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This work uses ZnO nanoparticles as the probe and a case, proving that the grey level can replace fluorescent intensity to realize a quantitative detection function of paper-based Cu2+ sensor. Portable Cu2+ test papers were obtained through dipping filter papers in as-prepared ZnO sol possessing the Cu2+ quenching property. Based on grey level which is obtained through ordinary digital camera and computer, the detection function of the fabricated Cu2+ test paper is extended from qualitative detection relied on naked eyes to quantitative detection whose detection range is calculated to be 10–1000 μM. The fabricated test papers also could resist the interruption of some competing ions and is a potential candidate for portable Cu2+ detection device with quantitative function. Since the strategy of replacing fluorescence intensity by grey level is based on the map relationship between the fluorescence intensity and the digital signal (grey level), it is promising to be applied to other fluorescent test papers to gain quantitative test papers aimed at corresponding chemicals. At the same time, the mechanism of Cu2+-induced fluorescence quenching was also investigated by fluorescence lifetime, UV–vis spectra, and photoluminescence spectra. And a static quenching mechanism based on the non-fluorescence complex formed by Cu2+ and O x − is brought up.

This paper reported the synthesis and gas-sensing properties of Pt nanoparticles modified Al-doped ZnO (AZO) macro-/mesoporous nanosheets, which were prepared via a solution combustion approach with a subsequent heat treatment at 400 °C for 50 min. The high performance in detecting butane were achieved for the well-adhered products with unique porous surface appearance on the sensors fabricated using indirect heating method, which demonstrated the superiority of solution combustion synthesis (SCS) in synthesizing complex oxides. The possible explanations of the high butane gas-sensing characteristics of these sensors were based on the results of BET and XPS. The large surface area could provide sufficient interface between the materials and butane gas, and the adsorbed oxygen species having strong oxidation activity could break the butane molecules into CO2 and H2O. The gas-sensing properties of Pt-modified AZO were investigated by testing the gas responses towards butane. The maximum response of the 5% Pt-AZO based gas sensor reached 56.52–3000 ppm butane at 200 °C. What’s more, the sensor also exhibited good short- and long-term stability, repeatability and selectivity, which made it a potential candidate in the application of monitoring butane. In the end, the possible mechanisms of gas-sensing properties were discussed.

Zinc oxide nanoparticles with the different Cd doping contents were prepared by with a surfactant-mediated method in this paper. The effects of Cd doping on the gas sensing properties of the ZnO nanoparticles were studied. The morphology and microstructure of as-prepared samples were characterized by X-ray diffraction (XRD); scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM), respectively. The results reveal that all the products are the high crystalline hexagonal wurtzite ZnO crystal structure. The gas-sensing characteristics of the Cd doped ZnO nanoparticles for volatile organic compounds (VOCs) were investigated. At its optimal operation temperature of 300 °C, the sensing properties of the Cd doped ZnO nanoparticles for n-butanol gas exhibit a high-performance gas sensing performances including high gas response, good selectivity, response/recovery time, and repeatability as well as stability. Especially, its response reaches 130 for 100 ppm n-butanol of ZnO nanoparticles with 2.5% Cd doping. Those values demonstrate the potential of using as-prepared Cd doped ZnO nanoparticles for n-butanol gas detection, making them to be promising candidates for practical detectors to n-butanol gas. Apart from these, the mechanism related to the advanced properties was also investigated and presented.

Allotetraploid is a new species produced by distant hybridization between red crucian carp (Carassius auratus red var., abbreviated as RCC) and common carp (Cyprinus carpio L., abbreviated as CC). There is a significant difference in growth rate between allotetraploid and its parents. However, the underlying molecular mechanism is largely unknown. In this study, to find direct evidence associated with metabolism and growth rate in protein level, we performed quantitative proteomics analysis on liver tissues between allotetraploid and its parents. A total of 2502 unique proteins were identified and quantified by SWATH-MS in our proteomics profiling. Subsequently, comprehensive bioinformatics analyses including gene ontology enrichment analysis, pathway and network analysis, and protein-protein interaction analysis (PPI) were conducted based on differentially expressed proteins (DEPs) between allotetraploid and its parents. The results revealed several significant DEPs involved in metabolism pathways in liver. More specifically, the integrative analysis highlighted that the DEPs ACSBG1, OAT, and LDHBA play vital roles in metabolism pathways including "pentose phosphate pathway," "TCA cycle," and "glycolysis and gluconeogenesis." These could directly affect the growth rate in fresh water fishes by regulating the metabolism, utilization, and exchange of substance and energy. Since the liver is the central place for metabolism activity in animals, we firstly established the comprehensive and quantitative proteomics knowledge base for liver tissue from freshwater fishes, our study may serve as an irreplaceable reference for further studies regarding fishes' culture and growth.

