Nanocomposites are at the heart of the present nanotechnology revolution in several strategic fields, including Green Chemistry, sensors and pollutant remediation. The promising and extensively examined nanotitania photocatalysts have performances hampered by the rapid recombination of photogenerated charge carriers. To better understand these materials, here we generalize the 2D–heterojunctions physics to 3D patchworks of intimately associated anatase and brookite mixed crystallites, i.e. multi–phase polymorphs, MPP. The synthesized composite material is fully characterized experimentally and by simulations. We demonstrate that the anatase–brookite interphase behaves as a ground–state nano-diode containing an almost ideal nanocapacitor, associated to a net migration of electrons from anatase to brookite. Implications of the direct observation of a polarized interphase on the understanding of nanotitania photocatalysts at the atomic scale are discussed.

Direct measurement and modeling of spontaneous charge migration across anatase–brookite nanoheterojunctions / L. Lo Presti, V. Pifferi, G. Di Liberto, G. Cappelletti, L. Falciola, G. Cerrato, M. Ceotto. - In: JOURNAL OF MATERIALS CHEMISTRY. A. - ISSN 2050-7488. - 9:12(2021), pp. 7782-7790. [10.1039/d1ta01040a]

Direct measurement and modeling of spontaneous charge migration across anatase–brookite nanoheterojunctions

L. LO PRESTI
Primo
Investigation
;
V. Pifferi
Secondo
Membro del Collaboration Group
;
G. Cappelletti
Formal Analysis
;
L. Falciola
Penultimo
Investigation
;
M. Ceotto
Ultimo
Conceptualization
2021

Abstract

Nanocomposites are at the heart of the present nanotechnology revolution in several strategic fields, including Green Chemistry, sensors and pollutant remediation. The promising and extensively examined nanotitania photocatalysts have performances hampered by the rapid recombination of photogenerated charge carriers. To better understand these materials, here we generalize the 2D–heterojunctions physics to 3D patchworks of intimately associated anatase and brookite mixed crystallites, i.e. multi–phase polymorphs, MPP. The synthesized composite material is fully characterized experimentally and by simulations. We demonstrate that the anatase–brookite interphase behaves as a ground–state nano-diode containing an almost ideal nanocapacitor, associated to a net migration of electrons from anatase to brookite. Implications of the direct observation of a polarized interphase on the understanding of nanotitania photocatalysts at the atomic scale are discussed.
titanium dioxide; nanotechnology; heterojunction; interfaces; DFT calculations; Impedance Spectroscopy; photocurrent; principal component analysis;
Settore CHIM/02 - Chimica Fisica
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/822112
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