摘要：
<jats:title>Abstract</jats:title><jats:p>In the recent years, Mn<jats:sup>4+</jats:sup>‐doped phosphors for indoor plant cultivation have received extensive concern owing to the far‐red emission that can match well with the absorption spectra of plant pigments. Whereas, many Mn<jats:sup>4+</jats:sup>‐doped phosphors still face some challenges such as poor light efficiency and low thermal stability. It is an effective way to resolve these problems via cation vacancies engineering. Herein, the Ca<jats:sub>14−</jats:sub><jats:italic><jats:sub>x</jats:sub></jats:italic>Al<jats:sub>10</jats:sub>Zn<jats:sub>6−</jats:sub><jats:italic><jats:sub>y</jats:sub></jats:italic>O<jats:sub>35</jats:sub>: Mn<jats:sup>4+</jats:sup> phosphors are successfully synthesized by combustion method. The luminescence intensity of Ca<jats:sub>14−</jats:sub><jats:italic><jats:sub>x</jats:sub></jats:italic>Al<jats:sub>10</jats:sub>Zn<jats:sub>6−</jats:sub><jats:italic><jats:sub>y</jats:sub></jats:italic>O<jats:sub>35</jats:sub>: Mn<jats:sup>4+</jats:sup> phosphor is enhanced through engineering Ca<jats:sup>2+</jats:sup> and Zn<jats:sup>2+</jats:sup> vacancies according to the charge compensation mechanism. The optimal content of each Ca<jats:sup>2+</jats:sup> and Zn<jats:sup>2+</jats:sup> vacancy is equal to be 0.3. Furthermore, the defect formation is accompanied with lattice distortion, which plays a vital role in driving the excited phonon traps to reduce the energy loss by non‐radiation transitions. Therefore, the thermal stability of Ca<jats:sub>14−</jats:sub><jats:italic><jats:sub>x</jats:sub></jats:italic>Al<jats:sub>10</jats:sub>Zn<jats:sub>6−</jats:sub><jats:italic><jats:sub>y</jats:sub></jats:italic>O<jats:sub>35</jats:sub>: Mn<jats:sup>4+</jats:sup> phosphor is also improved via engineering cation vacancies. In addition, the Ca<jats:sub>14−</jats:sub><jats:italic><jats:sub>x</jats:sub></jats:italic>Al<jats:sub>10</jats:sub>Zn<jats:sub>6−</jats:sub><jats:italic><jats:sub>y</jats:sub></jats:italic>O<jats:sub>35</jats:sub>: Mn<jats:sup>4+</jats:sup> phosphors can be effectively excited by blue light and it exhibits far‐red emission due to the Mn<jats:sup>4+</jats:sup> spin‐forbidden <jats:sup>2</jats:sup>E→<jats:sup>4</jats:sup>A<jats:sub>2</jats:sub> transition. The results suggest that the Ca<jats:sub>14−</jats:sub><jats:italic><jats:sub>x</jats:sub></jats:italic>Al<jats:sub>10</jats:sub>Zn<jats:sub>6−</jats:sub><jats:italic><jats:sub>y</jats:sub></jats:italic>O<jats:sub>35</jats:sub>: Mn<jats:sup>4+</jats:sup> phosphors can have a tremendous potential in indoor plant cultivation.</jats:p>
摘要：
Three-dimensional (3D) porous graphene oxide-maize amylopectin (GO-MA) composites with controllable pore-sizes composites in the range of 6-40nm were prepared by facile hydrothermal-assisted assembly approaches. The morphologies, pore sizes, specific surface area (SSA) and compositions of GO-MAx:y composites with and different GO-to-MA mass ratios (x:y) were characterized by scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). To reveal the adsorption-desorption mechanism, effects of contact time, temperature, initial adsorbate concentration, pH value of the solution on the adsorption process were studied in detail. The adsorption capacities of 3D GO-MA20:1 composite for organic contaminants including tert-butyl hydroquinone (TBHQ), p-aminophenol (PAP), p-nitrophenol (PNP), o-nitrophenol (MNP), hydroquinone (HQ), alizarin red S (ARS) and neutral red (NR) were 22.17, 116.4, 44.78, 36.96, 16.10, 39.92 and 24.23mgg(-1), respectively. The adsorption capacities of GO-MA30:1 composite for inorganic substances including Pb(2+), Mn(2+), Cr2O7(2-), Cd(2+), Cu(2+), Nd(3+), La(3+), Y(3+), Yb(3+) and Er(3+) were 84.76, 7.92, 13.6, 17.64, 30.56, 25.52, 12.48, 16.96, 23.32 and 30.32mgg(-1), respectively. In addition, GO-MAx:y composites also exhibited high mechanical properties and good reusability. Consequently, GO-MAx:y composites could be used as reusable adsorbents for removal/enrichment inorganic/organic substances in aqueous solutions.
