CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Jie Min,Wei Song,Tianding Hu,Yunfei Zhi,Zhenhao Xia,Tiecheng Zhang,Shaoyun Shan,Hongying Su
Magnetic nanoparticle-supported heterogeneous catalysts have been widely researched in green catalysis, due to their convenient magnetic separation and nanometer effects. Herein, a magnetic Co(III)-Salen heterogeneous catalyst with uniform spherical core-shell structure was synthesized for the chemical fixation of CO 2 into cyclic carbonate based on the sustainable protocol development and green chemistry principles. Fe 3 O 4 @SiO 2 nanoparticles with uniform spherical core-shell structure were prepared by the reverse microemulsion method, and Co(III)-Salen complexes were subsequently immobilized on the resulted Fe 3 O 4 @SiO 2 nanoparticles via covalent bonding, leading to Fe 3 O 4 @SiO 2 @Co(III)-Salen nanocomposites with particle size of 29 nm and saturation magnetization value of 27.2 emu/g. The catalytic performance study indicated that the catalyst exhibited high yield of 99% with selectivity of 100% for the ring-opening addition reaction of CO 2 and epoxide under solvent-free reaction condition. A plausible reaction mechanism was proposed that the Lewis acidic sites of Co(III)-Salen and nucleophilic bromine ion components played synergetic roles in promoting cycloaddition reactions. A stable geometry of the Co(III)-Salen complex and a detailed evidence for the reaction mechanism were provided by the density functional theory (DFT) calculations. Based on their excellent magnetic properties , the Co(III)-Salen nanocomposites could be easily recovered by using an external magnet and reused for 5 times without significant leaching of metal center and loss of catalytic activity.
研究领域:
材料科学
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绿色化学
·
催化反应
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DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 35
·25247-25255
·
IF 3.9
Ruina Xuan,Jieqiong Mo,Jiwen Chen,Yixin Dou,Xiaofang Li,Zhuo jiang,Bo Chai,Chunlei Wang,Deng Ding,Juntao Yan,Xiaobo Wang
Photocatalytic CO2 reduction into value-added chemical fuels using sunlight as the energy input has been a thorny, challenging and long-term project in the environment/energy fields because of to its low efficiency. Herein, a series of CdS/Co-BDC composite photocatalysts were constructed by incorporating CdS nanoparticles into Co-BDC using a dual-solvent in situ growth strategy for improving photocatalytic CO2 reduction efficiency. The composites were characterized through XRD, SEM, TEM, XPS, DRS and EPR techniques in detail. 18% CdS/Co-BDC composites showed superior performance for the photocatalytic CO2 reduction to CO, which was 8.9 and 19.6 times higher than that showed by the pure CdS and Co-BDC, respectively. The mechanism of enhanced photocatalytic CO2 reduction performance was analyzed. The CdS/Co-BDC composites showed better adsorption for CO2. Detailed analysis of XPS, transient photocurrent responses, and electrochemical impedance spectroscopy (EIS) shows the existence of strong charge interaction between CdS and Co-BDC and the photo-electrons of CdS can be transferred to Co-BDC. Additionally, Co-oxo of Co-BDC plays the role of a redox-active site and promotes the reduction performance via the method of valence transition of Co(II)/Co(III) redox.
研究领域:
环境科学
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能源科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
WATER SCIENCE AND TECHNOLOGY
·
2021
·Vol. 83
·期 4
·841-853
·
IF 1.915
Li Dongmei,Li Wenjie,Zhang Quan,Wang Yizhi,Lin Hongyu,Feng Li,Li Shaoxiu,Deng Yue,Xiao Qiurong,Chen Jiongxi,Dong Qi
The promising synergistic electrocatalytic system of phosphate (PO 4 3− ) with the mediator cobalt(II) (for short E-Co(II)-PO 4 3− ) was employed to degrade cationic dye methylene blue (MB). The exploration in the electrocatalytic process revealed that the main intermediate active oxidation products were Co(III), accompanied with hydroxyl radicals and peroxodiphosphates (P 2 O 8 4− ). Their synergistic electrocatalytic degradation rate to MB and total organic carbon (TOC) was up to 100 and 60% in 40 min, respectively, which was 5 times and 2.6 times that in a direct electrocatalytic system, correspondingly. The degradation process of the E-Co(II)-PO 4 3− system on MB started with the bond being broken at the N-C junction of the MB molecule and intermediate active oxidation substances being generated, such as phenothiazine, 2-amino-5-(N-methylformamide) benzene sulfonic acid and N 1 ,N 1 -dimethyl-1,4 diaminobenzene. Then, the intermediates were degraded into aniline, phenol and benzene sulfonic acid, and eventually decomposed into inorganic substances like CO 2 and water. The electrocatalytic degradation mechanism of E-Co(II)-PO 4 3− system on MB was the combination of indirect oxidation of the intermediate oxidants like Co(III), P 2 O 8 4− and the hydroxyl radical with direct electrocatalysis on the platinum titanium electrode, where the electrocatalytic oxidation of Co(III) was dominant. Active Co(III) and peroxodiphosphate generated in a novel electrocatalytic system have synergistic electrocatalytic effect. MB removal rate reached 100% in 40 min in the novel electrocatalytic system with phosphate and the mediator cobalt(II). Co(III) is the dominant active oxidation substance in MB oxidation and mineralization.
