A series of nanocrystalline V-doped （0.0-3.0 at.%） TiO2 catalysts have been successfully prepared by the one-step solution combustion method using urea as a fuel. The obtained powders were characterized by XRD, SEM,...A series of nanocrystalline V-doped （0.0-3.0 at.%） TiO2 catalysts have been successfully prepared by the one-step solution combustion method using urea as a fuel. The obtained powders were characterized by XRD, SEM, Raman, XPS and UV-Vis DRS. The effects of V doping concentration on the phase structure and photocatalytic properties were investigated. XRD, Raman, and XPS show that V doping diffuses into TiO2 crystal lattice mainly in the form of V5＋ and causes a phase transition from anatase to mille. V doping can widen the light absorption range of TiO2, with the absorption threshold wavelength shifting from 425 to 625 nm. The photocatalytic activity of V-doped TiO2 powders were evaluated by the photocatalytic degradation of methyl orange （MO） under visible light irradiation. It is found that V doping enhances the photoeatalyilc activity under visible light irradiation and the optimal degradation rate of MO is about 95.8% with 1.0 at% V-doped TiO2.展开更多
CuO nanoparticles were synthesized using an energy-efficient and rapid solution combustion technique with malic acid employed as a fuel. The combustion-derived CuO nanoparticles were used as catalysts in a one-pot syn...CuO nanoparticles were synthesized using an energy-efficient and rapid solution combustion technique with malic acid employed as a fuel. The combustion-derived CuO nanoparticles were used as catalysts in a one-pot synthesis of aromatic nitriles from aromatic aldehydes and hydroxylamine hydrochloride. The catalyst was characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, and Brunauer-Emmett-Teller surface area analysis. The catalytic activity of the CuO nanoparticles in the synthesis of aromatic nitriles from aromatic aldehydes was evaluated. The present protocol offers the advantages of a clean reaction, simple methodology, short reaction duration (1-2 min), and high yield (85%-98%). The catalytic activity of the CuO nanoparticles was found to be higher than that of bulk CuO powder under the same conditions. The catalyst can also be recovered and reused up to four times with no significant loss of catalytic activity. The present approach is inexpensive and is a convenient technique suitable for industrial production of CuO nanoparticles and nitriles.展开更多
Ordered mesoporous copper incorporated Al;O;（Cu/Al;O;） with high Cu dispersion were prepared by a facile solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and urea as fuel. I...Ordered mesoporous copper incorporated Al;O;（Cu/Al;O;） with high Cu dispersion were prepared by a facile solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and urea as fuel. It is a facile and green route to synthesize catalysts for dimethyl ether directly from syngas. Cu/Al;O;catalysts were characterized by XRD, N;adsorption–desorption, SEM-EDS, and H;-TPR.The results indicate that the catalysts obtain an ordered mesoporous structure and copper is homogenously dispersed. The mesoporous Cu/Al;O;catalysts were utilized as bifunctional catalysts in syngas to dimethyl ether reaction（STD）. The copper content affects the catalytic performance in STD reaction. The CO conversion and DME selectivity of Cu/Al;O;with 15% copper molar ratio achieve 52.9% and 66.1%,respectively. Moreover, the mesoporous Cu/Al;O;catalysts show excellent stability in STD reaction.展开更多
Pure, and Europium ion doped Zinc oxide nanocrystals (ZnO:Eu3+) were synthesized by a solution combustion technique. The X-ray diffraction patterns (XRD) reveals the existence of the Eu2O3 phase. From the results of b...Pure, and Europium ion doped Zinc oxide nanocrystals (ZnO:Eu3+) were synthesized by a solution combustion technique. The X-ray diffraction patterns (XRD) reveals the existence of the Eu2O3 phase. From the results of both, X-ray diffraction and photoluminescence spectra (PL) reveal that Eu3+ ions successfully substitute for Zn2+ ions in the ZnO lattice, moreover, when the amount of doped Europium was varied, this changes are showed in changes in the luminescence intensity. The PL is broad and a set of colors was emitted which originates from ZnO and the intra 4f transitions of Eu3+ ions. The existence of the Zn-O, Eu3+-O and O1s bonding energies were confirmed by X-ray photoelectron spectroscopy (XPS) technique. The samples morphology was registered by a scanning electron microscopy (SEM) technique, and reveals that Europium ions are present on the surface of the ZnO nanocrystals.展开更多
