JOURNAL OF MOLECULAR STRUCTURE
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2021
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IF 3.196
Jingyan Zhu,Baolin Liu,Weibing Zhang,Jun Jiang,Xinhua Li
Single-molecule magnets in cobalt clusters is much less well known than it is in manganese(II)/(III)/(IV) clusters. To explore new types of cobalt clusters and their potential applications, a new mixed valence coordination polymer ([Co(III) 3 Co(II) 2 (mba) 6 (Hdtba) (H 2 O) 4 ] n , H 2 dtba=2,2’-dithiodibenzoic acid, H 2 mba=2-mercaptobenzoic acid) ( 1 ) is constructed by employing cobalt chloride hexahydrate and H 2 mba as starting reactants under hydrothermal conditions. Single-crystal XRD studies indicate that 1 consists of a trinuclear cobalt(III)-sulfur cluster moiety and two discrete cobalt(II) nodes, which result in the formation of a covalent three-dimensional complex network. Similarly, the cobalt(III) cluster moiety acts as a building unit in this infinite coordination polymer 1 instead of the discrete and tiara-like clusters previously reported in the literature. Magnetic studies show its slow magnetic relaxation in the absence of an applied dc field, which is characteristic behavior of single-ion magnets, caused by the individual Co(II) ions.
研究领域:
无机化学
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材料科学
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DOI
高影响因子
CATALYSIS TODAY
·
2019
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IF 4.888
Le Yang,Rui Ma,Hui Zeng,Zebao Rui,Yongdan Li
This work provides a facile strategy to prepare core-shell structured catalysts with MOF-templated metal active species embedded carbon matrix core and a functional metal oxide shell in a controllable way. The procedure features with the facile introduction of functional shell metal oxide and delivery of MOF morphology. Co(II/Ⅲ)@ZnO hexagonal prisms are fabricated with this procedure and ZIF-67 as the template. When being used in the selective oxidation of vanillyl alcohol to produce vanillin, ZnO shell plays an important role by faciliating redox of Co 3+ /Co 2+ for promoting vanillyl alcohol oxidation to vanillin and protecting the Co species against leaching into the reaction system. Co(II/Ⅲ)@ZnO exhibits a conversion of 20% with a selectivity of 80% after a 2 h reaction and shows stability after 3 catalytic cycles.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2019
·Vol. 57
·期 7
·767-775
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IF 2.591
Xianhui Zhang,Guangqian Zhu,Qaiser Mahmood,Mengmeng Zhao,Liang Wang,Chuyang Jing,Xiaowu Wang,Qinggang Wang
A stereoselectivity switchable polymerization of isoprene has been developed, which is catalyzed by iminoimidazole-Co(II) and -Fe(II) complexes. The influence of substituents ranging from electron donating to the electron withdrawing on the iminoimidazole-Co(II) and -Fe(II) catalysts is investigated for isoprene polymerization. Two sets of iminoimidazole-Co(II) and -Fe(II) complexes have been prepared and fully characterized. X-ray crystallography analysis reveals that the complexes Co1 and Fe1 adopt distorted tetrahedral geometries. In the presence of AlEt 2 Cl as co-catalyst, all the Co(II) complexes are active and the catalytic activity is highly dependent on the molar ratio of Al/Co. All the Co(II) complexes exhibit higher activities at low Al/Co ratio. Compared with the Co(II) complexes, the Fe(II) complexes are essentially inactive under the identical condition. However, on activation with combination of AlEtCl 2 and [Ph 3 C][B(C 6 F 5 ) 4 ], both Co(II) and Fe(II) complexes display high activities with good conversions of isoprene (up to >99%). Additionally, low molecular weight and high trans -1,4-unit (>96%) selectivity are characteristics of the resultant polyisoprene. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57 , 767–775
研究领域:
化学
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材料科学
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DOI
高影响因子
Polymers
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2016
·Vol. 8
·期 11
·389
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IF 2.944
Lihua Guo,Xinyu Jing,Shuoyan Xiong,Wenjing Liu,Yanlan Liu,Zhe Liu,Changle Chen
A series of alkyl- and aryl-substituted iminopyridine Fe(II) complexes1a–7aand Co(II) complexes2b,3b,5b, and6bwere synthesized. The activator effect, influence of temperature, and, particularly, the alkyl and aryl substituents’ effect on catalytic activity, polymer molecular weight, and regio-/stereoselectivity were investigated when these complexes were applied in isoprene polymerization. All of the Fe(II) complexes afforded polyisoprene with high molecular weight and moderatecis-1,4 selectivity. In contrast, the Co(II) complexes produced polymers with low molecular weight and relatively highcis-1,4 selectivity. In the iminopyridine Fe(II) system, the alkyl and aryl substituents’ effect exhibits significant variation on the isoprene polymerization. In the iminopyridine Co(II) system, there is little influence observed on isoprene polymerization by alkyl and aryl substituents.Keywords:iminopyridine;Iron(II);Cobalt(II);isoprene polymerization;selectivity
研究领域:
化学
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高分子科学
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DOI
PubMed
高影响因子
Photonic Sensors
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2021
·Vol. 12
·期 2
·152-163
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IF 2.433
Xu Ouwen,Liu Wei,Li Jiawei,Wan Shuyu,Zhu Xiashi
A novel nitrogen-doped carbon quantum dots (N-CDs) were prepared by the microwave irradiation method. The fluorescence quenching effect of Co(II) on the N-CDs was studied in the sodium dodecyl sulfate (SDS) medium and the fluorescence quenching was sensitized in the SDS. The linear range of calibration curve for the determination of Co(II) was 0.17µg/mL-11.8µg/mL and the limit of detection was 0.052µg/mL. The method has been applied for the determination of Co(II) in samples with satisfactory results.
