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
A novel layered hexagonal boron nitride/titanium dioxide(h-BN/TiO2) composite photocatalyst has been constructed by anchoring TiO2 nanoflakes on the surface of hBN flakes via a solvothermal method. The morphology and ...A novel layered hexagonal boron nitride/titanium dioxide(h-BN/TiO2) composite photocatalyst has been constructed by anchoring TiO2 nanoflakes on the surface of hBN flakes via a solvothermal method. The morphology and dispersion of TiO2 can be tuned by controlling the amount of flake h-BN. Benefiting from the unique hetero-structure, the photocatalytic performance of the obtained composite toward rhodamine B(Rh B) degradation is greatly enhanced, among which 12 wt% h-BN/TiO2 composites show 3.5 and 6.9 times higher degradation rate than the synthesized TiO2 and commercial TiO2(P25), respectively, and an excellent cycling stability has also been obtained. Moreover, the first-principles calculation reveals the synergetic catalytic effect between TiO2 and h-BN flake, which is found to be responsible for the significantly enhanced photocatalytic performance of h-BN/TiO2 composites.展开更多
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.
基金supported by the National Natural Science Foundation for Excellent Young Scholars of China (51522402)the National Postdoctoral Program for Innovative Talents (BX20180034)+1 种基金the Fundamental Research Funds for the Central Universities (FRF-TP-18-045A1)China Postdoctoral Science Foundation (2018M641192)
文摘A novel layered hexagonal boron nitride/titanium dioxide(h-BN/TiO2) composite photocatalyst has been constructed by anchoring TiO2 nanoflakes on the surface of hBN flakes via a solvothermal method. The morphology and dispersion of TiO2 can be tuned by controlling the amount of flake h-BN. Benefiting from the unique hetero-structure, the photocatalytic performance of the obtained composite toward rhodamine B(Rh B) degradation is greatly enhanced, among which 12 wt% h-BN/TiO2 composites show 3.5 and 6.9 times higher degradation rate than the synthesized TiO2 and commercial TiO2(P25), respectively, and an excellent cycling stability has also been obtained. Moreover, the first-principles calculation reveals the synergetic catalytic effect between TiO2 and h-BN flake, which is found to be responsible for the significantly enhanced photocatalytic performance of h-BN/TiO2 composites.
