Two polyoxometalates based on {P2Mo5} catalysts: synthesis, characterization, and photocatalytic degradation of RhB

The incorporation of simple molybdate via the single-step assembly reaction of H3PO4, copper chloride and N-donor ligand yielded two new {P2Mo5}-based polyoxometalates, (C10N2H9)2[H2P2Mo5O23][Cu(C10N2H8)2]·18H2O (1) and [Cu(C12N2H8)2][Cu(C12N2H8)(H2O)]2[P2Mo5O23]·27H2O (2). Single crystal X-ray diffraction reveals the architectures and connection modes of two clusters, and further verified by XRD, IR spectrum, TGA and CHN elemental analysis. More interesting, compound 1 possessing 3D framework structure shows an exceptional photocatalytic degradation of Rhodamine B and remaining stability after four cycles. The degradation rate reaches to 89.57 % within 3 h with only 15 mg sample. Besides, the results reveal that the degradation process belongs to pseudo first-order kinetic reaction for the degradation of Rhodamine B.