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Defective NH_(2)-UiO-66(Zr) effectively converting CO_(2) into cyclic carbonate under ambient pressure,solvent-free and co-catalyst-free conditions

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Chinese Journal of chemical engineering 2022年第3期35卷 222-229页

作者： Xueting Liu Chunhui Hu Jingjing Wu Peng Cui Fengyu Wei School of Chemistry and chemical engineering Hefei University of TechnologyAnhui Key Laboratory of Controllable Chemical Reaction&Material Chemical EngineeringHefei 230009China

In this study,a series of metal-organic frameworks(MOFs)NH_(2)-UiO-66-x HAc catalysts were synthesized by solvothermal method using acetic acid(HAc)as a modulator,and were applied to the cycloaddition of CO_(2)and epichlorohydrin(EPIC)under ambient *** of the modulation by HAc on morphologies and structures of the MOFs are demonstrated via PXRD,FESEM,FTIR,N_(2)adsorption-desorption,XPS and ^(1)H NMR *** results show that the MOFs containing mesoporous pores can be prepared by adjusting the concentration of *** optimizing the amount of HAc added,the specific surface area of NH_(2)-UiO-66-8 HAc is as high as 879.17 m^(2)·g^(-1),which is 28.3%higher than that of the original *** the evaluation of catalytic performance showed that HAc modulation enhanced the activity of NH_(2)-UiO-66-x HAc under mild *** exposure of Lewis acid sites,increased specific surface area and porosity via the modulation of HAc defective ligand can be supposed the key factors to determine the enhanced catalytic *** addition,considering the influence of gas concentration on the reaction,the concept of TOP(Turnover of Pressure,defined as the mass of conversions of a unit mass catalyst under unit pressure and unit time)was first proposed in this article.

关键词： CO_(2)conversion Metal-organic frameworks Acetic acid modulation Defect Mild conditions

Novel hierarchical yolk-shell α-Ni(OH)_(2)/Mn_(2)O_(3) microspheres as high specific capacitance electrode materials for supercapacitors

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Frontiers of chemical Science and engineering 2021年第5期15卷 1322-1331页

作者： Xiqing Luo Miaomiao Jiang Kun Shi Zhangxian Chen Zeheng Yang Weixin Zhang School of Chemistry and chemical engineering Hefei University of Technology and Anhui Key Laboratory of Controllable Chemical Reaction&Material Chemical EngineeringHefei230009China

For high performance supercapacitors, novel hierarchical yolk-shell α-Ni(OH)_(2)/Mn_(2)O_(3) microspheres were controllably synthesized using a facile two-step method based on the solvothermal treatment. The unique α-Ni(OH)_(2) based yolk-shell microstructures decorated with numerous interconnected nanosheets and the heterocomposition features can synergistically enhance reactive site exposure and electron conduction within the microspheres, facilitate charge transfer between electrolyte and electrode materials, and release structural stress during OH− chemisorption/desorption. Moreover, the Mn2O3 sediments distributed over the α-Ni(OH)_(2) microspheres can serve as an effective protective layer for electrochemical reactions. Consequently, when tested in 1 mol·L^(−1) KOH aqueous electrolyte for supercapacitors, the yolk-shell α-Ni (OH)_(2)/Mn_(2)O_(3) microspheres exhibited a considerably high specific capacitance of 2228.6 F·g^(−1) at 1 A·g^(−1) and an impressive capacitance retention of 77.7% after 3000 cycles at 10 A·g^(−1). The proposed α-Ni(OH)_(2)/Mn_(2)O_(3) microspheres with hetero-composition and unique hierarchical yolk-shell microstructures are highly promising to be used as electrode materials in supercapacitors and other energy storage devices.

关键词： α-Ni(OH)_(2)/Mn_(2)O_(3) yolk-shell microspheres electrode material high specific capacitance supercapacitors

A chemical etching route to controllable fabrication of TiO2 hollow nanospheres for enhancing their photocatalytic activity

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Frontiers of chemical Science and engineering 2013年第2期7卷 192-201页

作者： Weixin ZHANG Jie XING Zeheng YANG Mei KONG Hongxu YAO School of chemical engineering Hefei University of Technology Anhui 230009 China anhui key laboratory of controllable chemical reaction & material chemical engineering Anhui 230009 China

The TiO2 hollow nanospheres with diameters of about 230 nm were prepared by a simple and controllable route based on hydrolysis of Ti（OBu）4 on the surfaces of the Cu20 solid nanospheres followed by inward etching of the Cu20 nanospheres. The as-prepared samples were characterized by X-ray diffraction, transmis- sion electron microscopy and scanning electron micro- scopy. The further post-heat treatment led to the high crystallization of the TiO2 hollow nanospheres. The photocatalytic performances of these samples were evaluated for the photodegradation of rhodamine B （RhB） under UV-light irradiation. The as-prepared TiO2 hollow nanospheres showed higher photocatalytic activity than the CuO and the CuO/TiO2 hollow nanospheres. Effects of temperature and time for post-heat treatment of TiO2 as well as initial RhB concentrations on the RhB photodegradation have also been studied. The results show that the TiO2 hollow nanospheres have the good reusability as photocatalysts and are promising in waste water treatment.

