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White light-emitting diodes (WLEDs), which have high luminous brightness, longevity, low energy consumption and friendliness of environment, could be employed in diverse fields. Nevertheless, commercial phosphors are short of red light component. New phosphors which can emit red light are required. Mn2+ doped aluminum nitride (marked as AlN) red phosphors were prepared by a simple solid-state reaction. X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS), as well as photoluminescence (PL) spectra are utilized to characterize the prepared samples. The preparing process of AlN phosphors, phase formation and crystal structure, morphology, and photoluminescence are detailedly investigated. For Mn2+ doped AlN phosphor(marked as AlN:Mn2+), it exhibits an intense red emission caused by the 4T1(4G)-6A1(6S) transition of Mn2+. The unusual red emission of Mn2+ is ascribed to the strong nephelauxetic and crystal field between Mn2+ and the tetrahedrally coordinated N3−. The oxygen-related defects in AlN have a great influence on the photoluminescence properties of the Mn2+ doped AlN. The AlN:Mn2+ phosphors exhibits a high brightness, high color purity, and lower saturation, which make it a great candidate of red phosphors for white light-emitting diodes (WLEDs).

The (Fe1-xDyx)3C@C composites were produced by a simple sol-gel route. The structure, composition, morphology and magnetism of the composites are studied by many characterization methods, for example, X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopy (SEM, TEM) as well as vibrating sample magnetometer (VSM). Analysis of the above results indicates that the (Fe1-xDyx)3C is embedded in carbon nanotubes and carbon matrix and displays ferromagnetic properties. Moreover, this indicates that saturation magnetization (MS) values of the composites tend to increase with the increase in Dy doping. More importantly, we investigates the electrochemical hydrogen production capacity of the (Fe1-xDyx)3C@C composites.

(Fe1−xNdx)3N was successfully prepared by a simple complex method. The as-synthetized (Fe1−xNdx)3N exhibits regular rod-like morphology and excellent magnetic properties. X-ray diffraction, scanning electron microscopy with Energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, as well as vibrating sample magnetometer are employed to analyze the structure, morphology and magnetic properties of the samples. What’s more, when the Nd doping concentration is 3%, the coercivity reaches a higher value of 664.61 Oe. It is much higher than the coercivity of 408.84 Oe for the pure Fe3N. The material shows a trend of transition to hard magnet. It opens the way for other soft magnet translating into hard magnet by doping rare earth ions.

We investigated the CT process between a 4-mercaptobenzoic acid (4-MBA) monolayer and TiO2 NPs under high pressure using surface-enhanced Raman scattering (SERS). Employing the CT enhancement mechanism of semiconductors, we explore the CT process and explain how the pressure affects the process in the 4-MBA@TiO2 system.

Semiconductor nanomaterial is a kind of important enhancement substrate in surface-enhanced Raman scattering (SERS), and the charge-transfer (CT) process contributes dominantly when they are used as the enhancement substrate for SERS. Doping has significant effect on the CT process of semiconductor nanomaterials. Yet till now, none attempts have been made to explore how doping affects the CT process between the semiconductor and probe molecules. For the first time, this paper investigates the effect of gallium (Ga) doping on the CT process between ZnO nanoparticles and 4-mercaptobenzoic acid (4-MBA) monolayer. In this paper, a series of Ga-doped ZnO nanoparticles (NPs) with various ratio of Ga and Zn are synthesized and their SERS performances are studied. The study shows that the doped Ga can cause the band gap shrinkage of ZnO NPs and then affect the CT resonance process form the valence band (VB) of ZnO NPs to the LUMO of 4-MBA molecules. The band gap of Ga-doped ZnO NPs is gradually narrowed with the increasing doping concentration, and a minimum value (3.16 eV) is reached with the Ga and Zn ratio of 3.8%, resulting in the maximum degree of CT. This work investigates the effects of doping induced band gap shrinkage on CT using SERS and provides a new insight on improving the SERS performance of semiconductor NPs.

MgFe2O4 with inverse spinel structure is demonstrated to be an efficient support for constructing practical potential Pt catalyst (Pt/MgFe2O4). The resultant Pt/MgFe2O4 exhibits excellent catalytic behavior in CO oxidation under normal temperature and humidity. TOF calculated based on the content of Pt is 0.131 s–1. The excellent performance of Pt/MgFe2O4 attributes to the presence of surface undercoordinated lattice oxygens on MgFe2O4 support. These oxygens could participate in the initial CO oxidation and then be recovered under O2 conditions. Over this Pt/MgFe2O4 catalyst, CO catalytic oxidation should mainly follow a redox mechanism.

