Synthesis of hydrophobic zeolite X@SiO2 core-shell composites

► Hydrophobic 13X zeolite composites with silicalite and mesoporous silica shells are designed. ► These core-shell composites are silynated and their hydrophobicity is tested. ► Addition of silica layer increases the density of surface hydroxyl groups which makes the improvement of the hydrophobicity possible by further silynation.