Fe-Doped α-MnO2 nanorods for the catalytic removal of NOx and chlorobenzene: the relationship between lattice distortion and catalytic redox properties

Abstract

Controllably tuning redox performance is one of the key targets in catalysis. Doping is one of the widely used methods to tune the performance of nanoparticles. However, the influence of dopants is generally focused on the effects of the dopant sites or nearby sites without considering the bulk distortion. In this work, Fe-doped α-MnO₂ nanorods were investigated combining experimental studies with DFT calculations to further understand the relationship between the lattice distortion induced by Fe doping and catalytic redox properties, and the bulk influence of substitutional doping and the disruption to chemical bonding were thoroughly evaluated. It was demonstrated that the embedding of Fe yielded a (t_2g)³(e_g)¹ configuration of Mn³⁺, which anisotropically distorted the α-MnO₂ lattice and significantly increased the Mn–O bond length along the local z direction. Accordingly, the lattice oxygen bonding with manganese was weakened and became more active in oxidation reactions. Two important environmental catalysis processes, namely, NO and chlorobenzene removal were thus promoted.