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Methane dehydroaromatization (MDA) is a promising approach for direct methane transformation to aromatics and hydrogen. The benchmark catalyst Mo/H-ZSM-5 struggles to find commercial adoption because of thermodynamically-limited yields and rapid coking on Brønsted acid and molybdenum carbide species, especially on zeolite external surfaces. Here, gas-phase atomic layer deposition (ALD) overcoats H-ZSM-5 external surfaces with SiO 2 or Al 2 O 3. NH 3 -TPD, HRTEM, and textural properties show that these overcoats exclusively passivate zeolite external surfaces. Under MDA conditions, SiO 2 gives softer coke and increases cumulative benzene yields by 25 %, while Al 2 O 3 strongly decreases yields. H 2 -TPR and UV–visible and Raman spectroscopy show how the overcoats redisperse the MoO x precatalysts, especially over multiple deactivation and isothermal oxidative regeneration cycles. Combined with 27Al-MAS NMR, MoO x redistribution and dealumination are seen as the causes of long-term deactivation over multiple regeneration cycles, and this process continues to occur regardless of the overcoat. Overall, the deposition of a small amount of silica on the outer surface of Mo/H-ZSM-5 reduces the formation of hard coke, which could be regenerated by milder methods such as hydrogen treatment. [Display omitted] • Atomic layer deposition (ALD) of Al 2 O 3 and SiO 2 on zeolite external surfaces. • Their impact on MDA cumulative aromatic formation increases by 25 % for SiO 2 and decreases by 50 % for Al 2 O 3. • Oxide overcoats consume external acid sites and redistribute MoO x domains was key for improved C 6 H 6 yields. • A small amount of silica on the outer surface of Mo/H-ZSM-5 reduces the formation of hard coke. • Permanent deactivation under oxidative-regeneration driven by dealumination and further MoO x redistribution. [ABSTRACT FROM AUTHOR]