The Study On The Construction And Photo/Electrocatalytic Properties Of Polyoxometalate Clusters Decorated By Transition Metal

In recent years,it has been an important part of the study of polyoxometalate chemistry to construct novel transition metal-modified polyoxometalate clusters by adding transition metals to vacant polyoxometalate.The doping of transition metal ions endows the synthesized polyoxometalate clusters with new photocatalytic and electrocatalytic properties.Herein,a series of novel polyoxometalate clusters modified by transition metals were constructed by conventional synthesis methods.The new transition metal-modified polyoxometalate clusters were characterized by X-ray single crystal diffraction analysis,powder XRD,IR and TG analysis.The electrocatalytic reduction of hydrogen peroxide or photocatalytic reduction of carbon dioxide were studied for the synthesized polyoxometalate clusters.1.Using hexavacant Wells-Dawson type polyoxometalate K₁₂[H₂P₂W₁₂O₄₈]·24H₂O,transition metal compound CoCl₂·6H₂O,organic ligand unit NaH₄Ale as raw materials and1 M LiOAc as solvent,a high nuclarity polyoxometalate Li₁₀Na₂[Co?H₂O?₃?CH₃COO?]₂{[Co₇?H₂O?₄?OH?₂?Ale?₂][PW₉O₃₄]₂}·20H₂O?1?were constructed by heating at 80?.The structure of 1 was analyzed by single crystal X-ray diffractometer,and its structural composition and purity were determined by IR,powder XRD and TG analysis.Electrochemical and electrocatalytic studies reveal that 1 exhibits good electrocatalytic activity toward the reduction of H₂O₂ in a neutral medium solution with pH=7?1 M LiOAc+HOAc?at room temperature.2.Using the three-vacancy Keggin-type Na₉[A-PW₉O₃₄]·7H₂O as precursor,the transition metal compound CoCl₂·6H₂O and the alkaline earth metal compound anhydrous CaCl2 as raw materials,and 1 M LiCl as solvent,compound 2 was constructed by refluxing at 60?.The structure of 2 was analyzed by single crystal X-ray diffractometer,and its structural composition were determined by IR and TG analysis.The photocatalytic CO2reduction was carried out by using compound 2 as catalyst,[Ru?phen?₃]?PF₆?₂ as photosensitizer and TEOA as electron sacrificial agent.Compound 2 showed good catalytic activity for photocatalytic reduction of CO₂ under the LED irradiation with a wavelength of450 nm.