Preparation and photocatalytic activity of La^3＋ and Eu^3＋ co-doped TiO2 nanoparticles： photo-assisted degradation of methylene blue

Rare earth ions La³⁺ and Eu³⁺ co-doped TiO₂ photocatalyst (La-Eu/TiO₂) was prepared by sol-gel method, and characterized by various techniques such as X-ray diffraction (XRD), specific surface area and porosity (BET and BJH), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the La-Eu/TiO₂ was evaluated by the degradation of methylene blue (MB) under UV light irradiation. The catalyst had a relatively uniform particle diameter distribution in the range of 40–60 nm. When calcining at 600°C, the XRD patterns of La-Eu/TiO₂ indicated the anatase phase, while the XPS patterns showed the Ti⁴⁺, La³⁺ and Eu³⁺ ions existence. The DRS spectra showed red shift in the band-gap transition. The experimental results of MB degradation demonstrated that the photocatalytic activity of La-Eu/TiO₂ was significantly enhanced due to better separation of photogenerated electron-hole pairs.     

Preparation and photocatalytic activity of La~(3+) and Eu~(3+) co-doped TiO_2 nanoparticles: photo-assisted degradation of methylene blue

Rare earth ions La3+ and Eu3+ co-doped TiO2 photocatalyst (La-Eu/TiO2) was prepared by sol-gel method, and characterized by various techniques such as X-ray diffraction (XRD), specific surface area and porosity (BET and BJH), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the La-Eu/TiO2 was evaluated by the degradation of methylene blue (MB) ...     

Preparation and photocatalytic activity of Fe3O4@SiO2@ZnO:La

In this study, Fe₃O₄@SiO₂@ZnO:La microspheres were successfully prepared. The microspheres have the advantages of both ZnO doped with La and the Fe₃O₄@SiO₂ structure such that the former improves the photocatalytic activity of ZnO and the latter can be reused. The X-ray diffraction (XRD), a field emission scanning electron microscope (SEM), a field emission transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and a vibrating sample magnetometer (VSM) were used to characterize Fe₃O₄@SiO₂@ZnO:La microspheres. Methyl orange was used as the model molecule to study the effect of the Zn²⁺ concentration and the doping amount of La on the photocatalytic activity of Fe₃O₄@SiO₂@ZnO:La microspheres. Results show that in the synthesis of Fe₃O₄@SiO₂@ZnO:La microspheres, photocatalytic activity of the microspheres is enhanced first and weakened later with the increase of Zn²⁺ concentration. In the La doping process, the photocatalytic activity of Fe₃O₄@SiO₂@ZnO:La microspheres is enhanced with the increase in the La doping amount. The magnetic photocatalysts not only have high photocatalytic activity, but also can be reused. After being reused five times, the photocatalyst's degradation rate of methyl orange is still as high as 81%, which shows that magnetic photocatalysts have prospective wider applications in photocatalytic degradation of dye wastewater.     

Gd2O3 nanoparticles modified g-C3N4 with enhanced photocatalysis activity for degradation of organic pollutants

Gd₂O₃ nanoparticles modified g-C₃N₄ photocatalytic composites were synthesized by a simple one-step hydrothermal method. The structure, morphology, optical properties of the prepared photocatalyst were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM) and X-ray photoelectron spectroscopy (XPS). The result demonstrates that gadolinium is mainly dispersed on the surface of g-C₃N₄ in the form of Gd₂O₃, and does not destroy the lattice structure of g-C₃N₄. Besides, the gadolinium can cause the red shift of the absorption edge of light, narrow the band gap, and increase the separation efficiency of the photogenerated electron and hole of g-C₃N₄. Especially, the specific surface area of g-C₃N₄ can be significantly increased. Furthermore, g-C₃N₄/Gd-0.05 displays the highest photodegradation performance when it is used for degradation of methyl orange (MO), methylene blue (MB) and Rhodamine B (RhB). The photodegradation rate of g-C₃N₄/Gd-0.05 composites is 72.4% for MO, 95.5% for RhB, 100% for MB after 120 min under visible light (λ > 420 nm) irradiation. Narrow band gap promotes the separation of photogenerated electron and hole, which enhances the photocatalytic activity of g-C₃N₄. It is noted that g-C₃N₄/Gd-0.05 exhibits excellent photocatalytic stability by the photocurrent and the cyclic photodegradation of MO.     

