Role of oxygen vacancy in the plasma-treated TiO2 photocatalyst with visible light activity for NO removal
Role of oxygen vacancy in the plasma-treated TiO2 photocatalyst with visible light activity for NO removal
复制标题
DOI：
10.1016/s1381-1169(00)00362-9
复制
发表时间：
2000-11-06
影响因子：
--
通讯作者：
Takeuchi, E
中科院分区：
文献类型：
--
作者：
Nakamura, I;Negishi, N;Takeuchi, E
在氧化气氛下的NO去除的光催化活性进行了研究，在商业TiO 2和等离子体处理的TiO 2粉末。通过等离子体处理，NO去除的光催化活性出现在可见光区域高达600 nm，而不降低紫外光活性。结果表明，NO被去除的硝酸盐（NO3-）通过光催化氧化在TiO 2粉末，其中NO3-的积累。在未加工的TiO2和等离子体处理的TiO2光催化剂之间没有观察到晶体结构、结晶度和比表面积的差异。在电子自旋共振（ESR）测量，尖锐的信号g = 2.004，这被确定为被困在氧空位上的电子，仅检测到等离子体处理的TiO 2在可见光照射下。ESR信号在g = 2.004处的饱和强度与氮氧化物的去除率成正比，表明捕集电子数决定了光催化氧化NO生成NO3-的活性。在等离子体处理的TiO 2光催化剂的可见光活性的外观归因于在TiO 2能带结构中的价带和导带之间的新形成的氧空位状态。(C)2000 Elsevier Science B.V.保留所有权利。
The photocatalytic activity for NO removal under an oxidative atmosphere has been studied over commercial TiO2 and plasma-treated TiO2 powders. By the plasma treatment, the photocatalytic activity for NO removal appeared in the visible light region up to 600 nm without a decrease in the ultraviolet light activity. It was found that the NO was removed as nitrate (NO3-) by photocatalytic oxidation over the TiO2 powders, where NO3- was accumulated. No difference in the crystal structure, the crystallinity, and the specific surface area was observed between the raw TiO2 and the plasma-treated TiO2 photocatalysts. In electron spin resonance (ESR) measurements, a sharp signal at g = 2.004, which was identified as the electrons trapped on oxygen vacancies, was detected only for plasma-treated TiO2 under visible light irradiation. The saturated intensity of the ESR signal at g = 2.004 was proportional to the removal percentage of nitrogen oxides, suggesting that the number of trapped electrons determined the activity for the photocatalytic oxidation of NO to NO3-. The appearance of the visible light activity in the plasma-treated TiO2 photocatalyst was ascribed to the newly formed oxygen vacancy state between the valence and the conduction bands in the TiO2 band structure. (C) 2000 Elsevier Science B.V. All rights reserved.