Summary Electron transport layer (ETL)/perovskite interface passivation is particularly challenging because of the use of polar solvents (e.g., DMF) for perovskite solution deposition, which usually destroy the bottom as-formed defect passivation layers. Herein, a novel multifunctional composite ETL, NH2-ZnO@SnO2, is prepared by mixing amino-capped ZnO (NH2-ZnO) nanocrystals (NCs) with SnO2 nanoparticles. The best-performing PSCs on the basis of NH2-ZnO@SnO2 achieve efficiency of 22.52%, which is significantly higher than that of the pristine SnO2 counterpart (18.45%). The enhanced performance of the NH2-ZnO@SnO2 ETL can be attributed to higher electron extraction capacity, better energy-level alignment with perovskite material, and more efficient carrier transport in device. Most important, the NH2 groups on the surface of ZnO NCs can effectively passivate the under-coordinated Pb2+ ions from perovskite films, thus reducing charge recombination at ETL/perovskite interface. The results suggest that NH2-ZnO NCs@SnO2 composite is a promising ETL for improving the performance of PSCs.

The mesoporous ZnCo2O4 nanosheets were synthesized via a facile hydrothermal method and subsequent thermal annealing treatment. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N2 adsorption/desorption isotherms (BET) to obtain information about its crystal structure, morphology, and BET surface area, respectively. The nanosheets present hexagonal shape with mesoporous structure in nature. The obtained mesoporous ZnCo2O4 nanosheets exhibit a high specific surface area of 191.64 m2/g. The electrochemical properties of the mesoporous ZnCo2O4 nanosheets were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) in 6 mol/L KOH aqueous electrolyte. The ZnCo2O4 nanosheets show a high specific capacity of 835.26 F/g at the current density of 1.0 A/g, as well as good cycle stability with specific capacitance remaining 73.28% of the initial value after 1000 continuous charge-discharge cycles under the current density of 8 A/g. These superior electrochemical features demonstrate that the mesoporous ZnCo2O4 nanosheet is a promising electroactive material for supercapacitor.

In this paper, a convenient solution combustion method to synthesis hierarchically porous Ag-loaded ZnO heterojunction nanocomposites with various Ag contents was reported. The analysis of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption were conducted to characterize the ingredients, microstructure and surface morphology. Ag and ZnO show separate phases due to the reduction of Ag + and the faster crystallization rate of ZnO. The as-synthesized powders were used as gas sensing materials to fabricate gas sensors. The gas-sensing performance was tested towards 100 ppm formaldehyde at an optimum operating temperature of 240 °C and Ag-loaded ZnO (with the different Ag atomic ratio) based gas sensors showed a superior gas-sensing performance comparing with pure ZnO. Especially 1 at% Ag-loaded ZnO has the highest gas response as 170.42. The possible gas-sensing mechanism was discussed in this paper. For example, the influence of surface area, the formation of heterostructure, Ag elements, adsorbed oxygen and so on.

Herein, core-shell carbon sphere@nickel oxide (Cs@NiO) composites were fabricated by a facile hydrothermal method followed by calcination. The resultant Cs@NiO composites are composed of randomly distributed NiO nanoneedles coated on carbon sphere surfaces, which exhibit the rambutan-like structure. As electrode materials for supercapacitor, the core-shell Cs@NiO delivers a high specific capacitance of 555 F/g at the current density of 1 A/g, and an outstanding rate capability of about 85.6% capacity retention from 1 to 10 A/g. Meanwhile, the capacitance degradation is only 5% after 1000 continuous charge-discharge cycles with a current density of 10 A/g. These excellent electrochemical performances can be attributed to the enhanced electronic conductivity, the improved surface activity and the facilitated charge transportation during charging and discharging process, which are caused by the introduction of carbon sphere and the appropriate structure, respectively.

SnO 2 -composite Pd nanoparticles (0, 2.5, 7.5, 10 mol% Pd loading) were synthesized via solvothermal method, followed by calcination. The structure, morphology, chemical state and specific surface area of the Pd-SnO 2 composite were analyzed with X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), N 2 physisorption, respectively. It is found that the composites consist of large amount of SnO 2 microspheres with average diameters up to hundreds of nanometers, and the microspheres are assembled by numerous nanoparticles with average sizes of about 8 nm. To demonstrate their potential application, gas sensors based on the as-synthesized Pd-SnO 2 composites were fabricated to test their sensing performances. The 10 mol% Pd-SnO 2 composite shows an excellent sensing response towards different concentrations of hydrogen at 200 °C. The highest sensing response is up to 315.34 for 3000 ppm hydrogen with a fast response-recovery time (4 s/10 s), which is over 8 times higher than that of pristine SnO 2 , and the lowest detection limit is down to 10 ppm. More significantly, it presents excellent selectivity and stability for hydrogen. The improved sensing response characteristics of the composite could be attributed to the chemical sensitization and electronic sensitization of Pd catalyst.

The natural coconut shell activated carbon (AC) was firstly treated with KOH in advance, and the Mn3O4/AC composites in various AC rations were prepared by the hydrothermal process and subsequent heat treatment. The resulting Mn3O4/AC composites were characterized by means of different techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and so on. Morphological studies reveal the hierarchical porous structure of Mn3O4/AC composites. Mn3O4/AC nanocomposite with the activated carbon quality percentage of 10% exhibits the highest specific capacitance of 491.2 F g−1 at the current density of 2 A g−1 in 6 M KOH aqueous electrolyte measured from the charge–discharge process. The value is nearly 6 times higher than that of the pure Mn3O4 nanoparticles as an electrode for supercapacitor. The good performance of the as-prepared Mn3O4/AC composites as electrode materials may be attributed to the synergistic effects of the activated carbon and the Mn3O4.

