ChemSusChem
·
2021
·Vol. 15
·期 4
·e202102049
·
IF 8.928
Pingping Huang,Tingting Fan,Xintao Ma,Jiguang Zhang,Yanping Zhang,Zhou Chen,Xiaodong Yi
Graphical Lowering barriers : Bimetallic ZnCo 2 O 4 catalyst can promote nitrate electroreduction at room temperature. The electron-deficient Co active site can lower the energy barriers for the formation of *NO 2 intermediate and suppress the hydrogen evolution reaction, thus enhancing the selectivity and yield rate of electrochemical NO 3 − reduction to ammonia. Nitrate (NO 3 − ) as a common pollutant of groundwater causes drinking water safety problems and seriously endangers people‘s health. Electrochemical reduction of nitrate to ammonia under ambient condition is a green and significant route to reduce the concentration of NO 3 − and produce ammonia (NH 3 ), known as a complement to the Haber–Bosch reaction. Currently, noble-metal electrocatalysts are often used in electrochemical reduction of NO 3 − , but high cost and scarcity limited their application. Herein, three-dimensional (3D) flower-like zinc cobaltite (ZnCo 2 O 4 ) electrocatalyst was developed to convert nitrate into ammonia at room temperature. The NH 3 yield rate could reach up to around 2100 μg mg −1 h −1 at a potential of −0.6 V vs. reversible hydrogen electrode (RHE), which was around 2.0 times higher than that of pristine Co 3 O 4 . In addition, the NH 3 faradaic efficiency of ZnCo 2 O 4 electrocatalyst could reach around 95.4 % at potential of −0.4 V vs. RHE with good structural and morphological stability, which surpassed most reported non-noble metal-based electrocatalysts. Further studies concluded that the improved activity of electrocatalytic NO 3 − reduction was ascribed to the existence of abundant active sites and the charge transfer from Co atoms to Zn atoms after Zn doping. Importantly, this work opens a new path for the development of Co-based materials as electrocatalysts for reducing nitrate to ammonia.
研究领域:
环境科学
·
电化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysts
·
2023
·Vol. 13
·期 7
·1119
·
IF 3.9
Yinke Zhang,Lu Li,Zihan Shang,Hang Xu
In this study, nickel cobaltate (NiCo2O4) powders are employed as a catalyst in conjunction with persulfate for the development of a catalytic oxidation system to enhance fuel desulfurization. The hydrothermal synthesis conditions of NiCo2O4powders, which significantly influenced the desulfurization efficiency, were optimized using a response surface methodology with a Box–Behnken design. These conditions were ranked in the following order: calcination temperature > hydrothermal temperature > calcination time > hydrothermal time. Through the optimization process, the ideal preparation conditions were determined as follows: a hydrothermal temperature of 143 °C, hydrothermal time of 6.1 h, calcination temperature of 330 °C, and calcination time of 3.7 h. Under these optimized conditions, the predicted desulfurization rate was approximately 85.8%. The experimental results closely matched the prediction, yielding a desulfurization rate of around 84%, with a minimal error of only 2.1%. To characterize the NiCo2O4powders prepared under the optimal conditions, XRD, SEM, and TEM analyses were conducted. The analysis revealed that the microscopic morphology of NiCo2O4exhibited a rectangular sheet structure, with an average particle size of 20 nm. Additionally, fan-shaped NiCo2O4particles were observed as a result of linear and bundle agglomerations. Thus, this work is innovative in its ability to synthesize nano-catalysts using hydrothermal synthesis in a controllable manner and establishing a correlation between the hydrothermal synthesis conditions and catalytic activity.Keywords:response surface methodology;hydrothermal synthesis;nickel cobaltate;desulfurization;optimization
