A highly atom-efficient and stable copper catalyst loaded on amorphous UiO-66-NH2 for HCl oxidation to chlorine

Cu-based catalysts are critical for the oxidation of hydrogen chloride (HCl) to chlorine, but they have low stability at high temperatures. In this study, the Cu/aUiO-66-NH2 catalyst was synthesized by an amorphous zirconium-based metal-organic framework (denoted by aUiO-66-NH2). Not only did the catalyst show higher activity (1.96 times that of CuO/Al2O3), but it also showed enhanced stability (no less than 100 h). Cu(0) and Cu(OH)2 were highly dispersed and evolved into partially chlorinated copper species during the reaction process, as revealed by X-ray diffraction, X-ray photoelectron spectroscopy, and scanning transmission electron microscopy. The interval XPS characterizations performed during the 100-hour reaction process showed that Cu/aUiO-66-NH2 had self-limited chlorination with a maximum chlorine capacity of approximately 19.60%. Additionally, the temperature-dependence experiment showed that the activation energy of Cu/aUiO-66-NH2 was 81.63 kJ/mol during HCl oxidation to chlorine. © 2022 Elsevier B.V.