Efficient photo-Fenton degradation performance, mechanism, and pathways of tetracycline hydrochloride over missing-linker metal–organic framework with mix-valence coordinatively unsaturated metal sites

•Missing-linker MIL-100(Fe) with mixed-valence coordinatively unsaturated site was fabricated.•Mixed valence coordinatively unsaturated site intensified Lewis acidity.•Ligand vacancy improved the charge separation efficiency to promote Fe3+ reduction.•CUS-Pac-MIL-100(Fe) exhibited superior photo-Fenton activity and mineralizationrate.•Degradation pathway and degradation mechanism of TC-HCl was proposed.