Preparation of cerium and yttrium doped ZnO nanoparticles and tracking their structural,optical,and photocatalytic performances

Yttrium(Y) and cerium(Ce) co-doped ZnO nanoparticles(NPs) were synthesized via the simple sol-gel auto-combustion route.The effect of Ce and Y doping on the structure,morphology,optical,Zeta potential,and photocatalytic activities of ZnO NPs was examined by Fourier transform infrared(FTIR)spectrometer,X-ray diffraction(XRD),transmission electron microscope(TEM),UV-vis spectrophotometer,and Zetasizer instrument.XRD data show that the fabricated samples crystallize into a hexagonal wurtzite struct...     

One-step solution combustion synthesis of micro-nano-scale porous Cu/CeO2 with enhanced photocatalytic properties

The Cu/CeO₂ nanoporous composite material was prepared via a one-step and energy-saving method of solution combustion synthesis(SCS).The phase composition,surface morphology and optical characteristics of Cu/CeO₂ were studied.The results show that the SCS products are composed of cubic fluorite CeO₂ and Cu.Due to the generation and escape of gas during the synthetic reaction,the SCS CeO₂ shows porous structure,in which the mesopores(diameter 10-17 nm) ...     

Synthesis and photocatalytic property of Ce-doped SnO2

Pure SnO₂ and Ce-doped (1%, 4%, 7%, 10% in mass ratio) SnO₂ powders were prepared by a simple sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) specific surface area analyzers. Results showed that the 7% Ce-doped sample has a particle size of 0.1-0.3 μm with a narrow particle size distribution while the pure SnO₂ was consisted of large agglomerated particles with a diameter up to several micrometers. When used as the catalyst to degrade methyl orange (MO), the 7% Ce-doped sample showed best photocatalytic property. These properties can be attributed to the large surface area and small particle size of the 7% Ce-doped sample.     

Novel lanthanide coordination polymers based on mixed N,O-donor ligands and their visible-light-driven photocatalytic performance

In the present work,we prepared three isostructural lanthanide(Ln) coordination polymers(CPs).namely [Ln(Hhpc)(phen)(NO₃)](Ln=Gd(1),La(2),Y(3),H₃ hpc=5-hydroxy-1 H-pyrazole-3-carboxyIic acid,phen=1,10-phenanthroline) by hydrothermal method.Their structures were characterized by single crystal X-ray diffraction,Fourier transform infrared spectrum,elemental analysis,powder X-ray diffraction and thermal gravimetric analysis.CPs 1-3 are isostrutural and exhibit two-dimensional(...     

Highly dispersed CeO2–x nanoparticles with rich oxygen vacancies enhance photocatalytic performance of g-C3N4 toward methyl orange degradation under visible light irradiation

CeO₂/g-C₃N₄ photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic pollutants. The design and construction of highly active CeO₂/g-C₃N₄ photocatalysts without harsh conditions are still challenging. Herein, highly dispersed CeO_2–x nanoparticles with rich oxygen vacancies were successfully precipitated on the surface of g-C₃N₄ under mild conditions. The fabricated CeO_2–x/g-C₃N₄ exhibits remarkable activity and stability for photocatalytic degradation of MO pollutant. The optimal rate constant of MO degradation over CeO_2–x/g-C₃N₄ is about 0.031 min^?1, which is three times higher than that of g-C₃N₄. A negligible activity decrease is observed after three cycling runs. The enhanced catalytic performance can be ascribed to the excellent dispersion of CeO_2–x with rich oxygen vacancies that benefit O₂ adsorption and visible light absorption. In addition, the proper band alignment between CeO_2–x and g-C₃N₄ is conducive to the highly efficient separation of photogenerated electron–hole pairs.     

