Green Synthesis of Anatase TiO2 Nanocrystals with Diverse Shapes and their Exposed Facets-Dependent Photoredox Activity

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• 作者：Nitish Roy ; Yohan Park ; Youngku Sohn ; Kam Tong Leung ; Debabrata Pradhan
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：October 8, 2014
• 年：2014
• 卷：6
• 期：19
• 页码：16498-16507
• 全文大小：549K
• ISSN：1944-8252

文摘

The exposed facets of a crystal are known to be one of the key factors to its physical, chemical and electronic properties. Herein, we demonstrate the role of amines on the controlled synthesis of TiO₂ nanocrystals (NCs) with diverse shapes and different exposed facets. The chemical, physical and electronic properties of the as-synthesized TiO₂ NCs were evaluated and their photoredox activity was tested. It was found that the intrinsic photoredox activity of TiO₂ NCs can be enhanced by controlling the chemical environment of the surface, i.e.; through morphology evolution. In particular, the rod shape TiO₂ NCs with 鈭?5% of {101} and 鈭?5% of {100}/{010} exposed facets show 3.7 and 3.1 times higher photocatalytic activity than that of commercial Degussa P25 TiO₂ toward the degradation of methyl orange and methylene blue, respectively. The higher activity of the rod shape TiO₂ NCs is ascribed to the facetsphilic nature of the photogenerated carriers within the NCs. The photocatalytic activity of TiO₂ NCs are found to be in the order of {101}+{100}/{010} (nanorods) > {101}+{001}+{100}/{010} (nanocuboids and nanocapsules) > {101} (nanoellipsoids) > {001} (nanosheets) providing the direct evidence of exposed facets-depended photocatalytic activity.

Keywords:

TiO₂ nanocrystals; shape-control; growth mechanism; photocatalysis; redox activity; capping agent