Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 21
·10495-10509
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IF 8.867
Jiying Long,Yun Gong,Jianhua Lin
Through an annealing method, Co9S8@CoS@CoO@C nanoparticles (NPs) of 5–20 nm size were synthesized using a metal–organic framework (MOF) as the precursor. The Co9S8@CoS@CoO@C NPs exhibited excellent electrocatalytic activity for the oxygen evolution reaction (OER) with a lower overpotential than RuO2 (0.37 V) and Pt NPs (0.60 V). The better electrocatalytic activity of the hybrid material is associated with its heterojunction structure, in which the strong electron coupling interactions between Co9S8, CoS, CoO and C give rise to a superior synergistic effect. The interconnected amorphous carbon not only anchored the active Co compounds to avoid aggregation, but also afforded conducting channels for electron transfer. Furthermore, the cobalt compounds were the active species in the sample during the OER process; they were converted into CoOOH and Co(OH)2 in the KOH electrolyte, and the S elements in the sample entered the solution. The Co9S8@CoS@CoO@C NPs can exhibit the best OER activity with minimum overpotential (0.028 V) to afford a stable OER current after activation in a KOH aqueous solution. The sample also showed obvious photoresponse to visible light irradiation with enhanced OER current and lowered onset potential, which was probably associated with the semiconducting characteristics of the spin-polarized CoO and the quantum confinement effect of the nanoparticles.
研究领域:
材料科学
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电化学
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催化科学
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
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IF 24.319
Wenyang Fu,Yingying Du,Jiana Jing,Chunhong Fu,Minghua Zhou
Electrochemical reduction of nitrate to ammonia (ERNA) is a new process to recycle nitrogen resource from nitrate polluted wastewater. Nevertheless, how to optimize active sites on electrode to improve activity is a key challenge. Here, we proposed that building interfacial electric field could enhance ERNA. XPS analysis, DFT calculations and in-situ electrochemical measurements confirmed that high Fermi level of Cu (1.09 eV) and low valence band maximum of CoO (−0.23 eV) formed interfacial electric field in CoO/Cu electrode to transfer electron from Cu to CoO, resulting in positively charged Cu (+0.01 eV) increase nitrate adsorption, whereas negatively charged CoO (−0.007 eV) decrease NO adsorption, improving removal and selectivity greatly for boosting ERNA. Eventually, CoO/Cu foam (Co/Cu ratio of 3.05) achieved the highest ammonia yield of 4.3 mg cm −2 h −1 with faradic efficiency of 96.7 %, surpassing Cu foam (1.2 mg cm −2 h −1 ) and CoO/Ni foam (1.3 mg cm −2 h −1 ) electrodes.
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高影响因子
CARBON
·
2023
·
IF 10.9
Yuan Shu,Tingkai Zhao,Xianghong Li,abdul Jalil,Lei Yang,Guyue Feng,Yatao Li,Weiyu Jia,Fa Luo
To optimize the electromagnetic wave performance for absorbers, it is crucial to implement rational structural designs and integrate multiple loss modes in a coordinated manner. Here, three-dimensional (3D) porous macroscopic coral-like Co/CoO/reduced graphene oxide aerogels (Co/CoO/RGO), are successfully fabricated by an ice-templated freeze-drying and thermal reduction techniques, and their pore structures , involving aperture and total pore volume , are availably regulated by manipulating the water addition. The electromagnetic parameters and electromagnetic wave performance appear strong response toward the variation of pore structure. By controlling the pore structure, these parameters can be efficaciously tunned, thus manipulating the performance. The optimized absorption performance is obtained when the water addition is 1 ml, the minimum reflection loss reaches to −61.8 dB and the effective bandwidth is 4.2 GHz. Such good performance is inseparable with the 3D crosslinked conductive framework, the hybrid of magnetic and dielectric units, numerous heterointerfaces and countless pores walls in aerogels, which brings multiple electromagnetic wave loss mechanism. Moreover, it is very important that Co/CoO/RGO aerogels also integrate good hydrophobicity and heat insulation properties, allowing their application in harsh conditions. This work shows the potential of pore structural control engineering for producing multifunctional aerogels.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
