Small ZSM-5 crystals with low defect density as an effective catalyst for conversion of methanol to hydrocarbons

•A nearly defect-free, nanosized ZSM-5(F) zeolite was synthesized by fluoride route.•ZSM-5(F) is morphologically and chemically similar to an alkali-synthesized ZSM-5(OH), produced with an analogous procedure.•The improved lifetime in MTH of ZSM-5(F) vs ZSM-5(OH) is correlated to the lower defectivity of the former.•Different deactivation mechanisms are postulated for the two materials accounting on spectroscopy and catalytic tests.