Search

Rare earth doped BaGdF5 compounds have received much attention because they not only exhibit excellent upconversion emission, but also present attractive paramagnetic properties derived from the large magnetic moment of Gd3+ ions. Although great efforts have been made to realize the controllable synthesis of BaGdF5 nano- or micro-crystals, more environmentally friendly solvents and reactants rather than organic solvents and trifluoroacetates were expected to be used. In this work, we have reported an ionic liquid/H2O two-phase system to synthesize Ce3+/Dy3+/Eu3+/Yb/Er doped BaGdF5 octahedra, in which an environmentally friendly ionic liquid was used as the reactant and morphology controller. The growth mechanism of BaGdF5 octahedra has been proposed. Furthermore, the luminescent color of BaGdF5:Ce3+/Dy3+/Eu3+ octahedra can be tuned by adjusting the doping concentration of Ce3+, Dy3+, and Eu3+ ions. In addition, the up-conversion emission related temperature sensing performance of BaGdF5:Yb/Er has been discussed and this phosphor showed potential application in thermal sensing. This work provides a new route for the synthesis of rare earth fluorides. [ABSTRACT FROM AUTHOR]

Three different transition metal elements doped Fe3N were prepared by a simple path. Their structure, morphology, and magnetic properties were carefully investigated by X‐ray diffraction, transmission electron microscopy as well as vibrating sample magnetometer. Moreover, we detailedly compared and analyzed the impact of different transition metal elements on the properties of Fe3N. Combining with the results of analysis and comparison, it indicates that this simple method can be used to explore the impact on the transition metal nitride incorporated with different transition metal elements in the carbon‐rich system. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a series of three‐dimensional porous flower‐like zinc doped NiCo2O4 (ZNCO) nanostructures with different Zn doping level are successfully prepared by a facile solvothermal process without using any templets. The obtained products are characterized by various techniques, and their electrocatalytic performances are also assessed by the oxygen evolution reaction (OER). According to the electrochemical characterization, it is demonstrated that ZNCO‐0.15 (i.e., Zn0.15Ni0.85Co2O4) nanoflowers show a lower overpotential, smaller Tafel slope, higher electrochemical active surface area (ECSA), as well as a larger turnover frequency (TOF) value than those of Co3O4, NiCo2O4, and ZnCo2O4 nanoflowers, indicating that introduction of an optimal content of zinc ions plays an important role in enhancing electrocatalytic performances for OER. The enhanced OER performance of ZNCO‐0.15 could be attributed to the increased number of active sites (Co3+), accelerated kinetic rate, and promoted conductivity of the catalyst with the incorporation of zinc ions. [ABSTRACT FROM AUTHOR]

Co-doping Eu2+/3+ in a single-phase phosphor is an efficient way to achieve emission color regulation, which possesses great prospective application prospects in anti-counterfeiting, optical temperature and optical pressure sensing. In this work, Eu2+/3+ co-doped Ca 5 (PO 4) 3 F microspheres were successfully prepared by ionic liquid-assisted electrospinning, and the morphologies changed from microspheres to microfibers by altering the viscosity of the solution. Furthermore, the formation mechanism of Ca 5 (PO 4) 3 F: Eu2+/3+ was proposed. The luminescence properties of Ca 5 (PO 4) 3 F: Eu2+/3+ samples were reported in detail, and emission behavior driven by excitation wavelength, temperature and pressure were revealed. Utilizing the excitation wavelength color development behavior of Ca 5 (PO 4) 3 F: Eu2+/3+ phosphors, the films prepared with Ca 5 (PO 4) 3 F: Eu2+/3+ and PVA displayed red or blue light at 254/365 nm. More importantly, the Ca 5 (PO 4) 3 F: Eu2+/3+ phosphor exhibited temperature and pressure sensitivity, due to the distinct emission behaviors of Eu2+ and Eu3+ ions in response to changes of temperature and pressure. Notably, Ca 5 (PO 4) 3 F: Eu2+/3+ phosphor exhibited remarkable pressure stability and sensitivity, with values of 84.6% and 24.98% GPa-1. Therefore, this multifunctional material possesses great potential applications in anti-counterfeiting and temperature as well as pressure sensing. In conclusion, this research furnishes a novel synthetic way for the preparation of fluorapatite, which holds significant importance in providing a relatively straightforward approach to combine these multi-functions in single-phase materials. [ABSTRACT FROM AUTHOR]

