Optical and Photocatalytic Properties of Single Crystalline ZnO at the Air鈥揕iquid Interface by an Aminolytic Reaction

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• 作者：Mukta V. Vaishampayan ; I. S. Mulla ; Satyawati S. Joshi
• 刊名：Langmuir
• 出版年：2011
• 出版时间：October 18, 2011
• 年：2011
• 卷：27
• 期：20
• 页码：12751-12759
• 全文大小：1099K
• 年卷期：v.27,no.20(October 18, 2011)
• ISSN：1520-5827

文摘

Crystalline flowerlike ZnO was synthesized by an aminolytic reaction at the air鈥搇iquid interface in an aqueous media at an alkaline pH. A thin visible film was formed at the air鈥搇iquid interface by self-assembly of flowerlike ZnO. Diffraction studies show rearrangement of the single crystalline units at the air鈥搇iquid interface leading to the formation of nanobelts. These nanobelts overlap systematically to form petals of the flowerlike structure; individual petals get curved with time. Each nanobelt is found to be single crystalline and can be indexed as the hexagonal ZnO phase. The organic product formed in the aminolytic reaction and dissolution鈥搑eprecipitation mechanism is the driving force for the formation of flowerlike ZnO at the air鈥搇iquid interface. A clear relationship between the surface, photocatalytic, and photoluminescent properties of ZnO is observed. The flowerlike structure exhibits a blue shift (3.56 eV) in the band emission as compared to bulk ZnO (3.37 eV). The photodegradation of methylene blue over the flowerlike ZnO catalyst formed at the air鈥搇iquid interface and in the sediments shows enhanced photocatalytic activity. The sub-bands formed due to surface defects facilitate separation of charge carriers increasing their lifetime, leading to enhanced photocatalytic activity of flowerlike ZnO.