College of Materials and Chemistry and Chemical Engineering, Chengdu University of Technology, Chengdu 610059, China and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics and CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics and CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology of China, Chinese Academy of Sciences, Beijing 100049, China.
Nanoscale. 2020 Apr 21;12(15):8415-8424. doi: 10.1039/d0nr00192a. Epub 2020 Apr 2.
Herein, we developed a general two-step gas expansion and exfoliation strategy based on a urea-assisted hydrothermal process combined with sonication exfoliation for the production of nitrogen (N)-doped plus defect-rich transition metal dichalcogenide (TMD) nanosheets (NSs) such as N-MoS and N-WS NSs. The interlayers of bulk MoS (or WS) were expanded with urea molecules dissolved in distilled water, which were decomposed to NH during the hydrothermal process. Simultaneously, sulfur atoms were partly replaced by N atoms to achieve N doping. Subsequently, sonication exfoliation of the urea-treated bulk MoS (or WS) promoted the production of defect-rich NSs. Importantly, the defect-rich N-MoS and N-WS NSs exhibit enhanced peroxidase-like catalytic activity after being captured by bacteria, and can catalyze hydrogen peroxide (HO) to produce more toxic hydroxyl radicals (˙OH) than non-N-doped MoS or WS NSs. As a result, the N-MoS or N-WS NSs were capable of effectively killing Gram-negative ampicillin resistant Escherichia coli (AmpE. coli) and Gram-positive endospore-forming Bacillus subtilis (B. subtilis) and promoting bacteria-infected wound healing. This work not only provides a simple, universal exfoliation strategy for producing defect-rich N-doped TMD NSs but also provides a promising catalytic antibacterial option and has potential for many other catalytic applications.
在此，我们开发了一种通用的两步气体膨胀和剥离策略，基于尿素辅助的水热过程结合超声剥离，用于生产氮（N）掺杂和缺陷丰富的过渡金属二硫化物（TMD）纳米片（NSs），如 N-MoS 和 N-WS NSs。体相 MoS（或 WS）的层间用溶解在蒸馏水中的尿素分子膨胀，这些尿素分子在水热过程中分解为 NH。同时，部分硫原子被 N 原子取代以实现 N 掺杂。随后，尿素处理的体相 MoS（或 WS）的超声剥离促进了富含缺陷的 NSs 的产生。重要的是，富含缺陷的 N-MoS 和 N-WS NSs 在被细菌捕获后表现出增强的过氧化物酶样催化活性，并且可以催化过氧化氢（HO）产生比非 N 掺杂的 MoS 或 WS NSs 更多的有毒羟基自由基（˙OH）。因此，N-MoS 或 N-WS NSs 能够有效杀死革兰氏阴性氨苄青霉素耐药大肠杆菌（AmpE. coli）和革兰氏阳性内生孢子形成芽孢杆菌（B. subtilis），并促进细菌感染伤口愈合。这项工作不仅为生产富含缺陷的 N 掺杂 TMD NSs 提供了一种简单、通用的剥离策略，还提供了一种有前途的催化抗菌选择，并且具有许多其他催化应用的潜力。
