Electrochemical studies of ceramic carbon electrodes for fuel cell systems: A catalyst layer without sulfonic acid groups

Ceramic carbon electrodes (CCEs) have been produced via the sol–gel process using 20% Pt on Vulcan XC72 carbon black and tetra ethyl orthosilicate (TEOS) as the organosilane precursor. This process produces a homogenous distribution of SiO2 and carbon supported Pt catalyst. Electrochemical experiments (cyclic voltammetry, electrochemical impedance spectroscopy) were performed to determine the effect of SiO2 loading on the active area of Pt in the catalyst layer. A volcano-type dependence was observed with the maximum active area of Pt occurring with an SiO2 loading of 45% by mass. Pt utilization was lower than that achieved with Nafion-based catalyst layers and was explained in terms of the lower proton conductivity of SiO2 compared to Nafion. These CCE structures may be useful for high temperature fuel cell systems.