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在氧气和波长大于320nm的紫外光作用下,TiO2能够催化氧化环己烷,生成环己酮和环己醇中间产物.在水悬浮液中加入少量氟化钠,能够显著提高锐钛矿型TiO2的光催化活性.随着氟离子浓度的增加,环己酮和环己醇的生成量,以及环己醇对环己酮的物质的量比均随之增加尔后达到饱和,且几乎与溶液的起始pH值(3.0和5.5)无关.随着TiO2煅烧温度的上升,环己酮和环己醇的生成量是先增加后下降;氟离子存在时也呈现类似的变化趋势,但环己酮和环己醇生成量的增加幅度与氟离子在TiO2表面的吸附量高低不尽一致.此外,金红石型二氧化钛的光催化活性较差,且加入氟离子反而抑制环己酮和环己醇的产生.对这些影响因素进行了讨论.再次假设,在二氧化钛双电层内形成的氟氢键能够促进表面羟基自由基脱附,从而加快环己烷的氧化,提高环己酮和环己醇的产率.
In the presence of oxygen and ultraviolet light with a wavelength greater than 320 nm, TiO2 can catalyze the oxidation of cyclohexane to produce the intermediate of cyclohexanone and cyclohexanol. Adding a small amount of sodium fluoride to the aqueous suspension can significantly increase the anatase TiO2 Of the photocatalytic activity.With the increase of fluoride ion concentration, cyclohexanone and cyclohexanol production, as well as the amount of cyclohexanol on the cyclohexanone content of both increased and then reached saturation, and almost with the solution The initial pH value (3.0 and 5.5) was not related to the calcination temperature.With the increase of calcination temperature of TiO2, the yields of cyclohexanone and cyclohexanol firstly increased and then decreased, while the fluoride ions also showed a similar trend, but cyclohexanone And cyclohexanol production increased with the amount of fluoride ion adsorption on the surface of TiO2 is not the same level.In addition, the photocatalytic activity of rutile titanium dioxide is poor, and the addition of fluoride ion but inhibit the production of cyclohexanone and cyclohexanol The influencing factors are also discussed.It is also assumed that the fluorine-hydrogen bond formed in the double-titania layer promotes the desorption of hydroxyl radicals on the surface, thereby accelerating the oxidation of cyclohexane and increasing the yield of cyclohexanone and cyclohexanol rate.