Ag/AgCl-loaded ordered mesoporous anatase for photocatalysis

Thin films of ordered mesoporous anatase have been prepared using a dip-coating procedure. Silver nanoparticles were introduced into the mesopores using wet impregnation followed by heat treatment. The cubic structured mesoporous titania had higher stability than the hexagonal structure and could be formed with a high content of nanocrystalline anatase with conservation of the meso-order. The high crystallite content was monitored by both X-ray diffraction and electron diffraction together with dark field transmission electron microscopy (TEM). The meso-order was studied using low-angle X-ray diffraction and TEM. The incorporated silver was formed within the mesopores of the titania, which acted as a template for the silver nanoparticles. X-ray photoelectron spectroscopy showed that both anatase and silver were present on the surface of the silver-loaded mesoporous titania. The synthesized titania films were evaluated for their photocatalytic activity for oxidation of stearic acid. It was found that the meso-ordered titania had a sufficiently high crystallite content to be photoactive and that the reaction mechanism resembled that of a non-meso-ordered titania sample. Upon incorporation of silver nanoparticles an apparent difference in reaction mechanism was found together with a. higher apparent initial activity.