Photocatalytic oxidation of NOx over TiO2/HZSM-5 catalysts in the presence of water vapor: Effect of hydrophobicity of zeolites

► The photooxidation of NOx over TiO2/HZSM-5 was tested in the presence of water vapor. ► TiO2/HZSM-5 exhibited higher NO conversion and lower NO2 formation than pure TiO2. ► Water vapor related to relative humidity and water pre-adsorption was effect factor. ► TiO2 hybridized with hydrophobic HZSM-5 zeolite retained high reactivity. ► Photocatalytic reactivity of TiO2/HZSM-5 depended on hydrophobicity of zeolites.