Scavenging activity and reaction mechanism of Ti3C2Tx MXene as a novel free radical scavenger

A novel free radical scavenger, multi-layered Ti₃C₂T_x MXene (ML-Ti₃C₂T_x), has been studied by evaluating its scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH?). It exhibits high scavenging efficiency (95% in 10 min) at low dosage (0.06 mg/mL). Based on the analysis of structure and surface states of ML-Ti₃C₂T_x before and after reaction with DPPH? and a series of comparative experiments, including few-layered Ti₃C₂T_x MXene (FL-Ti₃C₂T_x), original Ti₃AlC₂, and soluble Ti species derived from ML-Ti₃C₂T_x, the observed high scavenging activity is attributed to the intrinsic reducing property of ML-Ti₃C₂T_x rather than the hydrogen donation ability from surface functional groups. A model is proposed to explain the scavenging mechanism.