Toward the Continuous Production of Multigram Quantities of Highly Uniform Supported Metallic Nanoparticles and Their Application for Synthesis of Superior Intermetallic Pt-Alloy ORR Electrocatalysts.

A fast and facile pulse combustion (PC) method that allows for the continuous production of multigram quantities of high-metal-loaded and highly uniform supported metallic nanoparticles (SMNPs) is presented. Namely, various metal on carbon (M/C) composites have been prepared by using only three feedstock components: water, metal-salt, and the supporting material. The present approach can be elegantly utilized also for numerous other applications in electrocatalysis, heterogeneous catalysis, and sensors. In this study, the PC-prepared M/C composites were used as metal precursors for the Pt NPs deposition using double passivation with the galvanic displacement method (DP method). Lastly, by using thin-film rotating disc electrode (TF-RDE) and gas-diffusion electrode (GDE) methodologies, we show that the synergistic effects of combining PC technology with the DP method enable production of superior intermetallic Pt-M electrocatalysts with an improved oxygen reduction reaction (ORR) performance when compared to a commercial Pt-Co electrocatalyst for proton exchange membrane fuel cells (PEMFCs) application.

Synthesis of Er- and Yb-doped gadolinium oxide polymorphs and influence of their structures on upconversion properties.

Nanocrystalline Gd(2)O(3) products doped with Er(3+) and Yb(3+) cations were synthesized by combustion method. We showed that the temperature of combustion can be tuned by using different types of organic fuels within reaction mixture. The combustion process is performed at lower temperature in the presence of urea as an organic fuel leading to pure cubic Gd(2)O(3):Er,Yb phase, on the other hand higher combustion temperature, yielding pure monoclinic Gd(2)O(3):Er,Yb polymorph is achieved in the mixture of urea and b-alanine. Effective doping of Er(3+) and Yb(3+) cations within Gd(2)O(3) were confirmed by XRD analysis. Both polymorphs show upconversion in green and red areas and possess strong dependence of fluorescence intensity ratios (I(525)/I(549) or I(525)/I(560) for monoclinic and cubic polymorphs, respectively) on temperature. This indicates that both phases can be applied for the temperature sensor devices based on upconversion intensity ratio changes.

Synthesis and fluorescent properties of chromium-doped aluminate nanopowders.

Nanocrystalline chromium-doped Al2O3 and MgAl2O4 products were synthesised by combustion method in the presence of urea. The powders were characterised by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), BET surface area analysis, induction coupled plasma analysis (ICP) and mapping energy dispersive X-ray analysis (EDX). Fluorescence properties of the products were investigated in order to find the applications in fluorescent sensor and in the production of transparent polycrystalline ceramic materials for laser and optical application.