Highly stable visible-light photocatalytic properties of black rutile TiO_2 hydrogenated in ultrafast flow

摘要

The hydrogenation and introducing oxygen vacancies (V_O) can lead to surface lattice disorder in TiO_2, which is a new form of TiO_2 named black TiO_2, with excellent visible-light photocatalytic activity, but this TiO_2 is easy to failure because oxidation makes the concentration of surface V_O decrease rapidly in a short time. In this work, black TiO_2 nanoparticles with V_O almost concentrated inside nanoparticles were fabricated under ultrafast hydrogen flow. These bulk V_O shortened the bandgaps of black TiO_2, enhanced its visible light absorption, and meanwhile provided extremely strong stability. The location of V_O in black TiO_2 was evident from EPR, XPS with HRTEM investigation, and other characteristics of black TiO_2 were obtained by XRD, UV-Vis, SEM, PL, and pho-tocurrent techniques. The degradation experiments on Cr~(6+) or rhodamine B demonstrated the good visible-light photocatalytic performance of our material. After 18 months of natural aging treatment (in the air), our samples showed no discoloration and maintained 89.5% photocatalytic efficiency, and further study exhibited that this black TiO_2 also contained excellent acid resistance and moderate alkaline resistance. This work could help design lattice disorder to obtain more stable and practical black TiO_2.