Controlling diffusion resistance, selectivity and deactivation of ZSM-5 catalysts by crystal thickness and defects

•A 35 nm thick and monodispersed ZSM-5 catalyst is synthesized in fluoride medium from defect-free 10 nm thick silicalite-1 seeds.•The use of TEAF as template is crucial for the synthesis.•The catalyst displayed superior activity, stability and selectivity to slower diffusing compounds, which resulted in high yield of e.g. gasoline and the 1,2,4-trimethylbenzene isomer with high octane number.•Strong correlations between crystal thickness and selectivity were observed, which was assigned to control of diffusion resistance by crystal thickness.