Electrocatalytic Materials for Sustainable Energy Conversion Systems

ANDREASEN GUSTAVO; ARES ALICIA ESTHER; RAMOS, SILVINA GABRIELA; TRIACA WALTER

Congreso; Advanced Energy Materials; 2019

The development of materials with electrochemical properties that make them suitable for use in energy and electrocatalysts applications are extensively studied. In high-efficiency electrochemical systems for renewable energy conversion, dispersed noble metal electrocatalysts on conductive supports are widely used. Platinum (Pt) is an effective electrocatalyst for electrodic reactions involved in electrochemical energy conversion technologies, as hydrogen/oxygen (H2/O2) proton exchange membrane (PEM) fuel cell (FC), particularly the oxygen electroreduction reaction (ORR). This reaction represents one limitation in H2/O2 PEM FC, due to its slow electrode kinetics. The oxygen electroreduction overpotential constitutes one of the main contributions to the loss in efficiency and power density in low temperature FC. The morphology and crystalline orientation of Pt are very important factors to be considered for understanding the effect of the electrocatalyst surface structure on the kinetics of electrocatalytic reactions. For this reason, the rational design and development of efficient Pt electrocatalyts have been prioritized in the last few years. In a previous work, it has been demostrated that the molecular ORR in acid media becomes strongly dependent on Pt surface morphology in the high overpotential range, being favoured on (111)-type facetted Pt nanoparticles. In this work, the preparation and characterization of high surface area carbon-supported facetted Pt electrocatalysts with a defined and well characterized morphology for using in PEM FC is presented. The influence of the electrodeposition time (tE) on the characteristics of the facetted Pt electrocatalyst for the ORR on H2/O2 PEM FC is evaluated.