Fabrication of Pt-Nanoparticle-Loaded Mesoporous Alumina Coating through Anodizing of an Al-Pt Alloy

Noble metal nanoparticles, usually dispersed in a mesoporous support, have widespread applications. However, uploading nanoparticles into mesoporous materials and preventing the nanoparticles from aggregation during the fabrication and application processes remain major challenges. Herein, we report a novel, simple and low-cost method for fabrication of Pt-nanoparticle-loaded mesoporous alumina coating through anodizing of an Al-Pt alloy (98.5 at% Al and 1.5 at% Pt) prepared by magnetron sputtering. It was found that the Al-Pt alloy could be effectively anodized at voltages between 2.8 and 4.5 V (SCE), in 0.4 M sulfuric acid solution, at room temperature. The anodizing processes resulted in Pt-nanoparticles of 5∼50 nm dimensions uniformly-dispersed in the porous anodic alumina film. The proposed method can be implemented on a large scale and extended to other alloy systems consisting of a valve metal and different alloying elements with Gibbs free energy of oxide formation less negative than that of the valve metal.