Synthesis and photocatalytic activity in methyl orange degradation of mesoporous-assembled SrTiO3 nanocrystals prepared by sol–gel method with the aid of structure-directing surfactant

A sol–gel method with the aid of structure-directing surfactant was successfully used to synthesize mesoporous-assembled SrTiO3 nanocrystal photocatalysts by using strontium nitrate (Sr(NO3)2) and tetraisopropyl orthotitanate (TIPT) as precursors. Anhydrous ethanol (EtOH), ethylene glycol (EG), or EtOH/EG was selected as a solvent, while laurylamine hydrochloride (LAHC), cetyltrimethylammonium bromide (CTAB), or cetyltrimethylammonium chloride (CTAC) was used as a structure-directing surfactant. The photodegradation of methyl orange by SrTiO3 was found to be affected by the crystallinity, specific surface area, and pore characteristic. The mesoporous-assembled structure with a high pore uniformity of SrTiO3 plays the most important role affecting the photocatalytic activity of the SrTiO3 photocatalyst. The SrTiO3 with the mesoporous-assembled structure and narrow pore size distribution synthesized at a calcination temperature of 700 °C, a heating rate of 1 °C min−1, a LAHC-to-TIPT molar ratio of 0.25:1, and using an EtOH solvent provided the highest photocatalytic degradation activity, which was much higher than that of the non-mesoporous-structured commercial SrTiO3.

The main objective of this work is to reveal a newly developed synthesis procedure for mesoporous-assembled SrTiO3 nanocrystal photocatalyst using a sol–gel process combined with structure-directing surfactant. The obtained photocatalyst exhibited much higher photocatalytic activity for degradation of methyl orange, used as a model azo dye pollutant in wastewater, than commercially available SrTiO3 nanopowder.Figure optionsDownload as PowerPoint slide