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
IONICS
·
2020
·Vol. 26
·期 12
·5897-5906
·
IF 2.394
Gu Fengling,Liu Wenbin,Song Yonghai,Liu Li-Min,Zhu Yongmei
Herein, a new activated porous carbon (APC) was proposed by carbonizing waste biomass of pinecone which could be obtained in large quantities and subsequently activation of zinc chloride. Then small Co 3 O 4 nanoparticles were loaded on the surface and holes of APC to prepare the final Co 3 O 4 /APC nanocomposites. The as-prepared APC had a lotus root-like and layered porous structure with a large number of mesopores and micropores. The APC reduced the agglomeration of small Co 3 O 4 particles which were uniformly anchored on the surface of APC. When applied for the anode of lithium-ion batteries, the Co 3 O 4/ APC nanocomposites had a reversible capacity of 625 mAh g −1 after 200 cycles at the current density of 500 mA g −1 . The Co 3 O 4/ APC nanocomposites also had a good rate performance. Above all, this work could transform waste biomass into sustainable resource, and the raw materials were easy to obtain in large quantities.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Fang Zhang,Yuchen Cui,Jingxin Gao,Ziang Li,Yiping Yu,Yuxuan Xia,Wei Lei,Jie Zhang,Nuofu Chen,Jikun Chen
While perovskite cobaltites ( Re CoO 3 , Re : rare-earth) exhibit multiple spin states and complex electromagnetic phase diagram, their intrinsic metastability at heavy rare-earth composition ( Re H CoO 3 ) impedes their synthesis. Herein, we effectively synthesized Re H CoO 3 ( Re H = Ho, Er, and Tm), without the necessity to use the previous high pressures, by descending their reaction temperatures within molten-salts. Owing to the intermediate valence of Co 3 + , their metastable perovskites cannot be stabilized by simply elevating oxygen pressures, in contrast to the synthesis of high-transitional valence metastable perovskites such as Re NiO 3 . Alternatively, the positive formation free energy of the Re H CoO 3 was reduced by introducing KCl that dissolve the precursors at lower temperatures to prevent varying the valence of Co without scarifying the reaction kinetics. The effective synthesis of metastable Re CoO 3 towards heavy rare-earth composition further extends the range for regulating both the electronic and magnetic phases of Re H CoO 3 , paving the way to their potential electromagnetic applications.
研究领域:
材料科学
·
凝聚态物理
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Chengqin Dai,Maosheng Chen,Yujing Lin,Ruijuan Qi,Chunhua Luo,Hui Peng,Hechun Lin
Metal oxide semiconductor have been widely used as sensing materials for detecting various gases with trace concentrations. However, the sensing properties of layered cobaltites with metallic conductivity have not been investigated to date. In this work, we developed a convenient preparation method of Na x CoO 2 nanoflakes via aqueous ultrasonic exfoliation of Na x CoO 2 single crystals. The sensor based on Na x CoO 2 nanoflakes was fabricated, whose resistance is obviously smaller than that of the typical metal oxide based sensors. It shows less response to n -hexane, toluene, xylene, ammonia, methanol, ethanol and acetone. However, it exhibits excellent sensing performance to n -butanol and good moisture-resistance, and the sensitivity to 50 ppm n -butanol is up to 4.48 with the response time of 95 s and the recovery time of 154 s at the optimum working temperature of 200 °C. Owning to the high electric conductivity of Na x CoO 2 layers, the sensor presents a very low noise and a high signal-to-noise ratio value with the detection limit at ppb level. The layered cobaltites exhibit the rich phase diagram and the nanoflakes are versatile surface functionalization. This work provides insight for layered cobaltites to be employed as highly sensitive sensors.
