本研究以氧乙酸、硝酸尿素和尿素为原料，构建了C缺陷和C-O带修饰的超薄多孔氮化碳材料。通过XRD、SEM、FTIR和XPS分析了材料的元素成分、能带结构和微观形态。测试了来自食品和饮料罐的各种双酚类污染物（BPA、BPE、BPF），以考察OA-UN-CN的光催化降解性能。利用DFT表明了碳缺陷和C-O带对新材料内部电子结构的影响以及对电荷转移的促进作用，并通过LC-MS对光降解产物进行了系统的分析。还采用了自由基捕获实验和ESR光谱法来检测体系中可能存在的活性自由基，并提出了双酚的潜在降解机制。
![]()
Fig. 1. (a) Synthesis of OA-UN-CN. (b) XRD patterns and (c) FTIR spectra of the catalysts, SEM micrographs of (d) g-C3N4, (e) UN-CN, (f) 0.05 OA-CN, (g) 0.05 OA-UN-CN, TEM micrographs of (h) g-C3N4 and (i) 0.05 OA-UN-CN.![]()
Fig. 2. X-ray photoelectron spectra of the g-C3N4 and 0.05 OA-UN-CN (a) C 1s, (b) N 1s and (c) O 1s. (d) UV–vis diffuse reflectance spectra, (e) band gap energies of catalysts.![]()
Fig. 3. Calculated band structures, corresponding DOS and electrostatic potential surface distribution for (a, b, c) g-C3N4 and (d, e, f) OA-UN-CN, respectively. (g) and (h) HOMO and LUMO distributions of catalysts (isovalue: 0.003 eÅ−3). (i) and (j) the electronic location function (ELF) of g-C3N4 and OA-UN-CN, respectively (k) Potential drop across the interface of g-C3N4 and OA-UN-CN.![]()
Fig. 4. (a) and (b) Photodegradation of BPA by catalysts under different conditions when exposed to visible light. (c) The k of reaction rate constant of BPA degradation over the catalysts. (d) Cyclic voltammetry of electrodes synthetized from the homologus catalysts, Reaction conditions: BPA concentration: 10 mg/L; Catalyst concentration: 1 g/L; PMS concentration: 1 mM. (e) Reusability of 0.05 OA-UN-CN/PMS/vis, (f) The XRD patterns of of 0.05 OA-UN-CN.![]()
Fig. 5. The mass spectra at different reaction time in the Vis-PMS/0.05 OA-UN-CN process for BPA degradation: (a) pure BPA; 15 min; 30 min. (b) The potential pathways of BPA in PMS/vis system. (c) Bioaccumulation factor and (d) mutagenicity of BPA and its photocatalytic oxidation intermediates.![]()
Fig. 6. Influence of (a) PMS concentration; (b) different anions. (c) and (d) Photodegradations of BPE over g-C3N4 and 0.05 OA-UN-CN. (e) and (f) Photodegradations of BPF over g-C3N4 and 0.05 OA-UN-CN. (g) Photodegradation rate of sodium lignosulfonate over samples. (h) The solution photos of 0.05 OA-UN-CN/PMS/vis before and after the degradation of sodium lignosulfonate. (i) GC–MS results of 0.05 OA-UN-CN/PMS/vis after degradation of sodium lignosulfonate.![]()
Fig. 7. g-C3N4 and 0.05 OA-UN-CN: (a) transient photocurrent map, (b) EIS spectrum, (c) room temperature luminescence spectrum and (d) Electron paramagnetic resonance image.![]()
Fig. 8. ESR spectra of (a) and (b) DMPO-•OH/•SO4−, (c) and (d) DMPO-•O2−, (e) and (f) TEMP-1O2 under disparate PMS/vis conditions. (g) Band structure of g-C3N4, UN-CN, 0.05 OA-CN and 0.05 OA-UN-CN. (h) The conceivable mechanism diagram for bisphenols pollutant and sodium lignosulfonate removal of 0.05 OA-UN-CN PMS/vis.
总之，我们利用硝酸脲、氧乙酸和尿素成功地合成了具有碳缺陷和C-O带修饰的超薄多孔氮化碳。与g-C3N4相比，0.05 OA-UN-CN在可见光下对PMS的光催化活化作用大幅增强。0.05 OA-UN-CN/PMS可以在30分钟内绝对去除双酚A，其光降解率分别是g-C3N4和0.05 OA-UN-CN的81.8倍和7.9倍。性能的提高归因于对0.05 OA-UN-CN的电子结构的有效调整，加强了PMS的活化和光生载体的快速转移。此外，0.05 OA-UN-CN同样可以去除其他双酚类污染物（BPE和BPF）和木质素磺酸钠。捕获实验和ESR表明，-O2-、1O2、h+、OH和-SO4-是反应过程中的主要活性基团。此外，我们用LC-MS测试了双酚A的分解产物，并提出了可行的光降解途径。这项工作为通过无金属光热催化剂处理双酚类污染物和木质素衍生物的先进光催化氧化过程的发展提供了一个范例。
Liquan Jing, Meng Xie, Yuanguo Xu, Chun Tong, Xia Du, Heng Zhao, Na Zhong, Huaming Li, Jinguang Hu, Advanced oxidation via the synergy of C-defective/ C–O band modified ultrathin porous g-C3N4 and PMS for efficient photothermal degradation of bisphenol pollutants and lignin derivatives, Green Energy & Environment, 2023, https://doi.org/10.1016/j.gee.2023.01.006
声明：本公众号仅分享前沿学术成果，无商业用途。如涉及侵权，请立刻联系公众号后台或发送邮件，我们将及时修改或删除！
邮箱：Environ2022@163.com
