Near-unity photocatalytic dehydrocoupling of thiophenols into disulfides and hydrogen using coupled CdS Nanorods and Ni-containing polyoxometalate

ABSTRACT Simultaneously harnessing the photogenerated electrons and holes to convert thiols into the value-added disulfides with the concomitant formation of H 2 represents a highly promising strategy for maximizing the conversion of solar energy into chemical energy. Herein, we report an effective catalytic system comprising CdS nanorods (NRs) and Ni-containing polyoxometalate (Na 6 K 4 [Ni 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] (Ni 4 P 2 )) (Ni 4 P 2 /CdS), which exhibited efficient photocatalytic activities towards the near-unity dehydrocoupling of 4-methoxythiophenol (4-MTP) into disulfide and H 2 evolution. The photooxidative dehydrocoupling of 4-MTP can be finished after 4 h photocatalysis , leading to 98.39% conversion of 4-MTP with the yield of disulfide and H 2 reaching 24.45 and 25.96 μmol, respectively. The Ni 4 P 2 /CdS catalytic system also showed good photocatalytic recycling stability. Comprehensive experimental and characterization results indicated that the synergistic cooperation between CdS NRs and Ni 4 P 2 facilitated the separation and migration of the photogenerated electron-hole pairs, thereby improving the photocatalytic dehydrocoupling of 4-MTP to disulfide coupling with hydrogen production .