An accurate grasp of our Party’s major theoretical and practical innovations in ethnic affairs for the new era is of far-reaching significance for maintaining the reunification and peace of our country, promoting eth...An accurate grasp of our Party’s major theoretical and practical innovations in ethnic affairs for the new era is of far-reaching significance for maintaining the reunification and peace of our country, promoting ethnic unity and social harmony, and realizing the Chinese dream of national rejuvenation. Since the Party’s 18th National Congress,General Secretary Xi Jinping has proposed a community of shared future and emphasized the creation of a strong sense of the Chinese national community.Written into the Party Constitution in the 19th Congress,this is the common will and fundamental guidance for all Party members and all Chinese people.展开更多
The establishment of Ningxia Hui Autonomous Region was an important event in the history of ethnic relations in China.In September 2018,we ushered in the 60th anniversary of its founding.Following the establishment of...The establishment of Ningxia Hui Autonomous Region was an important event in the history of ethnic relations in China.In September 2018,we ushered in the 60th anniversary of its founding.Following the establishment of Inner Mongolia Autonomous Region,Xinjiang Uygur Autonomous Region,and Guangxi Zhuang Autonomous Region, the central government established Ningxia Hui Autonomous Region six decades ago, supported by Communist Party ethnic policies and ethnic people in Ningxia uniting to overcome difficultiesl The result is historic achievement in building a new socialist Ningxia and great contributions to national development and stability.展开更多
Synthesizing a stable and efficient photocatalyst has been the most important research goal up to now. Owing to the dominant performance of g-C3N4 (graphitized carbonitride), an ordered assemble of a composite photoca...Synthesizing a stable and efficient photocatalyst has been the most important research goal up to now. Owing to the dominant performance of g-C3N4 (graphitized carbonitride), an ordered assemble of a composite photocatalyst, Zn-Ni-P@g-C3N4, was successfully designed and controllably prepared for highly efficient photocatalytic H2 evolution. The electron transport routes were successfully adjusted and the H2 evolution was greatly improved. The maximum amount of H2 evolved reached about 531.2 μmol for 5 h over Zn-Ni-P@g-C3N4 photocatalyst with a molar ratio of Zn to Ni of 1:3 under illumination of 5 W LED white light (wavelength 420 nm). The H2 evolution rate was 54.7 times higher than that over pure g-C3N4. Moreover, no obvious reduction in the photocatalytic activity was observed even after 4 cycles of H2 production for 5 h. This synergistically increased effect was confirmed through the results of characterizations such as XRD, TEM, SEM, XPS, N2 adsorption, UV-vis DRS, transient photocurrent, FT-IR, transient fluorescence, and Mott-Schottky studies. These studies showed that the Zn-Ni-P nanoparticles modified on g-C3N4 provide more active sites and improve the efficiency of photogenerated charge separation. In addition, the possible mechanism of photocatalytic H2 production is proposed.展开更多
Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be exte...Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.展开更多
Graphdiyne(GDY,g-C_(n)H_(2n-2)),a novel two-dimensional carbon hybrid material,has attracted significant attention owing to its unique and excellent properties.As a new type of carbon material,GDY has a layered struct...Graphdiyne(GDY,g-C_(n)H_(2n-2)),a novel two-dimensional carbon hybrid material,has attracted significant attention owing to its unique and excellent properties.As a new type of carbon material,GDY has a layered structure and can be used in the field of photocatalytic water splitting.Therefore,herein,new progress in the preparation of graphene using Cu I powder as a catalytic material and the combination of a facile hydrothermal method to prepare a new composite material,Co_(9)S_(8)-GDY-Cu I,is reported.The hydrogen production activity of Co9S8-GDY-Cu I in the sensitization system reached 1411.82μmol g^(-1) h^(-1),which is 10.29 times that of pure GDY.A series of characterization techniques were used to provide evidence for the successful preparation of the material and its superior photocatalytic activity.Raman spectroscopy showed that the material contains acetylenic bonds,and the X-ray photoelectron spectroscopy carbon fitting peaks indicated the presence of C-C(sp^(2))and C-C(sp),further demonstrating that GDY was successfully prepared.A possible reaction mechanism was proposed by making use of UV-visible diffuse reflectance and Mott-Schottky analyses.The results showed that a double S-scheme heterojunction was constructed between the samples,which effectively accelerated the separation and transfer of electrons.In addition,the introduction of Co9S8 nanoparticles greatly improved the visible light absorption capacity of Co_(9)S_(8)-GDY-Cu I.Photoluminescence spectroscopy and related electrochemical characterization further proved that recombination of the electron-hole pairs in the composite material was effectively suppressed.展开更多
