Platinum Sputtered on Nb-doped TiO2 Films Prepared by ALD: Highly Active and Durable Carbon-free ORR Electrocatalyst

Abstract

The oxygen reduction reaction (ORR) activity and durability of Pt nanoparticles sputtered on Nb-doped TiO2 coated glassy carbon and titanium electrodes were investigated. The Nb-TiO2 thin-film coatings were deposited by atomic layer deposition. Scanning electron microscopy and atomic force microscopy analysis revealed a uniform coating of the electrode substrates with doped-metal oxide. X-ray photoelectron spectroscopy analysis confirmed the presence of Nb, Ti, and Pt metals on the electrode surface. Electrochemical characterization of the prepared catalysts was performed by cyclic voltammetry and CO stripping experiments in 0.05 M H2SO4 solution. The Pt/Nb-TiO2 catalyst showed remarkable electrocatalytic activity toward the ORR at a very low Pt loading of 8.6 μg cm−2. The accelerated durability test confirmed that Pt/Nb-TiO2 catalyst was more durable than the commercial Pt/C (20 wt.%). More importantly, the prepared Pt/Nb-TiO2 electrocatalyst showed a considerable increase in the electrochemically active surface area as well as the ORR activity after the durability test.