Metallic-semiconductor nanosystem assembly for miniaturized fuel cell applications

In this paper, a new metallic-semiconductor nanosystem was studied for potential integration in a micro fuel cell as a proton exchange membrane (PEM)/electro-catalyst assembly using specific processes to nano-micro-electromechanical system (N/MEMS) technology. In order to increase the active area of Si based support layers for catalyst particles, two types of technologies have been developed: (i) an electrochemical etching process leading to a nanostructurated silicon layer; (ii) a precipitation technique based on controlled hydrolysis of a silicon alkoxide leading to SiO2 nanoparticles. The pores/fibrils of porous silicon have comparable dimensions with silica nanoparticles, being tens of nanometers, and present a similar chemical map of the internal walls due to the oxidation process achieved by exposure to ambient air. A Pt precursor solution (3.5 mM H2PtCl6) was used for catalyst chemical deposition, and the experimental samples have been analyzed from the morphological and compositional point of view using microscopic (SEM) and compositional (EDX, XRD) techniques.