Skin B/N-doped anatase TiO2 {001} nanoflakes for visible-light photocatalytic water oxidation

The limited visible-light-responsive photoactivities of most doped wide-bandgap photocatalysts with widened absorption range have long been the obstacles for the efficient conversion of solar energy to chemical energy by photocatalysis. The weak transport ability of visible-light-induced low-energy charge carriers, and numerous recombination centers arising from the energy-band modifiers along the transport path are two major factors responsible for such a mismatch. A potential solution is to shorten the transport path of photo-induced charges in well-modulated light absorbers with low-dimensional structure and the spatially concentrated dopants underneath their surfaces. As a proof of concept, skin B/N-doped red anatase TiO2 {001} nanoflakes with the absorption edge up to 675 nm were synthesized in this study. Experimental results revealed that boron dopants in the TiO2 nanoflakes from the hydrolysis of nanosized TiB2 played a crucial role in controlling nitrogen doping in the surface layer of the nanoflakes. As visible light excitation occurs at the surface layer, the photons can be sufficiently absorbed by the formed energy levels at the surface layers, and the photogenerated charge carriers can effectively migrate to the surface, thus leading to efficient visible-light-responsive photocatalytic oxygen evolution activity from water oxidation.

Automated summary

In this study, skin B/N-doped red anatase TiO2 {001} nanoflakes were synthesized to overcome the limited visible light response of photocatalysts. The introduction of boron dopants and nitrogen atoms on the surface of TiO2 nanoflakes effectively shortens the charge transport path, leading to efficient visible light responsive photocatalytic activity.