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目的构筑具有尺寸选择性光催化功能的复合纳米结构,在维持二氧化钛材料光催化性能的同时,减少其对有机大分子材料及有机基底材料的腐蚀行为,拓宽光催化材料的使用范围。方法采用一锅法,通过TEOS围绕P25为核进行水解,制备了多孔SiO_2包覆TiO_2(P25)复合核壳结构(P25@SiO_2)纳米颗粒。结果 TEM、XRD、BET表征显示,这种复合核壳纳米结构具有较好的分散性和很高的比表面积(约528 m2/g)。光催化性能实验证实,这种复合核壳结构具有尺寸选择性光催化效应,即小分子氮氧化物气体(NOx)能通过壳层SiO_2孔道进入核层并降解90%以上,被氧化成硝酸盐固定下来;小分子有机物亚甲基蓝能穿过壳层孔道进入复合结构的核层部分,被氧化分解;大分子有机物胭脂红被壳层有效隔离而不被分解。老化试验显示,涂覆有这种核壳结构材料的有机基材(PET膜)被氧化老化的现象受到抑制。相反,与裸露的有机基材(PET膜)相比,由于壳层的保护作用,涂覆有核壳纳米结构的有机基材具有更好的抗紫外线性能。结论开发的这种具有尺寸选择性光催化的复合核壳结构材料,可以涂覆在各种有机基材的表面,赋予其一定的光催化功能,同时由于壳层的隔离保护作用,对基材的腐蚀作用受到抑制。这种复合核壳纳米结构也可以作为功能添加材料添加到各种涂料材料中,并赋予涂料一定的光催化性能,同时对涂料中的有机物不会产生强烈的分解作用,因此具有很好的应用前景。
Objective To construct a composite nanostructure with size-selective photocatalytic activity, which can reduce the corrosion of organic macromolecule materials and organic substrates while maintaining the photocatalytic activity of titanium dioxide materials and broaden the application range of photocatalytic materials. Methods A one-pot method was used to prepare P25 @ SiO_2 nanoparticle with porous SiO 2 -coated TiO_2 (P25) composite by pyrolysis of TEOS around P25 core. Results The results of TEM, XRD and BET showed that this composite core-shell nanostructure has good dispersibility and high specific surface area (about 528 m2 / g). Photocatalytic performance experiments confirmed that this composite core-shell structure with size-selective photocatalytic effect, that small molecules of nitrogen oxide gas (NOx) through the shell SiO 2 channel into the nuclear and degradation of more than 90%, was oxidized to nitrate Fixed; small molecules of organic methylene blue through the shell pore into the composite structure of the nuclear layer part, oxidative decomposition; macromolecular organic carmine is effectively separated from the shell without being decomposed. Aging tests have shown that the oxidation of an organic substrate (PET film) coated with such a core-shell structure material by oxidation is suppressed. In contrast, organic substrates coated with core-shell nanostructures have better UV resistance than bare organic substrates (PET films) due to their protective effect. Conclusions This kind of composite core-shell structure material with size-selective photocatalysis can be coated on the surface of various organic substrates to give certain photocatalytic function. At the same time, due to the isolation and protection of the shell, The corrosion is inhibited. This composite core-shell nanostructures can also be added as a functional additive material to a variety of coating materials, and give the coating a certain photocatalytic properties, while the coating of organic matter does not produce strong decomposition, it has good application prospect.