Plasmonic Ti3C2Tx MXene tuned by Tx moieties in 2D/2D heterojunction for boosting the photocatalytic degradation performances

Abstract

Expediting the separation and transfer of photogenerated carriers is crucial for plasmonic materials to improve the performance of photocatalysts. However, it remains a significant challenge to strengthen the local surface plasma resonance (LSPR) through the modulation of surface functional groups. Herein, Ti₃C₂T_x MXene is combined with two typical semiconductor materials to form Ti₃C₂T_x/CdS (TCS) with dominated surface O_x groups and Ti₃C₂T_x/C₃N₄ (TCN) with surface-terminated F_x species. The obtained TCS composite shows a higher photocatalytic performance (96.7 %) than TCN (86.7 %) and the corresponding bare catalysts in the degradation of tetracycline within 60 min under visible-light irradiation. Moreover, the degradation rate of Ti₃C₂T_x/CdS composite decreases by only 2.3 % after 4 cycles photocatalytic process, which is more stable than Ti₃C₂T_x/C₃N₄ (3.3 %) and CdS (39.3 %). The improved photocatalytic activity and stability mainly result from the enhanced LSPR effect of Ti₃C₂T_x MXene. In particular, the better performance of TCS compared to TCN indicates that the LSPR effect is highly related to the surface-terminated [O]/[F] ratio. These results directly provide a strategy to enhance the electric field dynamics of MXene materials for improving photocatalytic performance.