The impact of the NH 4 F etching on the textural and catalytic properties of TS-1 was investigated. Two TS-1 with different crystal sizes, i. e. 200 and 100 nm; were achieved, with different textural properties as inferred from nitrogen physisorption isotherms at 77 K, mercury porosimetry, powder X-ray diffraction patterns and transmission electron microscopy. The generation of larger mesopores within the parent samples was observed together with a reduction of the coherent crystal size (CCS) upon NH 4 F etching. The generation of secondary porosity further did not result in an alteration of the Si/Ti ratio, allowing to compare the catalytic outcomes of the samples as a function of the textural properties. It was found that the methyl-phenyl sulfide (MPS) conversion kinetics importantly depend on the textural properties of the catalysts. The initial velocity was found to increase linearly with the reduction of the CCS until reaching a plateau, indicating that diffusion limitation occur up to a CCS of approximately 100 nm. Likewise, mono-and dioxidation product selectivity was governed by diffusion issues.