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

Abstract

The CuO, CuMnO_x and MnO_x 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 are flux method under acidic conditions, by an impregnation method and tested for CO oxidation. These catalysts and OMS-2 support were characterized by the advanced analyzations of X-ray diffraction and FTIR patterns; and SEM performances; and H₂-TPR profiles. For CO oxidation reaction, CuO and CuMnO_x catalysts showed extremely higher activities than that of MnO_x catalyst and OMS-2 support. For the lowest temperature for 100% conversion of CO (T₁₀₀), the CuO and CuMnO_x catalysts were observed at 55 ^oC and 65 ^oC, respectively. Due to the present of Cu²⁺– O²⁻ – Mn⁴⁺ ↔ Cu⁺–□–Mn³⁺ + O₂ redox couple in the structure of these solid catalyst. Additionally, the CuMnO_x catalyst showed higher activity (~ 1.74 folds) and better stability than that of CuO catalyst in CO oxidation. Due to the advance functional of binary oxide structure of CuMnO_x catalyst As known, CO oxidation may follow the Mars-van-Krevelen mechanism with Cu²⁺– O²⁻ – Mn⁴⁺ ↔ Cu⁺–□–Mn³⁺ + O₂ redox couple. This study shows the high applicating potential of CuMnO_x/OMS-2 material in exhaust treatment for environmental safety.