Scientific Reports
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2017
·Vol. 7
·期 1
·1-12
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IF 4.259
Song Jun,Wang Xueqin,Yan Jianhua,Yu Jianyong,Sun Gang,Ding Bin
Self-standing photocatalytic membranes constructed from TiO 2 nanofibers hold great promise in environmental remediation; however, challenges still remained for the poor mechanical properties of polycrystalline TiO 2 nanofibers. Herein, soft Zr-doped TiO 2 (TZ) nanofibrous membranes with robust mechanical properties and enhanced photocatalytic activity were fabricated via electrospinning technique. The Zr 4+ incorporation could effectively inhibit the grain growth and reduce the surface defects and breaking point of TiO 2 nanofiber. The as-prepared TZ membranes were composed of well-interconnected nanofibers with a high aspect ratios, small grain size and pore size, which exhibited good tensile strength (1.32 MPa) and showed no obvious damage after 200 cycles of bending to a radius of 2 mm. A plausible bending deformation mechanism of the soft TZ membranes was proposed from microscopic single nanofiber to macroscopical membranes. Moreover, the resultant TZ membranes displayed better photocatalytic performance for methylene blue degradation compared to a commercial catalyst (P25), including high degradation degree of 95.4% within 30 min, good reusability in 5 cycles, and easiness of recycling. The successful preparation of such fascinating materials may open up new avenues for the design and development of soft TiO 2 -based membranes for various application.
研究领域:
环境科学
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材料科学
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Molecular Catalysis
·
2023
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IF 4.6
Jianhong Zheng,Xi Chen,Xiaoxiao Yin,Kai Chen,Aili Liu,Xiaochun Yu,Shun Wang,Zhongwei Chen
A highly efficient and organic solvent-free synthetic strategy for the selective oxidation of anilines to azoxybenzenes was developed by employing porous Zr-MOFs as catalysts in aqueous hydrogen peroxide solution. The impact of cluster nodes, pore size, and linker functionalities on the catalytic performance of Zr-MOFs was fully evaluated and discussed. Featuring abundant bridging Zr-OH-Zr catalytic sites and confined microenvironments, the pristine UiO-66(Zr) could create abundant reactive oxygen species (ROS) with high H 2 O 2 efficiency, affording quantitative yield of azoxybenzene under mild conditions. Furthermore, the UiO-66(Zr)/H 2 O 2 heterogeneous catalytic system exhibited broad and size-selective substrate scope and excellent stability in consecutive catalytic cycles. Mechanism studies demonstrated that the azoxybenzenes were produced through radical pathway on bridging Zr-OH-Zr sites. This study provided alternative strategies exploiting green catalytic systems with porous MOFs, which might further expand the potential application of the MOFs family.
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INORGANIC CHEMISTRY COMMUNICATIONS
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2023
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IF 3.8
Fuhua Wei,Haiyan Liu,Qinhui Ren,Lu Yang,Lan Qin,Hongliang Chen,Yufu Ma,Zhao Liang,Siyuan Wang
Zr-MOF was prepared under solvothermal conditions using zirconium acetate as the metal ion and 2,5-dihydroxyterephthalic acid as the organic ligand. It was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetry (TG). Zr-MOF was used as an adsorbent to remove norfloxacin from aqueous solutions. The experimental results were fitted, and the results showed that the pseudo-second-order kinetics model was appropriate for studying the removal of norfloxacin. We investigated the adsorption capacity of Zr-MOF under different masses, concentrations, and pH values. At pH 10, the maximum adsorption capacity after 5 h was 134.5 mg/g.Compared with another adsorbent,the adsorption capacity of Zr-MOF was higher.The removal of norfloxacin from an aqueous solution using Zr-MOF was feasible, inexpensive, and effective. Our findings indicate that Zr-MOF has broad application prospects for the purification of an aqueous solution.
