A porous V/SiO2 sphere composite for the selective oxidation of benzyl alcohol to benzaldehyde in aqueous phase through peroxymonosulfate activation

Abstract

A porous V/SiO2 sphere composite (VOX@SiO2) was synthesized using one-step sol-gel method. Benefiting from the redox properties of vanadium and the hydrophilic property, VOX@SiO2 showed good catalytic performances for the selective oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) in aqueous phase through peroxymonosulfate (PMS) activation, and performed far better in water than in various organic solvents. The redox cycle of VV/VIV was supposed to be responsible for PMS decomposition in the VOX@SiO2/PMS system. The SO4∙-, 1O2 and mediated electron transfer were revealed to play a major role in the selective oxidation of BzOH to BzH. The intrinsic kinetics was analyzed to calculate the chemical reaction rate (ra) and reaction order (n = 0.33) with respect to BzOH. This study provided some insights into the development of vanadium-based heterogeneous catalyst for the selective oxidation of BzOH to BzH through PMS activation.