Atomic layer deposition of TiO2 for stabilization of Pt nanoparticle oxygen reduction reaction catalysts

Atomic layer deposition (ALD) was used to modify two different types of carbon black-based Pt oxygen reduction catalysts with protective TiO 2 nanostructures to increase catalyst durability. Rates of ALD growth and the structure of deposited TiO 2 were observed to be highly dependent on oxygen content of the catalyst substrate. Electrochemical durability was enhanced with the addition of TiO 2 ALD nanostructures, with up to 70% retention in mass activity measured over accelerated durability testing. High-temperature treatment of the top-performing ALD catalyst, which was found to promote structural rearrangement of the TiO 2 and Pt phases into hybrid nanoparticles, yielded a twofold increase in activity but was detrimental to durability. Graphical Abstract