Efficient photocatalytic conversion of xylose to co-produce xylonic acid and CO via a dual S-scheme heterojunction photocatalyst between carbon nitride and CuInS2 quantum dot-sensitized ZnIn2S4

Abstract

Heterojunction photocatalysts receive significant interest due to their high performance and easy fabrication. An S-scheme heterojunction is developed on the basis of conventional type II heterojunctions, which can further promote charge separation and migration. In this work, a photocatalyst with a dual S-scheme heterojunction (denoted as C-s-ZIS/CN) is developed by the hybridization of CuInS₂ quantum dot-sensitized ZnIn₂S₄ nanosheets and g-C₃N₄ nanosheets. CuInS₂ quantum dot sensitization efficiently enhanced light absorption. Meanwhile, the unique charge migration pathway in the dual S-scheme heterojunction accelerated the separation and transfer of photogenerated carriers. The photocatalyst was innovatively employed in the simultaneous photocatalytic production of xylonic acid and CO. Under 10 W LED light irradiation (790 mW cm⁻²), the CO evolution rate reached a high of 228.94 μmol g⁻¹ h⁻¹. When a xenon lamp was employed, the CO evolution rate increased to 964.27 μmol g⁻¹ h⁻¹. Moreover, the optimal xylonic acid yield achieved was up to 58.56%.