Photocatalytic degradation of imidacloprid by composite catalysts H3PW12O40/La-TiO2

A series of La-doped TiO2 with different mass fractions were prepared by sol-gel method. Composite catalysts H3PW12O40/La-TiO2 with different loading levels were synthesized using impregnation method. The prepared samples were characterized by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS) and nitrogen adsorption-desorption analysis. The Keggin structure of H3PW12O40 (HPW) remained intact on the surface of the composites, they had relatively uniform spherical grains of diameter less than 20 nm. The visible light activity of prepared composites were improved by loading HPW and doping La. The prepared composites were used as photocatalysts in degradation of pesticide imidacloprid. Results revealed that 20%H3PW12O40/0.3%La-TiO2 possessed the best photocatalytic activity. Thus, the degradation conversion of imidacloprid reached 98.17% after 60 min irradiation when 20%H3PW12O40/0.3% La-TiO2 was used as catalysts. The degradation of imidacloprid corresponded with first-order kinetic reaction, and the half life of the degradation of imidacloprid was 9.35 min in the optimal conditions.     

Synthesis of yttrium and cerium doped ZnO nanoparticles as highly inexpensive and stable photocatalysts for hydrogen evolution

Yttrium and cerium co-doped ZnO nanoparticles were synthesized by combustion route and characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET),energy dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),UV-visible diffuse reflectance spectroscopy(UV-vis DRS),photoluminescence(PL)and electrochemical impedance spectroscopy(EIS)techniques.The introduction of yttrium ions has efficiently increased the relative percentage of Ce³⁺ions in ZnO.Yttrium and cerium co-doped ZnO shows efficient photo activity for hydrogen evolution(10.61 mmol/((g·h))higher than previously reported optimal value for rare earth codoped ZnO photocatalysts.This remarkably increased hydrogen evolution can be ascribed to the synergy between electronic anchoring effect of Y³⁺/Y²⁺and Ce⁴⁺/Ce³⁺redox couples.This report presents new idea for the synthesis of efficient photocatalyst using economical route and ion anchoring effect.The hydrogen evolution was also tested using Na₂S and Na₂SO₃as electron donors under visible light illumination.The synthesized photocatalysts also exhibit high stability.     

A stable and efficient La-doped MIL-53(Al)/ZnO photocatalyst for sulfamethazine degradation

Photocatalytic technology can solve various environmental pollution problems, especially antibiotic pollution. A novel La-doped MIL-53(Al)/ZnO composite material was successfully synthesized by a combination of hydrothermal method and calcination, showing high photocatalytic degradation percent of sulfamethazine (SMT). The 2 mol% La MIL-53(Al)/ZnO photocatalyst shows the highest degradation efficiency toward SMT (92%) within 120 min, which is 4.1 times higher than pure ZnO (increased from 18% to 92%). In addition, the degradation analysis of SMT by high performance liquid chromatography proves that the products are CO₂ and H₂O. The improved photocatalytic activity is mostly caused by the following factors. (1) Doping La ions can decrease the band gap of ZnO, enhance light response, and effectively enhance the separation rate of photo-generated holes and electrons. (2) MIL-53(Al) can adsorb SMT and promote the separation of electron. This work shows that the synthesized La-doped MIL-53(Al)/ZnO photocatalyst is expected to be used as a green and effective method for treatment of environment water pollution.     

Synthesis,Characterization and Photocatalytic Studies of La,Dy-doped ZnO nanoparticles

Rare earth La Dy co-doped ZnO nanoparticles (Zn_0.98La_0.01Dy_0.01O, Zn_0.96La_0.02Dy_0.02O, Zn_0.94La_0.03Dy_0.03O, and Zn_0.92La_0.04Dy_0.04O) were synthesized by co-precipitation method at temperature of 500 °C for 2 h in air. The synthesized samples were characterized by powder X-ray diffraction (XRD), FE-SEM/EDS and UV–Visible spectrophotometer. The prepared nanoparticles exhibit a hexagonal wurtzite structure as observed from XRD measurements. It was observed that the La Dy co- doped ZnO nanoparticles (Zn_0.98La_0.01Dy_0.01O, Zn_0.96La_0.02Dy_0.02O, Zn_0.94La_0.03Dy_0.03O, and Zn_0.92La_0.04Dy_0.04O) exhibit higher optical absorbance spectrum at 400 nm to 800 nm wavelength due to its smaller crystal size (12.2 nm) as compared to the un- doped ZnO nanoparticles (253.1 nm). The photocatalytic activity of rare earth La Dy co- doped ZnO nanoparticles were studied by performing the decomposition of methylene blue dye solution under UV light irradiation within 0–4 h. The methylene blue dye solution was considerably photodegraded by Zn_0.92La_0.04Dy_0.04O photocatalyst under UV light irradiation within 2–4 h to the efficiency of 96 %. The pseudo first order rate constant of the degradation was found to be 0.0264 S^?1. The degradation mechanisms are discussed in this work.     

