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Issue 24, 2019
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Hydrogenated nanotubes/nanowires assembled from TiO2 nanoflakes with exposed {111} facets: excellent photo-catalytic CO2 reduction activity and charge separation mechanism between (111) and ([1 with combining macron][1 with combining macron][1 with combining macron]) polar surfaces

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Abstract

Nanotubes/nanowires assembled from TiO2 nanoflakes with exposed {111} facets were prepared via heating a mixture of titanium(IV) oxysulfate–sulfuric acid hydrate, glacial acetic acid and water. The photocatalytic CO2 reduction activity of the as-prepared TiO2 nanoflake based nanotubes/nanowires was remarkably increased through hydrogenation. The apparent quantum yield for CH4 evolution of the hydrogenated TiO2 nanotubes/nanowires is as high as 17.4%, which is higher than that of all the TiO2 based photocatalysts reported until now. The excellent photocatalytic performance is ascribed to the exposed clean TiO2 {111} facets and enhanced solar absorption. On the basis of the polar structure of the exposed TiO2 {111} crystal facets, we proposed a separation mechanism of photocreated electrons and holes. A spontaneous electric field (Es) is created between polar TiO2 (111) and ([1 with combining macron][1 with combining macron][1 with combining macron]) planes. Under Es, the photocreated electrons and holes transit to TiO2 (111) and ([1 with combining macron][1 with combining macron][1 with combining macron]) surfaces, respectively. Redox reactions selectively take place at the Ti–TiO2 (111) and O–TiO2 ([1 with combining macron][1 with combining macron][1 with combining macron]) polar planes. The charge separation mechanism provides a clear insight for understanding the photocatalysis of high performance semiconductor nanocrystals and offers guidance for the design of high performance photocatalysts for CO2 reduction.

Graphical abstract: Hydrogenated nanotubes/nanowires assembled from TiO2 nanoflakes with exposed {111} facets: excellent photo-catalytic CO2 reduction activity and charge separation mechanism between (111) and ( [[1 with combining macron]]  [[1 with combining macron]]  [[1 with combining macron]] ) polar surfaces

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Publication details

The article was received on 20 Jan 2019, accepted on 15 May 2019 and first published on 16 May 2019


Article type: Paper
DOI: 10.1039/C9TA00736A
J. Mater. Chem. A, 2019,7, 14761-14775

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    Hydrogenated nanotubes/nanowires assembled from TiO2 nanoflakes with exposed {111} facets: excellent photo-catalytic CO2 reduction activity and charge separation mechanism between (111) and ([1 with combining macron][1 with combining macron][1 with combining macron]) polar surfaces

    J. Liu, B. Liu, Y. Ren, Y. Yuan, H. Zhao, H. Yang and S. (. Liu, J. Mater. Chem. A, 2019, 7, 14761
    DOI: 10.1039/C9TA00736A

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