·
IF 15.1
Yuan Shu,Tingkai Zhao,Jalil abdul,Xianghong Li,Lei Yang,Fa Luo
Addressing the growing issue of electromagnetic radiation calls for urgent exploration of effective electromagnetic wave absorbers. Herein, a series of coral-like Co/CoO nanoparticles/reduced graphene oxide (Co/CoO/RGO) hybrid aerogels were synthesized via a freeze drying-thermal reduction strategy. Their advantages involving porous interconnected framework, abundant heterogeneous interfaces, and integration of dielectric/magnetic units could bring multiple loss modes. By manipulating the Co(CO 3 ) 0.5 (OH)·0.11H 2 O (CCOH) addition and reduction temperature, the electromagnetic parameters could be tuned, ultimately resulting in optimal absorption capability with maximal reflection loss of –32.4 dB and effective bandwidth of 4.2 GHz. More importantly, excepting the high electromagnetic wave loss, Co/CoO/RGO hybrid aerogels also exhibit good hydrophobicity and thermal insulation properties, making them suitable for application in harsh environment. Besides, the special structure and multiple components lead to multiple heterointerfaces in aerogels, the resultant interface polarization is deemed to contribute to electromagnetic wave loss. Here, Density Functional Theory (DFT) simulation based on first-principles is adopted to verify the contribution of interface polarization from the theoretical level. According to the simulation results, the electron-occupied states near the Fermi level are significantly different among the different phases comprising the heterointerfaces, and there is a noticeable accumulation of charge at these interfaces, successfully affirming the interface polarization behavior at different interfaces.
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高影响因子
NEW JOURNAL OF CHEMISTRY
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2022
·Vol. 46
·期 40
·19161-19167
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IF 3.925
Peng Miao,Weixing Chen,Kailei Li,Weifeng Zhao,Jie Kong
Design of microwave absorbents with hierarchical interfacial structures has become an effective method to scatter microwaves. Metal/carbon composites derived from metal–organic frameworks (MOFs) have attracted considerable attention due to their tunable chemical composition and microstructure. We describe the facile synthesis of a Co/CoO/FeO/C nanocomplex employing Co(OH)2 on NH2-MIL-88B as the “sacrificial template” through one-step pyrolysis. The as-prepared flaky-like Co/CoO/FeO/C nanocomplex showed an effective absorption width of 4.7 GHz at 1.86 mm and a minimum reflection loss of −45.5 dB at 2.01 mm. Our study can aid design of a microstructural strategy for preparing high-performance microwave absorbents.
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高影响因子
Journal of Physical Chemistry C
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2022
·
IF 4.177
Lin Zhu,Zhen Ai,Baoli Wang,Siyue Zhang,Ruyi Zou,Yuhao Huang,Wei Sun
This paper presents an attempt on deconvoluting diffusion-control current (id) and surface-control current (is) from total current in a galvanostatic charge–discharge (GCD) test. Using this strategy, the pseudocapacitive behavior of nanosized Ce-CoO dispersed on graphene support was studied in detail. The results show that id is greatly affected by operating potential and occupies some proportion of the total pseudocapacitive current. The main functions of Ce in the composite material include promoting the proportion of is or inhibiting id and finally stimulating a specific capacitance (Cs) value increased from 192 to 726 F g–1. The Bode curve in the low-frequency region also proves that Ce can promote the performance of pseudocapacitance.