关键词： TiO2 hollow nanospheres rhodamine B,photocatalytic activity

Recovery of lithium using H_(4)Mn_(3.5)Ti_(1.5)O_(12)/reduced graphene oxide/polyacrylamide composite hydrogel from brine by Ads-ESIX process

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Chinese Journal of chemical engineering 2022年第4期35卷 20-28页

作者： Jingsi Cui Huanxi Xu Yanfeng Ding Jingjing Tian Xu Zhang Guanping Jin anhui key Lab of controllable chemical reaction&material chemical engineering School of Chemistry and Chemical EngineeringHefei University of TechnologyHefei 230009China

Powdery Li^(+)-imprinted manganese oxides adsorbent was widely used to the recovery of Li^(+),but there are some difficulties,such as poor stability in acid solution,inconvenience of operation and *** this work,a useful hydrogel composite based H_(4)Mn_(3.5)Ti_(1.5)O_(12)/reduced graphene oxide/polyacrylamide(HMTO-rGO/PAM)was fabricated by thermal initiation method with promising stable,conductive and selective *** resulting materials were characterized by field emission scanning electron microscope,infrared absorption spectrum,X-ray diffraction,X-ray photoelectron spectroscopy and electrochemical *** recovery of Li^(+)was investigated using HMTO-rGO/PAM from brine by a separated two-stage sorption statically and electrically switched ion exchange desorption *** adsorption capacity of 51.5 mg·g^(-1)could be achieved with an initial Li^(+)concentration of 200 mg·L^(-1)in pH 10,at 45℃ for 12 ***^(+)ions could be quickly desorbed by cyclic voltammetry(CV)in pH 3,0.1 mol·L^(-1)HCl/NH;Cl accompanying the exchange of Li^(+)and H+(NH;)and the transfer of LMTO-rGO/PAM to HMTO-rGO/PAM.

关键词： Lithium recovery Titanium doped lithium ion sieve Hydrogel Adsorption-electrically switched ion exchange(Ads-ESIX)

Potential-aided recovery of iodide using 2-D nanosheet CuxO coating polymer/graphene/carbon fibers composite

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Chinese Journal of chemical engineering 2020年第4期28卷 1046-1054页

作者： Yexiao Yu Guanping Jin Yuhong Fang Zheng Xu Xiaoyuan Lü Chunnian Chen anhui key Lab of controllable chemical reaction&material chemical engineering School of Chemistry and Chemical EngineeringHefei University of TechnologyHefei 230009China

2-D nanosheet Cu2O doped CuO coating poly m-phenylenediamine and melamine/graphene/carbon fibers composite(CuxO/MPM/GFs)was firstly fabricated by compound electrochemical ***/MPM/GFs was successfully used to the recovery of iodide(I-)from salt water by lower potential-aided sorption and desorption *** potential-aided recovery of I-at CuxO/MPM/GFs was characterized by FE-SEM,XRD,IR,Raman,XPS,UV-vis and electrochemical techniques in *** maximal adsorption capacity of 86.82 mg·g^-1 could be obtained with a pseudo-second-order model at 0.8 V for 210 min in pH 5.0,0.1 mol·L^-1 NaCl,and the process accompanied the generation of CuI,CuO and I5-.The I-could be quickly desorbed from the electrode with a transfer of CuI to Cu2O by cycle voltammetry from-1.0 to 0.5 V for 90 cycles in pH 9.0,0.1 mol·L^-1 ***,CuxO/MPM/GFs was renewable in the continuous electrochemical-adsorption-desorption processes.

关键词： Potential-aided recovery Iodide Cu2O Carbon fibers composite

Fast and highly reversible Na^(+)intercalation/extraction in Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)cathode material for high-performance Na-ion batteries

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Nano Research 2021年第10期14卷 3531-3537页

作者： Xiaoqin Huang Deli Li Haijian Huang Xiao Jiang Zeheng Yang Weixin Zhang School of Chemistry and chemical engineering Hefei University of TechnologyHefei 230009China anhui key laboratory of controllable chemical reaction&material chemical engineering Hefei 230009China

P2-type layered Na_(0.67)MnO_(2)has been considered to be a promising candidate cathode material for sodium ion ***,the undesired phase transitions during operation and the large Na^(+)radius induced sluggish ion diffusion remain the stumbling blocks to realize its high ***,we propose a Zn/Mg co-doping strategy,which is proved to have bifunctional ***,relative to the pristine P2-Na_(0.67)MnO_(2)and the single-ion(Zn/Mg)doped samples,the Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)demonstrates a lower Mn^(3+)/Mn^(4+)ratio and a higher lattice O content,which facilitate the structural stability of the cathode *** intriguingly,the Zn/Mg co-doping gives rise to enlarged interplanar spacing,which provides spacious ion diffusion channels for fast Na^(+)intercalation/*** a result,the Zn/Mg dual-doped sample exhibits a high Na^(+)diffusion coefficient and a solid-solution reaction during charge/discharge,with a cell volume change determined to be only 0.55%.Taking advantages of the above favorable features,the Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)demonstrates a high rate performance with 67.2 mAh·g^(-1)delivered at 10 C and a decent cycling stability with a capacity retention of 93.8%achieved at 1 C after 100 *** work introduces the Zn/Mg co-doping strategy to simultaneously improve the cycling stability and rate capability of P2-Na_(0.67)MnO_(2),which may offer a promising avenue for further performance enhancement of the layered Na-ion batteries cathode materials.