Hollow Gd 2 O 3 :Eu 3+ (denoted as H-Gd 2 O 3 :Eu 3+ ) nanospheres with excellent magnetic and luminescence properties were prepared through a self-template method using Gd(OH)CO 3 :Eu as template to form hollow precursors. The size of Gd 2 O 3 :Eu 3+ shell is 20 nm for H-Gd 2 O 3 :Eu 3+ nanospheres annealed at 600 °C with particle diameter of 200 nm. The hollow structure improved the luminescent intensity in contrast to solid spheres. The systematic studies about the effect of calcination temperature on the luminescence and magnetic properties were reported. Luminescent spectra shows that the I 610/590 (asymmetry factor of luminescence) varies with the calcination temperature, indicating that the color purity and local environment of Eu 3+ in Gd 2 O 3 changes. Moreover, the magnetization (M) becomes stronger while increasing the calcination temperature. The H-Gd 2 O 3 :Eu 3+ nanospheres may have potential application in magnetic resonance image (MRI), drug delivery, and drug loading and release.

Fe3C is a promising material with both high saturation magnetization and chemical stability. In this article, we present a facile sol–gel route for the synthesis of Fe3C/Fe nanocomposites, in which bromide was found to be the inducing agent for the conversion of FeCl3 to Fe3C. X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer were used to characterize the composites. The experimental results show that the composition and magnetic properties of Fe3C/Fe composites can be controlled by changing reaction temperatures, reaction time and the amount of inducing agent. Moreover, the possible formation mechanism of as-prepared nanostructures is discussed.

A method for the investigation of photocatalytic degradation of organic molecules adsorbed on the surface of a compound nanostructure, silver nanoparticle (Ag NP) modified titania nanotubes (TiO 2 NTs), namely Ag/TiO 2 NTs, was proposed. The method was applied to the photocatalytic degradation of rhodamine 6G (R6G) dye molecules in order to determine its effectiveness. The surface-enhanced Raman scattering (SERS) technique was employed to monitor the photodegradation processes on these bifunctional nanostructures. The photocatalytic characteristic was attributed to the TiO 2 NTs; however, the SERS activity was caused by the Ag NPs. The Ag/TiO 2 NTs were able to detect R6G molecular probes with concentration down to 10 −8 M. The substrates could not only degrade the adsorbates, but also discard them off under ultraviolet irradiation owing to the high photocatalytic activity of TiO 2 . Thus, the substrates were able to self-clean and be reused for a new SERS detection cycle. The photodegradation and SERS results revealed that Ag/TiO 2 NTs acted as promising candidates for photocatalytic activity and SERS substrates; and exhibited high recyclability in the detection of organic molecules. The optimized SERS-active substrates were then employed to study the photodegradation of R6G. The photodegradation kinetics analysis was assessed by selecting the strongest SERS peaks which indicated that the kinetics of the photodegradation of R6G followed the pseudo-first order reaction. Finally, the results presented herein demonstrated that the fabricated Ag/TiO 2 NTs nanostructures were remarkably suitable as photocatalytically active SERS substrates. Further, the substrates could be effectively utilized for highly sensitive in situ monitoring of the surface photodegradation processes of organic molecules and could be recycled in a more environmentally sustainable manner.

The synthetic strategy for the creation of Double-shell structure is based on a facile calcining process, in which carbon middle layer of Fe 3 O 4 @C@Y 2 O 3 :Eu 3+ @C@Y 2 O 3 :Eu 3+ composite nanostructures was calcined away. We obtained the Fe 3 O 4 @Y 2 O 3 :Eu 3+ @Y 2 O 3 :Eu 3+ nanocomposites with luminescent and magnetic properties. X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and photoluminescence spectroscopy (PL) were used to analyze the structure, morphology, magnetic and luminescence properties of the composites. The nanocomposites has spherical morphology with narrow size distribution. In addition, they exhibit good magnetization with the saturation magnetization of 1.99 emu/g) and unique red emission for Eu 3+ at 610 nm.

