共查询到20条相似文献，搜索用时 15 毫秒
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Ping Chen Tian‐Yuan Xiao Yu‐Hong Qian Shan‐Shan Li Shu‐Hong Yu 《Advanced materials (Deerfield Beach, Fla.)》2013,25(23):3192-3196
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Defect Engineering toward Atomic Co–Nx–C in Hierarchical Graphene for Rechargeable Flexible Solid Zn‐Air Batteries 
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下载免费PDF全文 Cheng Tang Bin Wang Hao‐Fan Wang Qiang Zhang 《Advanced materials (Deerfield Beach, Fla.)》2017,29(37)
Rechargeable flexible solid Zn‐air battery, with a high theoretical energy density of 1086 Wh kg?1, is among the most attractive energy technologies for future flexible and wearable electronics; nevertheless, the practical application is greatly hindered by the sluggish oxygen reduction reaction/oxygen evolution reaction (ORR/OER) kinetics on the air electrode. Precious metal‐free functionalized carbon materials are widely demonstrated as the most promising candidates, while it still lacks effective synthetic methodology to controllably synthesize carbocatalysts with targeted active sites. This work demonstrates the direct utilization of the intrinsic structural defects in nanocarbon to generate atomically dispersed Co–Nx–C active sites via defect engineering. As‐fabricated Co/N/O tri‐doped graphene catalysts with highly active sites and hierarchical porous scaffolds exhibit superior ORR/OER bifunctional activities and impressive applications in rechargeable Zn‐air batteries. Specifically, when integrated into a rechargeable and flexible solid Zn‐air battery, a high open‐circuit voltage of 1.44 V, a stable discharge voltage of 1.19 V, and a high energy efficiency of 63% at 1.0 mA cm?2 are achieved even under bending. The defect engineering strategy provides a new concept and effective methodology for the full utilization of nanocarbon materials with various structural features and further development of advanced energy materials. 相似文献
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Lei Lu Qingli Hao Wu Lei Xifeng Xia Peng Liu Dongping Sun Xin Wang Xujie Yang 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(43):5833-5843
Catalysts with low‐cost, high activity and stability toward oxygen reduction reaction (ORR) are extremely desirable, but its development still remains a great challenge. Here, a novel magnetically separable hybrid of multimetal oxide, cobalt ferrite (CoFe2O4), anchored on nitrogen‐doped reduced graphene oxide (CoFe2O4/NG) is prepared via a facile solvothermal method followed by calcination at 500 °C. The structure of CoFe2O4/NG and the interaction of both components are analyzed by several techniques. The possible formation of Co/Fe N interaction in the CoFe2O4/NG catalyst is found. As a result, the well‐combination of CoFe2O4 nanoparticles with NG and its improved crystallinity lead to a synergistic and efficient catalyst with high performance to ORR through a four‐electron‐transfer process in alkaline medium. The CoFe2O4/NG exhibits particularly comparable catalytic activity as commercial Pt/C catalyst, and superior stability against methanol oxidation and CO poisoning. Meanwhile, it has been proved that both nitrogen doping and the spinel structure of CoFe2O4 can have a significant contribution to the catalytic activity by contrast experiments. Multimetal oxide hybrid demonstrates better catalysis to ORR than a single metal oxide hybrid. All results make the low‐cost and magnetically separable CoFe2O4/NG a promising alternative for costly platinum‐based ORR catalyst in fuel cells and metal‐air batteries. 相似文献
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Zinc–Air Batteries: Flexible Rechargeable Zinc‐Air Batteries through Morphological Emulation of Human Hair Array (Adv. Mater. 30/2016) 下载免费PDF全文
下载免费PDF全文 Jing Fu Fathy Mohamed Hassan Jingde Li Dong Un Lee Abdul Rahman Ghannoum Gregory Lui Md. Ariful Hoque Zhongwei Chen 《Advanced materials (Deerfield Beach, Fla.)》2016,28(30):6420-6420
