Since scientists Fujishima and Honda discovered water cracking on TiO 2 photoelectrodes, research on the photocatalysis of semiconductors has attracted widespread attention, and various photocatalysts have been developed. Among them, due to its high photocatalytic activity and chemical stability, TiO 2 has been widely studied in the field of photocatalysis. However, the limited light absorption region (λ <390 nm) and the rapid recombination of electron-hole pairs severely hindered the application of TiO 2 . In order to improve the utilization of light, there are many strategies to extend the spectral response of TiO 2 to the visible region and suppress the high recombination rate of photo-generated carriers to improve its photocatalytic performance.

Achievements

Recently, Nanjing University of Yuanjian Zhang professor well-known in the international journal Applied Catalysis B: Environmental ( IF14.229 ) published entitled "Single 2D MXene precursor-derived TiO 2 nanosheets with A Uniform Decoration of Amorphous Carbon for Enhancing Water photocatalytic splitting" Papers. Using two-dimensional MXene as a precursor, an ordered nanosheet structure was constructed and a uniform carbon layer was modified to prepare a TiO 2 photocatalyst with high visible light activity . Under visible light conditions, the photocatalytic activity of titanium dioxide nanosheets / C composites is three times higher than that of titanium dioxide . The results indicate that the high photocatalytic activity can be attributed to three reasons. One is an ordered nanosheet structure inherited from two-dimensional MXene , which facilitates hole separation and transport of electrons. Secondly, the modification of the carbon layer will obviously expand more visible light absorption regions. In addition, the carbon layer also promotes the separation and migration of photo-generated carriers. The proposed in situ carbon modification strategy enhances the visible light photocatalytic activity and develops the photocatalytic mechanism.

Figure 1 Schematic diagram of the preparation of TiO 2 / C composites .

Fig. 2 Morphology of TiO 2 / C composites .

Figure 3 Structure of TiO 2 / C composites .

Figure 4 Ultraviolet spectrum and XPS patterns of TiO 2 / C composites .

Figure 5 Photocatalytic performance of TiO 2 / C composites .

Figure 6 Photocatalytic mechanism of TiO 2 / C composites .

in conclusion

In summary, the ordered TiO 2 nanosheets / C composites exhibit excellent visible light catalytic performance. After pyrolysis, the nano titanium dioxide not only inherited the 2D characteristics, but also a carbon layer was uniformly deposited on the surface. The ordered structure and uniform carbon modification layer structure not only enhances the absorption of visible light but also promotes the separation and migration of photo-generated carriers. This work will provide a new approach for the preparation of homogeneous TiO 2 composite photocatalysts with enhanced activity .

Original link:

https://www.sciencedirect.com/science/article/pii/S0926337320303003

Source: MXene Academic