Anodic alcohol fuel cell reactions at platinum active sites on doped metal oxide supports

Abstract

Fuel cells produce electrical energy via chemical reactions, which take place on the carbon supported platinum catalyst (Pt/C). As attractive as these devices may seem, their practicality is often limited by the functionality of the carbon support, which can be prone to corrosion. To limit the corrosion associated with a carbon-based catalyst, metal oxide supports are an area of interest as they display high stability in the harsh conditions associated with fuel cell operations. In this work, the employment of various doped metal oxide supports; silicon & molybdenum doped titanium oxide (TOMS), silicon doped titanium oxide (TOS), and silicon doped niobium oxide (NbOS) were investigated to replace carbon as a supporting material in alcohol fuel cells. In an alkaline environment, Pt/TOMS displayed faster kinetics and less poisoning during the methanol and ethanol oxidation reactions compared to the commercial Pt/C. When compared in an acidic ethanol and methanol oxidation, Pt/TOS and Pt/NbOS exhibit smaller activation energies than Pt/C, however, only Pt/NbOS produces smaller charge transfer resistances and higher peak oxidation currents. These studies highlight the promise of replacing the carbonaceous material presently found in fuel cells with metal oxide, or doped metal oxide, materials.