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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.)

Heterostructure formation from hydrothermal annealing of preformed nanocrystals

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de Mendonca, Vagner R. [1, 2] ; Dalmaschio, Cleocir J. [1, 3] ; Leite, Edson R. [1] ; Niederberger, Markus [2] ; Ribeiro, Caue [4]
Total Authors: 5
[1] Univ Fed Sao Carlos, Dept Chem, BR-13565905 Sao Carlos, SP - Brazil
[2] ETH, Dept Mat, CH-8093 Zurich - Switzerland
[3] Univ Fed Espirito Santo, Dept Nat Sci, BR-29932540 Sao Mateus, ES - Brazil
[4] Embrapa CNPDIA, BR-13560970 Sao Carlos, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: JOURNAL OF MATERIALS CHEMISTRY A; v. 3, n. 5, p. 2216-2225, 2015.
Web of Science Citations: 15

One of the primary challenges in obtaining heterostructures is control of the morphology and surface features of the components that are suitable for a specific application. In this sense, the use of preformed nanoparticles as building blocks is interesting. However, to create heterojunctions between preformed nanoparticles, a further calcination step is usually needed that can result in changes in nanoparticle morphology and surface chemistry. Therefore, the main goal of this study was to explore collision-induced heteroaggregation and oriented attachment under hydrothermal conditions to obtain heterostructures from preformed nanoparticles without further thermal treatment or addition of capping agents. We use anatase TiO2 and rutile SnO2 nanoparticles as a model system. A kinetic model based on a diffusion-controlled reaction is adapted to describe the process. For tracking charge migration across the interface and, consequently, heterojunction formation, we employ an indirect method based on the detection of hydroxyl radicals formed over a semiconductor during UV radiation. The rate of hydroxyl radical formation is directly proportional to the photogenerated charge lifetime, which, in turn, depends on the number of heterojunctions formed. The insights presented here suggest the possibility of obtaining the benefits of heterostructures by using nanoparticles with controlled morphology and surface characteristics. (AU)

FAPESP's process: 98/14324-0 - Multidisciplinary Center for Development of Ceramic Materials
Grantee:Elson Longo da Silva
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC