Ordered integrated arrays of Pd and Pt nanotubules on Al with controllable dimensions and tailored morphologies

We reported an approach to fabricate integrated arrays of palladium (Pd) and platinum (Pt) nanotubules with high aspect ratios on aluminum sheets by a critical-potential anodization and an electroless deposition. The critical-potential anodization provided ordered porous anodic alumina (PAA) films as supporting materials, with controllable pore intervals of 50-980 nm by anodizing potentials and adjustable pore sizes in 20-900 nm by chemical dissolution in acidic or alkali solutions. The successive electroless deposition endowed uniformly hollow coatings of Pd and Pt nanoparticles upon the pore walls, thus leading to nanoporous films or integrated nanotubule arrays embedded in the PAA films on aluminum. The nanotubule arrays connected at the pore entrance of the PAA films and gave a good mechanical strength and electrical conductivity. Moreover, cyclic voltammogram experiments showed that the Pd and Pt nanotubule arrays as electrodes were stable and durable even in a sulfuric acid solution with a high concentration of 50 wt %. Especially, the Pd nanotubule electrodes exhibited characteristic hydrogen-adsorption/desorption peaks, inferring a promising nanomaterial as highly effective catalytic electrodes for various applications. (C) 2008 The Electrochemical Society.