Morphology and photocatalytic performance of nano-sized TiO_2 prepared by simple hydrothermal method with different pH values  

作　　者：Hao Xu Shi-Qi Liu Shan Zhou Tang-Zhi-Jiu Yuan Xiang Wang Xia Tang Jian Yin Hui-Jin Tao 

机构地区：[1]School of Material Science and Engineering,Central South University [2]State Key Laboratory for Powder Metallurgy,Central South University [3]Key Lab of Nonferrous Materials Science and Engineering,Ministry of Education,Central South University

出　　处：《Rare Metals》2018年第9期750-758,共9页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Nos.51302322 and 21373273);the Open-End Fund for the Valuable and Precision Instruments of Central South University (No.CSUZC201613);the Open Foundation of Guangdong Provincial Key Laboratory for Technology and Application of Metal Toughening,Guangdong Institute of Materials and Processing (No.GKL201605);the Education Reform Project of Central South University (No.2016jy03)

摘　　要：pH value is a key factor in the preparation of nano-sized TiO2 with hydrothermal method. Using Ti（SO4）2 as the titanium source, H2O2 as the complexing agent, NaOH and HCl as the pH value regulator, nano- sized TiO2 powder with various morphologies and sizes was synthesized. Changes in morphology, size and phase type with pH values of samples were characterized by X-ray diffraction （XRD） and transmission electron micro- scopy （TEM） measurements. Results show that under the present preparation conditions, TiO2 powder is an anatase phase with pH value less than 11, but is more likely to be a brookite phase with pH value more than 11. With the increase in pH value from 1 to 11 in hydrothermal envi- ronment, nano-sized anatase TiO2 gradually grows up in all directions. {001 }, { 101 } and { 100} groups of crystal plane are the exposed crystal planes of nano-sized anatase TiO2 for the （004）, （101） and （200） facets found in high-reso- lution TEM image. The photocatalytic performance of nano-sized TiO2 with different morphologies was com- pared by measuring their photocatalytic degradation rates for methylene blue under ultraviolet light. Results show that anatase TiO2 prepared under the alkalescenthydrothermal environment （pH = 9, 11） has a better pho- tocatalytic degrading performance. Different sizes and phases of nanoscaled TiO2 powders with different photo- catalytic performances can be prepared by the control of pH value of hydrothermal solutions.pH value is a key factor in the preparation of nano-sized TiO2 with hydrothermal method. Using Ti（SO4）2 as the titanium source, H2O2 as the complexing agent, NaOH and HCl as the pH value regulator, nano- sized TiO2 powder with various morphologies and sizes was synthesized. Changes in morphology, size and phase type with pH values of samples were characterized by X-ray diffraction （XRD） and transmission electron micro- scopy （TEM） measurements. Results show that under the present preparation conditions, TiO2 powder is an anatase phase with pH value less than 11, but is more likely to be a brookite phase with pH value more than 11. With the increase in pH value from 1 to 11 in hydrothermal envi- ronment, nano-sized anatase TiO2 gradually grows up in all directions. {001 }, { 101 } and { 100} groups of crystal plane are the exposed crystal planes of nano-sized anatase TiO2 for the （004）, （101） and （200） facets found in high-reso- lution TEM image. The photocatalytic performance of nano-sized TiO2 with different morphologies was com- pared by measuring their photocatalytic degradation rates for methylene blue under ultraviolet light. Results show that anatase TiO2 prepared under the alkalescenthydrothermal environment （pH = 9, 11） has a better pho- tocatalytic degrading performance. Different sizes and phases of nanoscaled TiO2 powders with different photo- catalytic performances can be prepared by the control of pH value of hydrothermal solutions.

关 键 词：Hydrothermal method pH value ANATASE BROOKITE Nano-sized crystal morphology 

分 类 号：O643.36[理学—物理化学] TB383.1[理学—化学]