ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Xuedong Wei,Na Li,Xianming Zhang
Two kinds of three-phase composite materials, Co/Co(OH) 2 /C@B directly from ZIF67 modified by NaBH 4 and Co/CoO/C@B through pyrolyzation of Co/Co(OH) 2 /C@B material, are successfully synthesized and used as catalysts for the oxygen evolution reaction (OER). The structure and morphology are mainly characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS). HBZ-1 sample with the structure of Co/Co(OH) 2 /C@B has the best onset potential of 1.075 V vs. RHE at 0.1 mA cm −2 and the best catalyst stability among all of the materials researched. Especially as its pyrolyzing product, the CBZ-1 sample with the structure of Co/CoO/C@B behaves the most excellent synthetically electrocatalytic performance with low onset potential of 1.444 V vs. RHE at 0.1 mA cm −2 and a small overpotential of 390 mV at 10 mA cm −2 , which is better than that of RuO 2 . This good catalytic activity is mainly attributed to the generation of CoO phase and synergistic effect of all the phases in the composite structure. Furthermore, the CBZ-1 sample has the appropriate catalytic stability which attributed to the three-phase structure of Co/CoO/C@B composite and the existing of a little B element.
研究领域:
材料科学
·
电催化
·
纳米材料
·
能量转换
·
无机化学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Keke Yang,Guilin Song,Yuanyuan Li,Qingda An,Shangru Zhai,Zuoyi Xiao
Nowadays there is much room for improvement in the designed synthesis of high-performance electromagnetic wave absorbers by combining metal-organic frameworks (MOFs) and biomass components. Herein, 3D N-doped porous carbon cobalt/cobalt oxide (NPC/Co/CoO) composites were successfully prepared by transforming in-situ grown ZIF-67 clusters on a chitosan matrix. Analysis results showed that the N-doped carbonaceous composites obtained had unique porosity, high specific surface area, and defect-enriched structure, which provided numerous paths for electron transfer , leading to big benefits to interfacial polarization and dipole polarization. Most importantly, the ferromagnetic resonance and magnetic coupling were enhanced by ZIF-67-derived Co/CoO nanoparticles . By adjusting the content of metallic cobalt salt, pyrolysis temperature, and sample filling content, the optimal impedance matching properties of the composites could be optimized. When the matching thickness is 2 mm, the RL min of NPC/Co/CoO-10/700–30 wt% achieved − 48.97 dB at 13.52 GHz, and the effective absorption bandwidth exceeds 5.36 GHz. The composites with excellent performance prepared by a controllable process using chitosan and ZIF-67 might be a promising alternative for the large-scale preparation of high-frequency electromagnetic wave absorbers.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Xiaoming Fan,Yuyin Fan,Xiao Zhang,Lin Tang,Jinxue Guo
Heterostructured materials favoring synergism, efficient charge transfer, and abundant active sites have aroused enormous interests for water electrolysis. Here heterogeneous Co@CoO encapsulated in P, N co-doped carbon nanofibers supported on carbon cloth (Co@CoO-PNC/CC) has been prepared to pursue attractive synergism for the application of pH-tolerant catalyst for oxygen evolution reaction (OER) in both alkaline and neutral solutions. The prepared Co@CoO-PNC/CC exhibits advanced OER performances, generating a current density of 10 mA cm −2 at overpotential of 289 mV in alkaline media and 371 mV in neutral media. The high OER activity can be assigned to the synergistic effect of abundant active sites and enhanced charge transfer between Co and CoO, as well as the specific P, N co-doped carbon nanofiber architecture.