In this experiment, pure, Y3+ doped ZnO and Cu2+ + Y3+ co-doped ZnO were synthesized by a solution combustion method. The Y3+ dopant concentration was fixed in 3%wt. and the Cu2+ dopant concentrations were 0, 1, 2, 3,...In this experiment, pure, Y3+ doped ZnO and Cu2+ + Y3+ co-doped ZnO were synthesized by a solution combustion method. The Y3+ dopant concentration was fixed in 3%wt. and the Cu2+ dopant concentrations were 0, 1, 2, 3, 10, and 20%wt. The XRD spectra showed that the original hexagonal wurtzite structure of ZnO is conserved after doping process, an increasing red shift until 10%wt. Cu2+ doping and decrease at higher Cu2+ doping and also, the chemical creation of the news Y2O3 and Y2Cu2O5 phases. The behavior of the photoluminescence of the samples as a function of Cu2+ doping reveal that the green emission band of the ZnO is quenching and the ZnO UV emission intensity decrease notably for all Cu2+ doping. The scanning electron microscope analysis of the Cu2+ + Y3+ co-doped ZnO samples reveal the existence of grains agglutinated forming like-spheres particles. However, the nano-sized characteristic of the crystals is confirmed.展开更多
Solution combustion synthesis of single-phase gadolinium gallium oxide （Gd3GasO12, GGG） nanopowders, by a fuel mixture approach using urea and glycine at a low temperature of 500 ℃, was being reported for the first...Solution combustion synthesis of single-phase gadolinium gallium oxide （Gd3GasO12, GGG） nanopowders, by a fuel mixture approach using urea and glycine at a low temperature of 500 ℃, was being reported for the first time. Based on the fact that urea and glycine are good fuels for gallium oxide and gadolinium oxide synthesis, the fuel mixture composition was obtained, which could lead to direct phase pure cubic Gd3Ga5O12 formation without any subsequent calcination step. Combustion was carried out in furnace pre-heated at 500 ℃. Thermogravimetric analysis （TGA） of combustion product showed negligible mass loss indicating direct formation of GGG powder. Fourier transform infrared （FTIR） spectrum of combusted product showed peak characteristic of GGG in case of mixed fuel. X-ray diffraction （XRD） confirmed formation of phase pure GGG at 500 ℃ in preheated furnace. Very fine, well dispersed nanometric particles of size range of 50-100 nm were obtained, being uniform and close to spherical morphology as observed by transmission electron microscope （TEM）.展开更多
In this research, the structural phase composition and room temperature luminescence properties of terbium doped zirconium oxide powders obtained by solution combustion synthesis method are presented as a function of ...In this research, the structural phase composition and room temperature luminescence properties of terbium doped zirconium oxide powders obtained by solution combustion synthesis method are presented as a function of the terbium content. The doping with terbium ions was performed during the redox combustion process and after annealing at 900°C during 20 hours. With the incorporation of the terbium ions into the zirconium oxide host, the stabilization of the high temperature tetragonal crystalline phase, as determined by x-ray diffraction technique, was obtained. Under ultraviolet radiation a bright green luminescence was observed at room temperature corresponding to the (4f) electron configuration of the Tb3+ ion, namely the electronic transitions 5D4 → 7Fn with n = 3 - 6. In addition, the undoped ZrO2 material showed green photoluminescence with high intensity.展开更多
