Efficient Charge Carrier Separation in l-Alanine Acids Derived N-TiO2 Nanospheres: The Role of Oxygen Vacancies in Tetrahedral Ti4+ Sites

Nanomaterials

卷:9

Zhiying Yan¹  Liang Jiang¹  Xiu Luo¹  Peiwen Xu¹  Yao Luo²  Jiao He²  Jiaqiang Wang²  Yongjuan Chen²  Junjie Li² 

[1] Technology, National Center for International Research on Photoelectric and Energy Materials, Yunnan Provincial Collaborative Innovation Center of Green Chemistry for Lignite Energy, Yunnan Province Engineering Research Center of Photocatalytic Treatment of Industrial Wastewater, The Universities’ Center for Photocatalytic Treatment of Pollutants in Yunnan Province, Yunnan University, Kunming 650091, China;

[2] School of Chemical Sciences &

关键词: N-doped TiO₂;    tetrahedral Ti⁴⁺ sites;    photocatalytic;    l-alanine acids;    time-resolved IR spectroscopy;   

DOI  :  10.3390/nano9050698

来源: DOAJ

【 摘 要 】

N-doped TiO₂ with oxygen vacancies exhibits many advantages for photocatalysis, such as enhanced visible light absorbency, inhibition of the photogenerated charge carrier recombination, etc. However, preparation of N-doped TiO₂ with oxygen vacancies under mild conditions is still a challenge. Herein, N-doped TiO₂ nanospheres with tetrahedral Ti⁴⁺ sites were synthesized by using dodecylamine as template and assisted by l-alanine acids. The obtained samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV−Vis diffuse reflectance spectra (UV−Vis DRS). It was found that the dodecylamine as a neutral surfactant controlled the structure of TiO₂ spherical, while l-alanine acids provided a nitrogen source. The existence of tetrahedral Ti⁴⁺ sites in N-doped TiO₂ was also confirmed. The N-doped TiO₂ sample with tetrahedral Ti⁴⁺ sites exhibited significantly improved photocatalytic performance for degradation of methylene blue solution under UV light or visible light irradiation. A combined time-resolved infrared (IR) spectroscopy study reveals that the enhanced photocatalytic performance could be attributed to a large amount of photogenerated charge carriers and efficient charge separation. It is demonstrated that the shallow donor state produced by oxygen vacancies of tetrahedral Ti⁴⁺ sites can effectively promote separation of charge carriers besides capturing electrons.

【 授权许可】

Unknown