Fluorescence ratiometric assay for discriminating GSH and Cys based on the composites of UiO-66-NH2 and Cu nanoclusters.

The discriminative detection of glutathione (GSH) from cysteine (Cys) remains a challenge because of their similarity in structure and chemical properties. This study reported a strategy for selective and sensitive detection of GSH based on the GSH-promoted blue fluorescence of UiO-66-NH2 and aggregation-enhanced emission (AEE) feature of orange emissive Cu nanoclusters (NCs). A relatively weak blue fluorescence of UiO-66-NH2 was converted to strong after reacting with GSH due to the rotation-restricted emission enhancement mechanism. In addition, the GSH-activated UiO-66-NH2 was further used as a template and reducing reagent for synthesizing orange-red AEE active Cu NCs composites (UiO-66-NH2@Cu NCs). A ratiometric fluorescence response was observed after forming UiO-66-NH2@Cu NCs, helping discriminate GSH over Cys. In addition, UiO-66-NH2@Cu NCs were further utilized for the detection of GSH in clinical samples. The present findings provide an efficient strategy to discriminate GSH over Cys and open a new door for utilizing and functionalizing metal-organic frameworks (MOFs) for various applications.

Electronic Structure Regulation of Iron Phthalocyanine Induced by Anchoring on Heteroatom-Doping Carbon Sphere for Efficient Oxygen Reduction Reaction and Al-Air Battery.

Aluminum-air batteries (AABs) are deemed as a potential clean energy storage device. However, exploiting high-efficiency and stable oxygen reduction reaction (ORR) electrocatalysts in AABs is still a challenge. Iron phthalocyanine (FePc) shows a great prospect in ORR but still far from Pt-based catalysts. Here, the hybrid electrocatalysts of monolayer FePc and hollow N,S-doped carbon spheres (HNSCs) are innovatively constructed through π-π stacking to achieve high dispersion. The resulting FePc@HNSC catalyst exhibits an outstanding ORR activity, outperforming that of pristine FePc and even most Fe-based catalysts reported to date. Moreover, the AAB using FePc@HNSC catalyst not only demonstrates a superior power density than the battery with Pt/C, but also displays stable discharge voltages and excellent durability. Furthermore, the theoretical calculations confirm that the charge distribution and d-band center of the Fe atom in FePc are efficiently optimized by hybrid configuration via the introduction of N,S-doped carbon substrate. The design leads to an enriched electron density around Fe active sites and significant reduction of energy barrier for OH* formation, which are favorable for the improvement of electrocatalytic ORR performance. This work provides a chance to expand the application of metallic macrocyclic compound electrocatalysts in various energy technologies.