Synthesis and characterization of highly-active nickel and lanthanum co-doped SrTiO3

A series of highly-active nickel and lanthanum co-doped SrTiO3 photocatalysts were synthesized via sol–gel process and their photocatalytic activities were evaluated by degradation of methylene blue (MB). The obtained samples were found by XRD, XPS and UV–vis to have a perovskite structure in which Ni and La atoms were incorporated into SrTiO3. After Ni and La doped into SrTiO3, the absorption edge of SrTiO3 powder was greatly shifted from 380 nm to 700 nm. Under a 100 W incandescent lamp irradiating for 14 h, a 100% of MB was degraded, which is much higher than those of pure SrTiO3 and commercial Degussa P25. The optimal range of Ni and La dopants is 0.1–1.0 mol%. The formation of a new absorption edge and the large surface area may be the main reasons for the high activity.

The large band gap of pure SrTiO3 was reduced by doping Ni ions via forming an electron donor level between the valence band and the conduction band. The photocatalytic activity was further enhanced by co-doping La ions because the oxygen vacancies, which act as electron–hole recombination centers, were reduced through keeping the charge balance.Figure optionsDownload as PowerPoint slide