Three Isostructural Keggin‐Type Polyoxometalate Hybrids for Effective Dye Degradation

ABSTRACT Three isostructural polyoxometalate–based hybrid materials, namely, [Zn 2 (Hppb) 3 (ppb)(H 2 O) 2 ][PW 12 O 40 ]·4H 2 O ( 1 ), [Co 2 (Hppb) 3 (ppb)(H 2 O) 2 ][PW 12 O 40 ]·4H 2 O ( 2 ), and [Co 2 (Hppb) 3 (ppb)(H 2 O) 2 ][PMo 12 O 40 ]·4H 2 O ( 3 ) (where Hppb = 2‐(3‐(Pyridin‐2‐yl)‐1H‐pyrazol‐1‐yl)benzoate), were successfully synthesized under hydrothermal conditions. These compounds were fully characterized by single‐crystal X‐ray diffraction, FT‐IR, PXRD, UV–Vis DRS, and TGA. In each structure, Keggin‐type polyoxometalate clusters are anchored within the metal–organic framework through hydrogen‐bonding interactions. The photocatalytic activities of these hybrids were evaluated through the degradation of organic dyes under xenon lamp irradiation. Compound 1 demonstrated exceptional performance, achieving 94.2% removal of MB and 87.9% removal of RhB. The degradation processes followed pseudo‐first‐order kinetics, and radical trapping experiments revealed that h + and ·OH serve as the main active species for MB and RhB degradation, respectively. The enhanced photocatalytic efficiency of 1 is attributed to the synergistic effect between the metal–organic matrix and the polyoxometalate units, which significantly improve light harvesting and charge transfer dynamics. This work provides valuable guidance for the development of high‐efficiency POM‐based hybrid materials for environmental photocatalytic applications.