Application of a composite structure of carbon nanoparticles and Nb–TiO2 nanofibers as electrocatalyst support for PEM fuel cells

► Deposited Pt nanoparticles on a mixed support of Nb-doped TiO2 nanofibers and carbon agglomerates. ► Characterized catalytic properties of the materials electrochemically and physically. ► Compared properties to a commercially available carbon supported Pt catalyst. ► Measured fuel cell performance with the synthesized materials as electrodes. Platinum catalyst nanoparticles (20wt.%) were deposited on a mixed support, which consisted of 25at.% Nb doped TiO2 nanofibers and carbon agglomerates. XRD analysis revealed that titania was present in the rutile phase. The catalyst was characterized electrochemically with respect to durability and oxygen reduction activity. Based on cyclic voltammetry tests, the Nb–TiO2/C supported catalyst was more stable compared to a commercially available carbon supported Pt catalyst (E-tek) over 1000 cycles. The apparent active Pt area decreased by 5% due to cycling, whereas in the case of Pt/C the decrease was 23%. The oxygen reduction performance was comparable for both cases. For example, during the anodic sweep the mass activity at 0.9V vs. the reversible hydrogen electrode (RHE) was 19AgPt−1 and 20AgPt−1 for the freshly prepared in-house prepared and commercial catalysts, respectively. After the durability experiment both types of catalysts yielded a mass activity of 17AgPt−1. Fuel cell tests with a single cell configuration were also carried out with the Nb–TiO2/C supported catalyst on the cathode side (gas diffusion electrode), yielding a peak power density of 0.34Wcm−2 at 75°C when pure oxygen was supplied on the cathode side.