Selenourea-assisted synthesis of selenium-modified iridium catalysts: evaluation of their activity toward reduction of oxygen

摘要: Abstract Carbon-supported selenium-modified iridium nanoparticles have been synthesized using IrCl 3 and selenourea serving as a precursor of selenium nitrogen atoms. Here nanostructured is chosen model base metal for fundamental catalytic considerations because it exhibits interfacial properties resembling both platinum ruthenium. The systems' electrocatalytic studied in sulfuric acid electrolyte toward reduction oxygen formation hydrogen peroxide intermediate comparison to bare catalysts. To get insight into the reaction dynamics mechanisms, such electrochemical diagnostic techniques cyclic voltammetry rotating ring-disk electrode considered. mimic operation catalysts real fuel cells, additional experiments utilizing gas diffusion also performed. Materials are subjected surface analytical, structural microscopic characterization X-ray photoelectron (XPS), fluorescence (EDX), diffraction (XRD) methods well transmission scanning electron microscopies. At low (optimum) coverages on surfaces nanoparticles, tends proceed at more positive potentials under analogous conditions. Apparently, strong affinity form oxo groups its (known inhibiting reduction) largely suppressed presence or But optimum system produces somewhat higher amounts presumably due partial physical blocking (metal oxo) sites (that would otherwise be active H 2 O intermediate). High tolerance (during oxygen) Ir-based catalyst (functionalized selenourea) parasitic (e.g. polymer membrane cells) simultaneous oxidation organic fuels methanol ethanol) should mentioned well.