Nanocrystalline zirconium（IV） oxide （nc-ZrO2） possessing high surface area was synthesized by a low tem- perature eco-friendly solution combustion method using a new organic fuel alanine. The powder XRD, SEM and s...Nanocrystalline zirconium（IV） oxide （nc-ZrO2） possessing high surface area was synthesized by a low tem- perature eco-friendly solution combustion method using a new organic fuel alanine. The powder XRD, SEM and surface area measurements were carried out for characterization of nc-ZrO2. The powder XRD results revealed that, the nc-ZrO2 has the pure tetragonal phase. The crystallite size calculated by Scherrer＇s formula and BET surface area were found to be ca. 53--57 nm and ca. 275 m2/g, respectively. SEM micrograph exhibited the macroporous nature of the powder, nc-ZrO2 has been employed as a catalyst for the solvent-free synthesis of 3,4-dihydro- pyrimidin-2-ones （DHPMs） by a microwave （MW） assisted one-pot, multicomponent Biginelli condensation reaction of araldehydes, ethylacetoacetate and urea or thiourea. DHPMs are obtained in good to excellent yields （85%-- 96%） under this reaction condition within short interval of time （10--20 min）.展开更多
The effect of different processing routes on the microstructure of nanocrystalline ceria powder has been investigated. The nanocrystalline ceria is produced by solid state high energy ball milling (HEBM) and liquid st...The effect of different processing routes on the microstructure of nanocrystalline ceria powder has been investigated. The nanocrystalline ceria is produced by solid state high energy ball milling (HEBM) and liquid state solution combustion synthesis (SCS) method. The liquid state route consists of a high temperature combustion reaction to form ceria from an aqueous solution of cerium ammonium nitrate (CAN) as an oxidizer and citric acid (CA) plus glycine (G) as mixed fuels. The powders have been characterized using techniques of X-ray diffraction (XRD), particle size analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The microstructural characterizations show that the particle size distribution of the ball milled ceria powder is much wider than that of ceria produced by the SCS. The scanning electron micrographs show that the ball milled ceria powders are compact and dense structure while SCS ceria powders are scattered and porous.展开更多
The Cu/Al_2O_3 catalysts were prepared by the solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and citric acid as fuel. The Cu/Al_2O_3 catalysts were characterized by XRD, N_2...The Cu/Al_2O_3 catalysts were prepared by the solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and citric acid as fuel. The Cu/Al_2O_3 catalysts were characterized by XRD, N_2 adsorptiondesorption, SEM-EDS, and H_2-TPR techniques. The test results indicated that this catalyst contained mesoporostity and highly dispersed copper. The Cu/Al_2O_3 catalysts were utilized as bifunctional catalysts in the syngas-to-dimethyl ether(STD) process. The CO conversion and DME selectivity were 70.9% and 58.8%, respectively. Moreover, the CO conversion kept increasing from 260 ℃ to 320 ℃ thanks to the high copper dispersion, which could reduce copper sintering at high reaction temperatures.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.51002054,51272079)the Fundamental Research Fundsfor the Central Universities,HUST(No.2011TS014)
文摘A series of nanocrystalline V-doped （0.0-3.0 at.%） TiO2 catalysts have been successfully prepared by the one-step solution combustion method using urea as a fuel. The obtained powders were characterized by XRD, SEM, Raman, XPS and UV-Vis DRS. The effects of V doping concentration on the phase structure and photocatalytic properties were investigated. XRD, Raman, and XPS show that V doping diffuses into TiO2 crystal lattice mainly in the form of V5＋ and causes a phase transition from anatase to mille. V doping can widen the light absorption range of TiO2, with the absorption threshold wavelength shifting from 425 to 625 nm. The photocatalytic activity of V-doped TiO2 powders were evaluated by the photocatalytic degradation of methyl orange （MO） under visible light irradiation. It is found that V doping enhances the photoeatalyilc activity under visible light irradiation and the optimal degradation rate of MO is about 95.8% with 1.0 at% V-doped TiO2.
