The enhancement of platinum surface area by alumina template assistance in Sn/Pt core–shell nano/sub-micron sphere structure

In this study, a tin/platinum (Sn/Pt) core–shell structure was deposited on anodizing aluminum oxide (AAO) substrate by sputtering technique. The AAO template had highly ordered nano/sub-micron holes that served as nucleation sites on the sidewall. It was found that Sn atoms clustered in islands on the AAO sidewalls, following the nucleation and growth model, due to the high surface energy. The island-shaped morphology of clustered Sn atoms adjacent to the AAO sidewall provided a rough surface for subsequent deposition of Pt catalysts. An oxide film on the Sn sphere surface would maintain the shape of the sphere. Soft Sn spheres can further merge into larger spheres during sonication treatment. The activity area of Pt was measured by Tafel and cyclic voltammetry curves. The dependence of chemical activity of the catalysts on the Sn/AAO morphology was explored.