研究领域:
环境化学
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电催化
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环境污染与控制
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高级氧化技术
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环境功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF COORDINATION CHEMISTRY
·
2025
·
IF 2.1
Hou Cong Li,Ming Zhu Wang,Ye Fan Zheng,Ning An,Min Hou,Jing Hu,Wen Ge Li
Three chlorinated metal complexes [Ni2(HL)2(C2H5OH)2Cl2]·2C2H5OH (complex 1), [Co(HL)(L)] (complex 2), and [Zn2(HL)2(CH3COO)2] (complex 3) derived from 5-chlorosalicylaldehyde and 2-(2-aminophenyl)-1H-benzimidazole Schiff base ligand (H2L). The crystal structures of the three complexes were characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, X-ray single-crystal diffraction, and UV-visible absorption spectrum. The in vitro cytotoxicity of chlorinated ligand and its metal complexes were evaluated on four different tumor cell lines (A-549 lung cancer, SMMC-7721 liver cancer, MDA-MB-231 breast cancer, and CNE-2Z nasopharyngeal carcinoma), and normal ovarian epithelial cell (IOSE 80) was determined by MTT assay. The results indicated that chloro-benzimidazole Schiff base Co (III) complex (complex 2) displayed higher cytotoxicity against MDA-MB-231 cell line than cisplatin, while the cytotoxicity on IOSE 80 was lower than that of cisplatin. The results of further study of MDA-MB-231 cells by complex 2 showed that complex 2 could inhibit MDA-MB-231 cells in the G0/G1 phase, inhibit cell proliferation and migration, promote cell apoptosis, and increase intracellular ROS level. The Western blot analysis demonstrated that complex 2 could increase Bax protein expression and decrease Bcl-2 protein expression in MDA-MB-231 cells.
研究领域:
无机化学
·
药理学
·
肿瘤学
✓ 已验证
产品关联
DOI
高影响因子
POLYHEDRON
·
2017
·
IF 1.926
Xiu-Mei Zhang,Jie Tang,Li-Na Wang,Di Yao,Qing Yu,Fu-Ping Huang,He-Dong Bian
Mimetics of superoxide dismutases (SOD), with certain ability to eliminate superoxide radicals under aerobic conditions, would be promising as drug candidates for antioxidant therapy. Many efforts have been devoted to synthesize small molecular compounds to mimic the functionality of natural SOD. In this paper, the Mn(III)/Co(III)/Fe(III) complexes have been synthesized with the Schiff base ligand (NaH 2 L), which was condensed from 2-hydroxynaphthalen-1-naphthaldehyde and 3,4-diaminobenzenesulfonic acid. The structures of complexes 1 and 3 have been determined by X-ray crystallographic method, and all the complexes have been investigated using FT-IR, MS. The binding constants between metal complexes and bovine serum albumin (BSA) have been determined by fluorescence spectroscopy. Meanwhile, we have synthesized 3 hybrid proteins through the interaction of the complexes and BSA. The SOD-like activity was tested by xanthine/xanthine oxidase method. The result shows that BSA molecule can increase the SOD activity of the transition metal complexes.
研究领域:
无机化学
·
生物化学
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药学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Wenyang Fu,Xuedong Du,Pei Su,Qizhan Zhang,Minghua Zhou
As nitrate contamination causes serious environmental problems, it is necessary to develop stable and efficient electrocatalysts for efficient electrochemical nitrate reduction reaction (ENRR). Here, a nonprecious Co3O4/carbon felt (CF) electrode with a 3D structure was prepared by integrating electrodeposition with calcination methods. This 3D structured Co3O4/CF electrode exhibits a high-rate constant of 1.18 × 10–4 s–1 cm–2 for the ENRR, surpassing other Co3O4 electrodes in previous literature. Moreover, it also has an excellent stability with a decrease of 6.4% after 10 cycles. Density functional theory calculations, electron spin resonance analysis, and cyclic voltammetry were performed to study the mechanism of the ENRR on the Co3O4/CF electrode, proving that atomic H* (indirect pathway) plays a prominent role in NO3– reduction and clarifying the synergistic effect of Co(III) and Co(II) in the Co(II)–Co(III)–Co(II) redox cycle for the ENRR: Co(III) prefers the adsorption of NO3– and Co(II) favors the production of H*. Based on this synergy, a relatively large amounts of Co(II) on the surface of the Co3O4/CF electrode (1.3 Co(II)/Co(III) ratio) was maintained by controlling the temperature of calcination to 200 °C with a lower energy barrier of H* formation of 0.46 eV than other ratios, which is beneficial for forming H* and enhancing the performance of the ENRR. Thus, this study suggests that building 3D structure and optimizing Co(II)/Co(III) ratio are important for designing efficient Co3O4 electrocatalyst for ENRR.
