Influence of the Distance between Brønsted Acid Sites and Mo Sites in Mo/HZSM-5 on the Mechanism of Methane Dehydroaromatization Performance

• • Methane conversion scales with BAS strength in M-80 zeolites (Al > Ga > Fe), but B-80 achieves exceptional MDA performance via deboronation-generated silanol nests anchoring Mo for monofunctional steps and residual framework boron providing weak BAS activity, demonstrating that weak acidity can outperform moderate acidity in bifunctional synergy. • • Ball milling achieves optimal nanoscale Mo-BAS spacing, increasing methane conversion by 33% and BTX yield by 31% relative to millimeter/micrometer mixtures, establishing spatial confinement as a performance-determining factor in MDA. • • DFT calculations confirm that deprotonation energy (DPE) correlates with experimental acid strength; strong-acid Al-ZSM-5 (DPE = -5.68 eV) significantly lowers the C–H bond dissociation barrier (ΔG = 1.467 eV), while IGMH analysis reveals mixed ionic-covalent character of Mo-O bonds stabilized by charge compensation and geometric compatibility. • • Metal substituents modulate the electronic structure of active centers—not merely serving as anchors—thereby governing CH3 C–H cleavage barriers and overall activity, providing a theoretical basis for rational design of high-performance MDA catalysts.