Constructing Δ-Mno2 Confined within Micro-Mesoporous Ssz-13 Boosts Catalytic Oxidation of Toluene

Abstract

Catalytic oxidation is a promising technology for VOCs removal with broad application prospects, whereas its catalysts usually face bottlenecks such as high ignition temperature and low turnover frequency (TOF). To this end, a micro-nano reactor is constructed by confining the δ-MnO2 particles to the micro-mesoporous H-SSZ-13. It is noteworthy that this composite material achieves a significant improvement in toluene catalytic oxidation activity. From the perspective of kinetics and physicochemical properties, this study revealed notable alterations of MnO2 before and after confining within the micro-mesoporous SSZ-13. Compared with the undispersed bulk δ-MnO2, TOF of 15 wt% δ-MnO2@H-SSZ-13 is 6.5 times higher at 190 °C and the T90 is 40 °C lower. Furthermore, in this composite system, due to the confinement, δ-MnO2 is nanoscale with lower average oxidation state of Mn. Combined with O2-TPD and H2-TPR, a large number of oxygen vacancy is induced on 15 wt% δ-MnO2@H-SSZ-13, which results in abundant adsorbed oxygen species and higher mobility of lattice oxygen, thus the redox cycle is promoted. This study provides a new method for constructing confined catalytic materials with excellent VOCs catalytic oxidation activity, and is expected to inspire future related researches.

Keywords: Micro-mesoporous SSZ-13, δ-MnO2, Confinement, Toluene catalytic oxidation