Vanadium‐chromium oxides(VCrO)were usually prepared by high‐temperature solid‐state reactions;however,mixed phases were frequently produced and the morphology of the products was not well controlled.In this work,we...Vanadium‐chromium oxides(VCrO)were usually prepared by high‐temperature solid‐state reactions;however,mixed phases were frequently produced and the morphology of the products was not well controlled.In this work,we prepared amorphous VCrO precursors by using V2O5 and CrO3 and alcohols or mixtures of alcohol and water via solvothermal reaction at 180°C.The precursors were then calcined under nitrogen at various temperatures.The products were characterized by powder X‐ray diffraction,transmission electron microscopy,and X‐ray photoelectron spectroscopy.It was revealed that pure‐phase nanocrystalline orthorhombic CrVO4 was obtained when methanol or methanol/water was used as the solvothermal medium and the precursor was calcined at 700°C.The size of the CrVO4 crystals was around 500 nm when methanol was used,whereas it reduced significantly to less than 50 nm when a mixture of methanol and water was used.The sizes could be effectively tuned from 10 to 50 nm by varying the methanol/water volume ratio.To the best of our knowledge,this is the first report on the synthesis of pure‐phase CrVO4 nanocrystals.The nano‐CrVO4 showed almost the highest catalytic activity for the ammoxidation of 2,6‐dichlorotoluene to 2,6‐dichlorobenzonitrile among the reported bi‐component composite oxides,owing to its smaller particle size,larger specific surface area,and more exposed active centers.展开更多
In-plane epitaxial growth of ZnIn_(2)S_(4) nanosheets on the surface of hexagonal phase WO_(3) nanorods was achieved by a facile solvothermal method.The unique 3D heterostructure not only enlarged the specific surface...In-plane epitaxial growth of ZnIn_(2)S_(4) nanosheets on the surface of hexagonal phase WO_(3) nanorods was achieved by a facile solvothermal method.The unique 3D heterostructure not only enlarged the specific surface area,but also red-shifted the absorption edge from 381 to 476 nm to improve the light harvesting ability,which largely enhanced the photocatalytic hydrogen evolution.The H_(2) production rate of the best performing ZnIn_(2)S_(4)/WO_(3) photocatalyst(ZIS-2.5/W,the material with a molar rate of ZnIn_(2)S_(4)(ZIS)to WO_(3)(W)of 2.5)was 300μmol·g^(–1)·h^(–1),around 417 times and 2 times higher than the rates of pristine WO_(3) and ZnIn_(2)S_(4),respectively.The apparent quantum efficiency for ZIS-2.5/W composite was up to 2.81%at 400 nm.Based on the difference in Fermi levels between WO_(3) and ZnIn_(2)S_(4),and the distribution of the redox active sites on WO_(3)/ZnIn_(2)S_(4) heterostructure,a S-scheme electron transfer mechanism was proposed to illustrate the improved photocatalytic activity of WO_(3)/ZnIn_(2)S_(4) heterojunction,which not only stimulated the spatial separation of the photogenerated charge carriers,but also maintained the strong reduction/oxidation ability of the photocatalyst.展开更多
In order to improve the pectin-degrading efficiency in wet processing of Arabica coffee in Yunnan, Box-Behnken design and single factor experiment were used to optimize the fermentation conditions of five pectinolytic...In order to improve the pectin-degrading efficiency in wet processing of Arabica coffee in Yunnan, Box-Behnken design and single factor experiment were used to optimize the fermentation conditions of five pectinolytic Wickerhamomyces anomalus strains from the fermentation broth of Arabica coffee in Baoshan, Yunnan during wet processing with pectase activity as an indicator. The results showed that the five strains all synthesized pectin lyase(PL), polygalacturonase(PG), and pectin methylesterase(PM).Among them, strain CAP5 had strong ability to produce PG and PL,while strain CAP4 secreted a large amount of PM. Under optimized conditions, the activity of PG, PL, and PM of the five strains came in at 250.17~411.20 U/mL, 12.98~16.55 U/mL, and 208.52~322.83 U/mL,respectively. The four factors of nitrogen source concentration,fermentation time, Mn2+ concentration, and pH value were optimized and the optimal pectinase-producing fermentation conditions for five strains were as follows: peptone 2.2 g/L, fermentation time 30 h, Mn2+ 1.5 mmol/L, and pH 4.3. After fermentation under the optimized conditions, the maximum PG activity of CAP5 amounted to 411.20 U/mL, 114.03% higher than that before optimization.Meanwhile, the PG activity of strains CAP3, CAP4, CAP8, and CAP10 increased by 86.74%, 114.55%, 65.79%, and 66.07%,respectively, and the activity of PL and PM of the five strains rose 150.35%~218.56% and 341.07%~418.52%, respectively. These findings suggested that W. anomalus strains could be used as coffee starter and had great potential for the lysis of pectin.展开更多