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
CHEMOSPHERE
·
2019
·
IF 5.108
Yongzhi Liu,Bin Si,Chun Zhao,Fan Jin,Huaili Zheng,Zhaoyang Wang
Cobalt ion is an environmental contaminant in general. But interestingly, it can also be used to degrade some refractory organic contaminants in water by mediated electrochemical oxidation process (MEOP) based on Co (III). MEOP is a very promising technology , and it can recycling use the mediator ions, Co (III), to degrade refractory organic contaminants in water. However, previous studies for this technology mainly conducted in strong acidic medium, the oxidation ability of this process for emerging contaminants near neutral pH condition was still unclear. Therefore, this study evaluated the emerging contaminants removal and mineralization efficiency of the MEOP-Co (III) around neutral pH, and investigated systematically the influence of series of operating parameters, including initial Co (II) concentration, current density, initial pH, electrolyte, and anions. Results from these studies indicated that the MEOP-Co (III) had a fairly good contaminants removal and mineralization ability for sulfamethoxazole, tetracycline , carbamazepine, diclofenac, and phenol at neutral pH. Besides, no radical was detected in MEOP-Co (III), and the main oxidizing substance was Co (III) ions, which was generated on anode surface. The addition of C O 3 2 − / H C O 3 − could weaken the oxidation ability of MEOP-Co (III), while C l − and P O 4 3 − could enhance the system's oxidation ability. Moreover, a reasonable energy consumption was achieved in MEOP-Co (III), and the highest electric energy per order (EE/O) value was 2.4 kWh·m −3 in this study.
研究领域:
环境科学
·
水处理
·
电化学
·
污染物降解
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2015
·
IF 5.528
Zhaobing Li,Zhi Chen,Yingying Xiang,Li Ling,Jingyun Fang,Chii Shang,Dionysios D. Dionysiou
Bromate formation in bromide-containing water through the cobalt (Co)-mediated activation of peroxymonosulfate (PMS) was investigated. Increasing the PMS dosage and the cobalt dosage increased the formation of bromate and bromate yields of up to 100% were recorded under the test conditions. The bromate yield increased to a maximum as the pH rose from 2.7 to 6 before decreasing by over 90% as the pH rose further from 6 to above 9. The bromate formation is a two-step process involving free bromine as a key intermediate and bromate as the final product. In the first step, apart from the known oxidation of bromide to free bromine and of free bromine to bromate by sulfate radicals (SO 4 − ), Co(III) produced from the oxidation of Co(II) by PMS and SO 4 − also oxidizes bromide to free bromine. The contribution of Co(III) to the bromate formation was verified with the addition of methanol and EDTA, a radical scavenger and a Co(III) ligand, respectively. In the presence of methanol, free bromine formation increased with increasing Co(II) dosage but no bromate was detected, indicating that Co(III) oxidized bromide to form free bromine but not bromate. In the presence of both EDTA and methanol, no free bromine or bromate was detected, as Co(III) was stabilized by EDTA to form the Co III EDTA – complex, which could not oxidize bromide. Mathematical simulation further suggested that Co(III) outweighed SO 4 − to oxidize bromide to free bromine. On the other hand, SO 4 − is essential for the oxidation of free bromine to bromate in the second step. In real water, the presence of NOM significantly decreased the bromate formation but caused the brominated organic DBP formation with high quantity. This is the first study to demonstrate the significant bromate formation in the Co/PMS system and the substantial contribution of Co(III) to the formation.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF THE CHINESE CHEMICAL SOCIETY
·
2020
·Vol. 67
·期 10
·1818-1826
·
IF 1.554
Yang Hu,Longchao Du,Cun Li,Jiale Shen,Weiju Zhu,Chenxi Shao
Carbon dioxide (CO 2 ) is an easily available renewable carbon source that can be used as a comonomer in the catalytic ring-opening polymerization of epoxides to form aliphatic polycarbonates. Herein, a series of new Salen-Co(III) bifunctional catalysts were synthesized for the first time, and they were studied to catalyze the copolymerization of CO 2 and propylene oxide (PO)/cyclohexene oxide (CHO). At the same time, the effects of reaction conditions (electronic effect, temperature, time) on catalytic activity and selectivity were investigated. The results show that the Salen-Co(III) complexes with electron-withdrawing groups have higher selectivity and activity for propylene carbonate (PPC)/cyclohexylene carbonate (PCHC). At the same time, the Salen-Co(III) complexes can better catalyze the copolymerization of CHO and CO 2 than that of PO and CO 2 . The catalytic efficiency of the four complexes increased with increasing temperature, and the best reaction condition is 80°C, 30 min and 2 MPa of CO 2 .