La-Ce共掺杂制备La3+-Ce3+/ZnO及其对亚甲基蓝的光催化降解

采用溶胶凝胶法制备了La-Ce共掺杂的La3+-Ce3+/ZnO光催化剂,同时用同种方法制备了ZnO、La3+/ZnO和Ce3+/ZnO以作对比.通过X射线衍射仪、透射电镜、紫外可见分光光度计,比表面及孔隙度分析仪等对制备的光催化剂进行了表征.以亚甲基蓝为模型污染物对所制备的光催化剂的光催化特性进行了评价.结果表明,所制备的La3+-Ce3+/ZnO光催化剂基本呈长方柱状,尺寸平均为57.3 nm,La-Ce共掺杂提高了ZnO的结晶度,促进了晶粒的长大.根据光催化实验结果,La-Ce共掺杂能够显著提高ZnO的光催化活性.在光催化降解500 mL的10 mg·L-1亚甲基蓝实验中,La3+-Ce3+/ZnO光催化剂对亚甲基蓝的降解率达93.7%,比纯ZnO、La3+-ZnO和Ce3+-ZnO分别提高了21.4%、19.2%和9.3%.      

Photocatalytic Activity of Nanosized TiO2 Enhanced by co-doping with Fe3+ and Nd3+ Ions

In this study, nanosized TiO2 co-doped with Fe3 and Nd3 ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was evaluated by degrading methylene blue (MB) solution. The results indicated that TiO2 crystalline size was reduced and phase transformation of anatase to rutile was suppressed as the content of doped Nd3 ion increased in the co-doped TiO2. The UV-vis spectra of co-doped TiO2 seemed to simply overlay two spectra of single metal doped TiO2, and had significantly increased absorbance in the ranges of 400~500 nm, 565~600 nm and 730~765 nm as compared to pure TiO2. The photocatalytic activity of co-doped TiO2 was obviously enhanced, and raised about 30% compared to that of pure TiO2 as doped Nd3 content was 0.15% and Fe3 content was 0.05%, respectively. The enhanced catalytic activity was attributed to a synergistic effect of two doped ions, where doped Fe3 ion inhibited the recombination of photogenerated electron and hole, and Nd3 ion brought more surface carboxyl to promote the degradation reaction.     

Hydrophilic and photocatalytic performances of lanthanum doped titanium dioxide thin films

Pure and La-doped TiO2 thin films were prepared on glass by sol-gel method using tetrabutyl titanate as Ti precursors. Their chemical composition, structure and properties were characterized by X-ray d...     

Synthesis,characteristics, and antibacterial activity of a rare-earth samarium/silver/titanium dioxide inorganic nanomaterials

An inorganic nanomaterials combination of Sm, Ag, and TiO2 was synthesized using supercritical fluid drying （SCFD） combined with solgel techniques. The structure, photocatalysis and bacteriostatic activity of the materials were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XRPS）, photocatalytic performance, and antibacterial activity experiments. The XRD results showed that the average particle diameter of Sm/Ag/TiO2 was 14.62 nm and Ag and Sm ions were dispersed on the surface of TiO2 in a highly dispersed, amorphous form. The TEM image showed that the size of the particle was 12 nm using the scherer formula. The XPS result showed that the element Sm was doped and Ag was loaded inorganic nanomaterials successfully. Sm/Ag/TiO2 exhibited optimal photocatalytic properties at 600 oC, the photocatalytic optimal proportion of Sm/Ag/TiO2 was 2：2：100. When the molar ratio was 2：2：100, the bacteriostatic circle diameter was 16 mm for Staphylococcus aureus, the minimum bacteriostatic concentration was 200μg/mL for white beads coccus, and the minimum bactericidal concentration was 2×10^4μg/mL for white beads coccus. The SEM results showed that the antibacterial material attached to the candida albicans cell surface, cells appeared fold deformation. Therefore the inorganic nanomaterials Sm/Ag/TiO2 had high temperature resistance, good photocatalytic and antibacterial characteristics in visible light.     

