Synthesis of Titanium Silicon Composite Oxide Supported Cobalt Oxide Catalyst and Its Catalytic Performance for <i>p</i>‐Diethylbenzene Oxidation

TiO₂-SiO₂ composite oxides with different Ti/Si ratios were synthesized by [sol-gel] method. The highest catalytic activity was obtained over T+S-0.75 loaded with 5 % Co₃O₄ by in-situ method using cobalt stearate as precursor. XPS, XRD, SEM, TEM, N₂ adsorption-desorption were used to characterize the state of titanium and cobalt species and the specific pore structure of catalyst. The characterization results combined with catalytic activity of p-Diethylbenzene (PDEB) oxidation show that the short-range mesoporous pore structure of T+S-0.75-C catalyst can facilitate the diffusion of large-volume reactants, intermediates and products. Meanwhile, the synergetic effect of Ti⁴⁺, Co³⁺ and Co²⁺ can promote the decomposition of H₂O₂ and the generation of bromonium ions, which proceeds towards the target product during the reaction. Under the preferred reaction conditions, the oxidative conversion of PDEB in H₂O₂ system is 31.1 %, and total selectivity of the target product reaches 85 %.