Transition metal doped semiconductor nanocrystals (d-dots) possess fundamentally different emission properties upon photo- or electroexcitation, which render them as unique emitters for special applications. However, in comparison with intrinsic semiconductor nanocrystals, the potential of d-dots has been barely realized, because many of their unique emission properties mostly rely on precise control of their photoluminescence (PL) decay dynamics. Results in this work revealed that it would be possible to obtain bright d-dots with nearly single-exponential PL decay dynamics. By tuning the number of Mn2+ ions per dot from ∼500 to 20 in Mn2+ doped ZnSe nanocrystals (Mn:ZnSe d-dots), the single-exponential PL decay lifetime was continuously tuned from ∼50 to 1000 μs. A synthetic scheme was further developed for uniform and epitaxial growth of thick ZnS shell, ∼7 monolayers. The resulting Mn:ZnSe/ZnS core/shell d-dots were found to be essential for necessary environmental durability of the PL properties, both steady-state and transient ones, for the d-dot emitters. These characteristics combined with intense absorption and high PL quantum yields (70 ± 5%) enabled greatly simplified schemes for various applications of PL lifetime multiplexing using Mn:ZnSe/ZnS core/shell d-dots.

One-dimensional (1D) PtM (M = Fe, Co, Ni) nanowires (NWs), which represent a thriving class of electrocatalysts for fuel cells, are experiencing a restriction in long-term durability because of the dissolving issue related to transition metals. Utilizing one-dimensional Pt3Co NWs as the basic catalyst model, here we have successfully demonstrated significant improvements in electrocatalytic durability and activity derived from doping of Ga atoms. The optimized surface energy caused by the doping of Ga atoms drives the resulting catalysts to exhibit good durability for oxygen reduction reaction (ORR) electrocatalysis. However, although oxygen binding energy (E O) would rather deviate from the optimal value because of excessive Ga on the surface, the formation of proper Ga–O bonding can also promote oxygen binding to approach an optimal value, which results in an enhanced ORR activity. It can be therefore concluded that doping of an appropriate amount of Ga atoms has a positive effect in improving the ORR performance of the catalyst, not only in terms of specific activity but also in durability. This interesting phenomenon was also further extended to improve the catalysis of methanol oxidation (MOR) and ethanol oxidation (EOR) reactions, thus reflecting multifunctionalities of lavender-like Ga-doped Pt3Co NWs on fuel cell reactions. This study highlights the great potential of Ga-doped strategies for surface and near-surface regulation, which can effectively address the poor durability of 1D Pt-based NWs for energy catalytic technology.

Single-crystalline CeOHCO 3 rods with an orthorhombic structure have been successfully synthesized by the sonochemical method from aqueous solution containing CeCl 3 and urea. Polycrystalline CeO 2 rods have been prepared by thermal conversion of single-crystalline CeOHCO 3 rods at 500 • C in air. CeOHCO 3 and CeO 2 rods were characterized by x-ray powder diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TG) and differential scanning calorimetric analysis (DSC).

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