Particle-Size Effect in Catalytic Oxidation Over Pt Nanoparticles
||Advanced Nanomaterials for Catalysis and Energy. Synthesis, Characterization and Applications
Elsevier. Amsterdam, Netherlands.2019.
587 c. ISBN 9780128148075.
Number: ch. 8,
||Pt nanoparticles Oxidation Size effect Catalytic activity Turnover frequency (TOF) Structure sensitivity Oxygen adsorption PtOx formation
Stakheev Alexandr Yu.
Bokarev Dmitry A.
Prosvirin Igor P.
Bukhtiyarov Valerii I.
Zelinsky Institute of Organic Chemistry RAS, Moscow, Russia
Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia
Relationships between turnover frequency and the size of supported Pt clusters are discussed for oxidation of hydrocarbons, CO, and NO by molecular oxygen. Analysis of the experimental data indicates that TOF tends to increase for bigger platinum particles. This tendency is particularly pronounced for the nanoparticles smaller than 4–5 nm. According to the most realistic models, the observed tendency stems from the deactivation of edge, corner, and neighboring atoms by two processes: (1) strong oxygen adsorption on edge and corner atoms with high degree of coordinative unsaturation, and (2) oxidation of Pt to PtOx, which is facilitated over undercoordinated sites. As the metal clusters grow in size, the fraction of undercoordinated edge and corner atoms decreases leading to the increase in experimentally observed TOF.