Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier t...Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and vibrating sample magnetometry,respectively.Photocatalytic performance of the straw@Fe_(3)O_(4)/Cu_(2)O was evaluated by measuring the degradation of methyl orange(MO)under irradiation of visible light.The introduction of Fe3O4 not only endowed the straw@Fe_(3)O_(4)/Cu_(2)O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs.The active species capture experiment showed that holes(h+),hydroxyl(∙OH)and superoxide(∙O2ˉ)radicals all took part in the MO degradation.In addition,the photocatalytic mechanism of straw@Fe_(3)O_(4)/Cu_(2)O was proposed based on the experimental results.After five cycles for the photodegradation of MO,the straw@Fe_(3)O_(4)/Cu_(2)O still displayed good photocatalytic activity,suggesting that the as-prepared composite had great potential for practical use in wastewater treatment.展开更多
Mesoporous Ti O2/Carbon beads have been prepared via a facile impregnation-carbonization approach, in which a porous anion-exchange resin and K2 Ti O(C2O4)2were used as hard carbon and titanium source, respectively.Ch...Mesoporous Ti O2/Carbon beads have been prepared via a facile impregnation-carbonization approach, in which a porous anion-exchange resin and K2 Ti O(C2O4)2were used as hard carbon and titanium source, respectively.Characterization results reveal that the self-assembled composites have disordered mesostructure, uniform mesopores,large pore volumes, and high surface areas. The mesopore walls are composed of amorphous carbon, well-dispersed and confined anatase or rutile nanoparticles. Some anatase phase of Ti O2 was transformed to rutile phase via an increase of carbonization temperature or repeated impregnation of the resin with Ti O(C2O4)22-species. X-ray photoelectron spectroscopy, carbon, hydrogen, and nitrogen element analysis, and thermal gravity analysis results indicate the doping of carbon into the Ti O2 lattice and strong interaction between carbon and Ti O2 nanoparticles. A synergy effect by carbon and Ti O2 in the composites has been discussed herein on the degradation of methyl orange under visible light. The dye removal process involves adsorption of the dye from water by the mesopores in the composites, followed by photodegradation on the separated dye-loaded catalysts. Mesopores allow full access of the dye molecules to the surface of Ti O2 nanoparticles.Importantly, the bead format of such composite enables their straightforward separation from the reaction mixture in their application as a liquid-phase heterogeneous photodegradation catalyst.展开更多
Bismuth containing nanomaterials recently received increasing attention with respect to environmental applications because of their low cost, high stability and nontoxicity. In this work, Bi–Bi_2O_2CO_3 heterojunctio...Bismuth containing nanomaterials recently received increasing attention with respect to environmental applications because of their low cost, high stability and nontoxicity. In this work, Bi–Bi_2O_2CO_3 heterojunctions were fabricated by in-situ decoration of Bi nanoparticles on Bi_2O_2CO_3 nanosheets via a simple hydrothermal synthesis approach. X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and high-resolution TEM(HRTEM) were used to confirm the morphology of the nanosheet-like heterostructure of the Bi–Bi_2O_2CO_3 composite. Detailed ultrafast electronic spectroscopy reveals that the in-situ decoration of Bi nanoparticles on Bi_2O_2CO_3 nanosheets exhibit a dramatically enhanced electron-hole pair separation rate, which results in an extraordinarily high photocatalytic activity for the degradation of a model organic dye, methylene blue(MB) under visible light illumination. Cycling experiments revealed a good photochemical stability of the Bi–Bi_2O_2CO_3 heterojunction under repeated irradiation. Photocurrent measurements further indicated that the heterojunction incredibly enhanced the charge generation and suppressed the charge recombination of photogenerated electron-hole pairs.展开更多
K4Ce2Nb10O30 ultrafine powders were prepared by stearic acid method (SAM). The obtained products were analyzed by X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning ele...K4Ce2Nb10O30 ultrafine powders were prepared by stearic acid method (SAM). The obtained products were analyzed by X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy and UV-visible absorption spectra. XRD patterns revealed that K4Ce2Nb10O30 powders treated at 900 oC for 2 h presented tetragonal structure without the presence of deleterious phases. Furthermore, the K4Ce2Nb10O30 prepared by SAM had considerable activity under visible light irradiation.展开更多
