Design and development of photocatalysts of high activity and highly efficient photocatalytic reaction systems based on the understanding of photocatalytic reaction mechanisms

1. 作用谱分析：亚甲基蓝作为一种常用的光催化反应底物，不仅通过光敏化机理分解，而且通过光催化反应分解，表明这是评价光催化剂和光催化反应的最佳方法之一。此外，采用光学截止滤波器获得的伪作用谱与真实作用谱的形状不同。新型气相反应制备高活性二氧化钛光催化剂：高温作为相合成金属氧化物颗粒是有利的，因为它促进了颗粒的结晶而不聚集得到更大的颗粒。本研究开发了一种新型的快速加热-快速冷却氯化钛的制备方法。所得锐钛矿小晶呈十面体状，暴露出101和001两种晶格面，在多种反应体系中表现出较高的光催化活性。对制备条件进行了优化。从Degussa P25中分离锐钛矿和金红石晶体：采用新方法从具有代表性的含锐钛矿和金红石混合晶体的商用钛白粉Degussa P25中分离出锐钛矿和金红石晶体。利用分离得到的样品制作各晶相的校准曲线，首次获得P25的精确组成，并从分离得到的两种纯晶和商用非晶二氧化钛中重建P25。对原始样品和光催化活性的比较表明，锐钛矿与金红石的混合对光催化活性似乎没有协同作用。

1. Action spectrum analyses: It was revealed that this is one of the best methods for the evaluation of photocatalysts and photocatalytic reaction by showing that methylene blue, a frequently employed photocatalytic reaction substrate, is decomposed through photosensitizing mechanism as well as photocatalytic reaction. Moreover, pseudo action spectra taken by using optical cut-off filters show different shape compared from true action spectra.2. Preparation of highly active titania photocatalyst through novel gas phase reaction: High temperature as-phase synthesis of metal oxide particles is favorable since crystallization of particles is promoted without aggregation to give larger particles. In this study, new type of titania preparation method enabling rapid heating-rapid cooling of titanium(IV) chloride was developed. The resulting anatase small crystallites were of decahedral shape exposing two kinds of lattice facet, 101 and 001 and showed high photocatalytic activity in several reaction systems. The preparation conditions were optimized.3. Isolation of anatase and rutile crystallites from Degussa P25: From Degussa P25, a representative commercial titania powder with anatase and rutile mixed crystallites, anatase and rutile crystallites were isolated through newly developed method. The isolated samples were used for making calibration curves of each crystal phase to obtain, for the first time, exact composition of P25 and for reconstruction of P25 from two kinds of isolated pure crystallites and commercial amorphous titania. Comparison of physical properties and photocatalytic activities between original and reconstructed samples revealed that there seems to be no synergetic effects by mixing anatase and rutile on the photocatalytic activity.