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Yingjie Chen,Chong Gong,Zhihao Shi,Di Chen,Xing Chen,Qian Zhang,Beili Pang,Jianguang Feng,Liyan Yu,Lifeng Dong
A melt-salt-assisted method is utilized to construct an onion-like hybrid with Co/CoO nanoparticles embedded in graphitic Fe-N-doped carbon shells (Co/CoO@FeNC) as a bifunctional electrocatalyst. The iron-polypyrrole (Fe-PPy) is firstly prepared with a reverse emulsion. Direct pyrolysis of Fe-PPy yields turbostratic Fe-N-doped carbon (FeNC) with excellent oxygen reduction reaction (ORR) electrocatalysis, while the melt salt (CoCl 2 ) mediated pyrolysis of Fe-PPy obtains onion-like Co/CoO@FeNC with a reversible overvoltage value of 0.695 V, largely superior to Pt/C and IrO 2 (0.771 V) and other Co-based catalysts reported so far. The ORR activity is mainly due to the graphitic FeNC and further enhanced by Co N x bonds, whereas the oxygen evolution reaction (OER) activity is principally due to the Co/CoO composite. Concurrently, Co/CoO@FeNC as cathode catalyst enables Zn-air battery with a high open circuit voltage of 1.42 V, a peak power density of 132.8 mW cm −2 , a specific capacity of 813 mAh g Zn −1 , and long-term stability.
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Yuanhui Zuo,Mujia Huang,Wenchao Sheng,Qian Xu,Wenquan Tao,Zhuo Li
To develop high-performance non-precious metal-based electrocatalysts for oxygen reduction reaction (ORR) is an urgent demand. We herein report an ingenious strategy to develop highly selective and competitive precious metal-free ORR electrocatalyst Co/CoO/SnO encapsulated in N-rich mesoporous carbon (CCS@NPC) nanocubes, via a simple one-step introduction of all functional components. Atomically mixed composites with significantly enhanced catalytic activity were obtained by adopting amorphous mesoporous ternary metal oxides CoSnO 3 nanocubes as precursor and template. The synergistic effect of the triphase nanohybrids (Co, CoO & SnO) anchored in nitrogen-doped mesoporous carbon nanocubes promoted the catalytic reactions , owning to the anisotropic morphology, great heterojunction interfaces, and structural stability. The large-scale prepared CCS@NPC exhibited excellent electrocatalytic activity toward ORR with an admirable onset potential (1.01 V) and diffusion-limited current density (5.88 mA cm −2 ). The CCS@NPC showed stronger stability (20 h) and higher methanol tolerance with the concentration up to 8.0 M, compared to that of commercial Pt/C.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Jie Yu,Yonghong Ni,Muheng Zhai
Co-based compounds, especially cobalt oxides, have been widely employed as the non-enzyme catalysts for the electro-oxidation of glucose. In this work, we designed a solution-combustion and subsequent heat-treating route to successfully prepare Co-CoO-Co 3 O 4 nanocomposites. Co-CoO nanocomposites were first obtained in one step via a simple solution-combustion method, employing CoCl 2 as the Co source, oxygen in air as the oxygen source, and ethanol as the solvent and fuel; and then, the freshly-prepared Co-CoO nanocomposites were annealed in air at 300–600 °C for 2 h. Experiments showed that the annealing temperature strongly affected the component of the final product. Co-CoO-Co 3 O 4 nanocomposites were produced at 300 and 400 °C; CoO-Co 3 O 4 nanocomposites were obtained at 500 °C; and Co 3 O 4 nanoparticles were formed at 600 °C. The above annealed products were labeled as T3, T4, T5 and T6. Electrochemical measurements showed that Co-CoO nanocomposite and its annealed products presented good electrochemical properties and could be employed as catalysts for the non-enzyme electro-oxidation of glucose. Among them, T4 sample (Co-CoO-Co 3 O 4 nanocomposites) possessed the best electrocatalytic activity. The as-prepared T4/GCE sensor showed rapid response time (<1s), high sensitivity (949.3 μA mM −1 cm −2 ), long linear range (0.005–0.6, 0.6–4.3 mM), low detection limit (0.92 μM), and good stability and selectivity.
