Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 9
·4699-4704
·
IF 10.733
Jing-Xuan Zhang,Lin-Nan Zhou,Jing Cheng,Xia Yin,Wen-Tao Kuang,Yong-Jun Li
MnO2/C composites are widely used as cathode active materials or electrocatalysts in electrochemical power sources. Compared with a physical mixture of MnO2 and carbon materials, the growth of MnO2 on the surface of carbon can greatly improve the electrochemical performance of MnO2/C, and is usually performed at a temperature higher than 100 °C. From the viewpoint of sustainable development, the room-temperature growth of MnO2 on carbon would greatly reduce the cost and thermal pollution. Herein, at room temperature, we successfully planted MnO2 nanosheets over carbon particles, achieving MnO2/C composites through a redox reaction between MnO4− ions and carbonized zeolitic imidazolate framework-67 (ZIF-67) crystals (CZIF-67). Room-temperature growth of MnO2 may be attributed to the catalytic effect of CoII ions of Co3O4 nanoparticles formed during ZIF-67 carbonization. The resulting MnO2/CZIF-67 composites exhibit excellent catalytic performance towards the oxygen reduction reaction: the onset potential, the half-wave potential, and the electron transfer number are ∼0.88 V, ∼0.79 V and 3.6, respectively, which are close to the corresponding values of the state-of-the-art Pt/C. Also, the resulting MnO2/CZIF-67 shows better long-term durability and methanol tolerance than Pt/C, indicative of its potential applications in fuel cells and metal–air batteries.
研究领域:
材料科学
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电化学
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可持续能源
✓ 已验证
产品关联
DOI
高影响因子
Small Science
·
2023
·Vol. 3
·期 4
·2200085
·
IF 12.7
Mingxiong Lin,Weishan Jiang,Tingshi Zhang,Bixia Yang,Zanyong Zhuang,Yan Yu
The design of advanced metal–organic framework (MOF) catalysts for solar-driven conversion of CO 2 into syngas (CO/H 2 mixture) is beneficial. Herein, the design of a joint MOF heterostructure consisting of orderly assembled Co II - and Co III -based Prussian blue analogs (PBAs) driven by their spontaneous lattice match in the growth process is reported. As-prepared H/Co III -PBA@Co II -PBA cage is a mesocrystal and exhibits superior photocatalytic syngas production activity ( V CO up to 50.56 mmol g −1 h −1 , CO/H 2 = 1:1), which is among the best state-of-the-art heterogeneous photocatalysts in the literature. Theoretical calculations and experimental results confirm that Co III -PBA exerts a stronger affinity for CO 2 molecules than Co II -PBA, thus serving as the active site. The built-in electric field in the Co III -PBA@Co II -PBA heterojunction can direct the fast transport of photogenerated electrons from Co II -PBA to the active Co III -PBA. In the present case, the engineering of electronics outweighs morphological engineering to enhance the catalytic properties of Co III -MOF@Co II -MOF for CO 2 -to-syngas conversion.
研究领域:
材料科学
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能源化学
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催化反应
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产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2018
·Vol. 47
·期 11
·3872-3879
·
IF 4.099
Yuanyuan Wen,Wei Meng,Chen Li,Lei Dai,Zhangxing He,Ling Wang,Ming Li,Jing Zhu
In this work, we demonstrate the synthesis and application of a novel CoII-based metal–organic framework {[Co2(Dcpp)(Bpe)0.5 (H2O)(μ2-H2O)]·(Bpe)0.5}n (CoII-MOF, H4Dcpp = 4,5-bis(4′-carboxylphenyl)-phthalic acid, Bpe = 1,2-bis(4-pyridyl)ethane) as an electrochemical sensor for glucose detection. Single-crystal X-ray diffraction analysis shows that the CoII-MOF has a two-dimensional (2D) bilayer structure composed of Co2 units and Dcpp4− ligands. There are two kinds of Bpe in the structure: one serves as a bidentate ligand linking two Co1 atoms in each 2D layer; the other is just free in the lattice. The CoII-MOF modified glassy carbon electrode (GCE) shows good electrocatalytic activity towards glucose oxidation. To further improve the catalytic activity of the electrode, a new composite of CoII-MOF/acetylene black (CoII-MOF/Acb) was constructed. The CoII-MOF/Acb modified electrode exhibits enhanced sensing behavior for glucose detection. The sensing performance of CoII-MOF/Acb/GCE with different Acb loadings was investigated in detail. The results demonstrate that CoII-MOF/GCE with 2% Acb (CoII-MOF/Acb-2%/GCE) exhibits the best sensing behavior, including a high sensitivity of 0.255 μA μM−1 cm−2 and a wide linear range of 5–1000 μM, as well as a low detection limit of 1.7 μM (S/N = 3). It's worth noting that the linear range of CoII-MOF/Acb-2%/GCE was extended by more than ten times when compared to that of CoII-MOF/GCE without Acb addition. In addition, CoII-MOF/Acb-2%/GCE shows good selectivity and stability in the sensing process.