研究领域:
材料科学
·
化学传感器
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Guohui Chen,Yi Yang,Yatang Dai,Wei Wang
NiCo 2 O 4 is a binary transition metal oxide with a spinel structure. It has higher theoretical specific capacitance, good cycle stability, lower cost, and environmental friendliness. In this paper, hollow silica microspheres were prepared by using carbon dioxide microspheres as templates. The physical characterization results of the materials show that the prepared nanospheres have a good hollow spherical structure. After the carbon coating, a very obvious carbon particle layer grows on the surface of the hollow sphere. Electrochemical test results show that the rate performance and cycle stability of the carbon-coated nickel cobaltate hollow microspheres have been significantly improved, and the charge transfer resistance has been significantly reduced. The specific capacitance reaches 637.5 F/g at a current density of 0.5 A/g. When the current density is changed from 0.5 A/g to 5 A/g, the capacitance retention is as high as 90.2%. At a current density of 5 A/g, the carbon-coated nickel cobaltate hollow microspheres can maintain a specific capacitance of 91.7% after 2000 charge and discharge cycles.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Yinghao Tao,Wendan Jiang,Hui Wang,Weiju Hao,Qingyuan Bi,Xinjuan Liu,Jinchen Fan,Guisheng Li
As a typical spinel oxide, nickel cobaltite (NiCo 2 O 4 ) is considered to be a promising and reliable oxygen evolution reaction (OER) catalyst due to its abundant oxidation states and the synergistic effect of multiple metal species. However, the electrocatalytic OER performance of NiCo 2 O 4 has always been limited by the low specific surface area and poor intrinsic conductivity of spinels. Herein, the hedgehog-like molybdenum-doped NiCo 2 O 4 (Mo-NiCo 2 O 4 ) catalyst was prepared as an efficient OER electrocatalyst via a facile hydrothermal method followed with high-temperature annealing. The Mo-NiCo 2 O 4 -0.075 with Mo doping concentration of ∼ 1.95 wt% exhibits excellent OER performance with a low overpotential of 265 mV at a current density of 10 mA·cm −2 and a Tafel slope of 126.63 mV·dec -1 , as well as excellent cycling stability. The results demonstrated that the hedgehog-like structure provides Mo-NiCo 2 O 4 with the high surface area and mesopores that enhance electrolyte diffusion and optimal active site exposure. The in-situ Raman spectra and density functional theory calculations show that the Mo cations doping improve the intrinsic conductivity of the NiCo 2 O 4 while modulating the chemisorption of intermediates. Meanwhile, the energy barriers of *OH and O* formation decrease significantly after Mo doping, effectively facilitating water dissociation and optimizing the reaction kinetics.
研究领域:
材料科学
·
电化学
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Xuefei Gong,J.P. Cheng,Fu Liu,Li Zhang,Xiaobin Zhang
Nickel–Cobalt hydroxide microspheres are electrodepositioned on the films of NiCo 2 O 4 nanowires grown on the current collector through a facile approach and the hierarchical structures are then investigated as an electrode material for high-performance supercapacitors . Owing to the superior electrical conductivity of NiCo 2 O 4 nanowires, the porous structure of the (Ni–Co)(OH) 2 microspheres and the synergic effect of the multi-components, the electrode can deliver a high areal capacitance of 6 F cm −2 and a corresponding specific capacitance of 1132 F g −1 at a current density of 2 mA cm −2 , as well as a good rate capability (61.8% capacitance retention from 2 mA cm −2 to 50 mA cm −2 ), and excellent cycling stability (90% capacitance retention after 2000 cycles). The results suggest that our research opens up the possibility for the fabrication of high-performance energy-storage devices of binder-free electrodes.
研究领域:
材料科学
·
能源存储
·
电化学
✓ 已验证
DOI
高影响因子
MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 4
·1-10
·
IF 5.3
Liu Yan,Xin Yuying,Wang Xin,Zhang Xianfa,Xu Yingming,Cheng Xiaoli,Gao Shan,Huo Lihua
An electrochemical sensor for detecting ketoprofen was constructed by in-situ grown copper cobaltate (CuCo 2 O 4 ) nanoneedle arrays on a carbon cloth (CC) substrate. The resulting porous nanoneedle arrays not only expose numerous electrochemically active sites but also significantly enhance the electrochemical apparent active area and current transmission efficiency. By leveraging its electrochemical properties, the sensor achieves an impressive detection limit for ketoprofen of 0.7 pM, with a linear range spanning from 2 pM ~ 2 µM. Furthermore, the sensor exhibits remarkable reproducibility, anti-interference capabilities, and stability. Notably, the developed sensor also performed ketoprofen detection on real samples (including drug formulations and wastewater) and demonstrated excellent recognition ability. These exceptional performances can be attributed to the direct growth of CuCo 2 O 4 nanoneedle arrays on the CC substrate, which facilitates a robust electrical connection, provides abundant electrocatalytic active sites, and expands the apparent active area. Consequently, these improvements contribute to the efficient trace detection capabilities of the ketoprofen sensor. Graphical Abstract
