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Facile method for iodide ion detection via the fluorescence decrease of dihydrolipoic acid/beta-cyclodextrin protected Ag nanoclusters
摘要： In this work, novel photoluminescent Ag nanoclusters (Ag NCs) with red emission are synthesized and successfully used for detecting iodide ion (I?). The dihydrolipoic acid (DHLA) is used as the stabilizing agent and beta-cyclodextrin (β-CD) is used as the auxiliary stabilizing agent. DHLA and β-CD are combined with Ag atoms by the formation of Ag-S bonds and hydrophobic interaction, respectively. Functionalization of β-CD endows good photoluminescent properties and solubility in water to the Ag NCs. The obtained DHLA and β-CD-protected Ag NCs (DHLA/β-CD-Ag NCs) are spherical and display a dispersed state. However, the DHLA/β-CD-Ag NCs are aggregated in the presence of I?, accompanied by the decrease in their fluorescence intensity. Because the integrity of β-CD cavities is retained on the surface of DHLA/β-CD-Ag NCs, which preserves their capability for I? host–guest recognition, the DHLA/β-CD-Ag NCs combine with I? through the formation of inclusion complexes. Based on this phenomenon, the prepared DHLA/β-CD-Ag NCs can be designed as a novel fluorescent probe for I? detection. The limit of detection (LOD) is calculated as 0.06 μM, indicating that it is an ideal probe for I? detection in practical applications.
关键词： Ag nanoclusters,Fluorescent probe,Beta-cyclodextrin,Dihydrolipoic acid,Iodide ion
更新于2025-09-23 15:23:52
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Size dependence of photocatalytic hydrogen generation for CdTe quantum dots
摘要： CdTe quantum dots (QDs) are attractive photosensitizers for photocatalytic proton reduction due to their broad absorbance profile that can extend from the ultraviolet to near-infrared regions, providing access to a larger portion of the solar spectrum than possible with analogous CdSe and CdS QD photosensitizers. Here, the photocatalytic hydrogen (H2) generation from various sizes of dihydrolipoic acid (DHLA)-capped CdTe QDs, ranging from 2.5 to 7.5 nm in diameter, and a molecular Ni-DHLA catalyst in aqueous solutions was evaluated, and an unusual size-dependent photocatalytic activity with CdTe QDs was observed. Under optimized conditions, using 3.4 nm CdTe-DHLA and a 1:20 ratio of QD/Ni-DHLA catalyst, as many as 38 000 turnover numbers (mol H2 per mol QD) were achieved. However, below this critical size, the H2 production efficiency decreased; this behavior is attributed to the rapid oxidation of the QD surface, resulting in detrimental surface trap states. These results are consistent with ultrafast transient absorption spectroscopic measurements, which suggest the presence of extremely fast charge-trapping processes in the oxidized CdTe-DHLA QDs. While fast electron transfer from CdTe-DHLA QDs is observed in the presence of the Ni-DHLA catalyst, the charge trapping processes occur on a competitive time scale, thus lowering the efficiency of the CdTe/Ni-DHLA H2 production system. Understanding rapid charge trapping in CdTe QDs may help suggest potential improvements for the overall CdTe photocatalytic system.
关键词： size dependence,photocatalytic hydrogen generation,Ni-DHLA catalyst,CdTe quantum dots,dihydrolipoic acid
更新于2025-09-12 10:27:22