Ultrafine CeO2 Nanodots Embedded in Porous ZrO2 for Efficient and Sustainable Chlorine Recycle through Hydrochloric Acid Catalytic Oxidation

Abstract

AbstractCeria (CeO2) has been regarded as one of the most promising industrial catalysts for hydrochloric acid (HCl) oxidation to replace RuO2‐based catalysts. Thermal sintering and chlorination of CeO2 limit its large‐scale application. In this work, ultrafine CeO2 nanodots embedded in a porous ZrO2 matrix (CeO2@ZrO2) are successfully prepared by a spontaneous deposition method and evaluated in HCl catalytic oxidation for sustainable Cl2 recycle. The physicochemical properties of CeO2@ZrO2 catalysts are characterized by means of XRD, Raman, SEM, TEM, BET, XPS, H2‐TPR and oxygen storage capacity (OSC). The results reveal that all CeO2@ZrO2 catalysts display large specific surface area, pore volume, perfect low‐temperature reduction performance and oxygen storage‐release capacity. More importantly, the unique structure of the CeO2 nanodots isolated by amorphous ZrO2 improves the dispersion and inhibits the sintering of active sites. The optimized 40CeO2@ZrO2 catalyst reveals superior activity (1.90 gCl2 ⋅ gcat−1 ⋅ h−1) and good durability (100 h under 430 °C). Kinetic studies reveal that the adsorption of O2 and HCl is competitive at the active sites, and the desorption of surface Cl is the rate‐determining step.