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CATALYSIS SURVEYS FROM ASIA
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2023
·Vol. 27
·期 3
·207-216
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IF 3
Li Shuying,Huang Bin,Jin Changzi,Wang Rui,Jiang Heng,Yang Guang-Sheng,Huang Shengjun
The conversion of ethanol and acetaldehyde to 1,3-butadiene has been an emerging process to produce key chemicals. The preparation of highly efficient catalysts and the understanding of reaction mechanism are current research priority. Herein, mesoporous silica framework confining zirconia (Zr-HMS) was prepared and act as catalyst for 1,3-butadiene production from ethanol and acetaldehyde. The prepared catalysts were characterized by Low-angle X-ray powder diffraction, transmission electron microscopy, N 2 physical adsorption-desorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectra. It has been shown that the Zr-HMS exhibits similar textural properties to supported catalyst (ZrO 2 /HMS). However, regardless of their comparable activities, higher 1,3-butadiene selectivity is obtained over Zr–HMS, which can be due to the different active zirconia species in two catalysts. Mesoporous framework confining character of Zr-HMS can achieve uniformly dispersed zirconia species. Further investigation toward the reaction process has presented new viewpoints for formation and consumption of some typical intermediates and byproducts, which will help to understand the reaction mechanism and construct efficient catalysts for conversion of ethanol and acetaldehyde to 1,3-butadiene.
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Frontiers in Chemistry
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2022
·
IF 5.545
Zhang Xiaojuan,Yu Rongfei,Wang Dandan,Li Weihua,Zhang Yutao
A series of bimetallic Zn-Zr metal-organic frameworks (Zn-Zr MOFs) with different Zn:Zr molar ratios has been synthesized via a green hydrothermal method. The structures and morphologies of these photocatalysts have been characterized and analyzed by FTIR, XRD, SEM, and nitrogen adsorption-desorption. The prepared Zn-Zr MOFs had large specific surface areas and pore volumes, favoring the adsorption of pollutant molecules, which in turn led to an improved photocatalytic effect. The photocatalytic activities of the Zn-Zr MOFs under visible light irradiation have been studied towards rhodamine B (RhB) as a target pollutant. The extent of degradation of RhB in a 40 mg/L aqueous solution reached 97.4%. The optimal photocatalyst could also degrade other dyes, suggesting a certain degree of universality.
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Materials Today Communications
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2022
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IF 3.662
Liyu Chen,Jiaxin Yang,Youjian Yang,Yifan Zhang,Zhaowen Wang
In this study, we investigated the thermodynamics and kinetics of the aluminothermic reduction of ZrO 2 . The results of thermal analysis and isothermal heat treatment showed that the aluminothermic reduction of ZrO 2 was an exothermic reaction that occurred at . 958.8°C. The aluminothermic reduction process does not produce metal Zr, but when the stoichiometric number of Al:ZrO 2 was 13:3, Al 3 Zr and Al 2 O 3 can be obtained by the reaction. The activation energy of the reaction was 1589.89 kJ/mol, and the reaction order was 1.90. The aluminothermic reduction process and mechanism of ZrO 2 in the presence of potassium cryolite as the molten salt medium was also studied. The results showed that ZrO 2 dissolved in potassium cryolite molten salt and participated in the reduction reaction in the form of Zr–O–F complex ions, while the by–product Al 2 O 3 also dissolved in potassium cryolite to further promote the formation of the Al–Zr alloy.
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INORGANIC CHEMISTRY COMMUNICATIONS
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2021
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IF 2.495
Xiaoya Ji,Jinhai Yang,Ning Zhao,Feng Wang,Fukui Xiao
Zn/Zr mixed oxide catalysts with different Zn-Zr molar ratios were prepared by coprecipitation method, and their catalytic performance for synthesis of ethylene carbonate (EC) from ethylene glycol and urea were investigated. The catalysts were also characterized by XRD, FT-IR, XPS, Raman, SEM, HRTEM and CO 2 -TPD. Compared with ZnO, Zn/Zr mixed oxide has suitable basicity and low lattice oxygen binding energy. The catalyst with Zn/Zr ratio of 5:1 showed the highest catalytic activity in the reaction with the EC yield of 91%. The results revealed that the yield of EC was closely related to the amount of the basic sites on the catalyst surface. Based on the characterization results, a possible mechanism was proposed.