研究领域:
分析化学
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材料科学
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环境科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Dongsheng Lu,Tiesen Liu,Jinyu Han,Jiankang Zhao,Hua Wang
Electroreduction of nitrate to ammonia, a potential route for producing ammonia, is still confronted with a great challenge on developing efficient electrocatalysts. In this work, a reduced yolk-shell Co-based oxides (R-Co 3 O 4 ) electrocatalyst with oxygen vacancy-rich Co 3 O 4 and CoO was designed for nitrate reduction . This catalyst presented a nearly 100 % Faradaic efficiency (FE) of ammonia in a low potential from −0.05 to −0.1 V vs. RHE, and a maximum ammonia production rate of 7.25 mg h −1 mg cat. -1 at −0.05 V vs. RHE in 0.1 M KOH + 1000 ppm KNO 3 electrolyte. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) pattern proved that the content of Co 2+ was dramatically increased in R-Co 3 O 4 . The kinetic correlation experiments and Operando Raman spectra preliminarily manifest that the potential limiting step is the reduction of adsorbed *NO 3 . The density functional theory (DFT) calculations consistently demonstrated that on both oxygen-rich Co 3 O 4 and CoO, the adsorption of key intermediates (*NO 3 , *NO and *NH) are greatly enhanced on the bridge site between two Co 2+ , boosting the nitrate reduction at low over-potential. This work is helpful to design the catalytic material with rich and low-valence sites towards electroreduction of nitrate to ammonia.
研究领域:
电化学
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2020
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IF 10.652
Peng Chen,Yejing Gou,Jiaming Ni,Yumeng Liang,Bingqiao Yang,Feifei Jia,Shaoxian Song
Base on the strong activation activity and affinity of transition metal ions and MoS 2 for peroxymonosulfate (PMS), respectively, Co(Ⅱ)-doped MoS 2 nano-flowers (Co-MoS 2 NFs) with a great photo-response property was facilely synthesized to achieve a more efficient PMS activation for ofloxacian (OFX) degradation. It was found that Co-MoS 2 NFs exhibits superior catalytic activity for OFX degradation under visible-light irradiation, which was attributed to the synergetic effect of doped Co(Ⅱ) and photo-generated carriers to PMS activation. Besides, Co-MoS 2 NFs was able to efficiently degrade OFX within 4 cycles in the presence of PMS while leaked minute amount of Mo and Co ions, implying the excellent cycle stability of Co-MoS 2 NFs. Furthermore, SO 4 •− and 1 O 2 were detected as the primary reactive radicals for OFX degradation in the Co-MoS 2 NFs-PMS system through EPR and quenching tests. This new strategy of coupling doped Co(Ⅱ) and photo-generated carriers for more efficient PMS activation, which will greatly benefit the development of SO 4 •− -based AOPs as well as cater to the demand for environmental remediation in the future.
研究领域:
环境科学
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材料科学
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化学工程
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DOI
高影响因子
Chemical Engineering Journal Advances
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2021
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IF 0
Xinhong Li,Zihao Zhao,Hongchao Li,Jieshu Qian
Cobalt ferrite (CoFe 2 O 4 ) has been widely employed as a catalyst for the activation of peroxymonosulfate (PMS), in which hydroxyl radicals ( • OH) and sulfate radicals (SO 4 •− ) are generally recognized as the main reactive species responsible for the degradation of pollutants. In this study, we find that both one-electron transfer and oxygen-atom transfer reactions are involved in the CoFe 2 O 4 /PMS process, by using methyl phenyl sulfoxide (MPSO) as a chemical probe. Results from radical quenching and electron paramagnetic resonance (EPR) experiments indicate that the free radicals (i.e., • OH and SO 4 •− ) play only a minor role in the degradation of sulfamethoxazole (SMX). A mechanism involving Co(II)-PMS complex both on the surface of CoFe 2 O 4 and in solution as the dominant reactive species is proposed. Furthermore, the degradation performance of SMX under different conditions were investigated to further cognize the Co(II)-PMS complex-mediated oxidation process. This study broadens our understanding of the role of transition metal-based catalysts in the activation of PMS for the degradation of organic pollutants.