Silicon carbide(SiC)was used as a support for SSZ‐13zeolite in an attempt to improve the high‐temperature stability and activity of Cu/SSZ‐13in the selective catalytic reduction(SCR)of NO with NH3.SSZ‐13was grown ...Silicon carbide(SiC)was used as a support for SSZ‐13zeolite in an attempt to improve the high‐temperature stability and activity of Cu/SSZ‐13in the selective catalytic reduction(SCR)of NO with NH3.SSZ‐13was grown via a hydrothermal method using the silicon and silica contained in SiC as the source of silicon,which led to the formation of a chemically bonded SSZ‐13layer on SiC.Characterization using X‐ray diffraction,scanning electron microscopy,and N2adsorption‐desorption isotherms revealed that the alkali content strongly affected the purity of zeolite and the crystallization time affected the coverage and crystallinity of the zeolite layer.Upon ion exchange,the resulting Cu/SSZ‐13@SiC catalyst exhibited enhanced activity in NH3‐SCR in the high‐temperature region compared with the unsupported Cu/SSZ‐13.Thus,the application temperature was extended with the use of SiC as the support.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fl...TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fluorinated TiO2‐HMSs were assembled from hollow nanoparticles by the hydrothermal reaction of the mixed Ti(SO4)2–NH4HF–H2O2solution at180°C.The effect of the calcination temperature on the structure and photoreactivity of the TiO2‐HMSs was systematically investigated,which was evaluated by photocatalytic oxidation of acetone in air under ultraviolet irradiation.We found that after calcination at300°C,the photoreactivity of the TiO2‐HMSs decreases from1.39×10?3min?1(TiO2‐HMS precursor)to0.82×10?3min?1because of removal of surface‐adsorbed fluoride ions.With increasing calcination temperature from300to900°C,the building blocks of the TiO2‐HMSs evolve from truncated bipyramidal shaped hollow nanoparticles to round solid nanoparticles,and the photoreactivity of the TiO2‐HMSs steady increases from0.82×10?3to2.09×10?3min?1because of enhanced crystallization.Further increasing the calcination temperature to1000and1100°C results in a decrease of the photoreactivity,which is ascribed to a sharp decrease of the Brunauer–Emmett–Teller surface area and the beginning of the anatase–rutile phase transformation at1100°C.The effect of surface‐adsorbed fluoride ions on the thermal stability of the TiO2‐HMSs is also discussed.展开更多
Ti^（3＋） self-doped anatase three-dimensional（3D） TiO_2 hollow nanoboxes were synthesized via a topological transformation process involving template participation by a facile one-pot hydrothermal treatment with a...Ti^（3＋） self-doped anatase three-dimensional（3D） TiO_2 hollow nanoboxes were synthesized via a topological transformation process involving template participation by a facile one-pot hydrothermal treatment with an ethanol solution of zinc powder and TiOF_2. It is worth noting that the 3D TiO_2 hollow nanoboxes are assembled from six single-crystal nanosheets and have dominant exposure of the {001} facets. It is found from EPR spectra that adding zinc powder is an environment-friendly and effective strategy to introduce Ti^（3＋） and oxygen vacancy（Ov） into the bulk of 3D hollow nanoboxes rather than the surface, which is responsible for their enhanced visible photocatalytic properties.The photocatalytic activity was evaluated by measuring the formation rate of hydroxide free radicals using 7-hydroxycoumarin as a probe. The sample prepared with zinc/TiOF_2 mass ratio of0.25 exhibited the highest RhB photodegradation activity under visible-light irradiation with a degradation rate of 96%, which is 4.0-times higher than that of pure TiO_2. The results suggest a novel approach to construct in-situ 3D hierarchical TiO_2 hollow nanoboxes doped with Ti^（3＋） and Ov without introducing any impurity elements for superior visible-light photocatalytic activity.展开更多
Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited ...Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited by ultraviolet light.In this paper,visible‐light‐responsive N and S co‐doped TiO2‐HNBs were prepared by calcining the mixture of cubic TiOF2 and methionine(C5H11NO2S),a N‐and S‐containing biomacromolecule.The effect of calcination temperature on the structure and performance of the TiO2‐HNBs was systematically studied.It was found that methionine can prevent TiOF2‐to‐anatase TiO2 phase transformation.Both N and S elements are doped into the lattice of TiO2‐HNBs when the mixture of TiOF2 and methionine undergoes calcination at 400°C,which is responsible for the visible‐light response.When compared with that of pure 400°C‐calcined TiO2‐HNBs(T400),the photoreactivity of 400°C‐calcined methionine‐modified TiO2‐HNBs(TM400)improves 1.53 times in photocatalytic degradation of rhodamine‐B dye under visible irradiation(?>420 nm).The enhanced visible photoreactivity of methionine‐modified TiO2‐HNBs is also confirmed by photocatalytic oxidation of NO.The successful doping of N and S elements into the lattice of TiO2‐HNBs,resulting in the improved light‐harvesting ability and efficient separation of photo‐generated electron‐hole pairs,is responsible for the enhanced visible photocatalytic activity of methionine‐modified TiO2‐HNBs.The photoreactivity of methionine modified TiO2‐HNBs remains nearly unchanged even after being recycled five times,indicating its promising use in practical applications.展开更多
不久前,国家体改委综合规划司、国家民委经济司组成联合调查组,赴云南德宏傣族景颇族自治州,就边贸的发展及其体制特点、政策状况进行了考察。现将有关情况及意见报告如后。一、德宏边贸发展的现状与特点云南省德宏傣族景颇族自治州成立...不久前,国家体改委综合规划司、国家民委经济司组成联合调查组,赴云南德宏傣族景颇族自治州,就边贸的发展及其体制特点、政策状况进行了考察。现将有关情况及意见报告如后。一、德宏边贸发展的现状与特点云南省德宏傣族景颇族自治州成立于1953年。辖五县一市(潞西、梁河、盈江、陇川、瑞丽县和畹町市),面积i l 73平方公里。展开更多
Graphdiyne(GDY)has attracted considerable attention as a new two-dimensional(2D)carbon hybrid material because of its good conductivity,adjustable electronic structure,and special electron transfer enhancement propert...Graphdiyne(GDY)has attracted considerable attention as a new two-dimensional(2D)carbon hybrid material because of its good conductivity,adjustable electronic structure,and special electron transfer enhancement properties.GDY has great potential in the field of photocatalytic water splitting for hydrogen evolution,owing to its unique properties.In this study,GDY was successfully prepared by the mechanochemical coupling of precursors C_(6)Br_(6) and CaC_(2) using a ball-milling approach.The prepared GDY,especially its microstructure and composition,was well characterized using different techniques such as X-ray diffraction,scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy(XPS),Fourier-transform infrared,and Raman characterization techniques.By exploiting the unique two-dimensional(2D)structure and outstanding light absorption properties of GDY,GDY/CdSe 2D/0D heterojunctions were successfully established and applied to photocatalytic hydrogen evolution.The hydrogen evolution activity of GDY/CdSe-20,a type of composite material,reached 6470μmol g^(-1) h^(-1),which is 461 and 40 times higher than that of GDY and CdSe,respectively.Moreover,the fine electrical conductivity of GDY enabled rapid and effective transfer of the photogenerated electrons in CdSe into the hydrogen evolution reaction.The transfer path of the photogenerated electrons was studied through XPS with in situ irradiation,and a reasonable mechanism for the hydrogen evolution reaction was proposed.This study provides a feasible approach for the large-scale preparation of GDY and demonstrates the prospects of GDY in the field of photocatalysis.展开更多
In the magnificent process of building China into a unified multi-ethnic country,the people of all ethnic groups participated with great sacrifice and dedication,and the Communist Party of China,from its establishment...In the magnificent process of building China into a unified multi-ethnic country,the people of all ethnic groups participated with great sacrifice and dedication,and the Communist Party of China,from its establishment,has stressed the importance of ethnic work.Combining Marxist ethnic theory with problem solving,the Party united and led ethnic groups to jointly create a new China.The preamble to our Constitution declares:the People's Republic of China is a unified multi-ethnic country jointly created by the people of all its ethnic groups.展开更多
文摘An accurate grasp of our Party’s major theoretical and practical innovations in ethnic affairs for the new era is of far-reaching significance for maintaining the reunification and peace of our country, promoting ethnic unity and social harmony, and realizing the Chinese dream of national rejuvenation. Since the Party’s 18th National Congress,General Secretary Xi Jinping has proposed a community of shared future and emphasized the creation of a strong sense of the Chinese national community.Written into the Party Constitution in the 19th Congress,this is the common will and fundamental guidance for all Party members and all Chinese people.
