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Ag/Al2O3–Gd2O3 showed high efficacy to photodegradate 4-chlorophenol, the strong interaction between silver nano-particles and micro-particles and Al2O3–Gd2O3 entities favors the decrease in the recombination rate.

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Synthesis of nanoporous SnO2 by a surfactant self-assembling sol–gel technique is described in this work. The synthesis was performed at room temperature by employing tin(IV) tetra-tert-amyloxide, Sn (OAmt)4, as the porous SnO2 frame precursor in the presence of the micelles of a cationic surfactant solution of cetyltrimethylammonium bromide (CTAB), which, in turn, acts as the SnO2 particle nanostructure director. The pH of the Sn alkoxide–CTAB mixture was adjusted to a value of 2 with HCl in order to eventually achieve a finely dispersed SnO2 gel structure. The final annealed materials were attained after thermal treatment of the above mentioned SnO2 gel systems between 300 and 500 °C. This annealing procedure burned off different numbers of CTAB micelles and caused some sintering of the substrates depending on the final calcination temperature, thus producing truly mesoporous (cylindrical) SnO2 skeletons of pore sizes 5–9 nm and surface areas between 60 and 100 m2 g−1 as well as some other assorted structural and textural characteristics.

A novel method of synthesis consisting of the production of ordered arrangements of tubular pores distributed inside SnO2 annealed thin films, which are prepared from a rotating disk process carried out at 2000-3500 rpm, is herein described. The main novelty is that no surfactant molecules are required in order to create these ordered pore structures; the templating entities are supramolecular assemblies of oligomeric chains formed during the extra-long aging allowed to the sol-gel processing of tin(IV) tetra-tert-amiloxide, Sn(OAm(t))4, chelated with acetylacetone molecules. Low angle X-ray diffraction peaks of SnO2 thin films calcined at 500 degrees C clearly certify the existence of ordered mesostructures when employing the right H2O/Sn(OAm(t))4 molar ratio during the SnO2 sol-gel synthesis. The final SnO2 ordered mesostructures are reminiscent of those linked to MCM-41 and SBA-15 substrates. Pore-size distribution analyses proceeding from N2 sorption isotherms at 76 K on the SnO2 thin films calcined at 500 degrees C unequivocally confirm the presence of tubular mesopores (mode pore sizes ranging from 5 to 7 nm). The thicknesses of the SnO2 films range from 80 to 150 nm after performing a drying process at 100 degrees C and from 70 to 125 nm after calcining in air at 500 degrees C; these film thicknesses show, in general, decreasing trends when either the spinning rate or the H2O/(Sn(OAm(t))4 ratio is increased.