Fe-based 2D materials exhibit rich chemical compositions and structures, which may imply many unique physical properties and promising applications. However, achieving controllable preparation of ultrathin non-layered FeS crystal on SiO 2 /Si substrate remains a challenge. Herein, the influence of temperature and molecular sieves is reported on the synthesis of ultrathin FeS nanosheets with a thickness as low as 2.3 nm by molecular sieves-assisted chemical vapor deposition (CVD). The grown FeS nanosheets exhibit a non-layered hexagonal NiAs structure and belong to the P6 3 /mmc space group. The inverted symmetry broken structure is confirmed by the angle-resolved second harmonic generation (SHG) test. In particular, the 2D FeS nanosheets exhibit exceptional metallic behavior, with conductivity up to 1.63 × 10 6 S m −1 at 300 K for an 8 nm thick sample, which is higher than that of reported 2D metallic materials. This work provides a significant contribution to the synthesis and characterization of 2D non-layered Fe-based materials.
Jin Jiayi,Wu Wenqin,Min Hui,Wu Huimin,Wang Shengfu,Ding Yu,Yang Shuijin
Iron sulfides with different atomic ratios were synthesized by a hydrothermal method and used to modify a glassy carbon electrode. The various sulfides were compared to each other for their amperometric response to H 2 O 2 . It is found that FeS is the most adequate material. Operated in 0.1 M NaOH solution at 0.4 V (vs. Ag/AgCl), the sensor based on FeS displays a linear response that extends from 0.50 μM to 20.5 mM of H 2 O 2 , with a sensitivity of 36.4 μA mM −1 cm −2 and a detection limit of 0.15 μM (at an S/N ratio of 3). The sensor is selective, stable and reproducible.
Schematic of the synthesis of pomegranate flower-like FeS by a hydrothermal route using ferric chloride and thiourea (SC(NH 2 ) 2 ) as the precursors, and ethanolamine (EA) as the structure-guiding auxiliary agent. A glassy carbon electrode (GCE) modified with this material allows for amperometric sensing of hydrogen peroxide in 0.1 M NaOH solution with a 0.15 μM detection limit.
The incorporation of heterostructure and vacancies will bring new strategies to improve the intrinsic activity of catalysts. Herein, the CoS@FeS heterostructure catalyst with sulfur vacancies (SVs) was fabricated by a simple hydrothermal strategy, which can synergistically trigger peroxymonosulfate (PMS) activation toward the efficient degradation of sulfamethoxazole (SMX) ( k obs , 0.3334 min −1 ) through a non-radical/radical oxidized pathway. SO 4 • – , •OH and 1 O 2 were regarded as the main reactive oxygen species (ROSs). Mechanism studies revealed that the synergy of SVs and heterostructure played an electron density adjusting role for the PMS activation into SO 4 • – and •OH, as well as the continuous generation of •O 2 − from O 2 , thereby in favor of 1 O 2 . The SVs availed the adsorption of PMS and dissolved oxygen (DO) on the surface, the continuous electron transmission would be consolidated through the charge transfer efficiency (CTE) of heterostructure. Meanwhile, the integration of SVs with heterostructure reduced the adsorption energy of PMS (-3.82 eV) on the interface of the catalyst according to the density functional theory (DFT) calculations, which overcame the repulsion effect between negatively charged HSO 5 – and CoS@FeS, and enhanced the charge transfer efficiency to accelerate the PMS activation for generating SO 4 • – and •OH. This work will propose a new approach for synergistically stimulating the intrinsic activity of catalysts to improve environmental remediation.
Qiang Zhang,Xiayin Yao,Jean Pierre Mwizerwa,Ning Huang,Hongli Wan,Zhen Huang,Xiaoxiong Xu
Transition metal sulfides have attracted particular interests owing to their extremely higher specific capacity and more compatible with sulfide electrolyte than lithium transition-metal oxide for all-solid-state lithium batteries. FeS nanosheets with thickness of 10 nm are synthesized by a poly (vinyl alcohol)-assisted precipitation method and further successfully employed in Li/70%Li 2 S-29%P 2 S 5 –1%P 2 O 5 /Li 10 GeP 2 S 12 /FeS all-solid-state lithium batteries. The obtained all-solid-state lithium batteries show reversible discharge capacity of 550 mAh g − 1 after 50 cycles at current density of 0.1 A g − 1 and exhibit superior rate performances.
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