Tin-anchored Ti3C2 quantum dots with high conductivity for efficient photocatalytic reduction

Abstract

Highly conductive Sn²⁺-anchored Ti₃C₂ quantum dots (Sn-TQDs) prepared by electrostatic attraction between Sn²⁺ and Ti₃C₂ quantum dots (TQDs) have a vital ability to transfer electrons. Herein, WO₃/Sn-TQDs/In₂S₃ heterojunctions have been fabricated for the first time by introducing Sn-TQDs as electron mediators to shuttle electrons from WO₃ to In₂S₃ efficiently, further realizing the rapid reduction of low-concentration Cr(VI) and H₂ generation by water splitting under visible light. The Cr(VI) reduction efficiency and H₂ evolution rate over WO₃/Sn-TQDs/In₂S₃ were 2.1 and 5.5 times that of WO₃/TQDs/In₂S₃, respectively. The enhanced photocatalytic activity of WO₃/Sn-TQDs/In₂S₃ can be attributed to the positively charged Sn²⁺ anchored around the negatively charged TQDs, facilitating the improvement of photogenerated electron transfer efficiency. Finally, the possible photocatalytic mechanism of Cr(VI) reduction and H₂ generation by WO₃/Sn-TQDs/In₂S₃ was proposed. This provides a new perspective on the surface modification of Ti₃C₂ quantum dots in photocatalysis.