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This study presents a novel metal‐organic‐framework‐engaged synthesis route based on porous tellurium nanotubes as a sacrificial template for hierarchically porous 1D carbon nanotubes. Furthermore, an ultrathin Fe‐ion‐containing polydopamine layer has been introduced to generate highly effective FeNxC active sites into the carbon framework and to induce a high degree of graphitization. The synergistic effects between the hierarchically porous 1D carbon structure and the embedded FeNxC active sites in the carbon framework manifest in superior catalytic activity toward oxygen reduction reaction (ORR) compared to Pt/C catalyst in both alkaline and acidic media. A rechargeable zinc‐air battery assembled in a decoupled configuration with the nonprecious pCNT@Fe@GL/CNF ORR electrode and Ni‐Fe LDH/NiF oxygen evolution reaction (OER) electrode exhibits charge–discharge overpotentials similar to the counterparts of Pt/C ORR electrode and IrO2 OER electrode. 相似文献
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Zinc‐Air Batteries: Facilitated Oxygen Chemisorption in Heteroatom‐Doped Carbon for Improved Oxygen Reaction Activity in All‐Solid‐State Zinc–Air Batteries (Adv. Mater. 4/2018) 下载免费PDF全文
下载免费PDF全文 Sisi Liu Mengfan Wang Xinyi Sun Na Xu Jie Liu Yuzhou Wang Tao Qian Chenglin Yan 《Advanced materials (Deerfield Beach, Fla.)》2018,30(4)
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Sisi Liu Mengfan Wang Xinyi Sun Na Xu Jie Liu Yuzhou Wang Tao Qian Chenglin Yan 《Advanced materials (Deerfield Beach, Fla.)》2018,30(4)
Driven by the intensified demand for energy storage systems with high‐power density and safety, all‐solid‐state zinc–air batteries have drawn extensive attention. However, the electrocatalyst active sites and the underlying mechanisms occurring in zinc–air batteries remain confusing due to the lack of in situ analytical techniques. In this work, the in situ observations, including X‐ray diffraction and Raman spectroscopy, of a heteroatom‐doped carbon air cathode are reported, in which the chemisorption of oxygen molecules and oxygen‐containing intermediates on the carbon material can be facilitated by the electron deficiency caused by heteroatom doping, thus improving the oxygen reaction activity for zinc–air batteries. As expected, solid‐state zinc–air batteries equipped with such air cathodes exhibit superior reversibility and durability. This work thus provides a profound understanding of the reaction principles of heteroatom‐doped carbon materials in zinc–air batteries. 相似文献
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Aijuan Han Wenxing Chen Shaolong Zhang Maolin Zhang Yunhu Han Jian Zhang Shufang Ji Lirong Zheng Yu Wang Lin Gu Chen Chen Qing Peng Dingsheng Wang Yadong Li 《Advanced materials (Deerfield Beach, Fla.)》2018,30(15)
A novel polymer encapsulation strategy to synthesize metal isolated‐single‐atomic‐site (ISAS) catalysts supported by porous nitrogen‐doped carbon nanospheres is reported. First, metal precursors are encapsulated in situ by polymers through polymerization; then, metal ISASs are created within the polymer‐derived p‐CN nanospheres by controlled pyrolysis at high temperature (200–900 °C). Transmission electron microscopy and N2 sorption results reveal this material to exhibit a nanospheric morphology, a high surface area (≈380 m2 g?1), and a porous structure (with micropores and mesopores). Characterization by aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy and X‐ray absorption fine structure confirms the metal to be present as metal ISASs. This methodology is applicable to both noble and nonprecious metals (M‐ISAS/p‐CN, M = Co, Ni, Cu, Mn, Pd, etc.). In particular, the Co‐ISAS/p‐CN nanospheres obtained using this method show comparable (E1/2 = 0.838 V) electrochemical oxygen reduction activity to commercial Pt/C with 20 wt% Pt loading (E1/2 = 0.834 V) in alkaline media, superior methanol tolerance, and outstanding stability, even after 5000 cycles. 相似文献
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Meiling Xiao Jianbing Zhu Ligang Feng Changpeng Liu Wei Xing 《Advanced materials (Deerfield Beach, Fla.)》2015,27(15):2521-2527
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Santosh K. Singh Kotaro Takeyasu Junji Nakamura 《Advanced materials (Deerfield Beach, Fla.)》2019,31(13)
