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. The MIL-100(Fe) MOF/MOX homojunctions with tunable hierarchical pores are obtained through a one-pot solvothermal method by adjusting the ratio of anions (NO3- and Cl-) in the metal precursors. Improved performance towards the photocatalytic removal of BTXS is achieved. The hierarchical pores provide channels for the migration of BTXS molecules to abundant active acidic sites and the formation of homojunction accelerates the separation of photon-induced charge carriers. [Display omitted] ●MIL-100(Fe) MOF/MOX homojunctions were obtained through a solvothermal method.●Hierarchical pores were obtained by adjusting the ratio of anions in the metal precursors.●The hierarchical pores provide channels for BTXS to migrate to active acidic sites.●The PCO of BTXS was enhanced due to hierarchical pores and homojunction.●The adsorption and degradation mechanism of BTXS were proposed.