文摘The establishment of Ningxia Hui Autonomous Region was an important event in the history of ethnic relations in China.In September 2018,we ushered in the 60th anniversary of its founding.Following the establishment of Inner Mongolia Autonomous Region,Xinjiang Uygur Autonomous Region,and Guangxi Zhuang Autonomous Region, the central government established Ningxia Hui Autonomous Region six decades ago, supported by Communist Party ethnic policies and ethnic people in Ningxia uniting to overcome difficultiesl The result is historic achievement in building a new socialist Ningxia and great contributions to national development and stability.
基金supported by the National Natural Science Foundation of China(21862002,41663012)the Innovation Team Project of North Minzu University(YCX18082)the Scientific Research Project of North Minzu University(2016 HG-KY 06)~~
文摘Synthesizing a stable and efficient photocatalyst has been the most important research goal up to now. Owing to the dominant performance of g-C3N4 (graphitized carbonitride), an ordered assemble of a composite photocatalyst, Zn-Ni-P@g-C3N4, was successfully designed and controllably prepared for highly efficient photocatalytic H2 evolution. The electron transport routes were successfully adjusted and the H2 evolution was greatly improved. The maximum amount of H2 evolved reached about 531.2 μmol for 5 h over Zn-Ni-P@g-C3N4 photocatalyst with a molar ratio of Zn to Ni of 1:3 under illumination of 5 W LED white light (wavelength 420 nm). The H2 evolution rate was 54.7 times higher than that over pure g-C3N4. Moreover, no obvious reduction in the photocatalytic activity was observed even after 4 cycles of H2 production for 5 h. This synergistically increased effect was confirmed through the results of characterizations such as XRD, TEM, SEM, XPS, N2 adsorption, UV-vis DRS, transient photocurrent, FT-IR, transient fluorescence, and Mott-Schottky studies. These studies showed that the Zn-Ni-P nanoparticles modified on g-C3N4 provide more active sites and improve the efficiency of photogenerated charge separation. In addition, the possible mechanism of photocatalytic H2 production is proposed.
文摘Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.
文摘Graphdiyne(GDY,g-C_(n)H_(2n-2)),a novel two-dimensional carbon hybrid material,has attracted significant attention owing to its unique and excellent properties.As a new type of carbon material,GDY has a layered structure and can be used in the field of photocatalytic water splitting.Therefore,herein,new progress in the preparation of graphene using Cu I powder as a catalytic material and the combination of a facile hydrothermal method to prepare a new composite material,Co_(9)S_(8)-GDY-Cu I,is reported.The hydrogen production activity of Co9S8-GDY-Cu I in the sensitization system reached 1411.82μmol g^(-1) h^(-1),which is 10.29 times that of pure GDY.A series of characterization techniques were used to provide evidence for the successful preparation of the material and its superior photocatalytic activity.Raman spectroscopy showed that the material contains acetylenic bonds,and the X-ray photoelectron spectroscopy carbon fitting peaks indicated the presence of C-C(sp^(2))and C-C(sp),further demonstrating that GDY was successfully prepared.A possible reaction mechanism was proposed by making use of UV-visible diffuse reflectance and Mott-Schottky analyses.The results showed that a double S-scheme heterojunction was constructed between the samples,which effectively accelerated the separation and transfer of electrons.In addition,the introduction of Co9S8 nanoparticles greatly improved the visible light absorption capacity of Co_(9)S_(8)-GDY-Cu I.Photoluminescence spectroscopy and related electrochemical characterization further proved that recombination of the electron-hole pairs in the composite material was effectively suppressed.