研究领域:
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Hang Lu,Siyi Kang,Yuxin Liu,Jingwei Chen,Jiaqiang E
The recycling of metals from spent lithium-ion batteries is currently a hotspot of research. This paper introduces a novel recovery method that integrates supercritical water and leaching-precipitation techniques to efficiently extract metals from lithium cobaltate electrodes. This study investigates the dissolution behavior of lithium cobaltate in supercritical water, and the interaction between lithium cobaltate and organic impurity (Polyvinylidene Fluoride and N-methylpyrrolidone) during the supercritical water treatment process. Lithium cobaltate reacts with supercritical water to form cobaltous hydroxide and reacts with polyvinylidene fluoride to form cobalt oxide. During the reaction of supercritical water with polyvinylidene fluoride and N-methylpyrrolidone in supercritical water, lithium cobaltate is reduced to cobalt oxide. The addition of N-methylpyrrolidone promotes the reduction of cobalt ion and the decomposition of polyvinylidene fluoride. Subsequently, the cathode materials treated with supercritical water are leached by using hydrochloric acid and sulfuric acid respectively. Cobalt and lithium ions in the leaching solution are precipitated by adding sodium hydroxide and sodium carbonate. The maximum recovery efficiencies of lithium and cobalt are 73 % and 79.60 %, respectively.
研究领域:
环境科学
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Materials Interfaces
·
2017
·Vol. 4
·期 16
·1700219
·
IF 4.279
Kundrakudi Ponsubramanian Annamalai,Lile Liu,Yousheng Tao
The design and assembly of innovative heterostructures comprising of multifunctional properties are technically important for the applications in efficient energy devices. Here, a novel method is reported to construct hierarchical nanostructures as functional materials for the fabrication of high-performance energy devices. Optimized conditions and extensive spectroscopic studies are performed to understand the morphology evolution. Tunable structure, richer redox active sites, enhanced mass storage, and fast electron transfer cumulatively ensure the tremendous energy storage competence. Resultant active nanomaterials of nickel cobaltite-graphene coupled with nanoporous graphene-single wall carbon nanohorns composites exhibit extraordinary energy density of 70.5 Wh kg −1 . Meanwhile, this nickel cobaltite-graphene is also recognized as a prominent water oxidation catalyst, which requires low overpotential of 220 mV to afford 20 mA cm −2 current density. High performance with availability, low cost, and subtle structural distinction acknowledge that the present approach is a promising direction in pursuit of replacing precious metals in energy storage and conversion technologies.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2018
·Vol. 21
·期 3
·470-477
·
IF 3.304
Huihua Peng,Chuan Jing,Jie Chen,Deyi Jiang,Xiaoying Liu,Biqin Dong,Fan Dong,Shaochun Li,Yuxin Zhang
Rational design of the crystal structures of electrode materials is considered as an important strategy to construct high-performance supercapacitors. Herein, the three-dimensional crystal structure NiMn LDH@Co3O4 composites on Ni foam with different feeding Ni/Mn molar ratios were well-designed with hydrothermal, calcination and co-deposition methods, wherein urea hydrolysis supplied the alkali and carbonate ions. The electrochemical properties of the produced electrode materials were analyzed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectroscopy (EIS) and cycling stability tests using 6 M KOH electrolyte. Indeed, the optimal feeding Ni/Mn molar ratio was determined to be 3 : 1. The resulting electrodes exhibited maximum specific capacitance (607.9 F g−1 at 0.5 A g−1), respectable rate capability and excellent cycling stability with less than 3% loss of capacitance after 1000 cycles, which could be ascribed to the well-designed core–shell architecture and ultrathin nanosheets structure of LDH. As for practical application, the asymmetric supercapacitor assembled using NiMn LDH@Co3O4 as the positive electrode and activated graphene (AG) as the negative electrode was also evaluated, which demonstrated a high energy density of 26.49 W h kg−1 at the power density of 350 W kg−1. The findings suggest that the three-dimensional crystal structure NiMn LDH@Co3O4 composites have potential application as promising electrode materials for energy storage devices or other applications.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）