Hierarchical MnOx loaded β zeolite as efficient catalyst for bulky aromatic hydrocarbon catalytic degradation

Conventional β zeolite exhibits limitations stemming from its constrained pore size and relatively low external surface area, impeding the efficient diffusion of bulky reactant molecules and limiting the accessibility and loading of active sites. Herein, we developed a hierarchical MnO_x loaded β zeolite (MnO_x/m-β) via a rational hydrothermal and subsequent redox-precipitation strategy. The hierarchical structure endows MnO_x/m-β with a higher external surface area and optimized pore architecture, facilitating both the uniform dispersion of MnO_x species and rapid diffusion of bulky molecules than conventional MnO_x/β. Taking adsorption and catalytic oxidation of toluene, o-xylene, and 1,3,5-trimethylbenzene (TMB) as probe reactions, m-β exhibits significantly enhanced adsorption capacities for o-xylene (45.3 mg/g) and TMB (91.4 mg/g), representing 1.7 and 3.8 times increases compared to conventional β, respectively. Furthermore, MnO_x/m-β achieves complete oxidation of toluene, o-xylene, and TMB at ca. 260 °C, 300 °C and 250 °C, respectively, significantly lower than those required for MnO_x/β. This superior catalytic performance is attributed to the synergistic effects of enhanced Mn^4 + -activated lattice oxygen mobility, hierarchical mass transfer channels, and abundant accessible active sites. The designed hierarchical architecture of β holds promise for the efficient removal of bulky aromatic hydrocarbon.