研究领域:
生物化学
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分析化学
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材料科学
✓ 已验证
DOI
高影响因子
ChemSusChem
·
2022
·Vol. 15
·期 8
·e202200090
·
IF 9.14
Wenwen Bao,Senhe Huang,Diana Tranca,Boxu Feng,Feng Qiu,Fermín Rodríguez-Hernández,Changchun Ke,Sheng Han,Xiaodong Zhuang
Graphical Beauty in balanced asymmetry : An asymmetric Co II porphyrin ( as -PorCo) is constructed with a substituent of 2,6-dimethylbenzene to enhance the charge transfer capability from carbon nanotubes to as -PorCo, resulting in large partial current density of 8 mA cm −2 and high turnover frequency of 5656 h −1 at −0.7 V vs. reversible hydrogen electrode in aqueous solution. The present study provides the new insight into molecular design of catalysts for efficient electrochemical CO 2 reduction. The electrochemical reduction of carbon dioxide (CO 2 ) based on molecular catalysts has attracted more attention, owing to their well-defined active sites and rational structural design. Metal porphyrins (PorMs) have the extended π-conjugated backbone with different transition metals, endowing them with unique CO 2 reduction properties. However, few works focus on the investigation of symmetric architecture of PorMs as well as their aggregation behavior to CO 2 reduction. In this work, a series of Co II porphyrins (PorCos) with symmetric and asymmetric substituents were used as model of molecular catalysts for CO 2 reduction. Owing to the electron donating effect of 2,6-dimethylbenzene (DMB), bandgaps of the complexes became narrower with the increasing number of DMB. As electrocatalysts, all PorCos exhibited promising electrocatalytic CO 2 reduction performance. Among the three molecules, asymmetric Co II porphyrin ( as -PorCo) showed the lowest onset potential of −288 mV and faradaic efficiencies exceeding 93 % at −0.6 V vs. reversible hydrogen electrode, which is highly competitive among the reported state-of-art porphyrin-based electrocatalysts. The CO 2 reduction performance depended on π-π stacking between PorCo with carbon nanotubes (CNTs) and adjacent PorCos, which could be readily controlled by atomically positioned DMB in PorCo. Density functional theory calculations also suggested that the charge density between PorCo and CNT was highest due to the weak steric hindrance in as -PorCo, providing the new insight into molecular design of catalysts for efficient electrochemical CO 2 reduction.
研究领域:
催化化学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COORDINATION CHEMISTRY
·
2017
·
IF 1.795
Yong-Qiang Chen,Yuan Tian,Dao-Li An
A new coordination framework, [Co2(L)2(bpy)2(H2O)]n (1) (H2L = (4-phenyl)-2,6-bis(4-carboxyphenyl)pyridine and bpy = 2,2′-bipyridine), has been prepared and structurally characterized. Complex 1 shows an interesting bi-chain substructure bridged by coordinated water molecules, which is further extended into a three-dimensional (3-D) supramolecular structure by π–π stacking interactions. Moreover, the magnetic properties and photocatalytic activity for degradation of methyl orange have been investigated.
