Synthesis and characterization of nano titania powder with high photoactivity for gas-phase photo-oxidation of benzene from TiOCl(2) aqueous solution at low temperatures.
Synthesis and characterization of nano titania powder with high photoactivity for gas-phase photo-oxidation of benzene from TiOCl(2) aqueous solution at low temperatures.
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DOI：
10.1021/la0489716
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发表时间：
2004-11
期刊：
影响因子：
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通讯作者：
Yuanzhi Li;N. Lee;D. Hwang;Jaesung Song;Eun Gu Lee;Sun-Jae Kim
中科院分区：
文献类型：
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作者：
Yuanzhi Li;N. Lee;D. Hwang;Jaesung Song;Eun Gu Lee;Sun-Jae Kim
通过调节起始溶液的 pH 值并添加不同的添加剂，在低温下由 TiOCl(2) 水溶液制备平均晶体尺寸低于 10 nm 的纳米金红石、锐钛矿和双晶（锐钛矿 + 板钛矿）二氧化钛粉末。在TiOCl(2)水溶液中添加少量辛基酚聚环氧乙烷，所得纳米二氧化钛颗粒形貌由针状晶体转变为纳米球形金红石晶体。二氧化钛的无定形锐钛矿转变可以在低温甚至室温下进行液固反应。提出了金红石、锐钛矿和板钛矿二氧化钛的形成机制。研究发现H(+)或H(3)O(+)对无定型二氧化钛向锐钛矿型二氧化钛的相变起催化作用，少量SO(4)(2)(-)离子的存在不利于金红石和板钛矿的形成。通过精心调整制备条件，获得了具有较高比表面积、良好结晶度和较低光生电子与空穴复合率的纳米纯锐钛矿。这种纳米纯锐钛矿对苯的气相光氧化表现出非常好的光催化活性。
Nano rutile, anatase, and bicrystalline (anatase + brookite) titania powders with an average crystal size of below 10 nm are prepared from aqueous TiOCl(2) solution at low temperatures by adjusting pH values of the starting solution and adding different additives. Adding a small amount of octyl phenol poly(ethylene oxide) into aqueous TiOCl(2) solution leads to the change of particle morphologies of obtained nano titania from needlelike to nano spherical rutile crystals. Amorphous-anatase transformation of titania could proceed in liquid-solid reaction at low temperatures, even at room temperature. A formation mechanism of rutile, anatase, and brookite titania was proposed. It is found that H(+) or H(3)O(+) plays a catalytic role in the phase transformation from amorphous to anatase titania and that the presence of a small amount of SO(4)(2)(-) ion is unfavorable to the formation of both rutile and brookite. By carefully adjusting preparation conditions, nano pure anatase with higher surface area, good crystallinity, and a lower recombination rate of photoexcited electrons and holes was obtained. This nano pure anatase showed a very good photocatalytic activity for gas-phase photo-oxidation of benzene.