Improvement of photocatalytic activity of brookite titanium dioxide nanorods by surface modification using chemical etching

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• 作者：Linjie Zhang^a ; ^{zhanglinjie138138@yahoo.co.jp} ; Victor M. Menendez-Flores^a ; Naoya Murakami^a ; Teruhisa Ohno^a ; ^b ; ^{tohno@che.kyutech.ac.jp}
• 关键词：Photocatalyst ; Brookite nanorods ; Chemical etching ; Redox site ; Photocatalytic activity
• 刊名：Applied Surface Science
• 出版年：2012
• 期刊代码：6_01694332
• 类别：ms
• 出版时间：15 May, 2012
• 卷：258
• 期：15
• 页码：5803-5809
• 文件大小：1388 K

摘要

Surface morphology of brookite titanium dioxide (TiO₂) nanorods was modified by chemical etching with aqueous hydrogen (H₂O₂)-ammonia (NH₃) or sulfuric acid (H₂SO₄) solution. The brookite nanorods after chemical etching were characterized by TEM, SAED, FE-SEM, XRD and specific surface area measurements. Brookite nanorods after chemical etching with H₂O₂-NH₃ solution exposed new crystal faces in the tips, and nanorods with sharper tips were observed. On the other hand, etching with H₂SO₄ at 200 掳C induced morphological changes in the tip faces and broadened the angle between tip faces as a result of dissolution along the [0 0 1] direction, though brookite nanorods were only slightly etched after etching with H₂SO₄ at room temperature. Photocatalytic activity of brookite nanorods was tested by toluene decomposition in gas phase under ultraviolet irradiation. Brookite nanorods etched with H₂O₂-NH₃ solution showed higher photocatalytic activity than that of brookite nanorods before etching. In the case of H₂SO₄ etching at 200 掳C, brookite nanorods after etching exhibited lower photocatalytic activity. One reason for this may be that the formation of newly exposed crystal faces by H₂O₂-NH₃ etching improved separation of redox sites due to their strong oxidation ability.