In situ anchoring of InOOH nanowires on NH2-MIL-68(In) to construct Z-type heterojunctions for enhanced visible photocatalytic performance

Metal-organic frameworks (MOFs), with tunable morphologies and porous architectures, show great potential in photocatalysis. A variety of MOFs can be synthesized by changing the types of metal ions and organic ligands. However, fewer studies have explored the influence of the metal-to-ligand molar ratio on the catalytic performance of the resulting MOF-related products. In this work, capsule-shaped NH 2 -MIL-68(In)/InOOH composites were synthesized by adjusting molar ratios of In(NO 3 ) 3 to 2-aminoterephthalic acid. Time-dependent characterization revealed sequential crystallization: rod-shaped NH 2 -MIL-68(In) initially formed in the solution, followed by the in-situ growth of InOOH nanowires on its surfaces via excess indium ions, ultimately constructing a Z-scheme heterojunction. The optimized NM/InOOH (8:1) composite exhibited a larger specific surface area and extended light absorption. The Z-scheme configuration significantly promoted charge carrier separation efficiency while maintaining strong redox potentials of the photoinduced holes and electrons, thereby resulting in 5–8-fold improvement in degradation rates for four dyes (AOII, RhB, MB, and Rh6G), highlighting its broad photocatalytic applicability.