Synthesis,Crystal Structure and Photocatalytic Properties of Nanosized La3+-Substituted Arsenotungstate Cluster
Based on the principle of molecular design and self-assembly,a novel rare earth based arsenotungstate was obtained by introducing rare earth LaⅢ ions into the lacunary polyoxotungstates clusters with vacancy structure by one-pot method with Na2WO4·2H2O,NaAsO2 and LaCl3·6H2 O as the main materials.The structure and composition of this complex was confirmed by single-crystal X-ray diffraction,X-ray powder diffraction(PXRD),infrared spectroscopy(IR)and so on.The single crystal X-ray diffraction results show that the complex is in the monoclinic system,C2/c space group,and with the cell parameters of a=3.595 56(14)nm,b=1.222 48(4)nm,c=2.247 34(9)nm,β=117.117 0(10)°,V=8.792 3(6)nm3,Z=4.The molecular formula of this compound is[(CH3)2 NH2]8 H 3.56[{ LaO(H2O)2 } { WO(H2O)｝ { W0.24(H2O)2 }｛AsW9O33}2].And the polyoxoanion[{LaO(H2O)2} {WO(H2O)} {W0.24(H2O)2} { AsW9O33 } 2]11.56-shows a novel sandwich type structure,which can be simply described as two trilacunary Keggin type { AsW9 O33 } units are linked by a{LaO(H2O)2} segment,a { WO(H2O)} segment and a {W0.24(H2O)2｝ segment.Catalytic degradation property of this compound for Rhodamine-B was further inverstigated.The results demonstrate that the compound shows good photocatalytic activity under the condition of 300 W Hg lamp irradiation,and the degradation efficiency reaches to 74％.
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