Nitrogen-Doped Ti2C MXene Quantum Dots as Antioxidants

MXenes, transition metal carbides, and nitrides or carbonitrides can be synthesized as zero-dimensional quantum dots (MQDs), which have great potential for antioxidizing applications due to their ability to react with many strong oxidizers. However, MQDs can be easily oxidized during hydrothermal synthesis, which damages their intrinsic structures and impairs their antioxidant abilities. To address this issue, ethylenediamine (EDA) was used as a precursor to protect Ti2C-MQDs from damage during synthesis, and N was introduced to generate N-doped MQDs (N–Ti2C-QDs). Compared to MQDs without EDA, the N–Ti2C-QDs had a more complete intrinsic structure and exhibited a stronger antioxidant performance, including highly effective scavenging of •OH, excellent protection of dye and rapid reduction of potassium permanganate (KMnO4). In addition, cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) were used to study the underlying antioxidation mechanism that follows oxidation. The results revealed that the intrinsic structure, doping with electron-rich functional groups and electron transfer all contribute to the strong antioxidant ability.