Enhanced visible-light absorption of nitrogen-doped titania induced by shock wave

This paper presents a new method to prepare nitrogen-doped titania by detonation-driven flyer impact. The samples were shocked at different flyer impact velocities and recovered successfully. XRD, UV-Vis and XPS spectra were employed to characterize the phase composition, N doping concentration and energy gap of recovered samples. The results show that anatase transforms to rutile and srilankite appears at a higher flyer velocity (1.9-2.52 km/s), and the concentration of doped nitrogen in the recovered samples increases with increasing flyer velocity, while the maximum concentration of nitrogen is 13.45 at.%. The edge adsorption wavelength of nitrogen-doped titania induced by shock wave is shifted from 435 nm to 730 nm and the corresponding energy gap is reduced from 2.85 eV to 1.73 eV. High concentration nitrogen-doped titania is achieved by lattice displacement-atomic exchange mechanism during the formation of srilankite high-pressure phase induced by shock wave.