Deep-ultraviolet（DUV） light-emitting devices（LEDs） have a variety of potential applications.Zinc-oxide-based materials,which have wide bandgap and large exciton binding energy,have potential applications in high-p...Deep-ultraviolet（DUV） light-emitting devices（LEDs） have a variety of potential applications.Zinc-oxide-based materials,which have wide bandgap and large exciton binding energy,have potential applications in high-performance DUV LEDs.To realize such optoelectronic devices,the modulation of the bandgap is required.This has been demonstrated by the developments of Mg_xZn_（1-x）O and Be_xZn_（1-x）O alloys for the larger bandgap materials.Many efforts have been made to obtain DUV LEDs,and promising successes have been achieved continuously.In this article,we review the recent progress of and problems encountered in the research of ZnO-based DUV LEDs.展开更多
We investigate the electron injection effect of inserting a thin aluminum（Al） layer into cesium carbonate（Cs2CO3）injection layer. Two groups of organic light-emitting devices（OLEDs） are fabricated. For the first...We investigate the electron injection effect of inserting a thin aluminum（Al） layer into cesium carbonate（Cs2CO3）injection layer. Two groups of organic light-emitting devices（OLEDs） are fabricated. For the first group of devices based on Alq3, we insert a thin Al layer of different thickness into Cs2CO3 injection layer, and the device＇s maximum current efficiency of 6.5 cd/A is obtained when the thickness of the thin Al layer is 0.4 nm. However, when the thickness of Al layer is 0.8 nm, the capacity of electron injection is the strongest. To validate the universality of this approach, then we fabricate another group of devices based on another blue emitting material. The maximum current efficiency of the device without and with a thin Al layer is 4.51 cd/A and 4.84 cd/A, respectively. Inserting a thin Al layer of an appropriate thickness into Cs2CO3 layer can result in the reduction of electron injection barrier, enhancement of the electron injection, and improvement of the performance of OLEDs. This can be attributed to the mechanism that thermally evaporated Cs2CO3 decomposes into cesium oxides, the thin Al layer reacts with cesium oxides to form Al–O–Cs complex, and the amount of the Al–O–Cs complex can be controlled by adjusting the thickness of the thin Al layer.展开更多
基金Science and Technology Project from Ministry of Housing and Urban-Rural Development of the People’s Republic of China(No.2014-K7-007)。
文摘Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and vibrating sample magnetometry,respectively.Photocatalytic performance of the straw@Fe_(3)O_(4)/Cu_(2)O was evaluated by measuring the degradation of methyl orange(MO)under irradiation of visible light.The introduction of Fe3O4 not only endowed the straw@Fe_(3)O_(4)/Cu_(2)O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs.The active species capture experiment showed that holes(h+),hydroxyl(∙OH)and superoxide(∙O2ˉ)radicals all took part in the MO degradation.In addition,the photocatalytic mechanism of straw@Fe_(3)O_(4)/Cu_(2)O was proposed based on the experimental results.After five cycles for the photodegradation of MO,the straw@Fe_(3)O_(4)/Cu_(2)O still displayed good photocatalytic activity,suggesting that the as-prepared composite had great potential for practical use in wastewater treatment.
基金supported by Natural Science Foundation of China(21303031,21353004,51472062)Natural Science Foundation of Heilongjiang Province of China(B201010)+2 种基金Fundamental Research Funds for the Central Universities(HIT.IBRSEM.201326)Program for Science&Technology Innovation Talent in Harbin(2013RFQXJ004,2007RFXXG018)China Postdoctoral Science Foundation(2012T50334,20100480991)
文摘Mesoporous Ti O2/Carbon beads have been prepared via a facile impregnation-carbonization approach, in which a porous anion-exchange resin and K2 Ti O(C2O4)2were used as hard carbon and titanium source, respectively.Characterization results reveal that the self-assembled composites have disordered mesostructure, uniform mesopores,large pore volumes, and high surface areas. The mesopore walls are composed of amorphous carbon, well-dispersed and confined anatase or rutile nanoparticles. Some anatase phase of Ti O2 was transformed to rutile phase via an increase of carbonization temperature or repeated impregnation of the resin with Ti O(C2O4)22-species. X-ray photoelectron spectroscopy, carbon, hydrogen, and nitrogen element analysis, and thermal gravity analysis results indicate the doping of carbon into the Ti O2 lattice and strong interaction between carbon and Ti O2 nanoparticles. A synergy effect by carbon and Ti O2 in the composites has been discussed herein on the degradation of methyl orange under visible light. The dye removal process involves adsorption of the dye from water by the mesopores in the composites, followed by photodegradation on the separated dye-loaded catalysts. Mesopores allow full access of the dye molecules to the surface of Ti O2 nanoparticles.Importantly, the bead format of such composite enables their straightforward separation from the reaction mixture in their application as a liquid-phase heterogeneous photodegradation catalyst.
