Study On Monolayer Dispersion Binding States Of Inorganic Metal Ions On The Surface Of Nanometer-Size TiO₂

The photoelectrical conversion efficiency of solar cell may increase greatly if inorganic metal ions are employed to modify its TiO2 nanocrystalline electrodes, so it is very important to study the monolayer dispersion binding state of inorganic metal ions on the surface of nanometer-size TiO21. The anatase nanometer-size TiO2 is prepared by sol-gel method first and then the influence of post-treatment method on crystalline type, particle size and surface binding state of nanometer-size TiO2 are studied in this paper. The anatase nanometer-size TiO2 with a certain size and perfect crystal structure is obtained by high-pressure hydrothermal disposal.2. A sequence of Sr2+/ TiO2 samples are obtained by nanometer-size TiO2 prepared in this paper. The monoplayer dispersion capacities of Sr2+ on the surface of nanometer-size TiO2 are researched. The capacity (1.0 Sr2+ion/nm2 TiO2) before calcinations is less than that after calcinations (3.3 Sr2+ ions/nm2 TiO2). 3. The analysis on surface binding state of Sr (NO3) 2/TiO2 is carried on. The binding state of Sr2+ before capacity is different with that of any compounds of Sr. The Sr-O surface bond is formed between Sr2+ and O2-on the surface of TiO2 and the binding state of Sr2+ doesn't change after calcinations when NO3- decompounds totally. There are essential differences in binding state between this kind Sr-O surface bond and Sr of SrO.The binding energy of Sr2+ after capacity increases gradually with the increasing content of Sr (NO3) 2, close to that of Sr2+ in Sr (NO3) 2. There are two kinds of binding state of Sr2+ after calcinations when NO3- decompounds partly, namely the surface bond of Sr-O and the bond of Sr in Sr(NO3)2.4.Sr2+/TiO2 namocrastalline film prepared in this paper absorbs 0.14 Sr2+ per square nanometer, and Sr2+ disperse on the surface of TiO2 nanocrystalline film in the form of monoplayer. Rather than SrTiO3 being formed, the Sr-O is formed between Sr2+ and O2- on the surface of TiO2 before and after calcination. N5+ in NO3- on the surface of the film is deoxidized into N in amine,and N in amine disappear after calcination.5.The dispersion capacity of ZnO on the surface of nanometer TiO2 is studied. The capacity is 4.57 ZnO/ nm2TiO2 and the coverage is 0.31. By analyzing the binding state of TiO2 nanocrystalline film modified by Zn2+, a conclusion may be drawn that existence of Zn2+ is in the form of ZnO before and after calcination. Similar to Sr2+/TiO2, N5+ in NO3- on the surface of the film is deoxidized into N in amine, and N in amine disappears after calcination.Zn2+/TiO2 nanocrystalline film prepared by impregnating method absorbs 0.68 ZnO per square nanometer, and ZnO disperse strongly on the surface of TiO2 film.