Synthesis and Properties of Platinum Nanocatalyst Supported on Cellulose-Based Carbon Aerogel for Applications in PEMFCs

Platinum nanoparticles supported on nanostructured cellulose-based carbon aerogels (carbonized aerocellulose, CAC) were evaluated in proton exchange membrane fuel cell (PEMFC). The CAC substrate was synthesized through the dissolution, gelation, regeneration, supercritical CO 2 drying and pyrolysis of cellulose. The Pt nanoparticles deposition was performed by impregnation of the CAC with H 2 PtCl 6 , followed by Pt z+ species reduction either under H 2 at 300–400°C or in basic NaBH 4 solution. While H 2 reduction leads to uniform Pt nanoparticles well-dispersed over the CAC surface, larger agglomerates form with NaBH 4 reduction, as revealed by transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). The reduction methods influences the quantity of platinum deposited, which may be increased by using multiple impregnation/reduction steps. The specific surface area of Pt and specific/mass activities towards oxygen reduction of the Pt/CAC materials, investigated using the rotating disk electrode setup, are similar to those of commercial Pt/Carbon Black (CB). Finally, PEMFC unit cell testing demonstrates that a Pt/CAC sample synthesized using three successive impregnation/reduction steps, loaded at ca . 14 wt % Pt/(Pt + C), competes with state-of-the-art Pt/CB electrocatalysts of comparable Pt loading.