文献速递|河海大学CEJ:单分散Co-N3负载氮化碳介导过硫酸盐活化，通过单线态氧快速降解痕量尿素

第一作者：Shilong Jiang

通讯作者：操家顺 教授

通讯单位：河海大学环境学院

DOI：10.1016/j.cej.2023.147526

本研究在二维 g-C3N4 纳米片（R0.50Co-N0.20）上锚定了单分散 Co-N3 位点，以激活 PMS 降解痕量尿素。原子高角度环形暗场扫描透射电子显微镜（HAADF-STEM）和 X 射线吸收精细结构光谱（XAFS）证实了 Co 位点的配位结构。在 Co-N3 配位结构的高度不饱和特性的驱动下，R0.50Co-N0.20 表现出优异的 PMS 活性能力和尿素去除效率。此外，还通过连续流柱实验和中试研究评估了在 UPW 生产系统中去除痕量尿素的实际应用潜力。这项研究提出了一种通过低配位单原子催化剂介导 PMS 活化去除痕量尿素的创新方法。

Fig. 1. (a) Schematic illustration of the preparation process of R0.50Co-CN0.20. (b) HRTEM image, (c) SAED pattern, and (d) representative aberration-corrected HAADF-STEM of Co-CN0.20. (e) HRTEM image, (f) SAED pattern and (g) representative aberration-corrected HAADF-STEM of R0.50Co-CN0.20. (h) HAADF-STEM image and (i-k) C, Co, and N elemental mapping images of R0.50Co-CN0.20.

Fig. 2. (a) and (b) XRD patterns of Co-CN0.20 and RyCo-CN0.20 (y = 0.10, 0.20, 0.50 and 1.00). (c) FTIR spectra of CN, Co-CN0.20, and R0.50Co-CN0.20. (d) C 1 s, (e) N 1 s XPS spectra of CN, Co-CN0.20, and R0.50Co-CN0.20. (f) Co 2p XPS spectra of Co-CN0.20 and R0.50Co-CN0.20.

Fig. 3. (a-b) XANES spectra of Co K-edge of Co-foil, Co3O4, CoO, CoPc, Co-CN0.20 and R0.50Co-CN0.20. (c) Fourier transforms at the Co K-edge of Co-foil, Co3O4, CoO, CoPc, Co-CN0.20, and R0.50Co-CN0.20. EXAFS fitting curves of (d) Co-Pc, (e) Co-CN0.20 and (f) R0.50Co-CN0.20 at R space. WT-EXAFS spectra of (g) Co-Pc, (h) Co-CN0.20 and (i) R0.50Co-CN0.20.

Fig. 4. (a) The degradation curves and (b) corresponding kobs of urea degradation in different catalytic systems. (c) Co leaching concentration in different catalytic systems at 30 and 60 mins. (d) PMS decomposition curves in CN/PMS, Co-CN0.20/PMS, and R0.50Co-CN0.20/PMS system. (e) S species variation before and after catalysis in R0.50Co-CN0.20/PMS system. (f) N and C species variation. (g) Degradation curves under different urea concentrations in R0.50Co-CN0.20/PMS system. (h) The cycling experiment of R0.50Co-CN0.20/PMS system. (i) XRD patterns of R0.50Co-CN0.20 before and after catalysis.

Fig. 5. (a) The degradation curves and (b) corresponding kobs of urea degradation under different quenching agents. (c) DMPOX and DMPO-·OH, (d) DMPO-·O2– and (e) TEMP-1O2 signal in CN/PMS, Co-CN0.20 and R0.50Co-CN0.20/PMS system. (f) kobs of FFA degradation and 1O2 steady concentration in Co-CN0.20/PMS and R0.50Co-CN0.20/PMS system. (g) EIS spectra of CN, Co-CN0.20 and R0.50Co-CN0.20. Real time (h) i-t and (i) v-t curve measurements upon the addition of PMS using Co-CN0.20 and R0.50Co-CN0.20 as the working electrodes.

Fig. 6. (a) Top view of the optimized Co-N4 structure. (b) Optimized configurations of PMS adsorbed on Co-N4 site. (c) Differential charge density diagram for PMS adsorbed at the Co-N4 site. Density of states (DOS) diagrams of Co 3d (d) before and (e) after PMS adsorption on Co-N4 site. (f) Top view of the optimized Co-N3 structure. (g) Optimized configurations of PMS adsorbed on Co-N3 site. (h) Differential charge density diagram for PMS adsorbed at the Co-N3 site. DOS diagrams of Co 3d (i) before and (j) after PMS adsorption on Co-N3 site.