基金supported by the National Natural Science Foundation of China(21172269)Innovation Group of Hubei Natural Science Foundation(2018CFA023)Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University(JDGD-201809)~~
文摘Vanadium‐chromium oxides(VCrO)were usually prepared by high‐temperature solid‐state reactions;however,mixed phases were frequently produced and the morphology of the products was not well controlled.In this work,we prepared amorphous VCrO precursors by using V2O5 and CrO3 and alcohols or mixtures of alcohol and water via solvothermal reaction at 180°C.The precursors were then calcined under nitrogen at various temperatures.The products were characterized by powder X‐ray diffraction,transmission electron microscopy,and X‐ray photoelectron spectroscopy.It was revealed that pure‐phase nanocrystalline orthorhombic CrVO4 was obtained when methanol or methanol/water was used as the solvothermal medium and the precursor was calcined at 700°C.The size of the CrVO4 crystals was around 500 nm when methanol was used,whereas it reduced significantly to less than 50 nm when a mixture of methanol and water was used.The sizes could be effectively tuned from 10 to 50 nm by varying the methanol/water volume ratio.To the best of our knowledge,this is the first report on the synthesis of pure‐phase CrVO4 nanocrystals.The nano‐CrVO4 showed almost the highest catalytic activity for the ammoxidation of 2,6‐dichlorotoluene to 2,6‐dichlorobenzonitrile among the reported bi‐component composite oxides,owing to its smaller particle size,larger specific surface area,and more exposed active centers.
文摘In-plane epitaxial growth of ZnIn_(2)S_(4) nanosheets on the surface of hexagonal phase WO_(3) nanorods was achieved by a facile solvothermal method.The unique 3D heterostructure not only enlarged the specific surface area,but also red-shifted the absorption edge from 381 to 476 nm to improve the light harvesting ability,which largely enhanced the photocatalytic hydrogen evolution.The H_(2) production rate of the best performing ZnIn_(2)S_(4)/WO_(3) photocatalyst(ZIS-2.5/W,the material with a molar rate of ZnIn_(2)S_(4)(ZIS)to WO_(3)(W)of 2.5)was 300μmol·g^(–1)·h^(–1),around 417 times and 2 times higher than the rates of pristine WO_(3) and ZnIn_(2)S_(4),respectively.The apparent quantum efficiency for ZIS-2.5/W composite was up to 2.81%at 400 nm.Based on the difference in Fermi levels between WO_(3) and ZnIn_(2)S_(4),and the distribution of the redox active sites on WO_(3)/ZnIn_(2)S_(4) heterostructure,a S-scheme electron transfer mechanism was proposed to illustrate the improved photocatalytic activity of WO_(3)/ZnIn_(2)S_(4) heterojunction,which not only stimulated the spatial separation of the photogenerated charge carriers,but also maintained the strong reduction/oxidation ability of the photocatalyst.
文摘In order to improve the pectin-degrading efficiency in wet processing of Arabica coffee in Yunnan, Box-Behnken design and single factor experiment were used to optimize the fermentation conditions of five pectinolytic Wickerhamomyces anomalus strains from the fermentation broth of Arabica coffee in Baoshan, Yunnan during wet processing with pectase activity as an indicator. The results showed that the five strains all synthesized pectin lyase(PL), polygalacturonase(PG), and pectin methylesterase(PM).Among them, strain CAP5 had strong ability to produce PG and PL,while strain CAP4 secreted a large amount of PM. Under optimized conditions, the activity of PG, PL, and PM of the five strains came in at 250.17~411.20 U/mL, 12.98~16.55 U/mL, and 208.52~322.83 U/mL,respectively. The four factors of nitrogen source concentration,fermentation time, Mn2+ concentration, and pH value were optimized and the optimal pectinase-producing fermentation conditions for five strains were as follows: peptone 2.2 g/L, fermentation time 30 h, Mn2+ 1.5 mmol/L, and pH 4.3. After fermentation under the optimized conditions, the maximum PG activity of CAP5 amounted to 411.20 U/mL, 114.03% higher than that before optimization.Meanwhile, the PG activity of strains CAP3, CAP4, CAP8, and CAP10 increased by 86.74%, 114.55%, 65.79%, and 66.07%,respectively, and the activity of PL and PM of the five strains rose 150.35%~218.56% and 341.07%~418.52%, respectively. These findings suggested that W. anomalus strains could be used as coffee starter and had great potential for the lysis of pectin.
