An ultraefficient surface functionalized Ti3C2Tx MXene piezocatalyst: synchronous hydrogen evolution and wastewater treatment

Abstract

The Ti₃C₂T_x surface contains hydroxyl groups that can be modified through self-assembled monolayers by using (3-chloropropyl) trimethoxysilane (CPTMS) and fluoroalkylsilane (FOTS). This study demonstrates that an ultrahigh level of piezoelectricity can be achieved by modifying the Si–O bond of organo-silane headgroups in Ti₃C₂T_x. The theoretical calculation of surface functionalized Ti₃C₂T_x-FOTS reveals that its Si–O bond causes localized lattice distortion and enhances the noncentrosymmetric structure on the Ti₃C₂T_x surface. Ti₃C₂T_x-FOTS exhibits significantly higher butterfly loops than pristine Ti₃C₂T_x. The calculated rate constant of Ti₃C₂T_x-FOTS for dye degradation was 0.9 min⁻¹, 15-fold higher than that of Ti₃C₂T_x-CPTMS and 111-fold higher than that of pristine Ti₃C₂T_x. The hydrogen evolution rate of Ti₃C₂T_x-FOTS is 900.46 μmo1 g⁻¹ h⁻¹, three times higher than that of Ti₃C₂T_x. The bifunctional surface functionalized Ti₃C₂T_x-FOTS can simultaneously catalyse the hydrogen evolution reaction (HER) and decomposition of wastewater, demonstrating that Ti₃C₂T_x-FOTS, obtained through the surface engineering of Ti₃C₂T_x, is a superior piezocatalyst.