研究领域:
化学催化
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2025
·
IF 3.6
Chaogang Fan,Qingyun Ge,Shujuan Lu,Xianshe Feng,Yingfeng Tu,Li Jia,Shaohui Lin,Qinmin Pan,Flora T. T. Ng
A Salen-Co(III)-Cl catalyzed copolymerization strategy is developed for the controlled synthesis of polycarbonate- b -polyester block copolymers through a one-pot process involving CO 2 , 4-vinyl-1-cyclohexene-1,2-epoxy (VCHO), and ε-caprolactone (ε-CL). This procedure is extended to the copolymerization of CO 2 , VCHO, and lactide. The catalytic system is designed and optimized with temperature and CO 2 acting as triggers to switch between CO 2 /epoxide copolymerization and ε-CL homopolymerization. In addition, introducing water as the chain transfer agent reduced the polydispersity index (PDI) of the block copolymers. The copolymer composition can be controlled by adjusting the concentration ratio of epoxides and ε-CL, yielding copolymers with carbonate molar ratios ranging from 14% to 67%. The block copolymers exhibit enhanced thermal stability, and the glass transition temperature ( T g ) can be controlled by adjusting the block composition. Graphical Polycarbonate- b -polyester was prepared via the Salen-Cobalt complex catalyzed copolymerization of CO 2 , epoxide, and ε-caprolactone in one pot. Copolymerization of CO 2 and epoxide and homopolymerization of ε-caprolactone were switched by the control of CO 2 and temperature. By introducing H 2 O as a chain transfer agent, polyester- b -polycarbonate- b -polyester with lower PDI could be obtained.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yiming Shen,Zhaoyi Yan,Kai Wang
The oxidation of toluene and its derivatives is crucial for the chemical industry. Traditional liquid-phase oxidation technologies require high-temperature and high-pressure conditions, which causes high safety risks and urgently requires alternatives. This article reports an electrochemical oxidation method using cobalt acetate as a mediator, which successfully realizes the mild oxidation of toluene. The method turns toluene into highly active radicals by the electrochemically generated Co(III) from cobalt acetate, which significantly reduces the anodic potential in contrast to the direct electro-oxidation and the other reported mediated oxidation processes. The target products, benzaldehyde and benzoic acid, exhibit high yields at 85 °C as the ratio of AcO - to Co(II) is close to 2 in the homogeneous anhydrous electrolyte. A benzyl radical-centered mechanism for the Co(II) mediated electro-oxidation of toluene is proposed based on the cyclic voltammetry tests and a radical inhibiting experiment. The method has also been successfully applied to the derivatives of toluene.
研究领域:
化学工程
·
电化学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2026
·
IF 5.9
Hao Ai,Qiushuo Li,Lei Xu,Huaqiao Lu,Yaofa Gao,Qiong Wu
Peripheral poly-bromination can significantly enhance the thermal stability of discrete coordination compounds. Here, we compare a pair of strictly isostructural Co(III)-Schiff base complexes that differ only by the presence of 3,5-dibromo substituents on the ligands. Thermogravimetric analysis shows that the onset decomposition temperature increases from approximately 100 °C in the unhalogenated complex to approximately 220 °C in the brominated analogue, accompanied by a shift from multistep to a sharper, more cooperative decomposition profile. Variable-temperature X-ray diffraction indicates improved structural persistence in the brominated crystal. Hirshfeld surface analysis, together with NCI, IGMH, QTAIM, and dispersion calculations, reveals that bromination strengthens the non-covalent interaction network, particularly through increased Br···H contacts and enhanced dispersion forces. Frontier orbital analysis shows a modest lowering of the LUMO energy level. These supramolecular and electronic changes collectively correlate with the observed improvement in thermal stability. This work demonstrates that peripheral poly-bromination offers a practical strategy to enhance the thermal robustness of discrete Co(III)-Schiff base complexes while preserving the core coordination structure.
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DOI
高影响因子
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