Promoting Photocatalytic Activity of Pd-Doped NH₂-MIL-125(Ti) for Degradation of Pollutants and Cross-Coupling...

The sustainable use of solar energy for dye degradation and organic transformations has gained significant attention. In this work, two-dimensional Pd-decorated Ti-based amine-functionalized metal-organic frameworks (Pd/NH₂-MIL-125 (Ti)) were synthesized via in situ Pd nanoparticle deposition. The heterojunctions were fully characterized by various techniques (XRD, BET, FE-SEM, TEM, FT-IR, XPS, AFM, Raman, and X-ray mapping). The optimized catalyst (4.46 wt % Pd) showed a large surface area (849.61 m²/g) and remarkable photocatalytic efficiency under visible light. It achieved 94% conversion in Suzuki cross-coupling and high degradation efficiencies for Rhodamine B (RhB, 98.10 ± 0.780%) and Congo red (CR, 94.8 ± 0.720%) within 60 min, without H₂O₂ or additional photosensitizers. The enhanced activity is attributed to the synergistic interaction of Pd and NH₂-MIL-125 (Ti), enabling efficient charge separation, narrowed band gap, and abundant active sites. Mechanistic studies identified superoxide radicals (·O₂^-) as key species in dye degradation. The catalyst also exhibited excellent recyclability, maintaining performance over five cycles.