One-pot Synthesis of the MIL-100 (Fe) MOF/MOX Homojunctions with Tunable Hierarchical Pores for the Photocatalytic Removal of BTXS

The construction of metal-organic frameworks (MOFs) with hierarchical pores is of great importance for the photocatalytic oxidation (PCO) of gaseous BTXS (benzene, toluene, xylenes and styrene) pollutants with large molecular size, but it is still challenging. Herein, by adjusting the ratio of anions (NO3- and Cl-) in the metal precursors, hierarchically porous MIL-100(Fe) MOF/MOX homojunctions were obtained through a one-pot solvothermal method. The existence of both micro- and mesopores (2–10 nm) made the active sites more accessible to guest molecules. The formation of MOF/MOX homojunctions promoted the separation of electron-hole pairs. Additionally, the coordinatively unsaturated acidic Fe3-O sites facilitated the capture of BTXS molecules and participated in the PCO process through the conversion between Fe(III) and Fe(II). The MIL-100(Fe) homojunctions showed improved performance towards the PCO of BTXS (over 80% for xylenes and styrene) compared with the crystalline or xerogel counterparts and exhibited great potential in the PCO of aromatic air pollutants.