In this paper, co-precipitation synthesized Fe 3 O 4 microspheres have been encapsulated with nonporous silica and further functionalized by the deposition of Y 2 O 3 :Eu 3+ phosphors through a simple co-precipitation process, realizing a hollow structured material with mesoporous, magnetic and luminescent properties. The results reveal that the material shows typical ordered mesoporous characteristics, and have monodisperse spherical morphology with smooth surface and narrow size distribution. Additionally, the multifunctional nanocomposite shows the characteristic emission of Eu 3+ ( 5 D 0 – 7 F 1–4 ). Magnetism measurement reveals the paramagnetic feature of the samples. Furthermore, we also compared the magnetic and fluorescent properties of solid Fe 3 O 4 @SiO 2 @Y 2 O 3 :Eu 3+ and Fe 3 O 4 @HM-SiO 2 @Y 2 O 3 :Eu 3+ .

In this study, the bifunctional Fe@C@Gd 2 O 3 :Eu 3+ composites were prepared via a simple co-precipitation progress followed by a subsequent heat treatment under N 2 atmosphere. The reactive carbon interlayer offers many advantages including separating photoluminescent material from magnetic material and reducing magnetite Fe 3 O 4 to metal Fe. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM) and photoluminescence spectroscopy (PL) were used to analyze the structure, morphology, magnetic and luminescence properties of the composites. The Fe@C@Gd 2 O 3 :Eu 3+ composites with well-crystallized and core–shell structure were prepared and displayed good ferrimagnetic behavior at room temperature and a strong red emission. In addition, due to the excellent magnetic and luminescence properties of the prepared composites, they may have many great potential applications in many fields, such as biological imaging, cell tracking and drug delivery.

Multifunctional Fe@C@Y2O3:Eu3+ nanocomposites were prepared by the solvo thermal method, and their structure, magnetic and luminescent properties were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and scanning electron microscope (SEM). Results show that the nanocomposites are spherical with a mean diameter of 700 nm and there are high special saturation magnetization (47.4 emu/g) and strong red emission under UV-light. Even dispersed in water solution, the nanocomposites also exhibit a strong red emission under ultraviolet light radiation, and it could be manipulated using an external magnet. Thus it looks promising for application in biomedicine field, especially in drug targeting and fluorescence label. And we also discussed the effect of the electron transfer process between the Fe magnetic core and Y2O3:Eu3+ shell.

GdAl3(BO3)4:Ln3+ (Ln3+:Eu3+, Tb3+, Dy3+) nano-phosphors were prepared by sol–gel method. The structure properties of the phosphors are characterized by XRD, and GdAl3(BO3)4:Ln3+ nano-phosphors have average sizes around 40 nm. The doping concentrations of Eu3+, Tb3+ and Dy3+ ions in GdAl3(BO3)4 nano-phosphors are from 1 to 9 mol% for Eu3+ ions, from 2 to 12 mol% for Tb3+ ions and from 1 to 5 mol% for Dy3+ ions, respectively. The luminescent properties of rare-earth ions doped GdAl3(BO3)4 nano-phosphors are analyzed by the photoluminescence spectra, which prime doping concentration of Eu3+, Tb3+, and Dy3+ ions are at 5, 12 and 3 mol%, respectively. The energy transfers in the luminescent processes of rare-earth ions doped GdAl3(BO3)4 nano-phosphors are discussed.

In this paper, we report on the bifunctional Fe 3 O 4 @SiO 2 @YP 0.1 V 0.9 O 4 :Dy 3+ nanocomposites were prepared by the solvothermal method and sol–gel method. The structure, photoluminescence (PL) and magnetic properties of the nanocomposites were characterized by means of X-ray diffraction, scanning electron microscope, transmission electron microscope, PL excitation and emission spectra and vibration sample magnetometry. It is shown that Fe 3 O 4 @SiO 2 @YP 0.1 V 0.9 O 4 :Dy 3+ nanocomposites with a core–shell structure present excellent fluorescent and magnetic properties. Additionally, the effects of the magnetic field on the luminescence properties of nanocomposites were discussed.

Multifunctional nanocomposites with Fe/Fe3O4 nanoparticles as the core and europium-doped yttrium oxide (Y2O3:Eu) as the shell (Fe/Fe3O4@Y2O3:Eu) have been obtained successfully employing a solvothermal method. The nanocomposites showed both ferrimagnetic behavior and unique europium fluorescence properties with high emission intensity. The spectra changes induced by the UV light irradiation and the magnetic field have been systematically studied and compared in detail. The relationship between fluorescence and magnetic properties of the multifunctional nanocomposites has been investigated in our manuscript. These multifunctional nanocomposites could be used in a number of biomedical applications, such as drug targeting, cell separation and bioimaging.

