第一作者：Zonghao Liu
通讯作者：宋敏 青年首席教授
通讯单位：东南大学能源与环境学院
DOI:10.1016/j.seppur.2024.129794
在生物和仿生过程中，高价铜（Cu(III)）是单键-氢键功能化的关键中间体，由铜酶促进并由多铜氧化酶稳定。本文通过炭化纳米片状金属-有机骨架（MOF），激活过氧单硫酸盐（PMS）生成Cu(III)，促进双酚a的降解，合成了一种高金属含量（29.1 wt%）且Cu分布均匀的氮掺杂铜亚纳米簇催化剂（SNC）。SNC的降解性能优于用块状MOF碳化的催化剂，并与报道的单原子催化剂相匹配。氮掺杂减少了Cu3d轨道的电子，增强了其与PMS分子内氧原子的键合，从而促进了Cu（III）的生成。Cu-SNC/PMS体系还显示出对阴离子、pH变化和不同水基质的强大抗性。重要的是，它可以通过Cu（III）的氧原子转移选择性地降解富电子污染物。该研究为SNC的制备、高价金属的控制形成及其在fenton类反应中降解污染物的作用提供了新的视角。
Fig. 1. (a) Formation process of n-CuCN and b-CuCN catalyst, respectively. TEM images of (b) b-CuBDC and (c) n-CuBDC. (d) XRD pattern of n-CuCN and b-CuCN catalyst. (e, f) TEM and HRTEM images, (g) SAED image, (h) AC-HAADF-STEM image, and (i) the corresponding HAADF-STEM image and EDS mapping of the n-CuCN sample, respectively. (j) Composition summary of metal loading in the as-prepared sub-nanocluster catalysts.
Fig. 2. The XPS spectra of (a) Cu2p3, (b) Cu LMM of the n-CuCN sample, and N 1s of (c) the n-CuCN and (d) the CN samples.
Fig. 3. (a) BPA degradation in various catalyst/PMS systems. (b) k values of BPA degradation in n-CuCN/PMS, b-CuCN/PMS, and CN/PMS processes. (c) Kinetics of BPA degradation via PMS activation by the state-of-the-art catalysts. (d) Effects of different anions, HA, initial pH, and different water matrices on the BPA degradation efficiency. (e) Degradation efficiencies and corresponding IP values of different ECs in n-CuCN/PMS process. (Conditions: [catalysts] = 0.1 g/L; [pollutants] = 10 mg/L; [PMS] = 1 mM (in a, b, d, and e); [PMS] = 0.25 mM (in c); [anions] = 1 mM; [HA] = 10 mg/L; pH = 5.5).
Fig. 4. (a) Effects of reactive oxidation species scavengers on BPA degradation. (b, c) EPR spectra in the n-CuCN/PMS process using DMPO and TEMP as trappers, respectively. (d) BPA degradation in the process of premixing n-CuCN and PMS. (e) In-situ Raman of n-CuCN in the presence of PMS. (f) Cu2p3 XPS spectra of the used n-CuCN catalyst. (g) The proposed mechanism for Cu(III) generation in the n-CuCN/PMS process. (Conditions: [catalyst] = 0.1 g/L; [BPA] = 10 mg/L; [PMS] = 1 mM; pH = 5.5; [EtOH] = 500 mM, [MeOH] = 500 mM, [TBA] = 500 mM, and [FFA] = 20 mM).
Fig. 5. (a, b) Electron density distribution of CuC and CuCN, respectively. (c) Bader charge of Cu atom in CuC and CuCN. (d) DOS of Cu3d in CuC and CuCN. (e) DOS of Cu and N in CuCN.
Fig. 6. (a, b) Charge density difference of PMS on CuC and CuCN, respectively. (c) DOS of Cu3d and O2p in CuCN-PMS*. (d) ICOHP of the −Cu–O- bond in CuC-PMS* and CuCN-PMS*.
在本研究中，利用纳米薄片MOF合成了高金属负载（29.1 wt%）的SNC催化剂（n-CuCN）。n-CuCN/PMS降解双酚a的活性为0.51 min−1，分别是b-CuCN/PMS和CN/PMS的45.1倍和128.5倍。此外，n-CuCN/PMS工艺对pH变化、有机阴离子和水基质具有较强的抗性。此外，n-CuCN催化剂对具有较低IP值的富电子ec表现出优异的选择性降解。在n-CuCN/PMS过程中，Cu（III）被确定为主要的ROS，吸附的HSO4−是Cu（III）生成的关键中间体。N掺杂降低了Cu三维轨道的电子密度，促进了PMS在Cu位点的吸附和活化。在n-CuCN/PMS过程中，对BPA、SMT和TC的降解均检测到M + 16和M + 32产物。一个氧原子从Cu（III）转移到目标污染物有助于n-CuCN/PMS系统在ec降解中的选择性。综上所述，本研究提出了一种新颖的SNCs合成策略，并为PMS激活机制提供了新的见解。
Zonghao Liu, Yan Zhao, Xian Cao, Chaoqun Tan, Shaofeng Wang, Chengye Song, Jiahao Lai, Zhihao Wang, Min Song, High metal-loaded sub-nanocluster catalyst enhanced Fenton-like reaction activity for emerging contaminants degradation by generating high-valent copper, Separation and Purification Technology, 2025, https://doi.org/10.1016/j.seppur.2024.129794
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