会会志》2017,64(12):1503-1509
The most common electrocatalysts for the oxygen reduction reaction (ORR) are platinum‐based ones. This work demonstrates the performance of iron‐containing metal organic frameworks (MOFs) as non‐platinum‐based nano‐electrocatalysts for ORR in an alkaline medium. As a new non‐platinum catalyst to achieve the active sites for the ORR, Mil‐100 (Fe) nanoparticles were used in aqueous KOH by the rotating‐disk electrode method. The main objectives of this study are the investigations on the electron transfer number (n ), Tafel slope, and catalytic performance. The particles size of the obtained powders is in the nanoscale range (approximately 25 nm). The electron transfer number for the ORR on the surface of iron‐containing catalyst is approximately 4, and the Tafel slope of diffusion‐corrected kinetic current density is ~50.7 mV per decade at low overpotential. This work might extend a new non‐precious‐metal catalyst structure for ORR for use in low‐temperature fuel cells. 相似文献
8.
Xue Feng Lu Bao Yu Xia Shuang‐Quan Zang Xiong Wen Lou 《Angewandte Chemie (International ed. in English)》2020,59(12):4634-4650
In view of the clean and sustainable energy, metal–organic frameworks (MOFs) based materials, including pristine MOFs, MOF composites, and their derivatives are emerging as unique electrocatalysts for oxygen reduction reaction (ORR). Thanks to their tunable compositions and diverse structures, efficient MOF‐based materials provide new opportunities to accelerate the sluggish ORR at the cathode in fuel cells and metal–air batteries. This Minireview first provides some introduction of ORR and MOFs, followed by the classification of MOF‐based electrocatalysts towards ORR. Recent breakthroughs in engineering MOF‐based ORR electrocatalysts are highlighted with an emphasis on synthesis strategy, component, morphology, structure, electrocatalytic performance, and reaction mechanism. Finally, some current challenges and future perspectives for MOF‐based ORR electrocatalysts are also discussed. 相似文献
9.
Prabu Mani Sharat Devadas Tamilselvi Gurusamy Pitchiah Esakki Karthik Balu P. Ratheesh Kothandaraman Ramanujam Sukhendu Mandal 《化学:亚洲杂志》2019,14(24):4814-4818
Inspired by copper‐based oxygen reduction biocatalysts, we have studied the electrocatalytic behavior of a Cu‐based MOF (Cu‐BTT) for oxygen reduction reaction (ORR) in alkaline medium. This catalyst reduces the oxygen at the onset (Eonset) and half‐wave potential (E1/2) of 0. 940 V and 0.778 V, respectively. The high halfway potential supports the good activity of Cu‐BTT MOF. The high ORR catalytic activity can be interpreted by the presence of nitrogen‐rich ligand (tetrazole) and the generation of nascent copper(I) during the reaction. In addition to the excellent activity, Cu‐BTT MOF showed exceptional stability too, which was confirmed through chronoamperometry study, where current was unchanged up to 12 h. Further, the 4‐electrons transfer of ORR kinetics was confirmed by hydrodynamic voltammetry. The oxygen active center namely copper(I) generation during ORR has been understood by the reduction peak in cyclic voltammetry as well in the XPS analysis. 相似文献
10.
Guoqiang He Zaoxue Yan Dr. Mei Cai Prof. Dr. Pei Kang Shen Dr. Min‐Rui Gao Dr. Hong‐Bin Yao Prof. Dr. Shu‐Hong Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8490-8497
Carbide‐based electrocatalysts are superior to traditional carbon‐based electrocatalysts, such as the commercial Pt/C electrocatalysts, in terms of their mass activity and stability. Herein, we report a general approach for the preparation of a nanocomposite electrocatalyst of platinum and vanadium carbide nanoparticles that are loaded onto graphitized carbon. The nanocomposite, which was prepared in a localized and controlled fashion by using an ion‐exchange process, was an effective electrocatalyst for the oxygen‐reduction reaction (ORR). Both the stability and the durability of the Pt‐VC/GC nanocomposite catalyst could be enhanced compared with the state‐of‐the‐art Pt/C. This approach can be extended to the synthesis of other metal‐carbide‐based nanocatalysts. Moreover, this straightforward synthesis of high‐performance composite nanocatalysts can be scaled up to meet the requirements for mass production. 相似文献
11.
Titanium Dioxide‐Grafted Copper Complexes: High‐Performance Electrocatalysts for the Oxygen Reduction Reaction in Alkaline Media 下载免费PDF全文
Fei‐Fei Wang Dr. Ping‐Jie Wei Guo‐Qiang Yu Prof. Dr. Jin‐Gang Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):382-389
The sluggish kinetics of the oxygen reduction reaction (ORR) at the cathodes of fuel cells significantly hampers fuel cell performance. Therefore, the development of high‐performance, non‐precious‐metal catalysts as alternatives to noble metal Pt‐based ORR electrocatalysts is highly desirable for the large‐scale commercialization of fuel cells. TiO2‐grafted copper complexes deposited on multiwalled carbon nanotubes (CNTs) form stable and efficient electrocatalysts for the ORR. The optimized catalyst composite CNTs@TiO2–ZA–[Cu(phen)(BTC)] shows surprisingly high selectivity for the 4 e? reduction of O2 to water (approximately 97 %) in alkaline solution with an onset potential of 0.988 V vs. RHE, and demonstrates superior stability and excellent tolerance for the methanol crossover effect in comparison to a commercial Pt/C catalyst. The copper complexes were grafted onto the surface of TiO2 through coordination of an imidazole‐containing ligand, zoledronic acid (ZA), which binds to TiO2 through its bis‐phosphoric acid anchoring group. Rational optimization of the copper catalyst’s ORR performance was achieved by using an electron‐deficient ligand, 5‐nitro‐1,10‐phenanthroline (phen), and bridging benzene‐1,3,5‐tricarboxylate (BTC). This facile approach to the assembly of copper catalysts on TiO2 with rationally tuned ORR activity will have significant implications for the development of high‐performance, non‐precious‐metal ORR catalysts. 相似文献
12.
