Photocatalytic active silver organic framework: Ag(I)‐MOF and its hybrids with silver cyanamide

Rational Design of MIL-68(In) Derived Multiple Sulfides with Well Confined Quantum Dots and the Promoted Photocatalytic Hydrogen Generation

Quantum dots (QDs) of metal sulfides were proven to be excellent cocatalysts in visible-light-driven photocatalytic reactions. Metal organic frameworks (MOFs) possess a 3D porous channel that effectively confines small QDs and preserves their high catalytic activity by preventing their aggregation. In order to precisely construct the ternary metal sulfides of ZnS/ZnIn2S4/In2S3 with well-maintained Zn-AgInS2 (ZAIS) QDs, an in situ sulfurization combining a subsequent Zn(II)-exchange strategy was employed in this work. First, the ZAIS QDs were incorporated into MIL-68(In), which were then used as the precursors to precisely construct the ternary metal sulfides of ZnS/ZnIn2S4/In2S3 with well maintained ZAIS QDs through an in situ sulfurization combining subsequent Zn(II)-exchange strategy. When the optimized nanocomposites (QDs@M-t-Zn, where t is the sulfurization time) were applied in visible light-induced photocatalytic hydrogen generation, the resulting QDs@M-24h-Zn showed a significantly improved hydrogen evolution rate of 448.96 μmol g-1 h-1, which values are clearly higher than those of MIL-68(In), QDs@MIL-68(In), and M-24h-Zn without the presence of ZAIS QDs. To elucidate the increased photocatalytic mechanism, the optical patterns and the batch electrochemical investigations were combined. It has been discovered that the matching band potentials and the close contact heterojunction enhance interface charge transfer, which in turn encourages photocatalytic hydrogen production. This study demonstrates the well-thought-out design of the uniform confinement architecture inherited from MOF QD-assisted multinary metal sulfides photocatalysts.

A novel highly active AgMOF-based silver single-atom catalyst and its application to the aptamer SERS/RRS for the determination of aflatoxin B1

A novel highly active silver single-atom catalyst (AgSAC) was prepared by a microwave-assisted solvothermal method using silver covalent organic frameworks (AgMOF) as precursors. It was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared (IR), and surface-enhanced Raman scattering (SERS). The experiment found that AgSAC has excellent catalytic performance and can heavily catalyze the nano-reaction of chloroauric acid-malic acid (HAuCl4-H2Mi) to generate gold nanoparticles (AuNPs). The produced AuNPs have strong SERS, resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs) signals. Aflatoxin B1 aptamer (AptAFB1) can be adsorbed to the surface of AgSAC through electrostatic interaction, to reduce the catalytic activity of AgSAC and the SERS/RRS/Abs signal of the system. When the target molecule (AFB1) was added, it will specifically bind to AptAFB1 and release AgSAC, restoring the catalytic activity of AgSAC, thereby restoring the SERS/RRS/Abs signal of the system. Based on this, a simple and sensitive aptamer sensing analysis platform for trace AFB1 was established, and a reasonable catalytic amplification mechanism of AgSAC was proposed. The SERS method exhibited the highest sensitivity, with a linear range of 0.005-0.225 μg/L and a detection limit of 0.002 μg/L.

A sensitive electrochemical sensor for glutathione based on specific recognition induced collapse of silver-contained metal organic frameworks

An electrochemical sensor capable of detecting glutathione (GSH) with high sensitivity and selectivity was developed based on the unique novel electroactive silver-based metal organic framework (Ag-MOF). The Ag-MOF obtained by silver nitrate and 1,3,5-benzoic acid (H3BTC) was thoroughly characterized and was modified onto the electrode via facile drop-casting method. The electrochemical response of GSH on the Ag-MOF modified electrode showed a significant reduction in the current signal because the Ag-GSH complex had stronger specific affinity than Ag-H3BTC and resulted in the collapse of the Ag-MOF. This sensor demonstrated an extensive linear dynamic range of 0.1 nM-1 µM, along with the low detection limit of 0.018 nM. Additionally, it exhibited good reproducibility, stability, and resistance to interfering compounds. The Ag-MOF modified electrode demonstrated superior performance attributed to its rapid electron transfer rate, outstanding electrochemical redox activity, and specific recognition/competitive reaction. These factors improved both sensitivity and selectivity. The high anti-interference ability allowed for the selective detection of GSH in intricate surroundings. In the real sample testing, the RSD was lower than 3.1% and the recovery was between 98.1 and 103%. This research highlights the potential of Ag-MOFs in developing electrochemical sensors and their promising applications in determining GSH for food screening and early disease diagnosis.