Co–Cr bimetallic oxides derived from layered double hydroxides with high catalytic performance for chlorinated aromatics oxidation

Abstract

Co–Cr bimetallic oxides with different Co/Cr molar ratios were prepared through a layered double hydroxide (LDH)-derived method. Their physicochemical properties together with catalytic performance for chlorinated aromatics (1,2-dichlorobenzene and chlorobenzene) oxidation were systematically investigated. The results demonstrated that the bimetallic oxides with Co/Cr ratios of 2–5 presented high activity (rate = 0.15–0.20 μmol m⁻² min⁻¹ at 250 °C) for 1,2-dichlorobenzene oxidation due to the synergetic effect of strong chlorinated aromatics adsorption/activation ability on acid sites and high oxidation ability over oxidative sites. Furthermore, the Cr incorporation effectively retarded the formation of polychlorinated by-products. The effects of water vapor and toluene on 1,2-dichlorobenzene catalytic oxidation over the catalysts were also carefully studied. Finally, the possible degradation mechanism of 1,2-dichlorobenzene over the as-prepared catalysts was proposed according to the results of in situ DRIFTS and TPSR.