Decomposition-Reassembly Synthesis of a Silverton-Type Polyoxometalate 3D Framework: Semiconducting Properties and Photocatalytic Applications.

Polyoxometalate-based all-inorganic three-dimensional (3D) frameworks have recently attracted attention as a unique class of materials due to their unique physicochemical properties and a wide field of application with excellent prospects. We herein synthesized a novel all-inorganic 3D framework material based on cobalt-substituted Silverton-type polyoxometalate, H 6 {Co 6 W 10 O 42 [Co(H 2 O) 4 ] 3 }·2H 2 O (Co 9 W 10 ), which was successfully constructed using Na 12 [WCo 3 II (H 2 O) 2 (Co II W 9 O 34 ) 2 ]·46-48H 2 O (Co 5 W 19 ) and Co(NO 3 ) 2 ·6H 2 O as starting materials in a hydrothermal reaction via a decomposition-reassembly route together with the rational adjustment of pH values. Co 9 W 10 has been structurally characterized using single-crystal X-ray diffraction. Photocurrent response, band-gap ( E g ) value, and the VB-XPS spectrum have been measured to reveal the semiconducting property of Co 9 W 10 . Furthermore, we synthesized x % PTh/Co 9 W 10 composites (PTh = polythiophene, x = 0.5, 1, 2, 5) for photodegradation of tetracycline hydrochloride (TH) to evaluate the photocatalytic activities of title composites. Due to the optimal molar ratio of hybrids and matching energy levels, 2% PTh/Co 9 W 10 composites show the best photocatalytic activities among these composites.