The oxygen reduction reaction (ORR) is a core reaction for electrochemical energy technologies such as fuel cells and metal–air batteries. ORR catalysts have been limited to platinum, which meets the requirements of high activity and durability. Over the last few decades, a variety of materials have been tested as non‐Pt catalysts, from metal–organic complex molecules to metal‐free catalysts. In particular, nitrogen‐doped graphitic carbon materials, including N‐doped graphene and N‐doped carbon nanotubes, have been extensively studied. However, due to the lack of understanding of the reaction mechanism and conflicting knowledge of the catalytic active sites, carbon‐based catalysts are still under the development stage of achieving a performance similar to Pt‐based catalysts. In addition to the catalytic viewpoint, designing mass transport pathways is required for O2. Recently, the importance of pyridinic N for the creation of active sites for ORR and the requirement of hydrophobicity near the active sites have been reported. Based on the increased knowledge in controlling ORR performances, bottom‐up preparation of N‐doped carbon catalysts, using N‐containing conjugative molecules as the assemblies of the catalysts, is promising. Here, the recent understanding of the active sites and the mechanism of ORRs on N‐doped carbon catalysts are reviewed. 相似文献
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Chenzhen Zhang Nasir Mahmood Han Yin Fei Liu Yanglong Hou 《Advanced materials (Deerfield Beach, Fla.)》2013,25(35):4932-4937
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Single‐atom catalysts (SACs) with maximum atom‐utilization efficiency and distinctive properties are emerging as a new frontier in the field of catalysis. Herein, a new strategy for synthesizing stable Co single atoms with content of about 1.52 wt% on defective bimodal mesoporous carbon materials (A‐Co@CMK‐3‐D) is reported. The dispersion and coordination structures of atomic Co species at carbon defect sites are confirmed by both aberration‐corrected high‐resolution transmission electron microscopy (AC‐HRTEM) and X‐ray absorption spectrometry, respectively. The obtained catalyst exhibits efficient electrochemical performance on oxygen reduction reaction (ORR) in an alkaline electrolyte with a half‐wave potential (0.835 V vs RHE), which is comparable to that of Pt/C (0.839 V vs RHE). Furthermore, the Zn–air batteries (ZABs) fabricated by this electrocatalyst display a superior discharging and charging performance with long‐term durability. This work provides a new approach on optimizing SAC‐based carbon materials from multiscale principles (simultaneous regulation of electronic structure and hierarchical morphology) to boost ORR reactivity. 相似文献
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Zheng Kun Yang Ling Lin An‐Wu Xu 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(41):5710-5719
It is an ongoing challenge to fabricate nonprecious oxygen reduction reaction (ORR) catalysts that can be comparable to or exceed the efficiency of platinum. A highly active non‐platinum self‐supporting Fe?N/C catalyst has been developed through the pyrolysis of a new type of precursor of iron coordination complex, in which 1,4‐bis(1H‐1,3,7,8–tetraazacyclopenta(1)phenanthren‐2‐yl)benzene (btcpb) functions as a ligand complexing Fe(II) ions. The optimal catalyst pyrolyzed at 700 °C (Fe?N/C?700) shows the best ORR activity with a half‐wave potential (E1/2) of 840 mV versus reversible hydrogen electrode (RHE) in 0.1 m KOH, which is more positive than that of commercial Pt/C (E1/2: 835 mV vs RHE). Additionally, the Fe?N/C?700 catalyst also exhibits high ORR activity in 0.1 m HClO4 with the onset potential and E1/2 comparable to those of the Pt/C catalyst. Notably, the Fe?N/C?700 catalyst displays superior durability (9.8 mV loss in 0.1 m KOH and 23.6 mV loss in 0.1 m HClO4 for E1/2 after 8000 cycles) and better tolerance to methanol than Pt/C. Furthermore, the Fe?N/C?700 catalyst can be used for fabricating the air electrode in Zn–air battery with a specific capacity of 727 mA hg?1 at 5 mA cm?2 and a negligible voltage loss after continuous operation for 110 h. 相似文献
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Yiyin Huang Yueqing Wang Cheng Tang Jun Wang Qiang Zhang Yaobing Wang Jintao Zhang 《Advanced materials (Deerfield Beach, Fla.)》2019,31(13)
