Vacancy defects of catalysts have been extensively studied and proven to be beneficial to various electrocatalytic reactions. Herein, an ultra‐stable three‐dimensional PtCu nanowire network (NNW) with ultrafine size, self‐supporting rigid structure, and Cu vacancy defects has been developed. The vacancy defect‐rich PtCu NNW exhibits an outstanding performance for the oxygen reduction reaction (ORR), with a mass activity 14.1 times higher than for the commercial Pt/C catalyst (20 %.wt, JM), which is currently the best performance. The mass activity of the PtCu NNW for methanol oxidation reaction (MOR) is 17.8 times higher than for the commercial Pt/C catalyst. Density‐functional theory (DFT) calculations indicate that the introduction of Cu vacancies enhances the adsorption capacity of Pt atoms to the HO* intermediate and simultaneously weakens the adsorption for the O* intermediate. This work presents a facile strategy to assemble efficient electrocatalysts with abundant vacancy defects, at the same time, provides an insight into the ORR mechanism in acidic solution.
Metal-free ordered mesoporous carbons were demonstrated to be robust catalysts for direct dehydrogenation of propane to propylene, in the absence of any auxiliary steam, exhibiting high activity and selectivity, as well as long catalytic stability, in comparison with nanostructured carbons.
Blue-emitting YPO4:Ce3+ and green-emitting YPO4:Tb3+ and YPO4:Ce3+,Tb3+ phosphor particles were
synthesized by coprecipitation method. Their structure and micromorphology have been analyzed by X-ray
powder diffraction (XRD), FTIR spectra, and scanning electronic microscope (SEM). The transitions of Ce3+
5d−4f and Tb3+
5D4−7F
J
(J = 6−3) were detected, and the photoluminescence intensity of the Tb3+ increased
on increasing the concentration of Ce3+. Finally, the energy-transfer process from Ce3+ to Tb3+ was investigated
in YPO4:Ce3+,Tb3+ nanoparticles in detail. These nanoparticles can be potentially used as labels for biological
molecules.
An aminolysis reaction between various aryl esters and inert tertiary amines by C-O and C-N bond activations has been developed for the selective synthesis of a broad scope of tertiary amides under neutral and mild conditions. The mechanism may undergo the two key steps of oxidative addition of acyl C-O bond in parent ester and C-N bond cleavage of tertiary amine via an iminium-type intermediate.
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