Palladium ultrathin films (around 2m) with different surface nanostructures are characterized by TEM, SEM, AFM, and temperature programmed reduction (TPR), and evaluated in terms of H-2 permeability and H-2-N-2 separation. A change in the characteristics of Pd seeds by controlled oxidation-reduction treatments produces films with the same thickness, but different surface and bulk nanostructure. In particular, the films have finer and more homogeneous Pd grains, which results in lower surface roughness. Although all samples show high permeo- selectivity to H-2, the samples with finer grains exhibit enhanced permeance and lower activation energy for H-2 transport. The analysis of the data suggests that grain boundaries between the Pd grains at the surface favor H-2 transfer from surface to subsurface. Thus, the surface nanostructure plays a relevant role in enhancing the transport of H-2 over the Pd ultrathin film, which is an important aspect to develop improved membranes that function at low temperatures and toward new integrated process architectures in H-2 and syngas production with enhanced sustainability.

Enhanced Hydrogen Transport over Palladium Ultrathin Films through Surface Nanostructure Engineering

ABATE, salvatore
Primo
;
GIORGIANNI, GIANFRANCO
Secondo
;
CENTI, Gabriele
Penultimo
;
PERATHONER, Siglinda
Ultimo
2015-01-01

Abstract

Palladium ultrathin films (around 2m) with different surface nanostructures are characterized by TEM, SEM, AFM, and temperature programmed reduction (TPR), and evaluated in terms of H-2 permeability and H-2-N-2 separation. A change in the characteristics of Pd seeds by controlled oxidation-reduction treatments produces films with the same thickness, but different surface and bulk nanostructure. In particular, the films have finer and more homogeneous Pd grains, which results in lower surface roughness. Although all samples show high permeo- selectivity to H-2, the samples with finer grains exhibit enhanced permeance and lower activation energy for H-2 transport. The analysis of the data suggests that grain boundaries between the Pd grains at the surface favor H-2 transfer from surface to subsurface. Thus, the surface nanostructure plays a relevant role in enhancing the transport of H-2 over the Pd ultrathin film, which is an important aspect to develop improved membranes that function at low temperatures and toward new integrated process architectures in H-2 and syngas production with enhanced sustainability.
2015
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/3063780
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