Nanoporous Pd alloys with compositionally tunable hydrogen storage properties prepared by nanoparticle consolidationElectronic supplementary information (ESI) available: UV-visible spectrometry of reaction intermediates, EDS spectra of nanoporous alloys, transmission electron microscopy of EDS selected areas, nitrogen adsorption and hydrogen absorption isotherms, and Rietveld refinement data. See DOI: 10.1039/c2jm30988b

Nanoporous palladium and palladium alloys are expected to have improved mass transport rates and cycle life compared to bulk materials for energy storage and other applications due to high ratios of surface area to metal volume. Preparation of such materials with high thermal stability and well-cont...

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Main Authors: Cappillino, Patrick J, Sugar, Joshua D, Hekmaty, Michelle A, Jacobs, Benjamin W, Stavila, Vitalie, Kotula, Paul G, Chames, Jeffrey M, Yang, Nancy Y, Robinson, David B
Format: Article
Language:English
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Summary:Nanoporous palladium and palladium alloys are expected to have improved mass transport rates and cycle life compared to bulk materials for energy storage and other applications due to high ratios of surface area to metal volume. Preparation of such materials with high thermal stability and well-controlled metal composition, however, remains a challenge. This work describes a scalable, bottom-up technique for preparing nanoporous palladium alloys based on partial consolidation of dendrimer-encapsulated nanoparticles (DEN). Destabilization of a colloidal suspension of DEN and purification yields high surface area material (60-80 m 2 g −1 ) with a broad pore size distribution centered between 20 and 50 nm. This approach allows for precise tuning of product composition through adjustment of the composition of the precursor DEN. Nanoporous Pd 0.9 Rh 0.1 alloys with uniform composition or with Rh enrichment at pore walls and grain boundaries have been prepared and these structures have been confirmed with high-spatial resolution, aberration corrected quantitative STEM-EDS. Compared to bulk alloys of the same nominal composition, the nanoporous bimetallics show much faster hydrogen uptake kinetics, and store hydrogen at much lower pressure. Pore structure remains intact to temperatures above 300 °C, suggesting that these materials will have long lifetimes at the temperatures used for hydrogen storage applications. Nanoporous Pd/Rh bimetallics with uniform and core-shell compositions are thermally stable, and feature kinetics and thermodynamics of H 2 storage that are tunable and substantially different from bulk.
ISSN:0959-9428
1364-5501
DOI:10.1039/c2jm30988b