Synthesis of efficient CuO-CeO₂ catalysts in limited nanospace for HCl oxidation

A series of meosoporous CuO-CeO₂ composite catalysts were prepared using the ordered pores of hard template KIT-6 as a limited nanospace. The prepared catalysts were characterized by XRD, BET, Raman, ESEM, TEM and H₂-TPR.The performance of catalysts for gas-phase HCl catalytic oxidation to Cl₂ were also investigated. The results showed that CuO species could highly disperse on the surface of CuO-CeO₂ catalysts with Cu loading below 35%, as well as some Cu²⁺ dissolved into the CeO₂ lattice. In addition, the catalysts gained good surface area (>140 m²·g^-1) and small grain size. Among all catalysts, 25CuO-CeO₂ obtained the highest surface oxygen vacancies concentrations, suitable CuO dispersion and best reducibility at low temperature, leading to a 90% conversion of HCl at 370℃ (O₂/HCl=6). Kinetic studies showed that the more highly dispersed CuO provided more active sites for HCl adsorption and activation, while the oxgen vacancies could obviously enhanced the adsorption and activation of gas-phase oxygen.