Anthracene-Based Rare-Earth MOF Assembly for Photocatalytic Cr(VI) Reduction and Dye Degradation

With the escalating complexity of composite contamination in industrial wastewater, exploring high-efficiency and robust photocatalysts has become a research hotspot in environmental remediation. Herein, five isostructural rare-earth metal-organic frameworks (RE-MOFs, LCUH-128-132) were solvothermally assembled via the coordination of anthracene chromophore ligand 9,10-anthracenedicarboxylic acid (H₂ADC) with five rare-earth metal ions (RE = Y, Eu, Gd, Tb, Dy). Remarkably, LCUH-129 (Eu-MOF) presents outstanding multifunctional photocatalytic activity without any additional photosensitizers or cocatalysts. It delivers a Cr(VI) reduction rate constant of 0.49 min^-1, along with RhB and MB degradation rate constants of 0.23 min^-1 and 0.026 min^-1, respectively. The anthracene moiety serves as a light antenna to efficiently capture visible light; photogenerated electrons are rapidly transferred to rare-earth catalytic centers via ligand-to-metal charge transfer, which effectively inhibits electron-hole recombination. Radical trapping experiments and EPR characterization verify that ·OH, ·O₂^- radicals, and photogenerated electrons dominate the pollutant elimination processes. Furthermore, LCUH-129 exhibits excellent recyclability. This work affords a facile strategy for fabricating high-performance RE-MOF photocatalysts and reveals their promising prospects in the practical remediation of water composite pollution.