Photocatalytic water splitting for hydrogen and oxygen evolution using cobalt- substituted polyoxometalates

Cobalt-substituted polyoxometalate H 18 [ α 1 -P 2 W 17 Co(H 2 O)O 61 ]-[Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] was synthesized, splitting it into α 1 -H 8 -[P 2 W 17 Co(H 2 O)O 61 ] and H 10 [Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] by adjusting the reaction condition and utilizing them for photocatalytic hydrogen and oxygen evolution. • A novel cobalt-substituted polyoxometalate H 18 [ α 1 -P 2 W 17 Co(H 2 O)O 61 ]-[Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] photocatalyst was synthesized. • H 18 [ α 1 -P 2 W 17 Co(H 2 O)O 61 ][Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] can split into α1-H 8 [P 2 W 17 Co(H 2 O)O 61 ] and H 10 [Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ]. • These catalysts exhibit excellent activity in photocatalytic hydrogen and oxygen generation. • The significantly enhanced performance can be attributed to the modulation of the electronic structures of these POMs. The synthesis and photocatalytic properties of cobalt-incorporated polyoxometalate H 18 [α 1 -P 2 W 17 Co(H 2 O)O 61 ]-[Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] ( 1 ) were reported, and split into α 1 -H 8 -[P 2 W 17 Co(H 2 O)O 61 ] ( 2 ) and H 10 [Co 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] ( 3 ) by adjusting the types of acids and solvents in the reaction. The photocatalytic production of O 2 and H 2 from water by compounds 1 , 2 and 3 was evaluated. Notably, compounds 1 and 2 demonstrate superior performance in the photocatalytic production of both hydrogen and oxygen, whereas compound 3 solely exhibits activity in the photocatalytic generation of oxygen. The significantly enhanced performance against the control [P 2 W 18 O 62 ] 6− can be attributed to the modulation of the electronic structures of these novel POMs facilitated by the incorporation of cobalt.