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

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.