Nanoporous SrTiO3 photocatalysts were fabricated via a novel technique, the nanotemplate assisted sol-gel hydrothermal reaction. In the alkaline-environment hydrothermal reaction, the SiO2 nanotemplate not only served as pore generator but also worked on adjusting the local reaction environment around the SrTiO3 nanocrystals. This contributed to a continuous modulation between the surface area and the crystallinity of the photocatalyst. The photocatalytic activities of the nanoporous SrTiO3 samples were evaluated by the degradation of gaseous isopropyl alcohol (IPA). Due to an optimal equilibrium between surface area and crystallinity, a SrTiO3 sample synthesized via adding 40% template (STO-SiO2-40%) showed the highest activity, which achieves 40 and 8 times of enhancement of CO2 evolution in comparison with the sample prepared without template and a commercial nano-SrTiO3, respectively. The photodegradation mechanism of IPA over this sample was also investigated in detail. This synthetic technique is also available to prepare the other nanoporous titanates, such as doped SrTiO3 samples and alkali-metal titanates.
Keywords: crystallinity; nanoporous material; nanotemplate; organic pollutant photodegradation; photocatalysis; surface area.