Synthesis of Crystal-Controlled TiO2 Nanorods by a Hydrothermal Method: Rutile and Brookite as Highly Active Photocatalysts

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• 作者：Zewei Yang ; Bing Wang ; Hao Cui ; Hao An ; Yang Pan ; Jianping Zhai
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：July 23, 2015
• 年：2015
• 卷：119
• 期：29
• 页码：16905-16912
• 全文大小：588K
• ISSN：1932-7455

文摘

Rutile, anatase, and brookite TiO₂ nanorods (TNs) with specific exposed crystal facets have been obtained by a hydrothermal method using peroxide titanic acid (PTA) solution of different pH values. Below pH_PTA 10, the condensing complex is uncharged Ti₂O₅(OH)₂(H₂O)₄ or cations Ti₂O₅(H₂O)₆²⁺, and the corner-shared bonding easily occurs to form rutile phase. Above pH_PTA 10, the condensing species is anions Ti₂O₅(OH)₄(H₂O)₂^{2鈥?/sup>, resulting in the larger probability of edge-shared bonding which favor the formation of anatase TiO₂. Brookite whose structure contains both corner-shared and edge-shared bonding can be formed when pH_PTA equals to 10. Rutile TN synthesized from PTA solution at pH 4 showed the optimal photocatalytic oxidation activity for MB degradation; Brookite TN exhibited the highest photocatalytic activity for reduction of Cr (VI) despite that it does not exhibit the largest surface area. The presence of a spatial separation of redox sites in faceted rutile TiO₂ nanorod determined the photocatalytic activity of MB decomposition. Compared with rutile and anatase phase, the optimal photocatalytic reduction activity of brookite TN might be resulting from a cathodic shift of the conduction band.}