Catalytic properties of Pd/SiO2 and Pt/SiO2 multilayer stacks

There is interest in the development of catalytic materials that are suitable for incorporation onto micromachined silicon gas sensors. To achieve good sensitivity from these devices, it is important to select a catalyst that has high activity and large surface area. The goal of the work is to explore methods to increase the activity and surface area of Pd and Pt catalysts. In particular, we report fabrication, characterization, and the catalytic properties of Pd/SiO2 and Pt/SiO2 multilayer stacks formed by successive sputter deposition of ultra-thin layers of the corresponding materials. The thickness of the individual layers was 1.25 and 5.0 nm which corresponds to island and continuous film structures, respectively. The enhanced catalytic properties of the Pd/SiO2 and Pt/SiO2 stacks are studied as well.