Binary copper and manganese oxide nanoparticles supported OMS-2 for enhancing activity and stability toward co-oxidation reaction at low temperature

Abstract

CuO, CuMnOx and MnOx catalysts were anchored on the manganese oxide support with the structure of octahedral molecular sieves (OMS-2), which were synthesized using MnSO₄ and KMnO₄ as precursors by refluxing under acidic conditions or impregnation. The catalysts were then tested for CO oxidation. These catalysts and OMS-2 support were characterized by X-ray diffraction, FTIR, SEM, and H2-TPR. For CO oxidation reaction, CuO and CuMnOx, catalysts showed extremely higher activities than that of MnOx, catalyst and OMS-2 support. The 100% conversion of CO (T100) for the CuO and CuMnOx, catalysts were observed at 55°C and 65°C, respectively. Due to the presence of Cu²⁺ − O²ˉ − Mn⁴⁺ ↔ Cu⁺ −□− Mn³⁺ + O₂ the redox couple in the structure of these solid catalyst. Additionally, the CuMnOx, catalyst showed higher activity (~1.74 folds) and exhibited better stability than CuO catalyst in CO oxidation, due to the advanced functionallity of binary oxide structure of CuMnOx, catalyst. As known, CO oxidation may follow the Mars-van-Krevelen mechanism with Cu²⁺ − O²ˉ − Mn⁴⁺ ↔ Cu⁺ −□− Mn³⁺ + O₂ redox couple. This study shows the high application potential of CuMnOx/OMS-2 material in treatment of CO.