Phosphoric acid treating of ZSM-5 zeolite for the enhanced photocatalytic activity of TiO2/HZSM-5

NaZSM-5 zeolite was modified by phosphoric acid and a sol–gel method was used to prepare the supported TiO2/HZSM-5. The composite photocatalysts were characterized by XRD, SEM, BET, FT-IR and XPS measurements. The TiO2 existed as anatase phase in both pure TiO2 and supported TiO2/ZSM-5. The TiO2 crystallite size became smaller after loading TiO2 on the zeolite. The surface areas of the composite 50%TiO2/χHZSM-5 were much higher than that of pure TiO2, while the surface areas of the composites decreased with increasing TiO2 loading contents. The TiO2/0.5HZSM-5 composites had higher photocatalytic activity than the pure TiO2. The maximum degradation rate was 49.7% on the 50%TiO2/0.5HZSM-5 using the support of 0.5HZSM-5 which was treated with 0.5 mol/L phosphoric acid. Nearly all of the absorption peaks of Reactive Brilliant Red X-3B disappeared after 2 h of degradation on 50%TiO2/0.5HZSM-5.

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► NaZSM-5 treated by phosphoric acid was used as support to prepare TiO2/HZSM-5.
► The effects of phosphoric acid concentration and TiO2 content were investigated.
► The TiO2/0.5HZSM-5 had much improved photocatalytic activity than pure TiO2.