A new 3 D {Na₂Cu₃}-substituted polyoxometalate: synthesis, structure and its photocatalytic and electrochemical properties

Abstract

A new 3 D polyoxometalate, H₇K₃[Na₂Cu₃(H₂O)(B-α-SbW₉O₃₃)₂]·8H₂O (1), has been hydrothermally made and characterized by IR spectroscopy, thermogravimetric analyses, powder X-ray diffraction and single crystal X-ray diffraction analysis. 1 crystallizes in the tetragonal system, space group P-42₁m, with a = 16.7532(7) Å, b = 16.7532(7) Å, c = 13.8335(11) Å and Z = 2. Structure analysis reveals that the polyanion in 1 consists of two B-α-SbW₉O₃₃ ({SbW₉}) units sandwiched by a U-shaped {Na₂Cu₃} cluster made by two Na⁺ and three Cu²⁺ ions. The most prominent structural feature of 1 is that the [Na₂Cu₃(H₂O)(B-α-SbW₉O₃₃)₂]^10– ({Na₂Cu₃(SbW₉)₂}) units are connected to construct a 2 D network through Cu–O = W bridges. To the best of our knowledge, 1 represents the first sample with an unclosed central belt between two {SbW₉} fragments. Furthermore, neighboring 2 D networks connect by K⁺ cations to form a 3 D framework. The semiconductor behavior, electrochemical properties and photocatalytic activities have been investigated, showing excellent photocatalytic and electrocatalytic activities for the photodegradation of MB/RhB and bromate reduction.

Graphical Abstract

Keywords:

• Polyoxometalates
• hydrothermal synthesis
• heterometallic cluster
• photocatalytic activity
• semiconductor behaviors

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Nos. 21831001, 21571016 and 91122028) and the National Natural Science Foundation of China for Distinguished Young Scholars (No. 20725101).