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高影响因子
ChemSusChem
·
2024
·
IF 7.5
Xin Tian,Mengnan Xu,Xin Ma,Guanyu Mu,Junwu Xiao,Shuai Wang
Graphical The 3D Co-based/graphene composite framework, prepared by spontaneous assembly, serves as the template and sources of Co and O.The as-formed Co-Nx sites, along with the Co/CoO nanoparticles and N-doped carbon nanosheets, synergistically function as the active sites to boost the electrocatalytic activity of the oxygen redox reaction. The Co/CoO-NG exhibits a low potential gap (ΔE=0.784 V) for ORR/OER. Reasonable design of low-cost, high-efficiency and stable bifunctional oxygen electrocatalysts is of great significance to improve the reaction efficiency of Zn-air batteries, which is still a huge challenge. Here, we report a highly efficient bifunctional oxygen electrocatalyst with three-dimensional (3D) N-doped graphene network-supported cobalt and cobalt oxide nanoparticles (Co/CoO-NG), which can be in situ synthesized by inducing metal ions on metal plates via graphene oxide as an inducer. This 3D network structure and open active center show excellent bifunctional oxygen electrocatalytic activity under alkaline conditions, and can be used as an air electrode in rechargeable Zn-air batteries, with significantly better power density (244.28 mW cm −2 ) and stability (over 340 h) than commercial Pt/C+RuO 2 mixtures. This work is conducive to advancing the practical application of graphene-based materials as air electrodes for rechargeable zinc-air batteries.
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PubMed
高影响因子
Materials
·
2024
·Vol. 17
·期 21
·5239
·
IF 3.1
He Han,Hui Chen,Rui Wang,Zhichao Lou
With the popularization of wireless communication, radar, and electronic devices, the hidden harm of electromagnetic radiation is becoming increasingly serious. The design of green biomass carbon-based interface heterojunctions based on lightweight porous materials can effectively protect against electromagnetic radiation hazards. In this work, we constructed an anisotropic heterojunction interface with magnetic and dielectric coupling based on a honeycomb-like periodic matrix multi-layer array repeating unit. The removal of lignin components from bamboo through oxidation enriches the impregnation pores and uniform adsorption sites of the magnetic medium. Further, in situ pyrolysis promotes the formation of a large number of electric dipoles at the interface between the magnetic medium and dielectric coupling inside the periodic cell carbon skeleton, enhancing interface polarization and relaxation. Local carrier traps and uneven electromagnetic density enhance dielectric and hysteresis losses, resulting in excellent impedance matching. Therefore, the obtained bamboo-based carbon multiphase composite absorbent has satisfactory electromagnetic loss characteristics. At a thickness of 1.55 mm, the effective absorption bandwidth reaches 5.1 GHz, and the minimum reflection loss (RL) value reaches −54.7 dB. In addition, the far-field radar simulation results show that the sample has an excellent RCS (radar cross-section) reduction of 33.3 dB·m2. This work provides new directions for the diversified development of green biomass and the optimization of the design of magnetic and dielectric coupling in periodic array structures.
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PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yongqian Shen,Guibin Zhang,Haiyan Wang,Xin Liu,Yuchen Zhang,Feng Gao,Fulong Yang,Jiqiang Ma,Jiafeng Cao,Huixia Feng,Xueyan Du
In recent years, magnetic metal nanoparticles (NPs)/carbon nanofibers (CNFs) composites have become very promising electromagnetic waves (EMWs) absorbers. However, how to achieve controllable growth of magnetic metals in CNFs is still an urgent problem to be solved. Herein, we reported a pore-confined strategy for constructing the porous Co/CoO/CNFs. By introducing different amounts of acetone (0.20 g, 0.30 g and 0.40 g) into the aqueous phase spinning solution to construct the porous structure , we achieved uniform distribution of Co/CoO NPs and ultimately obtained the porous Co/CoO/CNFs microwave absorbers (MAs) with excellent microwave absorption performance. Thanks to the excellent impedance matching and enhanced polarization loss, the porous Co/CoO/CNFs obtained the minimum reflection loss (RL) of −52.2 dB with a thickness of 3.0 mm, and the effective bandwidth (EBW) was 3.02 GHz when the acetone addition in the spinning solution was 0.30 g. Therefore, the pore-confined strategy proposed herein is conducive to the design of the MAs with excellent performance and low infilling rates based on CNFs. Furthermore, the porous structure of CNFs also improves the lightweight performance of the MAs.