研究领域:
配位化学
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材料科学
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物理化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Zhuyu Sun,Dan Geng,Chaojie Zhang,Jiabin Chen,Xuefei Zhou,Yalei Zhang,Qi Zhou,Michael R. Hoffmann
Due to the extremely high stability of perfluorooctane sulfonate (PFOS), effective defluorination is difficult. Previous studies indicated that PFOS can be decomposed under the catalysis of vitamin B12 (VB12) with strong artificial reductants such as Ti(III)-citrate and nZn 0 . In this study, we explored if naturally occurring reductant like sulfide (S 2− ) could initiate the reaction. In S 2− /VB12 system, branched PFOS (br-PFOS) can undergo effective decomposition and defluorination at the temperature of 70 °C and pH greater than 12. The degradation of br-PFOS fits pseudo-first-order kinetic with a rate constant of 0.0984 ± 0.0034 d -1 in the presence of 30 mM Na 2 S and 300 μM VB12, while linear PFOS (L-PFOS) remained stable during 30 d reaction process. UV–Vis spectral characterization indicates that S 2− reduces VB12(Co III ) to Co II , which is able to initiate the reductive defluorination. Based on the product analysis, HF/2F elimination followed by C–C scission is the dominant degradation pathway of br-PFOS instead of stepwise H/F exchange. The primary products include F − and polyfluorinated sulfonates and carboxylates. The degradation of br-PFOS is strongly dependent on temperature due to a relatively high apparent activation energy of 62.86 kJ/mol. Strong alkaline condition can greatly enhance the decomposition efficiency since S 2− is the primary reactive form. This study provides new insights into the VB12-catalyzed defluorination of PFOS and a feasible approach for future natural or engineered remediations of br-PFOS.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 5
·2125
·
IF 4.6
Qing Li,Bo-Wei Xu,Yi-Ming Zou,Ru-Jie Niu,Jin-Xiang Chen,Wen-Hua Zhang,David James. Young
The delivery of biocompatible reagents into cancer cells can elicit an anticancer effect by taking advantage of the unique characteristics of the tumor microenvironment (TME). In this work, we report that nanoscale two-dimensional FeII- and CoII-based metal–organic frameworks (NMOFs) of porphyrin ligand meso-tetrakis (6-(hydroxymethyl) pyridin-3-yl) porphyrin (THPP) can catalyze the generation of hydroxyl radicals (•OH) and O2in the presence of H2O2that is overexpressed in the TME. Photodynamic therapy consumes the generated O2to produce a singlet oxygen (1O2). Both •OH and1O2are reactive oxygen species (ROS) that inhibit cancer cell proliferation. The FeII- and CoII-based NMOFs were non-toxic in the dark but cytotoxic when irradiated with 660 nm light. This preliminary work points to the potential of porphyrin-based ligands of transition metals as anticancer drugs by synergizing different therapeutic modalities.Keywords:metal–organic frameworks;Fenton reaction;photodynamic therapy;anticancer drugs;two-dimensional materials
研究领域:
肿瘤学
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材料科学
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生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 48
·18061-18068
·
IF 4.39
Jiahui Guo,Xueqing Feng,Songrui Wang,Qikang Wu,Shanshan Lv,Yan Zhou,Han Li,Zheng Chen,Yuzhong Zhang
Novel hexagonal α-cobalt hydroxide nanosheets are synthesized through a 2-methylimidazole-induced hydrolysis strategy with cetyltrimethylammonium bromide (CTAB) as a surfactant. The weak alkaline environment provides favorable conditions for the formation of metastable α-Co(OH)2, while the same raw material will produce β-Co(OH)2 when a strong alkali solution is used. CTAB plays a vital role not only in hexagonal oriented growth, but also in the formation of the hydrotalcite-like structure of α-Co(OH)2 with high crystallinity. The crystallinity of both α- and β-Co(OH)2 is very poor without CTAB as a surfactant. The Co in this Co(OH)2−x layer presents most of the CoII and a small part of the CoIII, and the interlayer nitrate anion balances the positive charge of the host layer. The redox function produced by the CoII and CoIII of α-Co(OH)2 together with the large layer spacing jointly promotes the electron and mass transfer. The use of hydrazine hydrate for transfer hydrogenation involves the transport of protons and electrons produced by decomposition, and the rapid transport is bound to be conducive to the reduction process. Nitro compounds with varieties of functional groups can be smoothly reduced to the corresponding amines with high selectivity, when α-Co(OH)2 was used as a catalyst under mild conditions.
研究领域:
材料科学
·
催化
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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