A graded nano-alloy of Au 100Àx Pt x (x ¼ 7, 15, 23, 32, 40, 51, 62, 73 and 86) nanoparticles (NPs) formed by co-reduction of HAuCl 4 and H 2 PtCl 6 and the details are presented in this work. Au 100Àx Pt x NPs were characterized using surface plasmon resonance (SPR) absorption spectroscopy and transmission electron microscopy (TEM). The NPs were dispersed in Vulcan carbon (Au 100Àx Pt x /C) and annealed at 250, 400, 600 and 800 C. The as-formed and annealed materials were characterized using TEM, high resolution transmission electron microscopy (HR-TEM), powder X-ray diffraction (XRD), cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS). The CV studies indicate excess Pt on the surface, which is corroborated by XPS and HR-TEM results. The XRD data show that Vegard's law is obeyed by the asformed material and the materials annealed at 250 and 400 C, indicating that these materials are not nano-alloys. The studies clearly indicate that the formation of Au 100Àx Pt x NPs is kinetically controlled rather than being controlled by the thermodynamic stability. The results demonstrate the formation of graded alloys of Au 100Àx Pt x NPs. Pt excess in the graded nano-alloy is reflected favourably in the electrochemical oxidation of small organics. In the methanol oxidation reaction (MOR), the peak current value per mg of Pt increases as a function of x, reaches a maximum value at x ¼ 23 and the ratio of forward current to reverse current for MOR reached an unprecedented value of 6.7, which shows the catalyst's stability against poisoning by carbonaceous intermediates.

Herein, we demonstrate a simple and unique strategy for the preparation of P-doped into the substructure of mesoporous carbon nitride materials (P-MCN-1) with ordered porous structures as a high-energy and high-power Li-ion battery (LIB) anode. The P-MCN-1 as an anode in LIB delivers a high reversible discharge capacity of 963 mAh g–1 even after 1000 cycles at a current density of 1 A g–1, which is much higher than that of other counterparts comprising s-triazine (C3H3N3, g-C3N4), pristine MCN-1, and B-containing MCN-1 (B-MCN-1) subunits or carbon allotropes like CNT and graphene (rGO) materials. The P-MCN-1 electrode also exhibits exceptional rate capability even at high current densities of 5, 10, and 20 A g–1 delivering 685, 539, and 274 mAh g–1, respectively, after 2500 cycles. The high electrical conductivity and Li-ion diffusivity (D), estimated from electrochemical impedance spectra (EIS), very well support the extraordinary electrochemical performance of the P-MCN-1. Higher formation energy, lower bandgap value, and high Li-ion adsorption ability predicted by first principle calculations of P-MCN-1 are in good agreement with experimentally observed high lithium storage, stable cycle life, high power capability, and minimal irreversible capacity (IRC) loss. To the best of our knowledge, it is an entirely new material with the combination of ordered mesostructures with P codoping in carbon nitride substructure which offers superior performance for LIB, and hence we believe that this work will create new momentum for the design and development of clean energy storage devices.

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Highly efficient yttrium oxide doped with trivalent europium (Y2O3:Eu) phosphor was prepared through precursors synthesized by hydrothermal method. Crystalline precursors, namely europium‐doped yttrium carbonate (Y2(CO3)3·2H2O:Eu) and europium‐doped yttrium hydroxy carbonate (Y(OH)CO3:Eu), were prepared by varying the concentration of yttrium to europium ions and urea in the reaction mixture. The precursor materials on annealing at 700°C gave nanocrystalline Y2O3:Eu, which was further processed at high temperatures in the absence and presence of sintering aid to yield phosphor materials with varying crystallite size and morphology. The precursors and phosphor material were characterized using FTIR, TGA, powder XRD, SEM, TEM, and photoluminescence (PL) spectral studies. The emission efficiency was found to depend on the crystallite size, morphology, and particle size of the phosphor materials. It was observed that phosphor material with spherical morphology and particle size of 0.5–1.0 μm with crystallite size of 100 nm has the highest PL efficiency.