With the extensive research and development of renewable energy technologies, there is an increasing interest in developing metal‐free carbons as a new class of bifunctional electrocatalysts for boosting the performance of metal–air batteries. Along with significant understanding of the electrocatalytic nature and the rapid development of techniques, the activities of carbon electrocatalysts are well‐tailored by introducing particular dopants/defects and structure regulation. Herein, the recent advances regarding the rational design of carbon‐based electrocatalysts for the oxygen reduction reaction and oxygen evolution reaction are summarized, with a special focus on the bifunctional applications in Zn–air and Li–air batteries. Specifically, the atomic modulation strategies to regulate the electrocatalytic activities of carbons and structure modification are summarized to gain deep insights into bifunctional mechanisms and boost advanced Zn–air and Li–air batteries. The current challenges and future perspectives are also addressed to accelerate the exploration of promising bifunctional carbon catalysts for renewable energy technologies, particularly metal–air batteries. 相似文献
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Zhao‐Qing Liu Hui Cheng Nan Li Tian Yi Ma Yu‐Zhi Su 《Advanced materials (Deerfield Beach, Fla.)》2016,28(19):3777-3784
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Jiuhui Han Gang Huang Zhili Wang Zhen Lu Jing Du Hamzeh Kashani Mingwei Chen 《Advanced materials (Deerfield Beach, Fla.)》2018,30(38)
Nitrogen‐doped graphene exhibits high electrocatalytic activity toward the oxygen reduction reaction (ORR), which is essential for many renewable energy technologies. To maximize the catalytic efficiency, it is desirable to have both a high concentration of robust nitrogen dopants and a large accessible surface of the graphene electrodes for rapid access of oxygen to the active sites. Here, 3D bicontinuous nitrogen‐doped mesoporous graphene synthesized by a low‐temperature carbide‐mediated graphene‐growth method is reported. The mesoporous graphene has a mesoscale pore size of ≈25 nm and large specific surface area of 1015 m2 g?1, which can effectively host and stabilize a high concentration of nitrogen dopants. Accordingly, it shows an excellent electrocatalytic activity toward the ORR with an efficient four‐electron‐dominated pathway and high durability in alkaline media. The synthesis route developed herein provides a new economic approach to synthesize bicontinuous porous graphene materials with tunable characteristic length, porosity, and chemical doping as high efficiency electrocatalysts for a wide range of electrochemical reactions. 相似文献
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《Small Methods》2017,1(12)
Zinc–air batteries (ZABs) have attracted extensive attention due to their remarkable high theoretical energy output. They represent one of the most promising future power sources. However, many barriers restrict their application on a large scale. One of the main challenges is the sluggish rates of the oxygen‐reduction reaction (ORR) and oxygen‐evolution reaction (OER), which govern the discharging and charging processes of the battery, respectively. Here, recent advances related to oxygen electrocatalyst materials for ZABs are discussed. Detailed discussions will focus on unifunctional ORR electrocatalysts and bifunctional ORR and OER electrocatalysts. Pt‐based nanomaterials, as the best ORR electrocatalysts, possess the virtue of high activity, but have the disadvantages of high cost, scarcity, and poor stability. Thus, materials based on transition metals (alloys, metal oxides, metal nitrides, and spinel oxides) and metal‐free materials are widely investigated as nonprecious ORR catalysts owing to their promising catalytic activities. As for bifunctional ORR and OER electrocatalysts, the following two categories are introduced: (i) metal‐based materials, including single metal/metal‐oxides‐based materials and mixed‐metal/metal‐oxides‐based materials; and (ii) metal‐free materials. Finally, perspectives on the continuous research and limitation of the current ZAB technology are provided. 相似文献
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