The multifunctional Fe3O4@Y2O3:Eu3+ nanocomposites were prepared by a facile solvothermal method with Fe3O4 nanoparticles as the core and europium-doped yttrium oxide (Y2O3:Eu3+) as the shell. It is shown that Fe3O4@Y2O3:Eu3+ nanocomposites have a strong photoluminescence and special saturation magnetization Ms of 6.1 emu/g at room temperature. The effects of the magnetic field on the luminescence intensities of the nanocomposites are being discussed. The multifunctional nanocomposites with magnetic resonance response and fluorescence probe properties may be useful in biomedical applications, such as cell separation and bioimaging.

Multifunctional Fe/Fe3O4@ZnS nanocomposites were synthesized by hydrothermal method, with Fe/Fe3O4 doped Co ion as the magnetic core and ZnS as the luminescent shell. The morphology, structure, luminescent and magnetic properties of the nanocomposites were investigated by XRD, FESEM, photoluminescence PL and VSM. The maximum emission peak and special saturation magnetization Ms of the nanocomposites are at 467 nm and 78.6 emu/g, respectively. For the nanocomposites, it is shown that there are both better magnetic behavior and fluorescence properties.

In this study, the hydrothermal synthesized Fe3O4 nanoparticles are encapsulated with SiO2 via the Stober method and further functionalized by the deposition of YVO4:Eu3+ phosphors, realizing a hybrid material with magnetic and luminescent properties. The bifunctional nanocomposites displayed a strong red emission and good ferrimagnetic behavior at room temperature. The high magnetization values make the nanocomposites quickly respond to the external magnetic field. The results also indicate that the nanocomposites may have potential applications for optical imaging or drug delivery. Moreover, we discussed the effects of the magnetic field on the luminescence intensity.

Fe–Co alloy and Sm3+-substituted magnetite nanowire composites (CoxFe1−x/CoyFe1−ySmzFe2−zO4) have been synthesized via a hydrothermal method without using surfactants or templates. The effects of substitution on structure and morphology were investigated by powder X-ray diffraction, X-ray photoelectron spectroscopy, Mossbauer spectroscopy, and transmission electron microscopy (TEM). The TEM image shows that the average diameter of the magnetite nanowires is about 40 nm and the length is several micrometers. The z=0.1 composite shows relatively high saturation magnetization (92.3 emu/g) detected by a vibrating sample magnetometer. The possible growth mechanism of the nanowires is discussed on the basis of the crystal structure of the materials. From the perspective of thermodynamics, we explain the postulated mechanism of the hydrothermal reaction.

A series of iron–cobalt alloy and cobalt–ferrite composites doped with La3+ (CoxFe1−x/CoyLazFe3−y−zO4) in which the Fe–Co alloy has either a bcc or a fcc structure and the oxide is a spinel phase, have been synthesized by using the disproportionation of Fe (OH)2 and the reduction of Co (II) by Fe0 in a concentrated and hot KOH solution. when x ≤ 0.1, the structures of the FexCo1−x alloy and cobalt–ferrite are fcc structure; and when x ≥ 0.25, the structures of the FexCo1−x alloy is bcc structure. The fcc structure of alloy is favored for [KOH] close to 9 N, Co(II)/Fe(II) ratios between 0.5 and 0.9 and short reaction time of synthesis. And the bcc structure of the alloy is favored for [KOH] close to 1 N, Co(II)/Fe(II) ratios between 0.1 and 0.5 and long reaction time of synthesis. A low [KOH] favors nucleation leading to octahedral of 1 µm. And [KOH] of 9–12 N favors particle growth. The metal occurs in square particles of 100–150 nm included within the spinel. Powder X-ray diffraction (XRD), thermal gravity analysis (TGA) and different thermal analysis (DTA), scanning electron microscope (SEM), transmission electron micrograph (TEM) and vibrating sample magnetometer (VSM) were employed characterize the crystallite sizes, structure, morphology and magnetic properties of the composites. And the effect of the Co(II)/Fe (II) ratio (0 ≤ Co/Fe ≤ 1), concentration of KOH, reaction time and substitution Fe3+ ions by La3+ ions on structure, magnetic properties of the composites were investigated.

