A New Multi-Copper-Substituted Tetramer Tungstoantimonate: Synthesis, Photocatalytic and Electrochemical Properties

Under hydrothermal conditions, a new “S”-shaped Cu-substituted tetramer tungstoantimonate, HKNa2(H2en)6[Cu(en)(H2O)]2[KNaCu3(H2O)7(B-a-SbW9O33)2]2⋅16H2O (1, en = 1,2-ethylenediamine) was synthesized in reactions of the Na9[SbW9O33]·19.5H2O precursor with CuCl2⋅2H2O and potassium acetate in the presence of en and characterized by IR spectrum, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction, respectively. Polyoxoanion 1 consists of two asymmetric sandwich-type polyanions {KNaCu3(H2O)7(B-a-SbW9O33)2} linked by two structurally equivalent [Cu4(en)(H2O)]2+ bridges. The electrochemical properties and photocatalytic activities have been investigated, displaying outstanding photocatalytic and electrocatalytic activities for the photodegradation of MB and H2O2/NO2−/BrO3− reduction.