Highly Efficient Ce and Co Codoped OMS-2 Catalyst for NO Oxidation

The catalytic oxidation of NO is crucial for NOx removal, yet developing low-cost, high-performance NO oxidation catalysts remains a great challenge. Cryptomelane-type Mn oxide (OMS-2) is a type of MnO2 possessing an open tunnel structure, abundant defect sites, high lattice oxygen mobility, and outstanding redox property, making it an excellent catalyst for catalytic oxidation reactions. Herein, OMS-2, Ce-doped OMS-2 (Ce-OMS-2), Co-doped OMS-2 (Co-OMS-2), and Ce, Co-codoped OMS-2 (Ce/Co-OMS-2) were synthesized for NO oxidation. Physiochemical characterization showed that Ce doping could increase the oxygen vacancy defects and specific surface area of OMS-2, while Co doping could increase the oxygen mobility of OMS-2. The synergistic effects between Ce dopants and Co dopants led to Ce/Co-OMS-2 achieving the highest NO conversion of 93.1% at 250 °C, significantly higher than the NO conversions achieved by mono- or nondoped OMS-2.