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CERAMICS INTERNATIONAL
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2021
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IF 4.527
Liangjun Zhou,Wenxi Wang,Dekang Xu,Zhenyu Wang,Zhibin Yi,Min Wang,Zhouguang Lu
Thermal quenching of luminescence is the most critical problem for rare earth doped phosphors used in light-emitting diodes (LEDs). Herein, we demonstrate that thermal quenching can be considerably suppressed via the negative thermal expansion effect in Zr(WO 4 ) 2 that serves as host for Eu 3+ red emission. The photoluminescence (PL) intensity is surprisingly enhanced by 130% when the temperature is raised from room temperature to 100 °C. As temperature further increases to 160 °C, the PL intensity turns to reduce, which is still 1.4 times of that at room-temperature. Moreover, Zr(WO 4 ) 2 :15%Eu phosphor has good durability, which still exhibits strong red luminescence (only 13% loss) after being kept in 85 °C/85% relative humidity chamber for 240 h. The anti-thermal quenching of Eu 3+ luminescence can be ascribed mainly to the following two factors: first one is the thermal-enhanced energy transfer between Eu 3+ ions induced by the contraction of Zr(WO 4 ) 2 unit-cell volume that leads to the strong structural rigidity of host lattice; second one would be electron traps in the host that favors the increase of electrons on the excited energy levels. This important anti-thermal quenching effect induced from the negative thermal expansion of the host matrix may stimulates a novel and efficient approach to design highly thermal stable phosphors for next-generation LEDs.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Qipeng Yang,Ru Song,Yameng Wang,Xianlong Hu,Zhiyue Chen,Zhuo Li,Weiqiang Tan
A new electrode material consisting of MOFs (Zr-TAA, TAA: trans-aconitic acid) and MWCNTs was simply synthesized by one-pot reflux method and applied to high-performance supercapacitor. With advantages of improved conductivity and uniform pore-size distribution, the composite material shows enhanced electrochemical performance with a specific capacitance of 562.06 F g −1 and retains almost 100% of its initial capacitance after 1000 cycles when measured in 6 M KOH electrolyte. Furthermore, an asymmetric supercapacitor assembled by Zr-TAA/MWCNTs-6 as positive electrode and carbon cloth as negative electrode exhibits a superior energy density of 17.53 Wh kg −1 at a power density of 902.5 W kg −1 , which demonstrates its great practical value in electrochemical energy storage applications.
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JOURNAL OF MATERIALS SCIENCE
·
2022
·Vol. 57
·期 4
·2909-2923
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IF 4.682
Zeng Sen,Hou Yaqi,Zhou Yaming,Zhou Xi,Ye Shefang,Wang Miao,Ren Lei
Protein-bound uremic toxins (PBUTs) are difficult to remove through dialytic procedures, and the accumulation of PBUTs is always associated with adverse symptoms in end-stage kidney disease. Hemoperfusions and novel membranes have been developed for the removal of PBUTs, but still suffer from low efficiency. Herein, we investigated the adsorption performance of three zirconium metal–organic frameworks (Zr-MOFs: UiO-66, UiO-66-SO 3 H, and UiO-66-(COOH) 2 ) for two typical PBUTs (indoxyl sulfate, IS; hippuric acid, HA). We found that Zr-MOFs could adsorb PBUTs efficiently with a capacity of as high as 49.5 mg g −1 for IS and 38.3 mg g −1 for HA, respectively, due to the van der Waals interactions, Coulomb interactions, and π – π interactions. Density functional theory simulations demonstrated that H-bonding on basis of the –SO 3 H and –COOH groups could endow MOFs with better absorptivity. Further, to expand to practical hemodialysis applications, we incorporated Zr-MOFs into a polylactide (PLA) matrix to fabricate MOFs-based mixed matrix membranes (MMMs). The MMMs showed excellent in vitro biocompatibility and high water flux up to 260 L m −2 h −1 . Under static conditions, the MMMs could remove HA and IS with a percentage of 75 and 78% in 4 h, respectively, whereas PLA membrane removed 12% of HA and 13% of IS. Under dynamic conditions, MMMs could remove 57% of IS and 54% of HA in 30 min; by contrast, PLA membrane only removed 2.9% of IS and 2.2% of HA. These MOFs-based MMMs with exceptional absorptivity, high water flux, and good biocompatibility might show great prospects in the foreground for the application of safe and efficient blood purification.
