Search

A series of novel yellow-emitting antimonate-based Mg2InSbO6:xDy3+ (x = 0.5, 1, 2, 10, 15, and 25 mol%) phosphors was firstly synthesized by a solid-state reaction. The crystal structure, X-ray diffraction (XRD), photoluminescence (PL) properties, and the thermal quenching behaviours of prepared Mg2InSbO6:Dy3+ samples were exhaustively studied. The Mg2InSbO6 lattice has a trigonal crystal system, which possesses the R 3 ¯ (#148) space group. The as-prepared Mg2InSbO6:Dy3+ phosphors show a bright yellow emission peak at 572 nm under near-ultraviolet (n-UV) 349 nm excitation, which is attributed to the 4F9/2–6H13/2 transition of Dy3+. The optimum product is Mg2InSbO6:10 mol% Dy3+ with the estimated Rc = 13.05 Å. The optimum sample Mg2InSbO6:10 mol% Dy3+ exhibits abnormal thermal quenching phenomenon. The emission intensity reaches a maximum at 420 K. The fluorescence lifetime of Mg2InSbO6:10 mol% Dy3+ phosphor is measured to be 0.416 ms. Besides, the CIE chromaticity coordinates of Mg2InSbO6:xDy3+ (x = 0.5–25 mol%) phosphors change slightly, which possess low correlated color temperature (CCT) and high color purity. All findings suggest that Mg2InSbO6:Dy3+ samples can serve as white emission candidates for white light-emitting diodes (w-LEDs). [ABSTRACT FROM AUTHOR]

Gold–palladium (AuPd) alloy nano-corolla are successfully prepared in high purity, followed by exploration as electrocatalysts for electroxidation of ethanol (EOR) in alkaline medium. Applying kinetics control on the one-pot formation process using a syringe pump is emphasized, where the Au/Pd precursor solution is dropwise titrated into the reaction mixture containing capping agent and reductant at an elevated temperature. We perform systematical investigation towards the morphology evolution pathway and effects of several key parameters. After loading on carbon black, the current AuPd alloy nano-corolla exhibit superb specific activity, reaction kinetics, and operation stability for EOR, showing morphological and structural merit. The present study provides insight into fabrication of bimetallic alloy nanocrystals with open structure, which could find important use in crystal engineering for multimetallic nanocrystals and rational design of fuel cell electrocatalyst. Gold–palladium (AuPd) alloy nanocrystals in the form of corolla are successfully prepared via kinetic-controlled synthesis in high purity, exhibit improved activity and stability as EOR electrocatalysts in KOH solution [ABSTRACT FROM AUTHOR]

Wavy gold@palladium-gold (Au@PdAu) core-shell nanoplates are successfully prepared via seeded growth. Starting with the use of plate-like Au nanocrystals with the thickness of ~10 nm as seeds, the preferential deposition of Pd atoms vertical to the upper/bottom surface plane allows the formation of the core-shell structure with tunable thickness, where the shell thickness can be limited to sub-10 nm. As confirmed by X-ray diffraction (XRD) analyses, further atomic diffusion allows the generation of PdAu alloy phase in the products, leading to the formation of Au@PdAu core-shell nanostructure. With the strong absorbance in near-infrared (NIR) region, they could work as efficient catalysts towards reduction of 4-nitrophenol under visible light irritation. In particular, the enhancement factor (the ratio of apparent rate constant in light to that in dark) reaches as high as 6.76 arising from the plasmonic-enhancement effect. The current work provides a feasible strategy to fabricate Pd-based bimetallic nanocrystals with plasmonic properties and validates their promising application in the plasmonic-enhanced catalysis. [ABSTRACT FROM AUTHOR]

A series of double-perovskite orange–red-emitting Ca(3−2x)SmxNaxTeO6 (x = 0.01–0.25) phosphors have been synthesized via high-temperature method. The single-phase and orthorhombic structure of Ca3TeO6:Sm3+, Na+ phosphors was confirmed by X-ray powder diffraction. Under 405 nm excitation, Ca3TeO6:Sm3+, Na+ phosphors emitted a series of orange–red emission due to the transition of Sm3+ from 4G5/2 to 6HJ/2 (J = 5, 7, 9, and 11). The optimal Sm3+-doping concentration of Ca(3−2x)SmxNaxTeO6 (x = 0.01–0.25) was x = 0.10. The thermal-quenching temperature of Ca3TeO6:0.10Sm3+, 0.10Na+ phosphor was above 480 K. A white light-emitting diode (w-LED) based on 410 nm UV chip was successfully fabricated, and it presented a good correlated color temperature and a high color-rendering index (Ra). Therefore, orange–red-emitting Ca3TeO6:Sm3+, Na+ phosphors have potential applications in UV-based w-LEDs. [ABSTRACT FROM AUTHOR]

Branched Au nanocrystals with sub-10-nm arms are synthesized via a one-pot reduction in aqueous phase. The success of current work relies on the use of octadecyltrimethylammonium chloride as the shape-directing capping agent to facilitate the formation of branched products in high purity. Their overall size could be controlled in the range of 16–60 nm by varying the Au precursor amount or concentration of capping agent, and the diameter of arms is limited to sub-10-nm size range. Interestingly, Au nanocrystals with a unique morphology, sheet-wrapped dendrites, could be obtained when the concentration of a reductant was varied. The current strategy is also validated effective in the fabrication of dendritic products composed of other noble metals or alloys in addition to Au by simply using the alternative metal precursor. As compared to spherical counterparts, the current branched Au nanocrystals exhibited noticeable red-shift in UV-Vis extinction spectrum and enhanced catalytic activities for electrooxidation of ethanol in alkaline media. [ABSTRACT FROM AUTHOR]