Fabrication of NH2-MIL-101(Fe)/few-layer Ti3C2 Schottky heterojunctions to boost charge separation for enhanced photocatalytic Cr(VI) elimination

NH 2 -MIL-101(Fe)/few-layer Ti 3 C 2 Schottky heterojunctions are constructed. • NH 2 -MIL-101(Fe)/Ti 3 C 2 composite shows higher photocatalytic activity for Cr(VI) removal. • The Schottky heterojunctions boost the separation of photogenerated charges. • The photogenerated electrons and •O 2 − dominate the Cr(VI) reduction process. The limited charge transfer efficiency of single-component semiconductor photocatalysts remains a critical bottleneck restricting the photocatalytic elimination of harmful pollutants. Here, NH 2 -MIL-101(Fe) nanoparticles are anchored onto few-layer Ti 3 C 2 nanosheets via electrostatic self-assembly to construct NH₂-MIL-101(Fe)/Ti 3 C 2 heterostructure. The few-layered 2D Ti 3 C 2 supplies abundant adsorption and catalytic active sites. Furthermore, benefiting from the Schottky junction and the superior conductive feature of Ti 3 C 2 MXene, the separation and transport of photoinduced carriers are remarkably promoted in the NH 2 -MIL-101(Fe)/Ti 3 C 2 . Accordingly, the optimized NH 2 -MIL-101(Fe)/Ti 3 C 2 –10% sample can remove 95.7% of Cr(VI) after 150 min of visible-light irradiation and still exhibits favorable reusability after three cycles. The electrons and •O 2 − are confirmed as the primary active species driving Cr(VI) reduction. Combined with comprehensive characterizations, a plausible photocatalytic mechanism of Cr(VI) reduction is put forward. This work offers fundamental guidance for developing MXene-based Schottky heterostructures toward improved photocatalytic activity.