基金DST,India for financial grant(SB/S1/PC-011/2013)DAE(India)for financial grant 2013/37P/73/BRNS,NTH-School‘‘Contacts in Nanosystems:Interactions,Control and Quantum Dynamics’’+1 种基金the Braunschweig International Graduate School of Metrology(IGSM)DFG-RTG 1952/1,Metrology for Complex Nanosystems
文摘Bismuth containing nanomaterials recently received increasing attention with respect to environmental applications because of their low cost, high stability and nontoxicity. In this work, Bi–Bi_2O_2CO_3 heterojunctions were fabricated by in-situ decoration of Bi nanoparticles on Bi_2O_2CO_3 nanosheets via a simple hydrothermal synthesis approach. X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM) and high-resolution TEM(HRTEM) were used to confirm the morphology of the nanosheet-like heterostructure of the Bi–Bi_2O_2CO_3 composite. Detailed ultrafast electronic spectroscopy reveals that the in-situ decoration of Bi nanoparticles on Bi_2O_2CO_3 nanosheets exhibit a dramatically enhanced electron-hole pair separation rate, which results in an extraordinarily high photocatalytic activity for the degradation of a model organic dye, methylene blue(MB) under visible light illumination. Cycling experiments revealed a good photochemical stability of the Bi–Bi_2O_2CO_3 heterojunction under repeated irradiation. Photocurrent measurements further indicated that the heterojunction incredibly enhanced the charge generation and suppressed the charge recombination of photogenerated electron-hole pairs.
基金Project supported by the National Natural Science Foundation of China (20872051) "Zijin Star" of NJUST
文摘K4Ce2Nb10O30 ultrafine powders were prepared by stearic acid method (SAM). The obtained products were analyzed by X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy and UV-visible absorption spectra. XRD patterns revealed that K4Ce2Nb10O30 powders treated at 900 oC for 2 h presented tetragonal structure without the presence of deleterious phases. Furthermore, the K4Ce2Nb10O30 prepared by SAM had considerable activity under visible light irradiation.
基金Project supported by the National Natural Science Foundation for Distinguished Young Scholars of China(Grant No.61425021)the Natural Natural Science Foundation of China(Grant Nos.11374296,61376054,61475153,and 61604132)
文摘Deep-ultraviolet（DUV） light-emitting devices（LEDs） have a variety of potential applications.Zinc-oxide-based materials,which have wide bandgap and large exciton binding energy,have potential applications in high-performance DUV LEDs.To realize such optoelectronic devices,the modulation of the bandgap is required.This has been demonstrated by the developments of Mg_xZn_（1-x）O and Be_xZn_（1-x）O alloys for the larger bandgap materials.Many efforts have been made to obtain DUV LEDs,and promising successes have been achieved continuously.In this article,we review the recent progress of and problems encountered in the research of ZnO-based DUV LEDs.
基金supported by the National Natural Science Foundation of China(Grant No.60906022)the Natural Science Foundation of Tianjin,China(Grant No.10JCYBJC01100)+2 种基金the Scientific Developing Foundation of Tianjin Education Commission,China(Grant No.2011ZD02)the Key Science and Technology Support Program of Tianjin,China(Grant No.14ZCZDGX00006)the National High Technology Research and Development Program of China(Grant No.2013AA014201)
文摘We investigate the electron injection effect of inserting a thin aluminum（Al） layer into cesium carbonate（Cs2CO3）injection layer. Two groups of organic light-emitting devices（OLEDs） are fabricated. For the first group of devices based on Alq3, we insert a thin Al layer of different thickness into Cs2CO3 injection layer, and the device＇s maximum current efficiency of 6.5 cd/A is obtained when the thickness of the thin Al layer is 0.4 nm. However, when the thickness of Al layer is 0.8 nm, the capacity of electron injection is the strongest. To validate the universality of this approach, then we fabricate another group of devices based on another blue emitting material. The maximum current efficiency of the device without and with a thin Al layer is 4.51 cd/A and 4.84 cd/A, respectively. Inserting a thin Al layer of an appropriate thickness into Cs2CO3 layer can result in the reduction of electron injection barrier, enhancement of the electron injection, and improvement of the performance of OLEDs. This can be attributed to the mechanism that thermally evaporated Cs2CO3 decomposes into cesium oxides, the thin Al layer reacts with cesium oxides to form Al–O–Cs complex, and the amount of the Al–O–Cs complex can be controlled by adjusting the thickness of the thin Al layer.