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高影响因子
Nanoscale
·
2016
·Vol. 8
·期 8
·4681-4687
·
IF 7.76
Zexing Wu,Jie Wang,Lili Han,Ruoqian Lin,Hongfang Liu,Huolin L. Xin,Deli Wang
Investigating active, stable, and low-cost materials for the oxygen reduction reaction is one of the key challenges in fuel-cell research. In this work, we describe the formation of N-doped carbon shell coated Co@CoO nanoparticles supported on Vulcan XC-72 carbon materials (Co@CoO@N–C/C) based on a simple supramolecular gel-assisted method. The double-shelled Co@CoO@N–C/C core–shell nanoparticles exhibit superior electrocatalytic activities for the oxygen reduction reaction compared to N-doped carbon and cobalt oxides, demonstrating the synergistic effect of the hybrid nanomaterials. Notably, the Co@CoO@N–C/C nanoparticles give rise to a comparable four-electron selectivity, long-term stability, and high methanol tolerance; all show a multi-fold improvement over the commercial Pt/C catalyst. The progress is of great importance in exploring advanced non-precious metal-based electrocatalysts for fuel cell applications.
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高影响因子
LANGMUIR
·
2026
·Vol. 42
·期 31
·22973-22982
·
IF 4.4
Jia Xiaomeng,Dong Kaiyu,Zheng Zhe,Sheng Tian,Yuan Qiang
Nonprecious metal oxygen reduction
reaction (ORR) electrocatalysts
have garnered increasing attention owing to their extremely low cost
compared with Pt-based electrocatalysts. However, realizing the four-electron
pathway and developing highly antipoisoning nonprecious metal ORR
electrocatalysts are key challenges in practical energy devices. Herein,
atomic-level Fe doping was applied to Co@CoO core–shell nanoparticles
anchored in a porous carbon–nitrogen framework (denoted Fe–Co@CoO/NC)
derived from FeCoZn metal–organic frameworks. The Fe–Co@CoO/NC
exhibits a half-wave potential of 0.895 V in an alkaline medium, superior
to that of commercial Pt/C (0.842 V), and high in situ methanol and
CO tolerance. In situ spectroscopic characterizations and Rotating
Ring-Disc Electrode (RRDE) investigations reveal that four-electron
ORR is achieved using Fe–Co@CoO/NC through O–O bond
breaking in OOH* intermediate species. In addition, density functional
theory calculations show that compared with Pt, Fe–CoO effectively
suppresses H 2 O 2 generation and favors a more
advantageous four-electron reaction pathway. Fe–Co@CoO/NC as
a cathode material for direct methanol fuel cells (DMFCs) reaches
a peak power density of 113.7 mW·cm –2 , markedly
outperforming commercial Pt/C (72.0 mW·cm –2 ). This work provides an effective strategy for preparing high-efficiency
nonprecious metal four-electron ORR catalysts with intrinsic tolerance
to methanol and CO for DMFC devices.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Yu Jiang,Jia Wang,Bo Liu,Wei Jiang,Tianyu Zhou,Yunchao Ma,Guangbo Che,Chunbo Liu
Herein, a N,S,O-doped Co/CoO/Co 9 S 8 @carbon hybrid (Co/CoO/Co 9 S 8 @NSOC) has been constructed by calcinating a Co-based metal–organic framework (Co-MOF) with 4,4-bipyridine and 2,5-thiophenedicarboxylic acid as linkers. Co/CoO/Co 9 S 8 @NSOC exhibited a high and recycled catalytic efficiency for peroxymonosulfate (PMS) activation to degrade sulfamethoxazole (SMX, 20 mg/L) with a reaction rate of 1.31 min −1 , which was 5.2 times than that of Co-MOF. The catalytic behavior should be attributed to the rich active sites, lamellar morphology, superhydrophilicity, and magnetism. Furthermore, the Co/CoO/Co 9 S 8 @NSOC was immobilized on a filter membrane (CMFM) to adapt to the flowing system, which could recycle 20 times without losing activity. To employ in a large-scale static environment, the Co/CoO/Co 9 S 8 @NSOC was loaded on the commercial sponge (CoSPG). In a 50 L water tank, the CoSPG realized to decompose 160 mg/L SMX solution with 37 h and had long-term stability over 10 days. Notably, the PMS cost of treating one ton of wastewater is only $0.34, indicating a huge industrial application value.
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高影响因子
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