退火温度对二氧化钛纳米颗粒结构、光学及光催化性能的影响

Effect of annealing temperature on structural, optical, and photocatalytic properties of titanium dioxide nanoparticles.

作者信息

Muthee Dorah Kawira, Dejene Birhanu Francis

机构信息

Department of Physics, University of the Free State (QwaQwa Campus), Private Bag, X13, Phuthaditjhaba, 9866, South Africa.

Machakos University, P.O box 136-90100, Machakos, Kenya.

出版信息

Heliyon. 2021 Jun 10;7(6):e07269. doi: 10.1016/j.heliyon.2021.e07269. eCollection 2021 Jun.

Titanium dioxide (TiO) nanoparticles (NPs) were produced by simple sol-gel technique and annealed for 2 h in air. The impact of annealing temperature on the physical, morphological, photocatalytic, and optical properties was studied. X-ray diffraction (XRD) measurements proved that a gradual phase change from anatase to rutile occurred with increased annealing temperature. The crystal structures of the NPs were found to change at different temperatures; anatase phase at 450 °C, mixed-phase (anatase/Rutile) at 550-650 °C, and rutile phase at 750 °C. The rise in the annealing temperature improved the crystallinity of the NPs. The crystal and grain size of the NPs increased with the annealing temperature hence reducing the specific surface area due to the condensed boundaries between subunits of the NPs. As per the Kubelka-Munk equation, the bandgap reduced as the temperature elevated. The photocatalytic activity of the NPs was higher in the anatase/rutile mixed-phase than in the single anatase and rutile phase. Experimental results indicated that annealing temperature could effectively change the properties of the TiO NPs.

通过简单的溶胶 - 凝胶技术制备了二氧化钛（TiO₂）纳米颗粒（NPs），并在空气中退火2小时。研究了退火温度对其物理、形态、光催化和光学性质的影响。X射线衍射（XRD）测量证明，随着退火温度的升高，从锐钛矿到金红石发生了逐渐的相变。发现纳米颗粒的晶体结构在不同温度下发生变化；450℃时为锐钛矿相，550 - 650℃时为混合相（锐钛矿/金红石），750℃时为金红石相。退火温度的升高提高了纳米颗粒的结晶度。纳米颗粒的晶体和晶粒尺寸随着退火温度的升高而增加，因此由于纳米颗粒亚基之间的凝聚边界而降低了比表面积。根据库贝尔卡 - 蒙克方程，带隙随着温度升高而减小。纳米颗粒在锐钛矿/金红石混合相中的光催化活性高于单一锐钛矿相和金红石相。实验结果表明，退火温度可以有效地改变TiO₂纳米颗粒的性质。