Preparation of La MnO_3/graphene thin films and their photocatalytic activity

A novel photocatalyst of La MnO3/graphene thin films with the perovskite-type was synthesized by sol-gel process assisted with spin-coating methods on glass substrates.The prepared samples were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), Brumauer-Emmett-Teller(BET) surface area analyzer, X-ray photoelectron spectroscopy(XPS) and UV-vis diffuse reflectance spectroscopy.Results showed that after the introduction of graphene, the perovskite structure was unchanged and the size of La MnO3 particles was about 22 nm, which uniformed growth in graphene sheet.Determination of contact angle indicated that the contact angle of glass substrate decreased and the hydrophilicity improved after treating with H2SO4 and APTES.The UV-Vis photocatalytic activity of the photocatalysts was evaluated by the degradation of diamine green B.La MnO3/graphene thin films had better photocatalytic ability than La MnO3 and Ti O2 films.The obtained k was 0.5627 and 0.3441 h–1 corresponding to La MnO3/graphene films and Ti O2 films, respectively.     

Preparation and photoluminescence enhancement of Li＋ and Eu3＋ co-doped YPO4 hollow microspheres

Li+ and Eu3+ co-doped YPO4 hollow microspheres were successfully synthesized by a sacrificial template method using polystyrene (PS) as template. Techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), as well as transmission electron microscopy (TEM) were employed to characterize the as-synthesized sample. Furthermore, the photoluminescence (PL) characterization of the Li+ and Eu3+ co-doped YPO4 microsphere was carried out and the effects of the doping concentration of Li+ and Eu3+ active center concentration as well as calcination temperature on the PL properties were studied in detail. The results showed that the incorporation of Li+ ions into the YPO4 :Eu3+ lattice could induce a remarkable improvement of the PL intensity. The highest emission intensity was observed with the compound of 5%Li+ and 5%Eu3+ co-doped YPO4 , whose brightness was increased by a factor of more than 2.2 in comparison with that of the YPO4 :5%Eu3+.     

Enhancement of luminescence intensity and spectroscopic analysis of Eu3+ activated and Li+ charge-compensated Bi2O3 nanophosphors for solid-state lighting

The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu~(3+)(1 mol%-11 mol%) doped and Li~+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical method. The average particle size was estimated using powder X-ray diffraction(PXRD)and transmission electron microscopy(TEM) and is found to be in the range of 30-35 nm. The scanning electron microscopy(SEM) images were highly dependent on sonication time and concentration of epigallocatechin gallate(EGCG) bio-surfactant. The energy gap of doped and co-doped Bi_2 O_3 nanophosphors was estimated using Kubelka-Munk(K-M) function and is found to be in the range of2.9-3.08 eV. The effect of Li+ co-doping on luminescence of optimized Bi_2 O_3:Eu~(3+) was studied and is found about more than 3 fold enhancement of emission intensity. Judd-Ofelt parameters(Ω_2, Ω_4 and Ω_6).transition probabilities(A_T), quantum efficiency(η), luminescence lifetime(τ_(rad)), color chromaticity coordinates(CIE) and correlated color temperature(CCT) values were estimated from the emission spectra and are discussed in detail. The estimated CIE chromaticity co-ordinates are very close to the NTSC(National Television Standard Committee) standard value of red emission. The synthesized NPs show excellent photocatalytic activity of acid red-88 under UV-light irradiation, which can degrade 98.1% in60 min. The decreasing electron-hole pair recombination rate with quick electron transfer ability is predominantly ascribed to the balance between crystallite size, morphology, band gap, defects, surface area, etc. These results show a light for the use of sonochemical route of Bi_2 O_3:Eu~(3+):Li~+ in solid state display and photocatalytic applications.