201.
为了提高水中有机染料的降解速率,采用超声和溶剂热法制备Fe3O4/ZIF-9复合催化剂,该催化剂为立方状的金属有机骨架ZIF-9且表面附着有类球形Fe3O4颗粒. Fe3O4的加入为ZIF-9提供了更多的成核位点,同时Fe3O4/钴盐比例的变化也会影响ZIF-9的成核与生长. 当Fe3O4/钴盐摩尔比为1∶1时,该催化剂在30 min内对亚甲基蓝的降解率达到95.1%,催化反应10 min的伪一阶动力学常数达到0.101 min−1,在pH为5～9范围内保持稳定的高催化性能. X射线光电子能谱（XPS）结果表明铁和钴位点之间存在电子转移,并且钴和铁的协同作用可以降低钴的还原电位,从而加速钴的价态变化,提升催化速率. 电磁共振实验（EPR）结果显示该催化剂可以活化过一硫酸盐生成单线态氧(1O2)、硫酸根自由基(3O4/ZIF-9 composite catalysts. The morphology of the catalyst revealed the attachment of cubic ZIF-9 particles to spherical-like Fe3O4 particles. The particle sizes of these ZIF-9s slightly varied, which might be due to the influence of the increased number of nucleation sites originating from the addition of Fe3O4 on the nucleation and growth of ZIF-9s as well as the effects of the variation in Fe3O4/Co salt ratio on the nucleation quantity and growth rate of ZIF-9s. Using this catalyst at a Fe3O4/Co salt molar ratio of 1∶1, 95.1% of the MB was degraded within 30 min. Its pseudo-first-order kinetic constant for a 10-min catalytic reaction reached 0.101 min−1, and it remained stable and had high catalytic performance within the pH range from 5 to 9. X-ray photoelectron spectroscopy results showed that the valence state changes of Fe and Co in Fe3O4/ZIF-9 after MB degradation, verifying the electron transfer between the Fe and Co sites. Meanwhile, the divalent unsaturated Fe and Co sites in the Fe3O4/ZIF-9 structure were likely to synergistically transfer electrons based on the fast degradation kinetics mentioned above. Consequently, compared with the pure ZIF-9, the addition of Fe ions can effectively reduce the reduction potential of Co ions and accelerate the valence state changes of Co ions and the corresponding redox cycle. Furthermore, electron paramagnetic resonance results demonstrated that Fe3O4/ZIF-9 can activate peroxymonosulfate to generate singlet oxygen (1O2), sulfate radicals(SO相似文献
