Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (10): 2072-2081.

• ARTICLE •

### Effect of the Amount of Hydrofluoric Acid on the Structural Evolution and Photocatalytic Performance of Titanium Based Semiconductors

Hao ZHANG,Xin-Gang LI*(),Jin-Meng CAI,Ya-Ting WANG,Mo-Qing WU,Tong DING,Ming MENG,Ye TIAN

• Received:2017-04-25 Published:2017-07-17
• Contact: Xin-Gang LI E-mail:xingang_li@tju.edu.cn
• Supported by:
the National Natural Science Foundation of China(21476159);Natural Science Foundation of Tianjin, China(15JCZDJC37400);Natural Science Foundation of Tianjin, China(15JCYBJC23000)

Abstract:

Herein, the synthesis of a series of titanium based nanocrystals using tetrabutyl titanate (TBT) as the titanium source and hydrofluoric acid (HF) as the fluorine source under solvothermal conditions has been described. The effect of the amount of HF on the structural evolution of the nanocrystals was studied. The catalytic performance of the as-prepared samples was measured by photocatalytic hydrogen evolution, photocatalytic RhB degradation, and chronoamperometric tests. The obtained results showed that anatase TiO2 nanoparticles with exposed {101} facets were synthesized in the absence of HF. After the addition of a small amount of HF, the F- ion adsorbed on the surface of the nanocrystal and decreased the surface energy of the {001} facets. Thus, sheet-shaped TiO2 was formed with exposed {001} facets. Furthermore, the as-prepared sample showed an enhanced photocatalytic performance because of the increased charge separation efficiency, which was dependent on the surface heterostructure generated between the {101} and {001} facets. On further increasing the amount of HF, F- ions started to enter the lattice and formed a new crystal phase. The as-prepared sheet-stacked sample was comprised of TiO2 and TiOF2 phases in both surface and bulk regions, which showed the decreased photocatalytic activity. With the addition of more HF, the F- ion moved completely into the crystal lattice and the large particle structure of (NH4)0.3TiO1.1F2.1 was formed. Although the as-prepared (NH4)0.3TiO1.1F2.1 displayed a low photocatalytic activity because of an improper band gap structure, it could be used as a precursor for the synthesis of N, F doped titanium based semiconductors.

MSC2000:

• O643