Understanding the Effects of Heat Treatment Temperature and Atmosphere on Platinum Nanoparticle Sintering Processes on Different Engineered Catalyst Supports (ECS) for Fuel Cell Applications

Proton exchange membrane (PEM) fuel cells are highly efficient devices for the conversion of chemical energy into electricity and are a promising candidate to sustain the growing clean energy demands. However, the tunability of the catalyst materials used in their electrodes is necessary to meet specific applications and to address some of the major challenges of this technology. In this work, we present a study on the effects of postsynthesis heat treatments on tunable PEM catalyst materials, containing 30 wt % Pt deposited on two different types of engineered catalyst supports (ECS) having different degrees of porosity and surface area. The role of temperature and atmosphere on the properties of these catalyst materials was studied by performing heat treatments at temperatures ranging from 400 to 1000 °C and in three different atmospheres of 7% H2/N2, N2, and Ar, followed by evaluation of the changes in Pt nanoparticles and carbon support properties by a wide range of physicochemical characterization techniques. The study showed that the temperature was the main driving force for the structural changes in the catalyst material, while the different atmospheres affected the Pt surface oxidation state. This work highlights the importance of studying catalyst properties during the stages of catalyst fabrication, a topic that has not been extensively reported.