基金supported by the INCOEmission project coordinated by BASF SE,Germanythe support from the Fundamental Research Funds for the Central Universities(DC201502080409)~~
文摘Silicon carbide(SiC)was used as a support for SSZ‐13zeolite in an attempt to improve the high‐temperature stability and activity of Cu/SSZ‐13in the selective catalytic reduction(SCR)of NO with NH3.SSZ‐13was grown via a hydrothermal method using the silicon and silica contained in SiC as the source of silicon,which led to the formation of a chemically bonded SSZ‐13layer on SiC.Characterization using X‐ray diffraction,scanning electron microscopy,and N2adsorption‐desorption isotherms revealed that the alkali content strongly affected the purity of zeolite and the crystallization time affected the coverage and crystallinity of the zeolite layer.Upon ion exchange,the resulting Cu/SSZ‐13@SiC catalyst exhibited enhanced activity in NH3‐SCR in the high‐temperature region compared with the unsupported Cu/SSZ‐13.Thus,the application temperature was extended with the use of SiC as the support.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
基金supported by the National Natural Science Foundation of China(51672312,21373275)the Science and Technology Program of Wuhan,China(2016010101010018,2015070504020220)the Dean’s Research Fund–04257 from the Education University of Hong Kong~~
文摘TiO2hollow microspheres(TiO2‐HMSs)have attracted much attention because of their high photoreactivity,low density,and good permeability.However,anatase TiO2‐HMSs have poor thermal stability.In this study,surface‐fluorinated TiO2‐HMSs were assembled from hollow nanoparticles by the hydrothermal reaction of the mixed Ti(SO4)2–NH4HF–H2O2solution at180°C.The effect of the calcination temperature on the structure and photoreactivity of the TiO2‐HMSs was systematically investigated,which was evaluated by photocatalytic oxidation of acetone in air under ultraviolet irradiation.We found that after calcination at300°C,the photoreactivity of the TiO2‐HMSs decreases from1.39×10?3min?1(TiO2‐HMS precursor)to0.82×10?3min?1because of removal of surface‐adsorbed fluoride ions.With increasing calcination temperature from300to900°C,the building blocks of the TiO2‐HMSs evolve from truncated bipyramidal shaped hollow nanoparticles to round solid nanoparticles,and the photoreactivity of the TiO2‐HMSs steady increases from0.82×10?3to2.09×10?3min?1because of enhanced crystallization.Further increasing the calcination temperature to1000and1100°C results in a decrease of the photoreactivity,which is ascribed to a sharp decrease of the Brunauer–Emmett–Teller surface area and the beginning of the anatase–rutile phase transformation at1100°C.The effect of surface‐adsorbed fluoride ions on the thermal stability of the TiO2‐HMSs is also discussed.
基金supported by the National Natural Science Foundation of China(20702064,21177161,31402137)Hubei Province Science Fund for Distinguished Yong Scholars(2013CFA034)+2 种基金the Program for Excellent Talents in Hubei Province(RCJH15001)the Opening Project of Key Laboratory of Green Catalysis of Sichuan Institutes of High Education(LYZ1107)the Fundamental Research Funds for the Central University,South-Central University for Nationalities(CZP17077)~~
文摘Ti^（3＋） self-doped anatase three-dimensional（3D） TiO_2 hollow nanoboxes were synthesized via a topological transformation process involving template participation by a facile one-pot hydrothermal treatment with an ethanol solution of zinc powder and TiOF_2. It is worth noting that the 3D TiO_2 hollow nanoboxes are assembled from six single-crystal nanosheets and have dominant exposure of the {001} facets. It is found from EPR spectra that adding zinc powder is an environment-friendly and effective strategy to introduce Ti^（3＋） and oxygen vacancy（Ov） into the bulk of 3D hollow nanoboxes rather than the surface, which is responsible for their enhanced visible photocatalytic properties.The photocatalytic activity was evaluated by measuring the formation rate of hydroxide free radicals using 7-hydroxycoumarin as a probe. The sample prepared with zinc/TiOF_2 mass ratio of0.25 exhibited the highest RhB photodegradation activity under visible-light irradiation with a degradation rate of 96%, which is 4.0-times higher than that of pure TiO_2. The results suggest a novel approach to construct in-situ 3D hierarchical TiO_2 hollow nanoboxes doped with Ti^（3＋） and Ov without introducing any impurity elements for superior visible-light photocatalytic activity.
