TiO2 nanoparticles anchoring on two-dimensional Bi2Se3 nanosheet as an enhanced visible light catalyst.

Titanium dioxide (TiO₂) has been widely studied in the field of photocatalysis. However, the development of TiO₂ was limited by the photoresponse only in the ultraviolet region and the rapid recombination of photogenerated electron–hole pairs. In this work, we prepare a novel TiO₂ and two-dimensional (2D) bismuth selenide (Bi₂Se₃) hybrid nanosheets (TiO₂/Bi₂Se₃ HNs) via a simple water bath ultrasonic route. X-ray diffraction pattern and Raman spectra were carried out to confirm that as-prepared samples were pure and well crystalized. Besides, TEM characterization proves that 2D Bi₂Se₃ nanosheets have high specific surface area and it can be clearly observed that the TiO₂ with 60 nm particles are uniformly supported on the surface. Furthermore, photoelectrochemical (PEC) measurements demonstrate that the TiO₂/Bi₂Se₃ HNs exhibit excellent photocatalytic performance of 4.3 µA/cm² under 100 W of visible light, which were almost 2.5 times that of pure TiO₂. More importantly, our results show that the photocurrent density was quite stable and only dropped by 10% after 125 cycles. In summary, the improved photocatalytic activity is due to the unique characteristic of 2D Bi₂Se₃ nanosheets, such as maximized reaction sites and good electrical conductivity, and the positive coupling effect of the TiO₂/Bi₂Se₃ heterojunction. These extraordinary properties make the TiO₂/Bi₂Se₃ HNs photocatalysts have excellent potential for photocatalytic application. [ABSTRACT FROM AUTHOR]