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

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.