焙烧温度对K_2Ti_6O_(13)薄膜光电化学和光催化的影响

Effect of calcined temperature on photoelectrochemical and photocatalytic properties of K_2Ti_6O_(13) thin films

采用溶胶凝胶法在导电玻璃上制备K2Ti6O13薄膜,考察焙烧温度对薄膜结构和光催化、光电化学行为的影响。采用XRD和AFM测定晶体和表面结构;以自组装在薄膜表面的十八烷基三氯硅烷(OTS)为光催化降解对象,评价K2Ti6O13薄膜光催化氧化性能;通过计时电位,循环伏安和光电流表征薄膜中光生载流子行为。结果表明,合适的结晶度和晶粒尺寸的匹配使500℃焙烧的K2Ti6O13薄膜具有较高的载流子激发、分离和迁移能力,体现出最高的光催化氧化能力和最大的光电流,光催化性能优于TiO2薄膜。由光电测试计算得其在254 nm光照下光电量子效率约为6.9%。

The potassium hexatitanate thin films on ITO glasses substrates were prepared by sol-gel method, and was calcined at different temperatures. The structure and surface morphology of the K2Ti6O13 film were examined by XRD and AFM, respectively. The photocatalytic activity of the K2Ti6O13 film was evaluated by the degradation of partial coverage of octadecyltrichlorosilane （OTS） grafted on K2Ti6O13 film, and the behaviour of photogenerated carrier was characterized by chronopotentiometry, cyclic voltammetry and chronoamperometry. The results show that the K2Ti6O13 film calcined at 500 ℃ has the highest photocatalytic activity and the highest photocurrent, it is even superior to TiO2. The reason that K2Ti6O13 film calcined at 500 ℃ has the higher performance may be appropriate crystallinity, lesser grain size and large specific surface area, and the quantum yield illuminated under 254 nm laser source is 6.9%.