具有抗硫抗水性能的以封装多酸的ZIF薄膜包覆的金属氧化物中空纳米材料构筑及其低温SCR脱硝性能研究

环境友好非钒过渡金属氧化物因其优异的低温SCR活性受到广泛关注，但烟气中水蒸气和SO2引起的中毒问题使催化剂寿命缩短，极大限制其推广应用。为实现金属氧化物催化剂的脱硝应用，提高抗水抗硫性能是关键。本项目拟通过优化制备条件，创造性地构筑包覆有POMs⊂ZIF功能薄膜的过渡金属氧化物中空纳米材料，用于含SO2和H2O氛围中NOx的NH3-SCR脱除。一方面，原位装配POMs的纳米化ZIF薄膜具有更大的比表面积和酸性，表现出更强的NOx和NH3吸附能力。POMs⊂ZIF薄膜的这种“分子阱”作用，可以加快反应速率，提高复合材料的低温活性。另一方面，ZIF的憎水性和POMs的憎SO2特性使POMs⊂ZIF薄膜表现出类皮肤屏障作用，保护活性位点，延长使用寿命。通过深入研究POMs⊂ZIF薄膜与中空纳米金属氧化物在SCR反应的协同作用机制和过程动力学，为新型高抗硫抗水低温脱硝催化剂设计与应用奠定基础。

Environmentally friendly non-vanadium transition metal oxides have received extensive attention due to their excellent low temperature SCR activity, however, the poisoning effect of H2O and SO2 in the flue gas could shorten the life of the catalysts, greatly holding back their potential applications in the deNOx field. In order to break through the bottleneck, improving the water and sulfur resistance of the materials is the key element to improve the life of the catalysts. This work intends to creatively construct hollow nanosized transition metal oxide materials coated with POMs⊂ZIF compound film by optimizing preparation conditions for deNOx by NH3-SCR. On the one hand, the nanosized film with polyoxometalate in-situ assembled in the cage of ZIF possesses greater specific surface area and acidity, showing stronger NOx and NH3 adsorption capacity. The "molecular trap" effect of POMs⊂ZIF film can speed up the reaction rate and improve the low temperature activity of the composites. On the other hand, the integration of hydrophobic ZIF and POMs with anti-sulfur ability qualifies POMs⊂ZIF super film to behave as a “skin-like barrier” to protect the active sites on the oxide surface, which extends their useful life. Thanks to the in-depth study of the synergistic mechanism of POMs⊂ZIF super film and hollow nano-metal oxides for deNOx, it would provides theoretical supplement and technical support for the design of novel low-temperature denitrification catalysts with high resistance to SO2 and H2O in practical application.