基金supported by the National Natural Science Foundation of China(31402137,51672312,21373275)Hubei Province Science Fund for Distinguished Yong Scholars(2013CFA034)+2 种基金the Program for Excellent Talents in Hubei Province(RCJH15001)the Science and Technology Program of Wuhan(2016010101010018)the Fundamental Research Funds for the Central University,South-Central University for Nationalities(CZP17077,CZP18016)~~
文摘Hierarchical TiO2 hollow nanoboxes(TiO2‐HNBs)assembled from TiO2 nanosheets(TiO2‐NSs)show improved photoreactivity when compared with the building blocks of discrete TiO2‐NSs.However,TiO2‐HNBs can only be excited by ultraviolet light.In this paper,visible‐light‐responsive N and S co‐doped TiO2‐HNBs were prepared by calcining the mixture of cubic TiOF2 and methionine(C5H11NO2S),a N‐and S‐containing biomacromolecule.The effect of calcination temperature on the structure and performance of the TiO2‐HNBs was systematically studied.It was found that methionine can prevent TiOF2‐to‐anatase TiO2 phase transformation.Both N and S elements are doped into the lattice of TiO2‐HNBs when the mixture of TiOF2 and methionine undergoes calcination at 400°C,which is responsible for the visible‐light response.When compared with that of pure 400°C‐calcined TiO2‐HNBs(T400),the photoreactivity of 400°C‐calcined methionine‐modified TiO2‐HNBs(TM400)improves 1.53 times in photocatalytic degradation of rhodamine‐B dye under visible irradiation(?>420 nm).The enhanced visible photoreactivity of methionine‐modified TiO2‐HNBs is also confirmed by photocatalytic oxidation of NO.The successful doping of N and S elements into the lattice of TiO2‐HNBs,resulting in the improved light‐harvesting ability and efficient separation of photo‐generated electron‐hole pairs,is responsible for the enhanced visible photocatalytic activity of methionine‐modified TiO2‐HNBs.The photoreactivity of methionine modified TiO2‐HNBs remains nearly unchanged even after being recycled five times,indicating its promising use in practical applications.
文摘不久前,国家体改委综合规划司、国家民委经济司组成联合调查组,赴云南德宏傣族景颇族自治州,就边贸的发展及其体制特点、政策状况进行了考察。现将有关情况及意见报告如后。一、德宏边贸发展的现状与特点云南省德宏傣族景颇族自治州成立于1953年。辖五县一市(潞西、梁河、盈江、陇川、瑞丽县和畹町市),面积i l 73平方公里。
文摘Graphdiyne(GDY)has attracted considerable attention as a new two-dimensional(2D)carbon hybrid material because of its good conductivity,adjustable electronic structure,and special electron transfer enhancement properties.GDY has great potential in the field of photocatalytic water splitting for hydrogen evolution,owing to its unique properties.In this study,GDY was successfully prepared by the mechanochemical coupling of precursors C_(6)Br_(6) and CaC_(2) using a ball-milling approach.The prepared GDY,especially its microstructure and composition,was well characterized using different techniques such as X-ray diffraction,scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy(XPS),Fourier-transform infrared,and Raman characterization techniques.By exploiting the unique two-dimensional(2D)structure and outstanding light absorption properties of GDY,GDY/CdSe 2D/0D heterojunctions were successfully established and applied to photocatalytic hydrogen evolution.The hydrogen evolution activity of GDY/CdSe-20,a type of composite material,reached 6470μmol g^(-1) h^(-1),which is 461 and 40 times higher than that of GDY and CdSe,respectively.Moreover,the fine electrical conductivity of GDY enabled rapid and effective transfer of the photogenerated electrons in CdSe into the hydrogen evolution reaction.The transfer path of the photogenerated electrons was studied through XPS with in situ irradiation,and a reasonable mechanism for the hydrogen evolution reaction was proposed.This study provides a feasible approach for the large-scale preparation of GDY and demonstrates the prospects of GDY in the field of photocatalysis.
文摘In the magnificent process of building China into a unified multi-ethnic country,the people of all ethnic groups participated with great sacrifice and dedication,and the Communist Party of China,from its establishment,has stressed the importance of ethnic work.Combining Marxist ethnic theory with problem solving,the Party united and led ethnic groups to jointly create a new China.The preamble to our Constitution declares:the People's Republic of China is a unified multi-ethnic country jointly created by the people of all its ethnic groups.
