Enhancement of Activity and Durability through Cr Doping of TiO 2 Supports in Pt Electrocatalysts for Oxygen Reduction Reactions

A challenging issue in the commercialization of fuel cells is to improve the kinetics of the sluggish oxygen reduction reaction (ORR) and durability of the cathode electrocatalyst under corrosive ORR conditions. In this paper, we report a promising approach to address these two major issues by Cr doping of TiO 2 supports in Pt‐based electrocatalysts. It was clearly revealed that Cr doping led to a marked enhancement of ORR kinetics, which was attributed to the compressive strain in the Pt lattice as well as the increased electronic conductivity of the Cr–TiO 2 supports. Furthermore, Pt/Cr–TiO 2 demonstrated a far superior durability to that of conventional Pt/C, which was assessed by accelerated durability tests (ADT) and in situ X‐ray absorption near‐edge structure studies. The specific activity of Pt/C decreased by 43 % after the ADT (141 μA cm −2 and 82 μA cm −2 before and after ADT, respectively), whereas that of Pt/Cr–TiO 2 was merely reduced by 13 % (472 μA cm −2 and 409 μA cm −2 ).