MgTi2O5 (magnesium dititanate) nanoparticles were prepared by a simple hydrothermal assisted post-annealing method and characterized with various analytical techniques. The catalytic properties (sonocatalytic, photocatalytic and sonophotocatalytic activity) were evaluated using the degradation of triphenylmethane dyes (crystal violet, basic fuchsin, and acid fuchsin). The sonophotocatalytic activity of MgTi2O5 nanoparticles towards crystal violet was found to be ~2.9 times higher than the photocatalytic activity and ~20 times higher than that of the sonocatalytic processes. In addition, the sonophotocatalytic efficiency of MgTi2O5 nanoparticles was found to be remarkable for the degradation of basic fuchsin (cationic dye) and acid fuchsin (anionic dye). The mechanism of these catalytic activities has been discussed in detail.

Experimental

Photocatalytic H2 production experiment

The photocatalytic H2 evolution from water was conducted in an online photocatalytic hydrogen production system( Aulight, Beijing, China, CEL-SPH2N). A podwer sample of the catalyst (0.1g) was suspended in amixture of 80ml of distilled water and 20 ml of methanol in the cell using  a magnetic stirrer. Ptloaded photocatalysts were prepared by the know standard method of in situ photo-depositon. For this， the photocatalyst powder was added to an aqueous methanol solytion containing the required amount (1wt% of Pt) of H2PtCl6. The solution was illuminated for 3 h under a Xe lamp with an AM 1.5 filter (Aulight), filtered, and then dried in a static oven at 80-100℃.