Selective styrene oxidation on alkaline tantalates ATaO3 (A = Li, Na, K) as heterogeneous catalysts

Abstract

A series of alkaline tantalates (LiTaO3, NaTaO3, KTaO3) prepared using citrate method were characterized by powder X-ray diffraction, nitrogen adsorption isotherms, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy-UV–Vis and differential thermogravimetric analysis techniques and evaluated as heterogeneous catalysts in selective oxidation of styrene towards benzaldehyde. An increase in the catalytic activity was observed with the atomic radii of the alkaline cation, attributed to the detected crystalline perovskite structure and presence of segregated phases. The largest styrene conversion (58.4 mol%) and benzaldehyde selectivity (77 mol%) was obtained for KTaO3 with no significant loss of activity after six catalytic reuses.