Synthesis of Visible-Light-Driven SrAl2O4-Based Photocatalysts Using Surface Modification and Ion Doping

The surface OH groups decorated monoclinic SrAl2O4 nanoparticles, Ce and Ce,Mn co-doped SrAl2O4 were synthesized by a gamma-ray irradiation assisted polyacrylamide gel method. The obtained material was used to study the color and optical properties and for the photocatalytic degradation of Congo red (CR) dye. The color and optical properties shows that the surface OH groups decorated SrAl2O4 nanoparticles is a potential white pigment. The Ce or Ce, Mn doping reduced the E-g value and significantly changed the light absorption capacity, the recombination rate of photogenerated carriers, photoluminescence properties and photocatalytic activity of SrAl2O4. Laser Raman spectroscopy shows three obvious luminescent background peaks at 398, 408, and 430 nm for the surface OH groups decorated SrAl2O4 nanoparticles. The photoluminescence spectrum detected at lambda(ex) = 295 nm shows four luminescence peaks located at 330, 368, 420, and 468 nm for the SrAl2O4:Ce and SrAl2O4:Ce:Mn samples. The SrAl2O4:Ce:Mn phosphor have a high photocatalytic activity for the photodegradation of CR dye can be ascribed to the synergistic effects of the band edge position, light absorption capacity, utilization and separation efficiency of photogenerated carriers.