Abstract
The photocatalytic reduction of Cr(VI) is investigated over iron(III)‐based metal–organic frameworks (MOFs) structured as MIL‐88B. It is found that MIL‐88B (Fe) MOFs, containing Fe
3
‐μ
3
‐oxo clusters, can be used as photocatalyst for the reduction of Cr(VI) under visible light irradiation, which is due to the direct excitation of Fe
3
‐μ
3
‐oxo clusters. The amine‐functionalized MIL‐88B (Fe) MOFs (denoted as NH
2
–MIL‐88B (Fe)) shows much higher efficiency for the photocatalytic Cr(VI) reduction under visible‐light irradiation compared with MIL‐88B (Fe). It is revealed that in addition to the direct excitation of Fe
3
‐μ
3
‐oxo clusters, the amine functionality in NH
2
–MIL‐88B (Fe) can also be excited and then transferred an electron to Fe
3
‐μ
3
‐oxo clusters, which is responsible for the enhanced photocatalytic activity for Cr(VI) reduction. The enhanced photocatalytic activity for Cr(VI) reduction is also achieved for other two amine‐functionalized iron(III)‐based MOFs (NH
2
–MIL‐53 (Fe) and NH
2
–MIL‐101 (Fe)).