Titanium substituted potassium tantalates (KTaxTi1-xO3 x= 1.0, 0.8, 0.6, 0.5): Catalysts for the methyl phenyl sulfide oxidation

Abstract

B-cation titanium substituted potassium tantalates KTaxTi1-xO3 (x=1.0; 0.8; 0.6; 0.5) materials were synthesized, characterized by XRD, N2 adsorption-desorption isotherms, FTIR, DRS-UV-vis, TGA, H2-TPR and XPS to be used as catalysts for the selective oxidation of methyl phenyl sulfide. The non-substituted KTaO3 catalyst displays a total methyl phenyl sulfide conversion greater than 87% that increases with Ti substitution. The increases in the amount of titanium substituted decrease the crystallinity and the perovskite structure is not obtained, resulting in an amorphous material. The improvement in the conversion and selectivity towards the sulfone, is attributed to the slight loss of crystallinity that allows greater mobility of the lattice oxygen, essential in oxidation reactions and to the presence of TiO2 as segregated phases. These results obtained indicate that the substitution of B-cation generates physicochemical changes in the perovskite structure which enhances the oxidation properties of the catalysts.