Pilot plant scale continuous hydrothermal synthesis of nano-titania; effect of size on photocatalytic activity
Pilot plant scale continuous hydrothermal synthesis of nano-titania; effect of size on photocatalytic activity
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DOI：
10.1016/j.mssp.2015.08.043
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发表时间：
2016-02
影响因子：
4.1
通讯作者：
N. M. Makwana;C. Tighe;R. Gruar;P. McMillan;J. Darr
中科院分区：
文献类型：
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作者：
N. M. Makwana;C. Tighe;R. Gruar;P. McMillan;J. Darr
采用中试规模的连续水热流合成（CHFS）工艺，控制纳米TiO 2的晶粒尺寸（和比表面积）在约100 nm左右。5-18 nm.在CHFS中，将含氧硫酸钛（和硼酸）的室温溶液与氢氧化钾溶液的进料（在24.1MPa下）在流动中混合，然后将该合并的流与过热水流（在400 ℃和24.1MPa下）在受限喷射混合器中混合。纳米二氧化钛颗粒立即形成，然后在线冷却，然后作为浆料从工艺出口收集。据观察，硼酸浓度的前体进料影响反应的pH值，这反过来又决定了纳米二氧化钛的平均晶粒尺寸;随着pH值的增加，获得更大的微晶。在牺牲光催化分解水系统（析氢）的纳米材料进行了评价，发现在温和的酸性条件下制备的TiO 2，产生最高的光活性。
A pilot plant scale continuous hydrothermal flow synthesis (CHFS) process was used to control the crystallite size (and surface area) for nano-TiO2in the range ca. 5–18 nm. In CHFS, a room temperature solution of titanium oxysulfate (and boric acid) was mixed in flow with a feed of potassium hydroxide solution (at 24.1 MPa), and then this combined stream was mixed with a flow of superheated water (at 400 °C and 24.1 MPa) in a confined jet mixer. Nano-TiO2particles were formed instantly and then cooled inline before being collected as a slurry from the exit of the process. It was observed that the boric acid concentration in the precursor feed affected reaction pH, which in turn, determined the average crystallite size of the nano-TiO2; as the pH increased, larger crystallites were obtained. The nanomaterials were evaluated in a sacrificial photocatalytic water splitting system (hydrogen evolution), and it was found that TiO2prepared under mildly acidic conditions, yielded the highest photoactivity.