Band Gap Engineering and Trap Depths of Intrinsic Point Defects in RAlO (R = Y, La, Gd, Yb, Lu) Perovskites.

The possibility of band gap engineering (BGE) in RAlO (R = Y, La, Gd, Yb, Lu) perovskites in the context of trap depths of intrinsic point defects was investigated comprehensively using experimental and theoretical approaches. The optical band gap of the materials, , was determined via both the absorption measurements in the VUV spectral range and the spectra of recombination luminescence excitation by synchrotron radiation. The experimentally observed effect of reduction from ∼8.

Rietveld refinement of the langbeinite-type phosphate KNiHf(PO).

Polycrystalline potassium nickel(II) hafnium(IV) tris-(orthophosphate), a langbeinite-type phosphate, was synthesized by a solid-state method. The three-dimensional framework of the title compound is built up from two types of [O] octa-hedra [the sites are occupied by Hf:Ni in ratios of 0.754 (8):0.

Mn luminescence of Gd(Zn,Mg)BO pentaborate under high pressure.

The results of X-ray diffraction studies of the Gd(Mg,ZnMn)BO down-converting phosphor as a function of Mg-Zn composition are presented. The lattice parameters and unit cell volumes of GdMgZnMnBO pentaborates are examined. The relationships between the structure and optical properties of these materials are explicated based on the results of theoretical calculations of the energy structure.

Bi(nanoparticles)/CN(nanosheets) nanocomposites as high capacity and stable electrode materials for supercapacitors: the role of urea.

The evolution of high-performance and stable electrode materials for supercapacitors plays a vital role in the next generation of energy storage devices. In this work we present a simple method for preparing Bi(nanoparticles)/CNx(nanosheets) nanocomposites as electrode materials for supercapacitors, which were synthesized by thermally treating bismuth citrate and urea at 550-700 °C under an Ar atmosphere. According to physicochemical studies (XRD, SEM, TG-DTA, XPS, FTIR, and BET), a "smeared" bismuth formation or the formation of nanoparticles on the CNx surface of interwoven 2D-nanosheets at different calcination temperatures was observed.

NaNiPO-Ni(OH) core-shell nanoparticles as hybrid electrocatalysts for the oxygen evolution reaction in alkaline electrolytes.

There is wide interest in developing efficient, robust and low-cost electrode materials for the electrolysis of water to produce clean hydrogen fuel. It is especially important to improve the performance and durability of electrocatalysts for the OER. Here we have shown that the transformation of nanoparticle (n-NNP) and crystalline (c-NNP) forms of mixed phosphate Na4Ni3(PO4)2P2O7 in highly alkaline solutions occurs along various routes and provokes the generation of 2D Ni(OH)2 nanosheets or stable core(phosphate)-shell(Ni(OH)2) particles, respectively.