Tantalum-based perovskite-like metal oxides (PLMOs) are one of promising candidates for photocatalytic water splitting due to their high stability, structural tunability and excellent photocatalytic activity. However, the photocatalytic hydrogen production activity is often hampered by their narrow light absorption range and severe photo-generated carrier recombination. In this research, a series of Fe-doped KCuTa 3 O 9 (FKCTO-x) oxides were synthesized for the first time via one-step high-temperature solid-state reaction. Based on the detailed characterization analysis, Fe atoms have been successfully incorporated into the lattice of KCuTa 3 O 9. An extended visible light absorption range and enhanced separation of the photogenerated carriers have been achieved in Fe-doped KCTO. As a result, all the FKCTO-x samples exhibit enhanced photocatalytic hydrogen evolution activities, among which FKCTO-2 shows an optimal hydrogen production rate of 5.51 µmol h−1 under visible light irradiation, far exceeding that of the pure KCTO. This work provides a simple and effective strategy to design and prepare highly efficient visible-light-driven PLMOs for photocatalytic water splitting. [Display omitted] • A series of novel Fe-doped KCuTa 3 O 9 photocatalysts were synthesized successfully. • Fe atoms have been successfully incorporated into the lattice of KCuTa 3 O 9. • The extended visible light absorption range has been achieved in Fe-doped KCuTa 3 O 9. • The internal electric field helps the separation of photogenerated carriers. • The optimized FKCTO-2 shows an excellent photocatalytic H 2 production performance. [ABSTRACT FROM AUTHOR]

Through hydrothermal synthesis and impregnation-reduction processes, a series of Pd-based nanocomposites using N-doped carbon layers coated ZrSBA-15 as the supports have been manufactured, aiming to upgrade the catalytic activity and stability of the catalysts. Pentaethylenehexamine (PEHA) was served as a nitrogen source to generate N-doped carbon (CN) layers that were pre-deposited into the acidic platelet framework ZrSBA-15, and then followed by introducing Pd 0 nanoparticles (NPs) onto it, finally leading to the formation of target composite Pd/CN-ZrSBA-15. The samples were characterized by XRD, TEM, SEM, N 2 adsorption-desorption isotherm, FTIR, XPS etc. The catalytic performance of as-prepared catalysts was evaluated by the aerobic oxidation of benzyl alcohol and the reduction of 4-NP, respectively. Duo to the platelet-like morphology with shortened channels and the modification of N-doped carbon layers, which could effectively decrease pore blocking in the process of preparation and reactions as well as enhance the metal-support interaction, the derived catalysts could afford 85% conversion of benzyl alcohol and 100% selectivity of benzaldehyde, and the conversion of 4-NP was also up to 96%. More remarkably, the catalysts could be reused at least ten times without significantly loss in catalytic activity. [ABSTRACT FROM AUTHOR]

Eu 3+ and Gd 3+ ions co-doped amorphous silica nanorods were prepared using a simple sol–gel method, and their luminescent properties were studied under the excitation of ultraviolet light. X-ray diffraction (XRD), Energy-dispersive X-ray (EDX) spectroscopy, Fourier transform infrared spectrum (FT-IR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM), and Photoluminescence (PL) spectra were employed to characterize the products in detail. The nanorods are uniform and their diameters and lengths are in the range of 200–300 nm and 500–700 nm, respectively. Energy transfer process in Gd 3+ and Eu 3+ co-doped silica, where a ground state of Gd 3+ , 8 S 7/2 , was selectively excited to a 6 I J state under the excitation of 274 nm, was studied in terms of luminescence spectra, which indict that the energy transfer of Gd 3+ –Eu 3+ is efficient. The mechanism of energy transfer from Gd 3+ to Eu 3+ is a resonant transfer, in which electric dipole–dipole interaction plays a leading role. Furthermore, the doping concentration-dependence of Eu 3+ ions on the energy transfer efficiency was also investigated. [ABSTRACT FROM AUTHOR]