effects of metallic dopants in photocatalytic efficiency of metal- sio2@ seo2-mcm- 1core-shells

A synthesis method was developed to produce uniform micro-size spheres of silica cores coated with mcm-41 mesoporous shell achieve sio2@ seo2-mcm-41 core-shells. some metal ions like lanthanum, titanium and cerium ions were dipped in silica cores, and also an active photocaralyst i.e. selenium dioxide was introduced in mcm-41 shells to form a core-shell structure. the final goal of this study was investigating the role of these cations on the overall photocatalytic activity. the combination of lanthanum ion in core and selenium dioxide in shell had the best efficiency for photocatalatic activity. the sio2@mcm-41, sio2@seo2-mcm-41, la-sio2@mcm-41 and la-sio2@seo2-mcm-41core-shells were prepared. a range of reliable instruments and methods including x-ray diffraction (xrd), transmission electron microscopy (tem), scanning electron microscopy (sem), barrett-joyner-halenda (bjh) and energy-dispersive x-ray spectroscopy (eds) were employed for characterization of the fabricated core-shells. the higher photocatalytic efficiency of la-doped core-shells can be related to the electron-scavenging effect of la3+. the prepared photocatalysts were used for degradation of 2,4-dichlorophenol (dcp) as a model pollutant. therefore, la-sio2@seo2-mcm-41 core-shell photocatalyst is known to be the best one among the other synthesized core-shells for photodegradation of dcp in current study. the optimized photocatalyst was also applied in some real aquatic media including river water and well water and it still was active in degrading organic pollutants.