Construction of Hexameric Ru-Substitution POMs to Improve Photocatalytic H 2 Evolution.

Converting solar energy into storable hydrogen energy by employing green photocatalytic technology offers a reliable alternative for meeting the energy crisis. The polyoxometalates are a promising candidate for hydrogen production photocatalysts because of their unique electronic and structural properties and controllable design at the molecular level. Introducing noble metals was proven to be an effective method to greatly enhance the photocatalytic efficiency of polyoxometalates. Herein, two unprecedented compounds of hexameric Ru-POMs, Na 4 H 10 [As 2 Ru IV 2 W 11 O 18 (OH) 4 (H 2 O) 6 {AsW 8 Ru IV O 31 (OH)Cl} 2 (B-β-AsW 9 O 33 ) 4 ]·93H 2 O ( 1 ) and Na 2 H 19 [AsRu III 2 W 11 O 20 (OH) 2 (H 2 O) 6 (Ru III Cl 3 )(B-β-AsW 9 O 33 ) 6 ]·90H 2 O ( 2 ), were successfully self-assembled. The H 2 evolution rates of 1 and 2 under optimal conditions were 3578.75 and 3027.69 μmol h -1 g -1 with TONs of 255 and 205, respectively. The stability of 1 was demonstrated by a series of characterizations. Besides, a possible photocatalytic mechanism was proposed.