Development of eco‐friendly, cost‐effective, and high‐performance electrocatalysts to replace precious metal platinum for oxygen reduction reaction (ORR) has received increasing attention. Herein, we adopt a facile one‐pot strategy to embed Cu nanoparticles onto N‐doped carbon‐graphene (Cu@NC‐700). The Cu@NC‐700 exhibits robust and efficient ORR catalysis with positive half‐wave potential (~0.86 V vs. RHE) and low Tafel slope (33.9 mV?dec–1) in 0.1 M KOH solution. Meanwhile, it manifests remarkable electrochemical stability, and strong tolerance to methanol crossover and carbon monoxide poisoning. The synergistic effect between Cu‐N‐C sites, Cu nanoparticles, and N‐doped carbon support speeds up ORR electrocatalysis. 相似文献
13.
Jing Liu Menggai Jiao Bingbao Mei Yuxin Tong Yuping Li Mingbo Ruan Ping Song Gongquan Sun Luhua Jiang Ying Wang Zheng Jiang Lin Gu Zhen Zhou Weilin Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1175-1179
Maximizing the platinum utilization in electrocatalysts toward oxygen reduction reaction (ORR) is very desirable for large‐scale sustainable application of Pt in energy systems. A cost‐effective carbon‐supported carbon‐defect‐anchored platinum single‐atom electrocatalysts (Pt1/C) with remarkable ORR performance is reported. An acidic H2/O2 single cell with Pt1/C as cathode delivers a maximum power density of 520 mW cm?2 at 80 °C, corresponding to a superhigh platinum utilization of 0.09 gPt kW?1. Further physical characterization and density functional theory computations reveal that single Pt atoms anchored stably by four carbon atoms in carbon divacancies (Pt‐C4) are the main active centers for the observed high ORR performance. 相似文献
14.
This paper studies the electrochemical properties of ppy/Pt‐Cu composite for oxygen reduction reaction (ORR) and compares it to the highly porous ppy/Pt‐Cu catalyst, which can be synthesized by galvanostatic method (ppy/Pt‐Cu(GS)). The results of the polarization, rotating disk electrode and electrochemical impedance tests are discussed to determine the electrochemical properties of the catalysts. According to the results, ppy/Pt‐Cu(GS) catalyst is more active toward ORR compared to ppy/Pt‐Cu catalyst. The rotating disk electrode data indicates four‐electron transfer mechanism for this catalyst. 相似文献
15.
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
16.
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
17.
Xiang‐Lan Chen Jia‐Wei Huang Yi‐Chen Huang Jie Du Yu‐Fei Jiang Yue Zhao Hai‐Bin Zhu 《化学:亚洲杂志》2019,14(7):995-1003
Fe‐Co‐N‐C electrocatalysts have proven superior to their counterparts (e.g. Fe‐N‐C or Co‐N‐C) for the oxygen reduction reaction (ORR). Herein, we report on a unique strategy to prepare Fe‐Co‐N‐C?x (x refers to the pyrolysis temperature) electrocatalysts which involves anion‐exchange of [Fe(CN)6]3? into a cationic CoII‐based metal‐organic framework precursor prior to heat treatment. Fe‐Co‐N‐C‐900 exhibits an optimal ORR catalytic performance in an alkaline electrolyte with an onset potential (Eonset: 0.97 V) and half‐wave potential (E1/2: 0.86 V) comparable to that of commercial Pt/C (Eonset=1.02 V; E1/2=0.88 V), which outperforms the corresponding Co‐N‐C‐900 sample (Eonset=0.92 V; E1/2=0.84 V) derived from the same MOF precursor without anion‐exchange modification. This is the first example of Fe‐Co‐N‐C electrocatalysts fabricated from a cationic CoII‐based MOF precursor that dopes the Fe element via anion‐exchange, and our current work provides a new entrance towards MOF‐derived transition‐metal (e.g. Fe or Co) and nitrogen‐codoped carbon electrocatalysts with excellent ORR activity. 相似文献
18.
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
19.
Haichao Yang Ao Xie Dr. Yang Tang Zixiang Wang Jinpeng Zhang Dr. Lingpo Kong Dr. Peng Song Dr. Yanzhi Sun Dr. Xiaojin Yang Prof. Pingyu Wan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(2):e202103275
It is a great challenge to fabricate highly efficient pH-universal electrocatalysts for oxygen reduction reaction (ORR). Herein, a facile strategy, which includes coating the Fe modified ZIF8 on Cu foil and in situ pyrolysis to evaporate and dope Cu into the MOF derived carbon, is developed to fabricate Fe/Cu−N co-doped carbon material (Cu/Fe−NC). Profiting from the modulated electron distribution and textual properties, well-designed Cu/Fe−NC exhibits superior half-wave potential (E1/2) of 0.923 V in alkaline, 0.757 V in neutral and comparable 0.801 V in acid electrolytes, respectively. Furthermore, the ultralow peroxides yield of ORR demonstrates the high selectivity of Cu/Fe−NC in full pH scale electrolytes. As expected, the self-made alkaline and neutral zinc-air batteries equipped with Cu/Fe−NC cathode display excellent discharge voltages, outstanding peak power densities and remarkable stability. This work opens a new way to fabricate highly efficient and pH-universal electrocatalysts for ORR through strategy of Fe/Cu−N co-doping, Cu foil evaporation and carbon defects capture. 相似文献
20.
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