The effect of SnO2(110) supports on the geometrical and electronic properties of platinum nanoparticles

Abstract

Abstract: While Pt-nanoparticles supported on SnO2 exhibit improved durability, a substantial detriment is observed on the Pt-nanoparticles’ activity toward the oxygen reduction reaction. A density functional theory method is used to calculate isolated, SnO2- and graphene-supported Pt-nanoparticles. Work function difference between the Pt-nanoparticles and SnO2 leads to electron donation from the nanoparticles to the support, making the outer-shell atoms of the supported nanoparticles more positively charged compared to unsupported nanoparticles. From an electrostatic point of view, nucleophilic species tend to interact more stably with less negatively charged Pt atoms blocking the active sites for the reaction to occur, which can explain the low activity of Pt-nanoparticles supported on SnO2. Introducing oxygen vacancies and Nb dopants on SnO2 decreases the support work function, which not only reduces the charge transferred from the Pt-nanoparticles to the support but also reverses the direction of the electrons flow making the surface Pt atoms more negatively charged. A similar effect is observed when using graphene, which has a lower work function than Pt. Thus, the blocking of the active sites by nucleophilic species decreases, hence increasing the activity. These results provide a clue to improve the activity by modifying the support work function and by selecting a support material with an appropriate work function to control the charge of the nanoparticle’s surface atoms. Graphic abstract: [Figure not available: see fulltext.]