研究领域:
环境科学
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化学
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DOI
PNAS Nexus
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2024
·Vol. 3
·期 2
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IF 2.2
Wu Jing-Hang,Yang Tian-Hao,Chen Fei,Yu Han-Qing
Aromatic amines (AAs), ubiquitous in industrial applications, pose significant environmental hazards due to their resistance to conventional wastewater treatments. Peracetic acid (PAA)-based advanced oxidation processes (AOPs) have been proposed as effective strategies for addressing persistent AA contaminants. While the organic radicals generated in these systems are believed to be selective and highly oxidative, acetate residue complicates the evaluation of AA removal efficiency. In this work, we explored transformation pathways of AAs in a representative Co(II)-catalyzed PAA system, revealing five side reactions (i.e. nitrosation, nitration, coupling, dimerization, and acetylation) that yield 17 predominantly stable and toxic by-products. The dominant reactive species was demonstrated as Co–OOC(O)CH3, which hardly facilitated ring-opening reactions. Our findings highlight the potential risks associated with PAA-based AOPs for AA degradation and provide insights into selecting suitable catalytic systems aimed at efficient and by-product-free degradation of pollutants containing aromatic –NH2.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
Journal of Water Process Engineering
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2025
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IF 6.7
Ganbin Luo,Bin Hu,Yuzhe Yang,Mingjie Ma,Huiling Cheng
Recovery of cobalt from wastewater is a key method for achieving resource sustainability. A novel temperature-sensitive Co(II)-ion-imprinted composite membrane based on polyvinylidene fluoride was synthesised using N-isopropylacrylamide as the temperature-sensitive monomer and diisooctylphosphinic acid as the ligand. The preparation conditions for the imprinted composite membrane were systematically optimised, resulting in an optimal polymer with an adsorption capacity of 938.61 mg·g −1 that achieved adsorption equilibrium in approximately 30 min, outperforming most reported cobalt ion adsorbents. The surface morphologies of the Co(II)-IICM 6 membranes prepared under the optimal conditions were analysed. The results showed that the ionic ligands enabled the polymer particles to grow successfully and uniformly on the membrane surface. The imprinted composite membrane's pore size increased as a result of this expansion, with the specific area increasing from 13.01 m 2 ·g −1 to 16.84 m 2 ·g −1 . The imprinted composite membrane maintained a high adsorption capacity over ten cycles and exhibited excellent selectivity for Co(II) ions in aqueous samples containing Co(II), Ni(II), Cr(III), Cd(II), Cu(II), and Pb(II). These results indicate that the prepared temperature-sensitive imprinted composite membrane is promising for the separation of Co(II) from real water samples.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
Scientific Reports
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2024
·Vol. 14
·期 1
·1-11
·
IF 3.8
Yin Cong,Peng Yinyin,Li Hongjiang,Yang Guang,Yuan Guoyuan
This study aimed to synthesize a novel nanofiber adsorbent based on metal–organic frameworks (MOFs), ZIF-94-PAN, by incorporating ZIF-94 into polyacrylonitrile (PAN) through electrospinning. The investigation of the adsorption characteristics of ZIF-94-PAN for cobalt ions was undertaken, yielding findings that suggest an optimum ZIF-94 loading content within the ZIF-94-PAN composite of 8%. The adsorption experiments revealed that, under pH 8.3 and 298 K, ZIF-94-PAN-8% attained cobalt ion equilibrium adsorption (139.08 mg/g). Additionally, the adsorption kinetics of cobalt ions exhibited conformity with the pseudo-second-order model, whereas adherence to the Freundlich isotherm model indicated a non-homogeneous, endothermic process. XPS analysis unveiled that the adsorption mechanism was characterized by the coordination of nitrogen and oxygen atoms within ZIF-94-PAN with cobalt ions. This study effectively addressed the challenges of separating and recovering MOFs adsorbents by fabricating them as nanofibers. The remarkable adsorption performance and stability of the ZIF-94-PAN nanofibers highlight their potential for removing cobalt-contaminated wastewater.
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
RSC Advances
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2018
·Vol. 8
·期 24
·13370-13387
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IF 2.936
Wenqiang Luo,Zhishan Bai,Yong Zhu
Porous carboxymethyl chitosan (PCMC) beads were synthesized via ionic coacervation/chemical crosslinking, using polyethylene glycol (PEG) as a porogen and calcium chloride and glutaraldehyde as physical and chemical cross-linkers. The as-synthesized PCMC beads were characterized using SEM, EDS, BET, TGA, FTIR and XPS analysis and then tested for the removal of Co(II) from aqueous solution. The effects of the initial pH, Co(II) concentration and temperature were investigated. It was found that the adsorption equilibrium is reached within 6 h and the maximum adsorption capacity is 46.25 mg g−1. In addition, the kinetics and equilibrium data are well described by pseudo-second-order kinetics and the Langmuir isotherm model. Moreover, the desorption and re-adsorption performance was also studied, and the results revealed that the prepared new adsorbent still showed good adsorption performance after five cycles of regeneration. Finally, the adsorption mechanism, including chemical and physical adsorption, was proposed on the basis of the microstructure analysis, adsorption kinetics and isotherm results, and chemical adsorption was found to be the main adsorption mechanism during the process of the removal of Co(II).
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
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