Hexanuclear nickel-based [P4Mo11O50] with photocatalytic reduction of CO2 activity

Abstract A new polyoxometalate based organic-inorganic hybrid [Ni6(trz)2(Htrz)13][H4P4Mo11O50]·7H2O (1), constructed from a hexanuclear [Ni6(trz)2(Htrz)13] building block and a new polyoxometalate [H4P4Mo11O50] cluster, was synthesized under a hydrothermal condition. In this 3D structure, each [Ni6(trz)2(Htrz)13] secondary building unit (SBU) connects with four neighbored [Ni6(trz)2(Htrz)13] and four [H4P4Mo11O50] clusters, forming an eight-connected node. While each [H4P4Mo11O50] cluster bridges four [Ni6(trz)2(Htrz)13] SBUs as a four-connected node. So the 3D framework of 1 can be simplified to a binodal (4, 8)−connected gsp2 topology with point symbol [44·62][416·612]. The photocatalytic reduction of CO2 under visible light reveals that the highest yield of CO was 689.86 μmol g−1 when 1 is used as catalyst, Ru(bpy)3Cl2 as a photosensitizer and TEOA as a sacrificial agent. The mechanism of the photoreduction of CO2 is confirmed by Mott-Schottky, photocurrent, and fluorescence quenching experiments. This research provides a new strategy for the design of cheap and efficient POM-based photocatalysts.