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CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Shi-Qing Wang,Xu Gu,Xinzhu Wang,Xiao-Yu Zhang,Xiao-Yao Dao,Xiao-Mei Cheng,Jing Ma,Wei-Yin Sun
Defects in MOFs can benefit light absorption and charge transfer for photocatalytic application, nevertheless, studies on interplay between structural defects and photocatalytic properties of MOFs are in infancy. Herein, a series of UiO-66-NH 2 with different kinds of defects were created for regulating CO 2 photocatalytic reduction. Theoretical calculations in combination with experimental data verified that the sample with ligand-vacant (UiO-66-NH 2 -LV) defect performed better than non-defect, missing-cluster and monocarboxylate compensated ones in the photocatalytic CO 2 reduction reactions. UiO-66-NH 2 -LV shows superior photocatalytic activity with the highest CO yield of 30.5 μmol g −1 h −1 , which is 9.2 times higher than that of the sample with missing-cluster (UiO-66-NH 2 -MC), as well as the highest quantum yield (QY) of 0.90%. DFT calculations further demonstrate the correlation between discriminative photocatalytic activities in defect structures and tunable electronic properties characterized by absorption energy, E abs , and charge transfer energy, E LMCT , in the photocatalytic process. The ligand-vacant defect with the lowest sum of E abs and E LMCT will lower photocatalytic reaction energy barrier in the rate-limiting step among the elementary reaction step during CO 2 photoreduction. The insights gained from this study will guide the MOFs defect-engineering for enhancing CO 2 photocatalytic capacity.
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ADVANCED FUNCTIONAL MATERIALS
·
2021
·Vol. 31
·期 42
·2104629
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IF 18.808
Li Xin,Dezhu Zhang,Kai Qu,Yuqin Lu,Yixing Wang,Kang Huang,Zhaohui Wang,Wanqin Jin,Zhi Xu
Membrane with ordered channels is the key to controlling ion sieving and proton conductivity in flow batteries. However, it remains a great challenge for finely controlling the nanochannels of polymeric membranes. Herein, two types of acid-stable Zr-metal organic framework (MOF-801 and MOF-808) with variable pore structures and channel properties are introduced as fillers into a non-fluorinated sulfonated poly (ether ether ketone) (SPEEK). The membrane incorporated with MOF-801 of a smaller triangular window (≈3.5 Å) successfully translates the molecular sieving property into the flow battery membrane, resulting in enhanced coulombic efficiency (98.5–99.2%) at 40–120 mA cm −2 compared with the pristine SPEEK membrane (97.1–98.5%). In contrast, more protophilic internal interconnected channels of MOF-808 yield faster proton highway, leading to a significant increase of voltage efficiency (93.7–84.1%) at 40–120 mA cm −2 compared with the pristine SPEEK membrane (91.7–78.9%). By regulating the ion sieving and proton conductivity, MOF-801/MOF-808 binary composite membrane exhibits synchronously improved performance in the vanadium redox flow battery system. The revealed structure–property relationship in the Zr-MOFs-based membranes provides a general guideline to design new proton exchange membranes with ordered channels for flow battery application.
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