材料科學(xué)與工程 材料物理與化學(xué)，外文文獻(xiàn)翻譯及原文

Photocatalytic Oxidation of Gaseous Formaldehyde on TiO2:An In Situ DRIFTS Study

氣態(tài)甲醛的二氧化鈦光催化氧化：原位紅外光譜研究

Abstract The adsorption and photocatalytic oxidation offormaldehyde on the pure TiO2under dry and humidconditions were studied by in situ diffuse reflectanceFourier transform infrared spectroscopy. It was found thatthe formaldehyde molecules can be adsorbed on thehydroxyl groups on the TiO2surface via hydrogen bonding.With UV irradiation, the adsorbed formaldehyde rapidlyconverts to the formate species even on the pure TiO2atroom temperature and atmospheric pressure. In the dryenvironment, the superoxide radical anion O2- , formed byadsorbed oxygen reacting with electrons, is suggested toplay an important role in the formaldehyde oxidation. Theintroduction of water vapor provides a large amount ofwater and hydroxyl groups on the catalyst surface. Oxi-dation of water and hydroxyl groups by the photogeneratedholes produces very active OH radicals, which take part inthe redox reactions and improve significantly the mineral-ization rate of formaldehyde on the TiO2due to its highredox potential.

在干燥和潮濕的的條件下，通過(guò)原位漫反射傅里葉變換紅外光譜，對(duì)吸附在純TiO2上的甲醛進(jìn)行光催化氧化研究。結(jié)果發(fā)現(xiàn)，甲醛分子可以通過(guò)氫鍵被吸附在在TiO2表面的羥基上。在紫外光照射下，即使是在純TiO2在室溫大氣壓力下，被吸附的甲醛可以迅速轉(zhuǎn)換為甲酸鹽。在干燥的環(huán)境下，由吸附的氧與電子反應(yīng)形成的超氧陰離子自由基O2-•，被認(rèn)為在甲醛氧化方面發(fā)揮重要作用。水蒸汽的引入在催化劑表面上提供了大量的水和羥基。水和羥基基團(tuán)的氧化，由光生的孔穴產(chǎn)生非?；顫姷?OH自由基，這種-OH自由基由于其高氧化還原性，可以參與氧化還原反應(yīng)，并顯著改善二氧化鈦礦化的甲醛率。