Faster H recovery in Pd nanoparticle layer based Gd switchable mirrors: Size-induced geometric and electronic effects

An investigation of the effect of the nanoparticle size in the Pd overlayer on the hydrogen-induced changes in the Gd switchable mirrors is reported in the present study. Deposition of a 10 nm thick Pd overlayer consisting of nanoparticles of 9 nm size results in a large increase in optical and electrical contrast and a substantial decrease in response and recovery time in Gd switchable mirrors. This study shows that a uniformly-deposited nanoparticle catalytic layer is important for improving H recovery. These results have been explained in terms of the size-induced increase in surface area, lattice contraction, and shift of Pd d-band centroid. The results of the present study, specifically the observation of decrease in recovery time has important implications for hydrogen sensor, storage, and switching applications. (c) 2005 American Institute of Physics.