Boosting H2 Production over C60 -Mediated NH2 -MIL-125(Ti)/Zn0.5 Cd0.5 S S-Scheme Heterojunction via Enhanced Interfacial Carrier Separation

Abstract

Improving greatly the separation efficiency of interfacial charge carrier is a major challenge in photocatalysis. Herein, a new class of C₆₀ -mediated NH₂ -MIL-125(Ti)/Zn_0.5 Cd_0.5 S S-scheme heterojunction with enhanced interfacial charge carrier separation is designed and synthesized. The constructed S-scheme heterojunction thermodynamically favors photocatalytic H₂ evolution because of the large driving force resulting from its strong redox abilities. As a consequence, the optimum proportion of C₆₀ -mediated NH₂ -MIL-125(Ti)/Zn_0.5 Cd_0.5 S S-scheme heterojunction displays comparable H₂ evolution activity with a rate of 7825.20 µmol h^-1 g^-1 under visible light irradiation, which is about 93.05 times, 6.38 times and 2.65 times higher than that of 2% C₆₀ /NH₂ -MIL-125(Ti), Zn_0.5 Cd_0.5 S and 45% NH₂ -MIL-125(Ti)/Zn_0.5 Cd_0.5 S, and outperforms the majority of the previously reported MOFs-based photocatalysts. Spectroscopic characterizations and theory calculations indicate that the S-scheme heterojunction can powerfully promote the separation of photogenerated carriers. This work offers a new insight for future design and development of highly active MOFs-based photocatalysts.

Keywords: C 60-mediated NH 2-MIL-125(Ti)/Zn 0.5Cd 0.5S; S-scheme heterojunction; interfacial charge carrier separation; photocatalytic H 2 evolution; strong redox abilities.