文摘CuO nanoparticles were synthesized using an energy-efficient and rapid solution combustion technique with malic acid employed as a fuel. The combustion-derived CuO nanoparticles were used as catalysts in a one-pot synthesis of aromatic nitriles from aromatic aldehydes and hydroxylamine hydrochloride. The catalyst was characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, and Brunauer-Emmett-Teller surface area analysis. The catalytic activity of the CuO nanoparticles in the synthesis of aromatic nitriles from aromatic aldehydes was evaluated. The present protocol offers the advantages of a clean reaction, simple methodology, short reaction duration (1-2 min), and high yield (85%-98%). The catalytic activity of the CuO nanoparticles was found to be higher than that of bulk CuO powder under the same conditions. The catalyst can also be recovered and reused up to four times with no significant loss of catalytic activity. The present approach is inexpensive and is a convenient technique suitable for industrial production of CuO nanoparticles and nitriles.
基金supported by the National Natural Science Foundation of China(No.51,451,002,No.21,371,129)Shanxi Province Science Foundation for Youths(2,013,021,008-3)the joint funds of the National Natural Science Foundation of China–China Petroleum and Chemical Corporation(the state key program grant No.U1463209)
文摘Ordered mesoporous copper incorporated Al;O;（Cu/Al;O;） with high Cu dispersion were prepared by a facile solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and urea as fuel. It is a facile and green route to synthesize catalysts for dimethyl ether directly from syngas. Cu/Al;O;catalysts were characterized by XRD, N;adsorption–desorption, SEM-EDS, and H;-TPR.The results indicate that the catalysts obtain an ordered mesoporous structure and copper is homogenously dispersed. The mesoporous Cu/Al;O;catalysts were utilized as bifunctional catalysts in syngas to dimethyl ether reaction（STD）. The copper content affects the catalytic performance in STD reaction. The CO conversion and DME selectivity of Cu/Al;O;with 15% copper molar ratio achieve 52.9% and 66.1%,respectively. Moreover, the mesoporous Cu/Al;O;catalysts show excellent stability in STD reaction.
文摘Pure, and Europium ion doped Zinc oxide nanocrystals (ZnO:Eu3+) were synthesized by a solution combustion technique. The X-ray diffraction patterns (XRD) reveals the existence of the Eu2O3 phase. From the results of both, X-ray diffraction and photoluminescence spectra (PL) reveal that Eu3+ ions successfully substitute for Zn2+ ions in the ZnO lattice, moreover, when the amount of doped Europium was varied, this changes are showed in changes in the luminescence intensity. The PL is broad and a set of colors was emitted which originates from ZnO and the intra 4f transitions of Eu3+ ions. The existence of the Zn-O, Eu3+-O and O1s bonding energies were confirmed by X-ray photoelectron spectroscopy (XPS) technique. The samples morphology was registered by a scanning electron microscopy (SEM) technique, and reveals that Europium ions are present on the surface of the ZnO nanocrystals.
文摘In this experiment, pure, Y3+ doped ZnO and Cu2+ + Y3+ co-doped ZnO were synthesized by a solution combustion method. The Y3+ dopant concentration was fixed in 3%wt. and the Cu2+ dopant concentrations were 0, 1, 2, 3, 10, and 20%wt. The XRD spectra showed that the original hexagonal wurtzite structure of ZnO is conserved after doping process, an increasing red shift until 10%wt. Cu2+ doping and decrease at higher Cu2+ doping and also, the chemical creation of the news Y2O3 and Y2Cu2O5 phases. The behavior of the photoluminescence of the samples as a function of Cu2+ doping reveal that the green emission band of the ZnO is quenching and the ZnO UV emission intensity decrease notably for all Cu2+ doping. The scanning electron microscope analysis of the Cu2+ + Y3+ co-doped ZnO samples reveal the existence of grains agglutinated forming like-spheres particles. However, the nano-sized characteristic of the crystals is confirmed.
