Design of Bifunctional Cu-SSZ-13@Mn<sub>2</sub>Cu<sub>1</sub>Al<sub>1</sub>O<sub><i>x</i></sub> Core–Shell Catalyst with Superior Activity for the Simultaneous Removal of VOCs and NO<sub><i>x</i></sub>
Zhe Li, Jiewen Xiao, Yanshan Gao, Rongrong Gui, Qiang Wang
Abstract
Synchronous control of volatile organic compounds (VOCs) and nitrogen oxides (NO x ) is of great importance for ozone and PM 2.5 pollution control. Balancing VOC oxidation and the NH 3 –SCR reaction is the key to achieving the simultaneous removal of these two pollutants. In this work, a vertically oriented Mn 2 Cu 1 Al 1 O x nanosheet is grown in situ on the surface of Cu-SSZ-13 to synthesize a core–shell bifunctional catalyst (Cu-SSZ-13@Mn 2 Cu 1 Al 1 O x ) with multiple active sites. The optimized Cu-SSZ-13@Mn 2 Cu 1 Al 1 O x catalyst delivered excellent performance for the simultaneous removal of VOCs and NO x with both 100% conversion at 300 °C in the presence of 5% water vapor. Physicochemical characterization and density functional theory (DFT) calculations revealed that Cu-SSZ-13@Mn 2 Cu 1 Al 1 O x possesses more surface acidity and oxygen vacancies. The charge transfer between the core and shell is the intrinsic reason for the improved activity for both VOC and NO x removal. The molecular orbital theory is used to explain the different adsorption energies due to the different bonding modes between the core–shell and mixed individual catalysts. This work provides a novel strategy for designing efficient catalysts for the simultaneous removal of VOCs and NO x or other multiple pollutants.