Composites formed by titania and graphitic C3N4, such as C3N4/TiO2and C3N4/SrTiO3/TiO2heterojunctions, have attracted a considerable interest in recent years as efficient photocatalysts. Experimental evidence shows that the charge carriers' favorable migration path in g-C3N4/TiO2is opposite to what predicted by looking at the band edges alignment of the two units, and follows a direct Z-scheme. On the other hand, the typical migration scheme predicted by the type II band edges alignment is found in the g-C3N4/SrTiO3/TiO2heterojunction, where a “buffer” layer of SrTiO3is present between the C3N4and the TiO2phases. In this paper we provide a rationalization of the different behavior of the two heterojunctions based on density functional theory calculations using a hybrid functional approach. The analysis of the nature, stability, interface dipole, and band edges alignment of both g-C3N4/TiO2and g-C3N4/SrTiO3/TiO2interfaces shows that the formation of the ternary system has the effect to reverse the sign of the interface dipole, thus reversing the junction nature in the two systems.

Di Liberto, G., Tosoni, S., & Pacchioni, G. (2021). Z-Schemeversustype-II junction in g-C3N4/TiO2and g-C3N4/SrTiO3/TiO2heterostructures. CATALYSIS SCIENCE & TECHNOLOGY, 11(10), 3589-3598 [10.1039/d1cy00451d].

Z-Schemeversustype-II junction in g-C3N4/TiO2and g-C3N4/SrTiO3/TiO2heterostructures

Di Liberto G.
;
Tosoni S.;Pacchioni G.
2021

Abstract

Composites formed by titania and graphitic C3N4, such as C3N4/TiO2and C3N4/SrTiO3/TiO2heterojunctions, have attracted a considerable interest in recent years as efficient photocatalysts. Experimental evidence shows that the charge carriers' favorable migration path in g-C3N4/TiO2is opposite to what predicted by looking at the band edges alignment of the two units, and follows a direct Z-scheme. On the other hand, the typical migration scheme predicted by the type II band edges alignment is found in the g-C3N4/SrTiO3/TiO2heterojunction, where a “buffer” layer of SrTiO3is present between the C3N4and the TiO2phases. In this paper we provide a rationalization of the different behavior of the two heterojunctions based on density functional theory calculations using a hybrid functional approach. The analysis of the nature, stability, interface dipole, and band edges alignment of both g-C3N4/TiO2and g-C3N4/SrTiO3/TiO2interfaces shows that the formation of the ternary system has the effect to reverse the sign of the interface dipole, thus reversing the junction nature in the two systems.
No
Articolo in rivista - Articolo scientifico
Scientifica
TiO2, g-C3N4, heterojunction, DFT
English
3589
3598
10
Di Liberto, G., Tosoni, S., & Pacchioni, G. (2021). Z-Schemeversustype-II junction in g-C3N4/TiO2and g-C3N4/SrTiO3/TiO2heterostructures. CATALYSIS SCIENCE & TECHNOLOGY, 11(10), 3589-3598 [10.1039/d1cy00451d].
Di Liberto, G; Tosoni, S; Pacchioni, G
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10281/326414
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