关键词： Na-ion batteries cathode materials co-doping Na-ion diffusion structural stability

Facile synthesis of α-MnO2 micronests composed of nanowires and their enhanced adsorption to Congo red

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Frontiers of chemical Science and engineering 2014年第1期8卷 64-72页

作者： Weixin ZHANG School of chemical engineering Hefei University of Technology Hefei 230009 China anhui key laboratory of controllable chemical reaction & material chemical engineering Hefei 230009 China

In this paper, α-MnO2 micronests composed of nanowires were fabricated via a hydrothermal reaction of MnSO4. H20 and K2S208 solutions. The α-MnO2 micron- ests were demonstrated to have a higher adsorption capacity than 7-MnO2 microspheres due to their large specific surface area. The amount of Congo red adsorbed per unit weight of α-MnO2 micronests increased signifi- cantly from 114 to 282mg.g-1 with concentration of Congo red solution increasing from 50 to 200 mg. L-1, but it had a little change with temperature. Kinetics, isotherms and thermodynamics for the adsorption of Congo red on α- MnO2 micronests were examined. The adsorption process followed the pseudo-second-order kinetics with good correlation. The experimental data were analyzed by Langmuir and Freundlich models, and equilibrium data fitted the Langmuir isotherm very well with maximum monolayer adsorption capacity of 625 mg. g-1 at 22 ℃. The adsorption was spontaneous and endothermic accord- ing to thermodynamic studies. The experimental results indicate that α-MnO2 micronests possess a high adsorption capacity and could be employed as a replacement of traditional sorbents.

关键词： MnO2 Congo red adsorption kinetics isotherm thermodynamics

Characterization and reactivity of γ-Al_2O_3 supported Pd–Ni bimetallic nanocatalysts for selective hydrogenation of cyclopentadiene

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Chinese chemical Letters 2015年第6期26卷 709-713页

作者： Yi-Si Feng Jian Hao Wei-Wei Liu Yun-Jin Yao Yue Cheng Hua-Jian Xu School of Chemistry and chemical engineering School of Medical EngineeringHefei University of Technology anhui key laboratory of controllable chemical reaction & material chemical engineering anhui Provincial laboratory of Heterocyclic Chemistry

Several γ-Al2O3 supported Pd-Ni bimetallic nanocatalysts （Pd-Ni （x：y）[Al2O3; where x and y represent the mass ratio of Pd and Ni, respectively） were prepared by the impregnation method and used for selective hydrogenation of cyclopentadiene to cyclopentene. The Pd-NiJAl2O3 samples were confirmed to generate Pd-Ni bimetallic nanoparticles by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and transmission electron microscopy （TEM）. The catalytic activity was assessed in view of the effects of different mass ratios of Pd and Ni, temperature, pressure, etc. Among all the samples, the Pd-Ni （1：1 ）/Al2O3 （PN-1：1 ） catalyst showed extremely high catalytic ability. The conversion of cyclopentadiene and selectivity for cyclopentene can be simultaneously more than 90%.

关键词： Impregnation method Hydrogenation Cyclopentadiene Cyclopentene Pd-Ni/Al2O3

Graphene quantum dots doped poly(vinyl alcohol)hybrid membranes for desalination via pervaporation

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Chinese Journal of chemical engineering 2023年第11期63卷 226-234页

作者： Yunyun Wan Lulu Yao Peng Cui School of Chemistry and chemical engineering Hefei University of TechnologyChina anhui Province key laboratory of controllable chemical reaction&materials chemical engineering Hefei230009China

Pervaporation desalination by highly hydrophilic materials such as poly(vinyl alcohol)(PVA)based separation membrane is a burgeoning technology of late ***,the improvement of membrane flux in pervaporation desalination has been a difficult ***,a novel hybrid membrane with doped graphene oxide quantum dots(GOQDs)which is rich in hydrophilic groups and small size into the matrix of PVA was prepared to improve the membrane *** membranes structures were described by field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM),Fourier transform infrared(FT-IR),differential scanning calorimetry(DSC),thermogravimetric analysis(TGA)and X-ray diffraction(XRD).And more,Water contact angle,swelling degree,and pervaporation properties were carried out to explore the effect of GOQDs in PVA *** addition,GOQDs content in the hybrid membrane,NaCl concentration,and feed temperature were investigated ***,the hydrogen bonds between PVA chains were weakened by the interaction between GOQDs and PVA ***,the hybrid membrane with optimized doped GOQDs content,200 mg·L^(-1),displays a high membrane flux of 17.09 kg·m^(-2)·h^(-1)and the salt rejection is consistently greater than 99.6%.

关键词： Pervaporation Desalination Graphene oxide quantum dots Poly(vinyl alcohol) Membranes