Bimetallic Mesoporous MCM-41 Nanoparticles with Ta/(Ti, V, Co, Nb) with Catalytic and Photocatalytic Properties

The bimetallic (Ta/(Ti, V, Co, Nb) mesoporous MCM-41 nanoparticles were obtained by direct synthesis and hydrothermal treatment. The obtained mesoporous materials were characterized by XRD, XRF, N2 adsorption/desorption, SEM, TEM, XPS, Raman, UV-Vis, PL spectroscopy. A more significant effect was observed on mesoporous structure, typi-cally for MCM-41, and optic properties if the second metal (Ti, Co) does not belong to the same Vb group with Ta as V, Nb. The obtained new nanoparticles were used as catalysts for oxidation with H2O2 of olefinic compounds (1,4 cyclohexadiene, cyclohexene, styrene) and photodegradation of organic pollutants (phenol, methyl orange) from water. The re-sults showed improving of activity and selectivity in oxidation reactions by addition of the second metal to Ta-MCM-41 catalyst. The slow addition of H2O2 was also be benefit for the selectivity in epoxide products and stability of the catalysts. The band gap energy values decrease in the presence of the second metal and the band edge diagram evidenced posi-tive potential for all the conduction band of the bimetallic samples except TaTi-MCM-41. The higher photocatalytic degradation was obtained for samples with TaTi and TaV.