Polyethylene terephthalate (PET) is one of the most widely used polymers for beverage packaging and fibers, with antimony-based catalysts currently dominating its synthesis. However, concerns about potential safety hazards associated with antimony leaching necessitate the development of environmentally benign catalysts free from heavy metals. In this work, we report the first-time utilization of Ti₃C₂T_x MXene as a polycondensation catalyst of PET. The intrinsic viscosity of Ti₃C₂T_x MXene-catalyzed PET could reach 0.78 dL/g within 2.1 h, which demonstrated a superior catalytic efficiency compared to antimony trioxide (Sb₂O₃). Moreover, Ti₃C₂T_x MXene exhibited a satisfactory performance not only in PET synthesis but also in the production of polypropylene terephthalate (PPT) and polybutylene terephthalate (PBT), thereby confirming its universality in polyester catalysis. The catalytic activity of Ti₃C₂T_x MXene in polycondensation reactions was attributed to the presence of strong Lewis acid sites, as supported by surface examinations and computational studies. Notably, Ti₃C₂T_x MXene-catalyzed PET exhibited satisfied crystallizability, as confirmed by the short crystallization half-time of only 6.9 s at 185 °C, signifying a high crystallization rate. This work highlights the potential applications of this thriving 2D material in polyester catalysis and, more importantly, provides a new perspective for the exploration and design of efficient and environmentally friendly catalyst/nucleation agents for polyester synthesis.

中文翻译：

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Ti3C2TX MXene 对聚酯合成的高效催化活性

聚对苯二甲酸乙二醇酯 (PET) 是饮料包装和纤维中使用最广泛的聚合物之一，目前其合成主要采用锑基催化剂。然而，由于担心锑浸出存在潜在的安全隐患，因此有必要开发不含重金属的环境友好型催化剂。在这项工作中，我们首次利用Ti ₃ C ₂ T _x MXene 作为PET 缩聚催化剂。 Ti ₃ C ₂ T _x MXene催化的PET的特性粘度可以在2.1小时内达到0.78 dL/g，与三氧化二锑（Sb ₂ O ₃）相比表现出优异的催化效率。此外，Ti ₃ C ₂ T _x MXene不仅在PET合成中表现出令人满意的性能，而且在对苯二甲酸丙二醇酯（PPT）和聚对苯二甲酸丁二醇酯（PBT）的生产中也表现出令人满意的性能，从而证实了其在聚酯催化中的通用性。 Ti ₃ C ₂ T _x MXene 在缩聚反应中的催化活性归因于强路易斯酸位点的存在，这得到了表面检查和计算研究的支持。值得注意的是，Ti ₃ C ₂ T _x MXene 催化的 PET 表现出令人满意的结晶性，185 °C 下的结晶半衰期短，仅为 6.9 s，这表明结晶速率很高。这项工作凸显了这种蓬勃发展的二维材料在聚酯催化中的潜在应用，更重要的是，为探索和设计高效环保的聚酯合成催化剂/成核剂提供了新的视角。