Catalyst in the process on glycolysis of poly (ethylene terephthalate) (PET) wastes is a significant critical factor, which determine the efficiency and the cost of PET degradation. In this study, a kind of transition-metal-substituted polyoxometalates (POMs) Na₁₂ [WZnM₂(H₂O)₂(ZnW₉O₃₄)₂] (M = Zn²⁺, Mn²⁺, Co²⁺, Cu²⁺, Ni₂₊) which have a sandwich-structure and more than two transition metal active sites show excellent catalytic performance in the glycolysis of PET under mild conditions. We investigated the effects of temperature, reaction time and catalyst amount on PET degradation and obtained the glycolysis optimal conditions. The PET could be fast and completely degraded at 190 °C for 40 min with low catalyst/PET molar ratio (0.018%) and high PET/Ethylene Glycol (EG) weight ratio (1:4), and the yield of bis(hydroxyethyl) terephthalate (BHET) is higher than 84.5%. After four-times recycling, the conversion of PET and the yield of BHET can still reach 100% and 84.5%. The exact structure of POMs Na₁₂ [WZnM₂(H₂O)₂(ZnW₉O₃₄)₂] is confirmed by Single Crystal X-ray Diffraction (SC-XRD). Compared with traditional heteropolyacid catalysts, this catalyst possessed of at least two transition metal active sites, which lead to its an excellent catalytic capacity. The possible coordination activates mechanism for PET glycolysis is also proposed.

聚对苯二甲酸乙二醇酯（PET）废物的糖酵解过程中的催化剂是一个重要的关键因素，它决定了PET降解的效率和成本。在这项研究中，一种过渡金属取代的多金属氧酸盐（POMs ）Na ₁₂ [WZnM ₂（H ₂ O）₂（ZnW ₉ O ₃₄）₂ ]（M = Zn 2 ⁺，Mn 2 ⁺，Co ²⁺，铜²⁺，镍₂₊）具有三明治结构和两个以上的过渡金属活性位，在温和条件下在PET的糖酵解中显示出优异的催化性能。我们研究了温度，反应时间和催化剂用量对PET降解的影响，并获得了糖酵解的最佳条件。PET可以在190°C下快速完全降解40分钟，催化剂/ PET摩尔比低（0.018％），PET /乙二醇（EG）重量比高（1：4），双（羟乙基）收率高对苯二甲酸酯（BHET）高于84.5％。经过四次回收利用，PET的转化率和BHET的收率仍可以分别达到100％和84.5％。POMs Na ₁₂ [WZnM ₂（H ₂ O）₂（ZnW ₉ O₃₄）₂ ]通过单晶X射线衍射（SC-XRD）确认。与传统的杂多酸催化剂相比，该催化剂具有至少两个过渡金属活性位，这使其具有出色的催化能力。还提出了可能的协调激活PET糖酵解的机制。