TiO2-carbon supported platinum electrocatalysts for oxygen reduction reaction: Synthesis, high activity and enhanced durability

Challenges still remain in catalysts cost, activity and durability for the commercialization of polymer electrolyte membrane (PEM) fuel cells. To preferably alleviate the durability problems with carbon corrosion (but secondarily not to compromise any activities), here we demonstrate composites supported Pt nanoparticles electrocatalysts (Pt/WPx-C4-x) for oxygen reduction reaction (ORR). Of interest the composite of warm plasma-synthesized TiO2 (WP, lab-made) and Vulcan (R) carbon, was used to support Pt nanoparticles using a simple ethylene glycol reduction method. In terms of physicochemical structures and properties, complimentary characterizations (e.g., SEM, TEM-EDX, XRD, XPS, EPR) and the electrochemical measurements have been conducted. This composite support definitely contributes to the uniform dispersion on surface and the electronic reconfiguration of Pt nanoparticles. Our Pt/WP1-C-3 catalyst has an ultrasmall Pt size (ca. 2.15 nm), and surprisingly outperforms commercial Pt/C catalyst. It has achieved 1.24 times electrochemical active surface area (ECSA), 1.85 times mass activity, and 1.5 times specific activity, compared to commercial Pt/C. More importantly, our synthesized catalysts with WP exhibited almost half the activities losses (in ECSA, mass activity, specific activity) after accelerated stress test (AST, a DOE protocol) compared to Pt/C and commercial Pt/C catalysts. Based on the extraordinary achievements on both high activity and enhanced durability, it is attributed to the synergistic effect of WP (of strong metal support interaction, oxygen vacancies, corrosion resistance), and carbon (of high surface area, electrical conductivity).