TAILIEUCHUNG - INTERFACIAL APPLICATIONS IN ENVIRONMENTAL ENGINEERING - CHAPTER 14
TiO2 hạt nano cho xúc tác quang Oxit kim loại chuyển tiếp cuộc triển lãm một loạt các hóa chất, vật lý, và các đặc tính cấu trúc. Một trong các oxit kim loại nghiên cứu rộng rãi nhất trong dioxide titanium bán dẫn oxit (TiO2). Titanium dioxide lần đầu tiên thu hút sự chú ý đáng kể khi năm 1972, Fujishima và Honda đã phát hiện ra rằng TiO2 có thể hoạt động như một chất xúc tác cho các photocleavage nước, sản xuất H2 và O2. . Trong sự hiện diện của một điện cực TiO2, họ quan sát. | 14 TiO2 Nanoparticles for Photocatalysis HEATHER A. BULLEN and SIMON J. GARRETT Michigan State University East Lansing Michigan . I. INTRODUCTION Transition metal oxides exhibit a wide range of physical chemical and structural properties. One of the most widely studied metal oxides in the semiconducting oxide titanium dioxide TiO2 . Titanium dioxide first attracted significant attention when in 1972 Fujishima and Honda discovered that TiO2 can act as a catalyst for the photocleavage of water producing H2 and O2 1 . In the presence of a TiO2 electrode they observed that water was dissociated using photons with Ầ 410 nm whereas direct photodissociation of water requires photons with Ầ 185 nm. This discovery sparked interest in the photocatalytic activity of TiO2 and other metal oxide semiconductors as a possible approach to inexpensively convert solar radiation to chemical energy 2 3 . Subsequent research efforts have focused on understanding the fundamental processes that drive these photoelectrochemical cells and in their application to energy storage applications 4 5 . The ability to oxidatively decompose organic molecules present as pollutants in the environment has recently refocused research attention toward utilizing semiconducting oxides for remediation applications. For example the TiO2 surface can participate in a wide range of redox chemistries for many types of adsorbed organic molecules including aromatic halogenated organic and commercial dye molecules 6 . The central mechanism involves the photoinduced generation of charge carriers at the surface of a semiconductor followed by interfacial charge transfer reactions with absorbed molecules. The mechanistic aspects of these reactions have been reviewed 6 7 but in many cases the identities of intermediates have not been firmly established. The photocatalytic activity of TiO2 in many redox reactions is limited by the relatively large bandgap Eg - eV of the material which limits absorption to .
đang nạp các trang xem trước