Lian Qiyu, Roy Amitava, Kizilkaya Orhan, Gang Daniel Dianchen, Holmes William, Zappi Mark E, Zhang Xu, Yao Hong
Department of Civil Engineering, University of Louisiana at Lafayette, P.O. Box 43598, Lafayette, Louisiana 70504, United States.
Center for Environmental Technology, The Energy Institute of Louisiana, P.O. Box 43597, Lafayette, Louisiana 70504, United States.
ACS Appl Mater Interfaces. 2020 Dec 23;12(51):57190-57206. doi: 10.1021/acsami.0c20341. Epub 2020 Dec 8.
Amorphous cobalt-inherent silicon oxide (Co-SiOx) was synthesized for the first time and employed as a highly active catalyst in the activation of peroxymonosulfate (PMS) for the rapid oxidation of 2,4-dichlorophenol (2,4-DCP). The characterization results revealed that the 0.15Co-SiOx possessed a high specific surface area of 607.95 m/g with a uniform mesoporous structure (24.33 nm). The X-ray diffraction patterns indicate that the substituted cobalt atoms enlarge the unit cell parameter of the original SiO, and the selected area electron diffraction pattern confirmed the amorphous nature of Co-SiOx. More bulk oxygen vacancies (O) existing in the Co-SiOx were identified to be one of the primary contributors to the significantly enhanced catalytic activation of PMS. The cobalt substitution both creates and stabilizes the surficial O and forms the adequately active Co(II)-O pairs which engine the electron transfer process during the catalytic activities. The active Co(II)-O pairs weaken the average electronegativity of Co/Si and Co/O sites, resulting in the prevalent changes in final state energy, which is the main driving cause of the binding energy shifts in the X-ray photoelectron spectroscopy (XPS) spectra of Si and O among all samples. The increase of the relative proportion of Co(III) in the spent Co-SiOx probably causes the binding energy shifts of the Co XPS spectrum compared to that of the Co-SiOx. The amorphous Co-SiOx outperforms stable and quick 2,4-DCP degradation, achieving a much higher kinetic rate of 0.7139 min at pH = 7.02 than others via sulfate radical advanced oxidation processes (AOPs), photo-Fenton AOPs, HO reagent AOPs, and other AOP approaches. The efficient degradation performance makes the amorphous Co-SiOx as a promising catalyst in removing 2,4-DCP or organic-rich pollutants.
首次合成了非晶态钴固有氧化硅（Co-SiOx），并将其用作过一硫酸盐（PMS）活化的高活性催化剂，用于快速氧化2,4-二氯苯酚（2,4-DCP）。表征结果表明，0.15Co-SiOx具有607.95 m²/g的高比表面积，具有均匀的介孔结构（24.33 nm）。X射线衍射图谱表明，取代的钴原子扩大了原始SiO的晶胞参数，选区电子衍射图谱证实了Co-SiOx的非晶态性质。Co-SiOx中存在的更多体相氧空位（O）被认为是PMS催化活化显著增强的主要贡献因素之一。钴取代既产生并稳定了表面O，又形成了足够活跃的Co(II)-O对，这些对在催化活性过程中推动电子转移过程。活跃的Co(II)-O对削弱了Co/Si和Co/O位点的平均电负性，导致最终态能量普遍变化，这是所有样品中Si和O的X射线光电子能谱（XPS）光谱中结合能位移的主要驱动原因。与Co-SiOx相比，用过的Co-SiOx中Co(III)相对比例的增加可能导致Co XPS光谱的结合能位移。非晶态Co-SiOx在2,4-DCP降解方面表现出色且稳定快速，在pH = 7.02时通过硫酸根自由基高级氧化过程（AOPs）、光芬顿AOPs、HO试剂AOPs和其他AOP方法实现了比其他方法更高的动力学速率0.7139 min⁻¹。高效的降解性能使非晶态Co-SiOx成为去除2,4-DCP或富含有机物污染物的有前景的催化剂。