(Y,Gd)BO 3 :Eu powders were prepared by conventional solid-reaction method. Surface-modified (Y,Gd)BO 3 :Eu powders with MgF 2 were prepared by the emulsion method. The best preparing way is that MgCl 2 was dropped to the mixture of NH 4 F and (Y,Gd)BO 3 :Eu powders to prepare surface-modified (Y,Gd)BO 3 :Eu powders. The interaction between F − ions and the phosphor particles was discussed. It is shown that the structures of surface-modified (Y,Gd)BO 3 :Eu powders were measured by XRD. The luminescent properties of (Y,Gd)BO 3 :Eu powders with MgF 2 are researched.

Nanocrystalline Ni 0.7 Mn 0.3 Nd x Fe 2− x O 4 ferrites (Nd 2 O 3 -doped Ni–Mn ferrites) have been prepared by the emulsion method. The structure and the morphology of the ferrite nanoparticles were measured by using X-ray diffractometer (XRD), Differential thermal analysis (DTA) and thermal gravity (TG). It is shown that the structure of Ni 0.7 Mn 0.3 Nd x Fe 2− x O 4 ferrite nanoparticles is single spinel structure. The average crystalline sizes of the samples are from 7.0 to 62.3 nm. The magnetic properties of samples were tested at room temperature by using a Vibrating Sample Magnetometer (VSM). The nanoparticles of the samples have superparamagnetisim which particle sizes are about 10 nm.

A series of MCM-48 mesoporous molecular sieves doped with Ti, Cr, Mo, Zr, and Cu were synthesized by hydrothermal crystallization and characterized by XRD, UV, HRTEM and N2 adsorption. Selectively catalytic oxidation of α-long chain eicosanol to the corresponding α-eicosanoic acid over this series of catalysts has been tested. The optimum reaction temperature and reaction time were given. Experimental results show that MCM-48 molecular sieves doped a suitable amount of transition metal may enhance the yield and the selectivity of α-eicosanoic acid. The sort and the amount of the doped transitional metal have important effect on the catalytic activity.

Luminescent Y2O3:Eu(3+) particles have been deposited on the surface of ferromagnetic mesoporous CoFe2O4@mSiO2 nanoparticles by a co-precipitation method, obtaining multifunctional CoFe2O4@mSiO2@Y2O3:Eu(3+) nanocomposites. XRD, SEM, TEM, EDX, XPS, N2-adsorption-desorption, FT-IR, VSM and PL were used to characterized the samples. The results reveal that the nanocomposites display typical mesoporous characteristics with high surface areas (BET), large pore volumes and core-shell structures. The composites show ferromagnetic properties and red luminescence from the (5)D0-(7)F2 transition at 610 nm. The size and the magnetic and luminescence properties of the composites could be tuned by systematically varying the experimental parameters, such as the annealing temperature, the mass ratio of CoFe2O4@mSiO2 to Y2O3:Eu(3+), and the volume of TEOS. A possible quenching mechanism of the luminescent Y2O3:Eu(3+) by the ferromagnetic CoFe2O4 is proposed. The high BET and large pore volume may give the composite potential application in controlled drug release.

Carbon-encapsulated Fe-Co alloy nanoparticles (Fe-Co(C)) have been fabricated with different Co/Fe ratios by an efficient solid-state route using melamine as carbon source. The structure and morphology of Fe-Co(C) nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The XRD characterization results reveal that all products are alloys with no carbide impurity. The TEM and HRTEM observations show that the alloy nanoparticles are encapsulated in carbon shells. Additionally, the reactions involved in the syntheses are postulated. The variation of magnetic properties of Fe-Co(C) with Co/Fe has been discussed according to the room temperature VSM measurement results.

Many efforts have been devoted towards the fabrication of multifunctional (mesoporous, magnetic and fluorescent) nanocomposites due to their growing applications as adsorbents, catalysts, and biomedical application, etc. Novel, flower-structured multifunctional Fe3O4/YVO4:Eu(3+)@SiO2 microspheres were successfully synthesized through a simple self-assembled process. The as-obtained products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption, photoluminescence (PL) spectroscopy and using a vibrating sample magnetometer (VSM). The results reveal that the novel composites exhibit typical mesoporous structure, narrow size distribution, good monodispersity, excellent luminescent properties and superparamagnetic features. The effects of magnetic field on the luminescent intensity of multifunctional composites have been discussed in our manuscript. Furthermore, the adsorption experiments indicate that the resulting multifunctional composites are powerful adsorbents for the removal of methylene blue from water with a maximum adsorption efficiency of 98%. It is envisioned that multifunctional composites with high surface area are of particular interest for adsorption of pollutants, separation, and water purification.