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Copper nanoclusters (CuNCs) as a new class of fluorescent materials have attracted a great deal of interest due to their outstanding fluorescence properties. In this work, a variety of organic solvents were used to induce self‐assembly of glutathione‐capped CuNCs (GSH‐CuNCs) to form ordered assemblies with enhanced fluorescence properties. Assemblies with multicolor fluorescence emission were constructed on the basis of the aggregation‐induced emission (AIE) of GSH‐CuNCs and the solvent effect. The fluorescence emission from these GSH‐CuNCs assemblies can also be tuned from yellow to purple by changing the organic solvent. A possible mechanism based on the size of the assemblies and electron transfer was explored to explain the solvent effects on GSH‐CuNCs. Stimuli‐responsive nanoswitches with excellent reversibility can be controlled by changing the type of organic solvent and the ratio of the organic solvent to the aqueous solution of GSH‐CuNCs. As the CuNCs assemblies exhibit strong, stable, and color‐tunable fluorescence, they were employed as color‐conversion materials for recognizing different organic solvents. [ABSTRACT FROM AUTHOR]

In this study, two-dimensional MXene Ti3C2Tx was modified on a glassy carbon electrode (GCE) to improve its performance for electrochemical detection. The morphology and structure of Ti3C2Tx were characterized by SEM and TEM. A new modified electrode was then fabricated by coating MXene solution on GCE for quercetin detection. The performance of MXene/GCE was determined by various methods, which showed an enhanced electrochemical activity. Direct electrochemistry of quercetin was investigated, and a pair of well-shaped redox peaks appeared with a peak-to-peak separation of 67 mV. The detection of quercetin by this proposed electrode was studied in detail, and presented a lower detection limit of 33 nM (3S0/S) with electrochemical parameters such as the electron transfer number (n), electron transfer coefficient (α) and reaction rate constant (ks) calculated as 1.99, 0.65 and 0.29 s−1, respectively. MXene/GCE was successfully utilized for the analysis of quercetin content in Ginkgo tablet samples with recoveries from 100.92% to 104.66%. Besides, MXene/GCE showed good anti-interference performance, good stability and reproducibility for the detection of quercetin. [ABSTRACT FROM AUTHOR]

Multicolor fluorescence emission assemblies with excellent reversibility were constructed based on aggregation-induced emission and the solvent effect of GSH-CuNCs. Stimuli-responsive nanoswitches with excellent reversibility can be controlled by changing the types of organic solvents and the ratio of organic solvent to GSH-CuNCs aqueous solution. As the CuNCs assemblies exhibit strong, stable, and color-tunable fluorescence, they are employed as the color conversion materials for recognizing different organic solvents. [Extracted from the article]

[Display omitted] • Two electron transfer pathways in R. pyridinivorans HR-1 MFC were identified. • As a pure strain MFC, HR-1 showed quick recovery of current after substrate exchange. • R. pyridinivorans strain HR-1 amplified the member of gram-positive exoelectrogen. • Co-existing biofilm and self-secreted electron shuttle were practical in real application. Microbial fuel cell (MFC) exhibits huge potentials in disposing wastewater and extra energy consumption. Exploring useful microorganisms for MFC is the crucial section. Herein, the electrochemical mechanism of extracellular anaerobic respiration in MFC inoculated with gram-positive Rhodococcus pyridinivorans HR-1, was first revealed. The MFC exhibited rapid recovery of currents on anode, and could recover to maximum output within one hour, with redox peaks near −0.38 and −0.18 V through electron transfer between the biofilm and anode. When the biofilm-based pathway was blocked by wrapping the anode with Millipore filter membrane, HR-1 inoculated MFC could still generate electricity within a longer recovery period (∼35 h) during anolyte exchange. This was proposed as a self-secreted electron shuttle pathway for electron transfer in R. pyridinivorans HR-1. Cyclic voltammetry analysis revealed that the biofilm-based and self-secreted electron shuttle-based pathways co-existed in R. pyridinivorans HR-1 inoculated MFC, which could play synergistic roles in electricity generation. [ABSTRACT FROM AUTHOR]