文摘Solution combustion synthesis of single-phase gadolinium gallium oxide （Gd3GasO12, GGG） nanopowders, by a fuel mixture approach using urea and glycine at a low temperature of 500 ℃, was being reported for the first time. Based on the fact that urea and glycine are good fuels for gallium oxide and gadolinium oxide synthesis, the fuel mixture composition was obtained, which could lead to direct phase pure cubic Gd3Ga5O12 formation without any subsequent calcination step. Combustion was carried out in furnace pre-heated at 500 ℃. Thermogravimetric analysis （TGA） of combustion product showed negligible mass loss indicating direct formation of GGG powder. Fourier transform infrared （FTIR） spectrum of combusted product showed peak characteristic of GGG in case of mixed fuel. X-ray diffraction （XRD） confirmed formation of phase pure GGG at 500 ℃ in preheated furnace. Very fine, well dispersed nanometric particles of size range of 50-100 nm were obtained, being uniform and close to spherical morphology as observed by transmission electron microscope （TEM）.
文摘In this research, the structural phase composition and room temperature luminescence properties of terbium doped zirconium oxide powders obtained by solution combustion synthesis method are presented as a function of the terbium content. The doping with terbium ions was performed during the redox combustion process and after annealing at 900°C during 20 hours. With the incorporation of the terbium ions into the zirconium oxide host, the stabilization of the high temperature tetragonal crystalline phase, as determined by x-ray diffraction technique, was obtained. Under ultraviolet radiation a bright green luminescence was observed at room temperature corresponding to the (4f) electron configuration of the Tb3+ ion, namely the electronic transitions 5D4 → 7Fn with n = 3 - 6. In addition, the undoped ZrO2 material showed green photoluminescence with high intensity.
文摘Nanocrystalline zirconium（IV） oxide （nc-ZrO2） possessing high surface area was synthesized by a low tem- perature eco-friendly solution combustion method using a new organic fuel alanine. The powder XRD, SEM and surface area measurements were carried out for characterization of nc-ZrO2. The powder XRD results revealed that, the nc-ZrO2 has the pure tetragonal phase. The crystallite size calculated by Scherrer＇s formula and BET surface area were found to be ca. 53--57 nm and ca. 275 m2/g, respectively. SEM micrograph exhibited the macroporous nature of the powder, nc-ZrO2 has been employed as a catalyst for the solvent-free synthesis of 3,4-dihydro- pyrimidin-2-ones （DHPMs） by a microwave （MW） assisted one-pot, multicomponent Biginelli condensation reaction of araldehydes, ethylacetoacetate and urea or thiourea. DHPMs are obtained in good to excellent yields （85%-- 96%） under this reaction condition within short interval of time （10--20 min）.
文摘The effect of different processing routes on the microstructure of nanocrystalline ceria powder has been investigated. The nanocrystalline ceria is produced by solid state high energy ball milling (HEBM) and liquid state solution combustion synthesis (SCS) method. The liquid state route consists of a high temperature combustion reaction to form ceria from an aqueous solution of cerium ammonium nitrate (CAN) as an oxidizer and citric acid (CA) plus glycine (G) as mixed fuels. The powders have been characterized using techniques of X-ray diffraction (XRD), particle size analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The microstructural characterizations show that the particle size distribution of the ball milled ceria powder is much wider than that of ceria produced by the SCS. The scanning electron micrographs show that the ball milled ceria powders are compact and dense structure while SCS ceria powders are scattered and porous.
基金supported by the joint funds of the National Natural Science Foundation of China–China Petroleum and Chemical Corporation (the state key program grant No.U1463209)the Shanxi coal based low carbon joint fund of the National Natural Science Foundation of China (the state key program grant No. U1610223)the Shanxi Province Science Foundation for Youths (201701D221040)
文摘The Cu/Al_2O_3 catalysts were prepared by the solution combustion synthesis method using aluminum nitrate and copper nitrate as oxidants and citric acid as fuel. The Cu/Al_2O_3 catalysts were characterized by XRD, N_2 adsorptiondesorption, SEM-EDS, and H_2-TPR techniques. The test results indicated that this catalyst contained mesoporostity and highly dispersed copper. The Cu/Al_2O_3 catalysts were utilized as bifunctional catalysts in the syngas-to-dimethyl ether(STD) process. The CO conversion and DME selectivity were 70.9% and 58.8%, respectively. Moreover, the CO conversion kept increasing from 260 ℃ to 320 ℃ thanks to the high copper dispersion, which could reduce copper sintering at high reaction temperatures.
