A general and facile approach has been developed to prepare various metal oxide nanocrystals from commercially available metal acetate precursors using an amine-mediated reaction. The influence of temperature and capping agents on the yield and final morphology of the metal oxides nanocrystals was investigated. The approach was applied in the synthesis of shape-controlled ZnO nanocrystals. ZnO nanowires, nanorods, bullets and triangular nanocrystals were successfully prepared by tuning the molar ratio between amine to zinc acetate precursor. On the basis of FTIR and NMR spectroscopic studies, we propose that the amine could mediate the breakdown of the metal acetates through a nucleophilic attack mechanism. The results suggest that amine can play dual role as both the attacking agent and capping agent in this new methodology.

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In spite of the excellent optical properties of all-inorganic halide perovskite quantum dots (PQDs), they still suffer from inherent poor stability even when exposed to moisture from the atmosphere, restricting their applications, especially in white-light-emitting diodes (LEDs) and cells imaging. Here, we proposed a strategy by encapsulating the CsPbX (X = Cl, Br, I) PQDs into silica nanoplates to prepare highly stable and water-soluble CsPbX/SiO nanocomposites. First, the 120 nm monodisperse CsPbX/SiO nanocomposites inlayed with several CsPbX PQDs were fabricated via the modified Stöber method. After coating, their stability exposed in the air was largely improved for all the CsPbX (X = Cl, Br, I) PQDs without changing their emission peaks and full-width at half-maximum, attributed to the suppression of the anion-exchange and decomposition. Moreover, further experiments demonstrated that the CsPbX/SiO nanocomposites were highly water-soluble and stable in the water. Their applications in LEDs and cell imaging demonstrated their ultrastability and high biocompatibility. Therefore, this study shows the possibility of their use in photoelectric devices and biological applications.

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In this work we investigated the hydrogen storage properties of stoichiometric Mg2Ni intermetallic nanoparticles produced from Mg and Ni nanoparticles. The mean size of the Mg2Ni particles is about 30–50 nm and the lattice constants of the Mg2Ni compound are a = 5.22 Å, c = 13.29 Å. The Mg2Ni compound showed excellent hydrogen storage properties without activation. It can absorb 2.77, 2.93 and 3.03 wt% hydrogen at 523, 573 and 623 K respectively. After one simple activation process, the obtained Mg2Ni absorbed 1.74, 2.07, 2.31 and 2.82 wt% hydrogen at 293, 348, 426 and 493 K respectively. The absorption and desorption plateau hydrogen pressures are about 2.5 and 0.8 bar at 523 K, 5.9 and 3.4 bar at 573 K and 12.7 and 9.7 bar at 623 K. The resulting van’t Hoff equation is log(P/bar) = −3464/T+6.541 and the formation enthalpy (ΔH) and entropy (ΔS) for the Mg2NiH4 are −66.32 kJ/mol H2 and −125.3 J K−1/mol H2.

Co-doped ZnO is a good dilute ferromagnetic semiconductor candidate with high Curie temperature. In this work, Zn 0.93 Co 0.07 O nanoparticles of about 5 nm in size were synthesized by the coprecipitation method. X-ray absorption fine structure spectra at both Co and Zn K-edges were acquired at an in situ and quick-scan mode while the sample was heated to 730 °C in air. The results show a good incorporation of cobalt ions into substitutional zinc sites in zinc oxide. Upon calcination, a systematic structural variation can be monitored, from removal of hydroxyl groups to cobalt oxide precipitation. The Einstein temperature, estimated from the Debye-Waller factor-temperature plot, indicates a stronger Co-ligand bond strength in the lattice compared to that of the ZnO matrix.

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