Enhanced Stability and Electrochemical Performance of Carbon-Coated Ti3+ Self-Doped TiO2-Reduced Graphene Oxide Hollow Nanostructure-Supported Pt-Catalyzed Fuel Cell Electrodes

Abstract

Stable alternative catalyst supports to replace conventional carbon-based materials in polymer electrolyte membrane fuel cells (PEMFCs) are being explored to achieve dramatic improvements in the performance and durability of fuel cells. Herein, conductive Ti3+ self-doped and carbon-coated TiO2-reduced graphene oxide (rGO) hollow nanosphere-supported Pt nanoparticles (Pt/rGO/TiO2) are investigated as cathode electrocatalysts for PEMFCs. Importantly, the rGO/TiO2 hollow nanospheres display excellent electrochemical stability under high potential cycling (1.2-1.7 V) compared with conventional carbon black (CB) support materials that normally induce electrochemical corrosion during fuel cell operation. The Pt/rGO/TiO2 is tested to establish its catalytic activity and stability using accelerated durability testing that mimics the conditions and degradation modes encountered during long-term fuel cell operation. The Pt/rGO/TiO2 cathode catalyst demonstrates comparable catalytic activity toward oxygen reduction and exhibits much higher stability than the Pt/CB one at high potentials in terms of minimal loss of the Pt electrochemical surface area. More importantly, Pt/rGO/TiO2 displays a negligible voltage drop over long-term cycling during practical fuel cell operation. The high stability of the Pt/rGO/TiO2 electrocatalyst synthesized in this investigation offers a new approach to improve the reliability and durability of PEMFC cathode catalysts.