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

Highly conductive Sn 2+ -anchored Ti 3 C 2 quantum dots (Sn-TQDs) prepared by electrostatic attraction between Sn 2+ and Ti 3 C 2 quantum dots (TQDs) have a vital ability to transfer electrons. Herein, WO 3 /Sn-TQDs/In 2 S 3 heterojunctions have been fabricated for the first time by introducing Sn-TQDs as electron mediators to shuttle electrons from WO 3 to In 2 S 3 efficiently, further realizing the rapid reduction of low-concentration Cr( vi ) and H 2 generation by water splitting under visible light. The Cr( vi ) reduction efficiency and H 2 evolution rate over WO 3 /Sn-TQDs/In 2 S 3 were 2.1 and 5.5 times that of WO 3 /TQDs/In 2 S 3 , respectively. The enhanced photocatalytic activity of WO 3 /Sn-TQDs/In 2 S 3 can be attributed to the positively charged Sn 2+ anchored around the negatively charged TQDs, facilitating the improvement of photogenerated electron transfer efficiency. Finally, the possible photocatalytic mechanism of Cr( vi ) reduction and H 2 generation by WO 3 /Sn-TQDs/In 2 S 3 was proposed. This provides a new perspective on the surface modification of Ti 3 C 2 quantum dots in photocatalysis. Sn-TQDs with excellent conductivity were prepared by homogeneously anchoring Sn 2+ around Ti 3 C 2 quantum dots as electron mediators for improving the photocatalytic reduction.