Size Effects of Platinum Colloid Particles on the Structure and CO Oxidation Properties of Supported Pt/Fe₂O₃ Catalysts

Abstract

Three supported Pt/Fe 2 O 3 catalysts were prepared by depositing platinum colloids with discrete particle sizes onto the surface of Fe(OH) 3 powders, which were then calcined at an elevated temperature. Pt nanoparticle colloids with mean diameters of 1.1, 1.9 or 2.7 nm were synthesized in order to investigate the effects of particle size on the structure and CO oxidation properties of these Pt/Fe 2 O 3 catalysts. All Pt/Fe 2 O 3 catalysts demonstrated activity in low-temperature CO oxidation, with the sample containing Pt nanoparticles with a mean diameter of 1.9 nm (designated Pt-Fe 2 O 3 -b) exhibiting relatively higher catalytic activity. Compared with the other two catalysts, Pt/Fe 2 O 3 -b exhibited an increased ability to activate oxygen and maintain the stability of Pt species, correlating with its higher catalytic activity. The results of various characterization techniques revealed that the mean particle size of the Pt nanoparticles could influence the chemical states of Pt species and the strength of metal-support interactions of the Pt/Fe 2 O 3 catalysts. It was observed that the metal-support interactions in Pt/Fe 2 O 3 catalysts were able to adjust the redox properties and the O 2 -activation abilities of the catalysts. Finally, it is proposed that the interacting Pt and Fe species located at the Pt-FeO x interface are the primary active sites for the activation of CO and O 2 , respectively.

Tuning Surface Properties and Catalytic Performances of Pt–Ru Bimetallic Nanoparticles by Thermal Treatment

“…In this case, oxidized Pt species, on which the adsorption of CO is much weaker, can function as O 2 -activation sites and enhance the activity towards CO oxidation. Such promotion effects of oxidized Pt species were also reported by Singh et al [19] and An et al [20] However, for the selective oxidation of benzyl alcohol, the first and rate-determining step is dehydrogenation of the alcohol, which leads to the formation of the aldehyde and the adsorption of hydrogen on the surface of the catalyst. [21] Metallic Pt species are much better hydrogen acceptors than oxidized species and could help to accelerate the dehydrogenation of benzyl alcohol.…”

High-loading and thermally stable Pt1/MgAl1.2Fe0.8O4 single-atom catalysts for high-temperature applications

“…As shown in Fig. 2b, for the Pt-CD-300 sample, the reduction of Pt species occurred at temperature below 150°C, similar to the reduction of Pt in the reported literature [41]. However, the reduction temperature of Pt increased with the calcination temperature (~200°C for Pt-CD-600 and~300°C for Pt-CD-800 sample), suggesting that the metal-support interaction became stronger.…”

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles

“…The size effects of metal nanoparticles on CO oxidation reactivity have also been reflected on group VIII metals. 377 By a colloid chemical method, Pt nanoparticles with a narrow size distribution (from ca. 1 to 3 nm) have been deposited on FeO x and tested for CO oxidation (under O 2 -rich condition), showing that Pt nanoparticles around 2 nm give the highest activity.…”