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ACS Applied Energy Materials
·
2021
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IF 6.024
Jingjing Wu,Jie Chen,Jingxuan Hao,Baoxin Ni,Dong Yang,Sheng Zhu,Qunjie Xu,Yulin Min
The use of light to directly reduce CO2 in the atmosphere is the actual development trend of photocatalysis applications in the future. However, it is still in the initial stage of exploration. In this work, oleylamine is used as a template in a one-step hydrothermal method to obtain the N-doped CoO catalyst that can be used to efficiently reduce CO2 in air. N-doped CoO achieves ultrahigh CO2 conversion efficiency (about 75%), amazing CO yield (2.902 mmol g–1 h–1), and superior CO conversion frequency (TOFCO > 300) in air. However, in a 0.03% simulated atmosphere (Ar/CO2), the CO precipitation rate drops by 18 times, while the H2 precipitation rate increases significantly. Quasi-in situ spectroscopy and experimental studies show that O2 in the CO2 reduction process will promote the formation of an amorphous layer with a small number of hydroxyl groups on the surface of N-doped CoO. This amorphous/crystalline interface will effectively promote the catalytic reduction of CO2. This work has inspired further research on the photoreduction process of low-concentration CO2 in the future.
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高影响因子
Journal of Materials Chemistry C
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2023
·Vol. 11
·期 19
·6336-6346
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IF 6.4
Dong Guo,Chen Chen,Yongqiang Wang,Youke Wang,Conglu Zhang
Two dimensional materials show unique advantages in catalysis. In this work, it was found that melamine could induce the directional growth of cobalt-based catalysts to form an ultra-thin two-dimensional hexagonal nanosheet structure with only 1.5 nm. In addition, these hexagonal nanosheets (HNs) could grow into a microporous structure under high temperature conditions, and the finally formed CoO hexagonal porous nanosheets (HPNs) had a surface area 11.3 times that of the nanoparticles. Embedding 1.25 wt% of monoatomic ruthenium in the CoO HPNs (CoO/Ru1.25% HPNs) allowed the catalyst to have more active charge storage and transfer centers. The results showed that the overpotential of CoO/Ru1.25% HPNs was 64 mV lower than that of CoO nanoparticles at 10 mA cm−2. The Tafel slope of CoO/Ru1.25% HPNs was only half that of CoO nanoparticles, indicating that a small amount of Ru dispersion and the two-dimensional structure control significantly increased the kinetic rate in the oxygen evolution reaction. The DFT results showed that the Ru single atoms in CoO/Ru HPNs (111) possessed the lowest energy barrier (1.19 eV). The Ru single atoms could effectively reconstruct the neighboring localized structure in the formation of ˙OOH, which desirably decreased the free energy of the system.
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高影响因子
CARBON
·
2020
·
IF 8.821
Venkata Sai Avvaru,Ivan Jimenez Fernandez,Wenliang Feng,Steven J. Hinder,Miguel Castillo Rodríguez,Vinodkumar Etacheri
Although secondary Li-ion batteries are widely used for electrochemical energy storage , low energy (100–300 Wh kg −1 ) and power density (250–400 W kg −1 ) are limiting their applications in several areas including long-range electric vehicles. Herein, we demonstrate high energy (400 Wh kg −1 ) and power density (1 kW kg −1 ) Li-ion batteries (considering the weight of both electrodes) based on extremely pseudocapacitive interface engineered CoO@3D-NRGO hybrid anodes. These values are 2.8 and 2.3-fold higher respectively compared to graphite‖LiNiMnCoO 2 full-cells under similar experimental conditions. Three-dimensional anode architecture presented here composed of ultrafine CoO nanoparticles (∼10 nm) chemically bonded to nitrogen-doped reduced graphene-oxide. This hybrid anode demonstrated excellent pseudocapacitance (∼92%), specific capacity (1429 mAh g −1 @ 25 mA g −1 ), rate performance (906 mAh g −1 @ 5 A g −1 ), and cycling stability (990 mAh g −1 after 7500 cycles @ 5 A g −1 ). Outstanding electrochemical performance of CoO@3D-NRGO‖LiNiMnCoO 2 full-cells is credited to the extreme pseudocapacitance of CoO@3D-NRGO anode resulting from Li 2 O/Co/NRGO nanointerfaces and Co–O–C bonds. The demonstrated strategy of interfacial engineering can also be extended for other environmental friendly/inexpensive transition metal oxide (Fe 2 O 3 , MnO 2 etc.) anodes for high energy/power density and ultra-long-life Li-ion batteries.
