Nitrogen doped titania stabilized Pt/C catalyst via selective atomic layer deposition for fuel cell oxygen reduction

Abstract

The electrochemical dissolution of platinum (Pt) based nanoparticles and the consequent Pt active sites losses and particle aggregation have become a critical stability issue for the commercial proton exchange membrane fuel cell. Herein, nitrogen doped titania (N-TiO2) stabilized Pt low-coordinated sites on a commercial Pt/C catalyst is achieved by simply coupling selective atomic layer deposition of TiO2 and following nitrogen doping process. Selectively deposited N-TiO2 on Pt nanoparticles keeps the exposure of Pt sites on (111) facets and increases the reduction states of Pt, which results in 1.7 times improvement of mass activity than commercial Pt/C. Besides, N-TiO2 stabilized commercial Pt/C catalyst exhibits outstanding durability enhancement, showing only a 14.0% loss of mass activity after 30,000 potential cycles of rotating disk electrode tests and 91.7% retention after durability tests in humid fuel cell condition. The shielding role of N-TiO2 could effectively inhibit the degradation of low-coordinated sites on Pt nanoparticles and maintain Pt size distribution, which is a promising strategy to prolong the lifetime of commercial Pt/C catalysts.