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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Catalytic Properties of AgPt Nanoshells as a Function of Size: Larger Outer Diameters Lead to Improved Performances

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Author(s):
Rodrigues, Thenner S. ; da Silva, Anderson G. M. ; Goncalves, Mariana C. ; Fajardo, Humberto V. ; Balzer, Rosana ; Probst, Luiz F. D. ; da Silva, Alisson H. M. ; Assaf, Jose M. ; Camargo, Pedro H. C.
Total Authors: 9
Document type: Journal article
Source: Langmuir; v. 32, n. 36, p. 9371-9379, SEP 2016.
Web of Science Citations: 8
Abstract

We report herein a systematic investigation on the effect of the site of silver (Ag) nanoparticles employed as starting materials over the-morphological features and catalytic performances of AgPt nanoshells produced by a combination of galvanic-replacement between Ag and PtCl62- and PtCl62- reduction by hydroquinone. Mote specifically, we focused on Ag nanoparticles of four different sizes as starting materials, and found that the outer diameter, shell thickness, and the number of Pt surface atoms of the produced nanoshells increased with the size of the starting Ag nanoparticles. The produced AgPt nanoshells were supported into SiO2, and the catalytic performances of the AgPt/SiO2 nanocatalysts toward the gas-phase oxidation: of benzene, toluene, and o-xylene (BTX oxidation) followed the order: AgPt 163 nm/SiO2 > AgPt 133 nm/SiO2 > AgPt 105 nm/SiO2 > AgPt 95 nm/SiO2. Interestingly, bigger AgPt nanoshell sizes lead to better catalytic performances in contrast to the intuitive prediction that particles having larger outer diameters tend to present poorer catalytic activities due to their lower surface to volume ratios as compared to smaller particles.: This is in agreement with the H-2 chemisorption results, and can be assigned to the increase in the Pt surface area with size due to the presence of smaller NPs islands at the surface of the nanoshells having larger outer diameters. This result indicates that, in addition to the overall diameters, the optimization-of the surface morphology may play an important role over the optimization of catalytic activities in metal-based nanocatalysts, which can be even mote pronounced that the size effect. Our data demonstrate that the control over surface morphology play a very important role relative to the effect of size to the optimization of catalytic performances in catalysts based on noble-metal nanostructures. (AU)

FAPESP's process: 15/21366-9 - Hybrid materials containing metal nanoparticles for catalytic applications
Grantee:Pedro Henrique Cury Camargo
Support type: Regular Research Grants