中文摘要：

应用密度泛函理论优化了锐钛矿型TiO2（001）,（110）和（100）晶面结构,发现（001）晶面能量最低.通过对甲醛吸附到（001）面的6种初始猜测方式的几何优化,发现从甲醛H—C—O侧面吸附方式为最稳定的吸附方式,吸附能最大,发生了化学吸附.吸附后甲醛中C—H键增长,键变弱,C—O键缩短,键增强.甲醛中C原子与邻近层Ti和O原子间电子云发生重叠,有新的Ti—O和Ti—C键生成.吸附前后锐钛矿型TiO2（001）能隙从2.88 eV降低为2.50 eV,光催化吸收波长从431增加到496 nm.

英文摘要：

The structures of（001）,（110） and（100） crystal faces,as well as the structure of formaldehyde absorbed on the（001） face of anatase by six kinds of modes were optimized with density function theory（DFT）.It is found that the energy of（001） crystal face is the lowest,and that the mode of formaldehyde absorbed on the（001） face of anatase beside H-C-O is the most stable,and has the biggest absorption energy,and taking place chemical absorption.When this absorption was conducted,the C-H bond length increases,and bond strength weakens,while the C-O bond length decreases,and bond strength increases.Meantime,the overlaps of the electronic clouds between titanium and oxygen atom in neighboring layer,and between titanium and carbon atom in formaldehyde,as well as new Ti-O and Ti-C bonds were found.The energy gap between the before and after adsorptions on anatase TiO2（001） is decreased from 2.88 to 2.50 eV,the wave length of adsorption light is increased from 431 to 496 nm.