关键词：
Activation energy;Citrus fruits;Emission spectroscopy;High temperature applications;Light emitting diodes;Phosphors;Solid state reactions;Thermodynamic stability;Chromaticity coordinates;Concentration quenching;Concentration-dependent;Diffuse reflection spectra;Excitation and emission spectra;High temperature solid-state reaction;Internal quantum efficiency;Plant growth;Light emission
摘要：
In this paper, a series of novel orange-red emission phosphors Sr8ZnY(PO4)(7):Sm3+ (SZYP:Sm3+) were synthesized by high-temperature solid-state reaction. The photoluminescence and concentration-dependent properties of this phosphor were investigated carefully through diffuse reflection spectra, excitation and emission spectra, Commission Internationale de l'Eclairage (CIE) chromaticity coordinate and decay times. SZYP:Sm3+ could be efficiently excited by n-UV and blue lights which center at 318, 345, 363, 376, 401, 410, 440 and 475 nm, respectively. The characteristic orange-red emission peaking at 563, 601 and 647 nm had been detected, which should be attributed to the characteristic f-f forbidden transition of Sm3+. The internal quantum efficiency (IQE) of ideal phosphor of SZYP:0.09Sm(3+) reached as high as 47%. In addition, The concentration quenching mechanism and thermal stability of SZYP:Sm3+ were further investigated. It was found SZYP:Sm3+ can maintain 93% of initial emission intensity at 150 degrees C and the corresponding activation energy was calculated to be 0.26 eV based on Arrhenius formula. The emission intensity of 1.0Mg(2+) and 0.02Al(3+) incorporated SZYP:0.09Sm(3+) reached up to 134% and 117% of the initial value, respectively. Moreover, (light-emitting diodes) LED devices were fabricated by employing the optimized samples as orange-red component with 365 nm n-UV chips. The desired emission in plant absorption region and extremely high thermal stability imply that SZYP:Sm3+ is suitable for the application in plant growth LED lighting. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
摘要：
Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review. Various fabrication methods of these oxides are introduced in detail, and their advantages and disadvantages are analyzed. Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides. As a bifunctional electrocatalyst, perovskite-type oxides are widely used in rechargeable metal-air batteries. The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized. This work is concentrated on the structural stability, the phase compositions, and catalytic performance of perovskite-type oxides in oxygen/air electrodes. The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.
作者机构：
[Zhuang, Shuxin; Peng, Zhengyu; Lu, Mi; Zhou, Litao; Lin, Daqin; Zhuang, SX] Xiamen Univ Technol, Sch Mat Sci & Engn, Key Lab Funct Mat & Applicat Fujian Prov, Xiamen 361024, Peoples R China.;[Zhou, Nan] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Wu, Qihui] Quanzhou Normal Univ, Sch Chem Engn & Mat Sci, Dept Chem Mat, Quanzhou 362000, Peoples R China.
通讯机构：
[Zhuang, SX; Lu, M] X;Xiamen Univ Technol, Sch Mat Sci & Engn, Key Lab Funct Mat & Applicat Fujian Prov, Xiamen 361024, Peoples R China.
关键词：
Dye-sensitized solar cells;Hydrothermal method;Cu modification;Zinc oxide
摘要：
The Cu-modified ZnO nanoflowers as photoanode material for dye sensitized solar cells are synthesized via a cetylmethylammonium bromide-assisted hydrothermal method. The main phase of the synthesized samples well matches the wurtzite type phase of ZnO. And the pure phase of Cu begins to appear and strengthen when the modified-Cu content excesses 1 wt%, indicating that Cu element not only dope into the lattice of ZnO but also cover on its surfaces. It is found that the morphologies of the ZnO samples can be tuned by the change of the modified-Cu content, from irregular nanoplates to cross-linked multi-leveled porous nanoflowers with a various Cu concentration of 0.5 wt%, 1 wt%, 1.5 wt% and 2 wt%, which further facilitate the dye adsorption and light-scattering. The photocurrent-voltage characteristics and electrochemical impedance spectroscopy are conducted to estimate the electrochemical properties of these solar cells with different Cu modification contents. Compared to the dye-sensitized solar cells with pure ZnO electrode, all the dye-sensitized solar cells with Cu-modified ZnO photoelectrodes present higher photovoltaic performance. The introduction of Cu into ZnO significantly enhances electron transport and retards charge recombination in the ZnO-dye interfaces, which induce the 84% improvement of short-circuit current density and 1.6 times enhancement of the power conversion efficiency for the dye-sensitized solar cells with 1.5 wt% Cu-modified ZnO photoelectrodes. (c) 2018 Elsevier Ltd. All rights reserved.
