Performance analysis of Pt/TiO2/C catalyst using a multi-scale and two-phase proton exchange membrane fuel cell model

Abstract

We present a detailed theoretical investigation into the effect of using titanium dioxide (TiO2) as support for Pt nanoparticles in proton-exchange membrane fuel cells (PEMFCs). In this context, TiO2 was exhibited excellent resistance towards carbon corrosion and Pt particle agglomeration despite being a semi-conductive metal with poor electric conductivity. The major focus of this study is on elucidating the merits and demerits of using a TiO2 support material in terms of PEMFC performance and durability. For the first time, the micro-scale catalyst model was improved and used to analyze the effects of electron transport in Pt/TiO2/C catalyst structure. The new model is coupled with a three-dimensional two-phase PEMFC model and multi-scale simulations are carried out for various PEMFCs, designed with both Pt/TiO2/C and traditional Pt/C catalysts, for comparison. The model predictions highlight that the suppression of Pt particle growth via the Pt/TiO2/C catalyst structure is clearly advantageous to maintain good catalyst performance during long-term PEMFC operations. However, the additional electronic ohmic loss by the TiO2 particles can be significant during high current density operations (e.g. 20 mV at 1.0 A/cm2). This study illustrates that the present multi-scale PEMFC model is a valuable instrument for designing and optimizing porous catalyst structures with various candidate catalyst support materials.