Two 2D inorganic—organic hybrid compounds containing Anderson—type polyoxometalate for electrocatalytic and capacitive performances

For constructing the compounds containing polyoxometalate with electrochemical properties, to employ 3,5 − di − [1,2,4]triazol − 1 − yl − benzonitrile (DTCN) as organic ligand, Anderson − type polyoxometalate {TeMo6O24}6− as inorganic building block, two inorganic–organic hybrid compounds were synthesized under hydrothermal condition, formulated as {M(H2O)4(DTCN)2}[M2(H2O)2(DTCN)2{TeMo6O24}]·2H2O [M = Co (1), Ni (2)]. Structural analysis indicated that two compounds have 2D structures. The {TeMo6O24}6− polyoxoanions were each other aggregated through paired transition metal centers to generate a 1D inorganic chain. The DTCN ligand played a role of bidentate linker, utilizing the nitrogen atoms of two triazole groups to link these inorganic chains into a 2D grid − like layer. Another kind of metal − organic fragments {M(H2O)4(DTCN)2}2+ were arranged in the grids. Compounds 1 and 2 displayed not only electrocatalytic activities for the reduction of Cr(VI), but also sensing activities with the limit of detection of 0.011 μM for 1 and 0.019 μM for 2, as well as capacitive performances with specific capacitances of 1297F·g−1 for 1 and 968F·g−1 for 2 at a current density of 1 A·g−1. The results might provide a potential approach for preparing polyoxometalate − based inorganic–organic hybrid compounds used as electrochemical materials.