Palladium nanoparticles &quot;breathe&quot; hydrogen; a surgical view with X-ray diffraction

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/50772

Title:	Palladium nanoparticles ";breathe";hydrogen;a surgical view with X-ray diffraction
Authors:	Vogel,W;He,W;Huang,QH;Zou,ZQ;Zhang,XG;Yang,H
Contributors:	化學學系
Keywords:	SUPPORTED PD NANOPARTICLES;NANOCRYSTALLINE PALLADIUM;STORAGE PROPERTIES;COUPLING REACTIONS;OXYGEN REDUCTION;CLUSTERS;ABSORPTION;ELECTROCATALYSTS;TRANSITION;OXIDATION
Date:	2010
Issue Date:	2012-03-27 18:09:53 (UTC+8)
Publisher:	國立中央大學
Abstract:	High resolution in situ XRD was used to study the hydriding behavior of palladium electrocatalysts, prepared from two precursors, (NH(4))(2)PdCl(6) (4.3 nm), and palladium acetylacetonate [Pd(acac)(2)] (6.2 nm), and supported on porous carbon XC-72R. X-ray line profile analysis revealed a defective fcc lattice with internal strains and a high stacking fault probability of 12%. Importantly, no change, neither of the size, nor the state of defects was observed during the phase transition (alpha <-> beta). Based on this finding, a two-phase model adopted from bulk palladium hydride was proposed to describe the transition trough the miscibility gap (MG). Apparently, Pd nanoparticles can "breathe" hydrogen, without modifying their intrinsic crystal structure: A 3-parameter algorithm perfectly reproduces the anomalous line profiles observed inside the MG by a simple rescaling of the intensity profiles measured outside the MG. The algorithm delivers accurate values for the phase boundaries alpha-max, beta-min. They depend sensitively on the particles size and surface state, but also surprisingly on the branch of the hysteresis loop. Time dependent studies verify a hindered kinetics of hydride formation in the presence of surface oxide species. (C) 2010 Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu.
Relation:	INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
Appears in Collections:	[Department of Chemistry] journal & Dissertation

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