A sandwiched Co 4 -added polyoxometalate for efficient visible light-driven hydrogen evolution.

A new Co 4 -added polyoxometalate (CoAP) Cs 4 [(Co(H 2 O) 5 ) 2 {(μ 2 -Co(H 2 O) 4 ) 2 Co 4 (H 2 O) 2 (B-α-GeW 9 O 34 ) 2 }]·6H 2 O (1) has been made using a lacunary directing strategy under hydrothermal conditions. Single-crystal X-ray diffraction analysis demonstrated that 1 is a one-dimensional (1D) chain, in which CoAP is linked by cobalt-oxygen octahedra to form a 1D structure with excellent chemical stability. The visible light-driven H 2 evolution test demonstrated that 1 has high activity, with an H 2 evolution rate of 1485.95 μmol h -1 g -1 . PXRD and FT-IR tests demonstrated that compound 1 exhibits excellent heterogeneous catalytic stability.