Hot Electron Transport on Three-Dimensional Pt/Mesoporous TiO₂ Schottky Nanodiodes

We present the design of a three-dimensional Pt/mesoporous TiO₂ Schottky nanodiode that can capture hot electrons more effectively, compared with a typical two-dimensional Schottky diode. Both chemically induced and photon-induced hot electrons were measured on the three-dimensional Pt/mesoporous TiO₂ Schottky nanodiode. An increase in the number of interfacial sites between the platinum and support oxide affects the collection of hot electrons generated by both the catalytic reaction and light injection. We show that hot electrons flowing 2.5 times higher are detected as the current in the mesoporous system, compared with typical two-dimensional nanodiode systems that have a planar Schottky junction. Identical trends for the chemicurrent and photocurrent in the mesoporous system demonstrate that the enhanced hot electrons are attributed to the larger interface area between the metal and the mesoporous TiO₂ support fabricated by the anodization process. This three-dimensional Schottky nanodiode can provide insights into hot electron generation on a practical catalytic device.