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

Simultaneously harnessing the photogenerated electrons and holes to convert thiols into the value-added disulfides with the concomitant formation of H₂ 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 (Na₆K₄[Ni₄(H₂O)₂(PW₉O₃₄)₂] (Ni₄P₂)) (Ni₄P₂/CdS), which exhibited efficient photocatalytic activities towards the near-unity dehydrocoupling of 4-methoxythiophenol (4-MTP) into disulfide and H₂ 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 H₂ reaching 24.45 and 25.96 μmol, respectively. The Ni₄P₂/CdS catalytic system also showed good photocatalytic recycling stability. Comprehensive experimental and characterization results indicated that the synergistic cooperation between CdS NRs and Ni₄P₂ 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.