Construction of Pt complex within Zr-based MOF and its application for hydrogen production under visible-light irradiation

The present article deals with Pt complex construction within Zr-based MOF having bipyridine units in the framework (Zr-MOF-bpy-PtCl2) and its photocatalytic activity for hydrogen production under visible-light irradiation (lambda > 420 nm). Zr-MOF-bpy-PtCl2 is prepared by the construction of a Zr-based MOF using 2,2'-bipyridine-5,5'-dicarboxylic acid (Zr-MOF-bpy), and subsequent complexation reaction with K2PtCl4. XRD and N-2 adsorption-desorption measurements have revealed that both Zr-MOF-bpy and Zr-MOF-bpy-PtCl2 have a UiO-type structure. From the results of UV-Vis and XAFS measurements, the incorporated Pt species has been proven to be in square planar geometry involving two N atoms and two Cl atoms as a result of the Pt coordination with bipyridine units in the framework. Zr-MOF-bpy-PtCl2 has been employed for a hydrogen production reaction from water containing a sacrificial electron donor under visible-light irradiation (lambda > 420 nm). Zr-MOF-bpy-PtCl2 realizes steady hydrogen production, and the amount of evolved hydrogen reaches 8.3 mu mol after the 9 h reaction period, while Zr-MOF-bpy exhibits no photocatalytic activity under the same conditions. It has also been found that the activity of Zr-MOF-bpy-PtCl2 is superior to that of the corresponding homogeneous complex analogue (bpy)PtCl2.