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高影响因子
DYES AND PIGMENTS
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2020
·
IF 4.613
Wenfang Liu,Haishuang Jia,Jie Zhang,Ling Shao,Jun Wang,Dawei Fang
In this work, a novel dual-excitation and dual-emission fluorescent probe , CDs–COO–Fluorescein (CDs–COO–F), for the specific detection of hydrazine (N 2 H 4 ) was designed and synthesized through esterification reaction of carbon dots (CDs) and fluorescein (F). The prepared CDs were characterized by TEM, XPS , XRD and FT-IR and the optical properties of CDs and CDs–COO–F were described by UV–vis and fluorescence spectra. On the other hand, the affecting factors including hydrazine (N 2 H 4 ) concentration and interfering substances on the hydrazine (N 2 H 4 ) detection were researched. The high sensitivity and high selectivity of CDs–COO–F in detection hydrazine (N 2 H 4 ) could be confirmed. Two good linear responses of fluorescence emission intensities of CDs–COO–F at 462 nm and 515 nm as functions of hydrazine (N 2 H 4 ) concentration were obtained, respectively. The limits of detection hydrazine (N 2 H 4 ) were 0.504 μM and 0.269 μM under 370 nm and 480 nm excitation wavelength lights, respectively. The detecting mechanism of hydrazine (N 2 H 4 ) by CDs–COO–F was deduced from the experimental results. Cell imaging and cytotoxicity experiments of CDs–COO–F were measured. The experiment results show that the fluorescent probe CDs–COO–F can be applied to detect hydrazine (N 2 H 4 ) in aqueous solution and living cells.
研究领域:
分析化学
·
生物医学
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高影响因子
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
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电催化
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纳米材料
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能量转换
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无机化学
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2024
·
IF 5.8
Zichuan Lu,Shuai Li,Tao Zhong,Ren Zhou,Fuying Wu,Daifen Chen,Wei Kong,Arkadii Proskurin,Liuting Zhang
s The development of heterostructure catalysts with high activity and reusability is of great significance for the green hydrogen production from NaBH 4 . In this paper, a novel CoNi-CoO x nanoparticle with Schottky heterostructure (UCC-30) was synthesized using a high-temperature annealing method. The successful preparation of catalysts with varying contents of CoO was achieved through the precise control of ultrasonication conditions. The experimental results demonstrated that the CoNi-CoO x catalysts exhibited remarkable catalytic performance and were capable of significantly reducing the activation energy for NaBH 4 hydrolysis, with an activation energy of 24.61 ± 0.51 kJ/mol. The hydrogen production rate (HGR) of NaBH 4 + UCC-30 reached 1245 mL min −1 g cat − 1 at 298 K, which was conspicuously higher than that of similar non-precious metal catalysts. Microstructural studies have demonstrated that CoNi-CoO x has a considerable catalytically active area in addition to Schottky moieties, which collectively contribute to the creation of multiple active sites, thereby improving the catalytic efficiency. Moreover, the catalytic capacity of NaBH 4 +UCC-30 remained at 81.9 % after five cycles at 298 K, indicating potential application in practical hydrogen production cases. It is noteworthy that the introduction of the Schottky structure can adjust the catalytic effect of CoNi alloy materials, thereby providing guidance for the future design and fabrication of efficient catalysts for hydrogen production and other energy related research areas.
研究领域:
材料科学
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催化化学
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能源化学
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纳米材料
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可再生能源
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电化学
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表面科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）