Hydrothermal synthesis of nanosized anatase and rutile TiO2 using amorphous phase TiO2
Hydrothermal synthesis of nanosized anatase and rutile TiO2 using amorphous phase TiO2
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DOI：
10.1039/b008974p
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发表时间：
2001
影响因子：
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通讯作者：
Hengbo Yin;Y. Wada;T. Kitamura;S. Kambe;S. Murasawa;H. Mori;T. Sakata;S. Yanagida
中科院分区：
文献类型：
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作者：
Hengbo Yin;Y. Wada;T. Kitamura;S. Kambe;S. Murasawa;H. Mori;T. Sakata;S. Yanagida
以非晶态TiO2为原料，采用水热法选择性地制备了具有窄粒径分布的纯相TiO2纳米晶。在HF和HCl协同催化剂存在下，热压处理无定形TiO2导致形成具有规则晶面的窄尺寸无定形TiO2。使用硝酸作为合作催化剂与HF也得到了一个窄的尺寸分布，但与一个相当不规则的结晶表面的TiO2。另一方面，无定形二氧化钛转化为相纯金红石型二氧化钛纳米晶通过高压灭菌在柠檬酸和硝酸的存在下。柠檬酸对TiO6八面体的螯合作用和硝酸对TiO6八面体的酸化作用是从非晶态到金红石相转变的关键。所有金红石纳米晶的形状都是棒状。二氧化钛的晶体生长相纯金红石或金红石提出进行通过各自的共享面和共享边的过程，通过溶解沉淀的溶解的二氧化钛八面体从非晶相。在异丙醇与氧气的氧化还原反应中，合成的金红石型和金红石型纳米碳酸钙的光催化活性相当。
Phase-pure TiO2 nanocrystallites with narrow particle-size distributions were selectively prepared by hydrothermal processes starting from amorphous TiO2. Autoclaving amorphous TiO2 in the presence of HF and HCl as cooperative catalysts led to the formation of narrow-sized anatase TiO2 with a regular crystalline surface. Use of nitric acid as a cooperative catalyst with HF also gave the anatase TiO2 with a narrow size distribution but with a rather irregular crystalline surface. On the other hand, amorphous TiO2 was converted to phase-pure rutile TiO2 nanocrystallites by autoclaving in the presence of citric and nitric acids. Chelation of TiO6 octahedra with citric acid and acidification with nitric acid are critical for the phase transition from amorphous to rutile. The shape of all rutile nanocrystallites was rod-like. The crystal growth of TiO2 to phase-pure anatase or rutile was proposed to proceed via respective face-sharing and edge-sharing processes through dissolution–precipitation of the dissolved TiO6 octahedra from the amorphous phase. The photocatalytic activity in the redox reaction of 2-propanol with oxygen was quite comparable among the synthesized anatase and rutile nanocrystallites.