摘要
采用浸渍提拉法,在平行条件下制备了钛、铝和玻璃载体上的TiO2膜TiO2/Ti、TiO2/Al和TiO2/G,利用X射线光电子能谱(XPS)、原子力显微镜(AFM)和光催化降解实验等手段对膜样品进行了表征和活性评价。实验结果表明,在铝和玻璃基材上制膜时发生了显著的基材元素溢出,使各膜样品的化学组成不同,同时TiO2粒子和膜表面形貌也因前驱物烧结行为不同而差异较大。TiO2/Ti的光催化活性较为稳定,TiO2/Al和TiO2/G则随着测试次数的增加逐渐失活。分析表明,表面碳物种的积累并不是TiO2膜失活的主要原因;TiO2/Al和TiO2/G上的溢出基材元素在反应条件下不稳定,发生流失和化学转变,引起了TiO2膜的晶界腐蚀,表面发生剥蚀和重构,失去了高比表面性质;同时XPS实验表明剥蚀后的膜表面Ti元素含有Ti4+、Ti3+和Ti2+3种价态,已经不是原来仅含有Ti4+的高活性表面。而TiO2/Ti样品表面腐蚀轻微,能够保持新鲜样品的高活性表面,失活程度很小。
TiO2 films were loaded on Ti, Al and glass from Ti(OC4H9)(4) precursor by dip-coating method, represented by TiO2/Ti, TiO2/Al and TiO2/G, respectively. XPS, AFM and phtotocatalytic reaction experiments were carried out to characterize the catalytic films. The films prepared on different substrates varies greatly in chemical composition because of the extravasation of Al, Na, Ca, and Si from Al and glass substrates, which also influences the agglomerating behavior of the precursor films, resulting in the difference of particle sizes and morphologies of TiO2 films. TiO2/Ti was proved to possess most stable photocatalytic activity, while TiO2/Al and TiO2/G deactivate obviously with the increase of photocatalytic experiment runs. It is concluded that accumulation of surface carbon species such as reactive intermediate was not the dominant cause of deactivation in this research. The remarkable leaching and chemical alternation of extravasated elements brought out intergranular corrosion of TiO2 films on Al and glass, leading to the flake-off of outmost TiO2 particles. The new surface contained three chemical states of Ti: Ti4+, Ti3+ and Ti2+, which was different from the new prepared TiO2 films with high activity, possessing only Ti4+.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2004年第11期1265-1272,共8页
Chinese Journal of Inorganic Chemistry
基金
国家高技术研究发展专项经费(No.2002AA601250)
国家自然科学基金(No.50274045)
国家自然科学基金重点项目(No.50238020)