3D macro-/nanoporous spinel MCo2O4 (M = Zn, Ni, Cu and Fe) have been successfully fabricated by means of an untemplate and flash synthesis via self-sustained decomposition of metal-organic complexes The effects of the combustion agent to metal nitrate ratio on the combustion behavior, phase and morphology of the products were studied. Pure cobaltites with the hierarchically porous morphology were obtained directly through the combustion of the precursors under fuel-lean conditions in one-step without further heat treatment. The samples were characterized by X-ray diffraction, SEM/TEM imaging, mercury intrusion porosimetry, which indicate that the products possess hierarchical porous structure. A possible forming mechanism was given based on the series of experimental data.

In this paper, the NiCo2O4 nanoparticles were synthesized via a facile one-step solvothermal method without annealing treatment. XRD, TEM, XPS, and N2 adsorption/desorption were used to characterize the composition, morphology, and BET surface area of as-prepared sample, respectively. The analysis results indicated that the NiCo2O4 nanoparticles with spinel structure were successfully obtained. The NiCo2O4 sample was prepared into supercapacitors electrode materials. At room temperature, the electrode materials were investigated with cyclic voltammetry (CV) and galvanostatic charging-discharging in a 6 mol L−1 KOH aqueous electrolyte. Three-electrode systems, in which Hg/HgCl was employed as reference electrode, were used. The NiCo2O4 exhibited a specific capacitance of 717.9 F g−1 at the current density of 0.5 A g−1. Moreover, the specific capacitance remained 84% after 1000 continuous charge-discharge cycles under the current density of 10 A g−1.

In this work, the conformations of isonicotinic acid hydrazide 4-aminosalicylate (pasiniazid) has been comprehensively investigated by analyzing the potential binding site on isoniazid and para-aminosalicylic acid. The powder X-ray diffraction and vibrational spectroscopy analysis with quantum chemical calculation are utilized to characterize the appropriate conformation of pasiniazid. Two hydrogen-bond systems are found in pasiniazid and the relevant vibrational modes have been assigned with the help of potential energy distribution analysis. Natural bond orbital analysis is implemented for evaluating interactions in pasiniazid. The result indicates that the intermolecular interaction is responsible for the stabilization of this complex. Furthermore, molecular electrostatic potential provides an intuitive vision for intermolecular interaction between isoniazid and para-aminosalicylic acid. The chemical stability is estimated by the frontier molecular orbitals analysis.

A sensitive nonenzymatic amperometric glucose sensor is described that relies on a glassy carbon electrode modified with a macro-/meso-porous NiCo2O4. NiCo2O4 with spinel structure has been prepared via a one-step solution combustion method. The material was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen absorption/desorption. An electrode was coated with the porous material and then displayed excellent electrocatalytic activity towards the direct oxidation of glucose in 0.15 M NaOH solution by cyclic voltammetry. Amperometric I-t curve demonstrated a sensitivity of 2100 μA·mM−1·cm−2 at an applied potential of 0.45 V (vs Hg/HgCl). The sensor has a linear response in the 0.001 to 1.0 mΜ glucose concentration range, a fast response time (3.9 s) and a low detection limit (0.38 μΜ).

Hybridization drives rapid speciation by shaping novel genotypic and phenotypic profiles. Genomic incompatibility and transcriptome shock have been observed in hybrids, although this is rarer in animals than in plants. Using the newly sequenced genomes of the blunt snout bream (Megalobrama amblycephala [BSB]) and the topmouth culter (Culter alburnus [TC]), we focused on the sequence variation and gene expression changes in the reciprocal intergeneric hybrid lineages (F1–F3) of BSB × TC. A genome-wide transcriptional analysis identified 145–974 expressed recombinant genes in the successive generations of hybrid fish, suggesting the rapid emergence of allelic variation following hybridization. Some gradual changes of gene expression with additive and dominance effects and various cis and trans regulations were observed from F1 to F3 in the two hybrid lineages. These asymmetric patterns of gene expression represent the alternative strategies for counteracting deleterious effects of the subgenomes and improving adaptability of novel hybrids. Furthermore, we identified positive selection and additive expression patterns in transforming growth factor, beta 1b (tgfb1b), which may account for the morphological variations of the pharyngeal jaw in the two hybrid lineages. Our current findings provide insights into the evolution of vertebrate genomes immediately following hybridization.

Background Polyploidization can induces a flurry of genetic events and plays an important role in speciation. In this study, we comparatively analyzed the molecular organization and chromosomal locus of 5S rDNA in natural autotriploid (3nCC, 3n=150) and artificial autotriploid gynogenetic (3nG, 3n=150) Carassius auratus as well as the related diploid ancestors, diploid Carassius auratus (2nCC, 2n=100) and Carassius auratus red var. (RCC, 2n=100), which provide a excellent model to ascertain the genomic changes in autotriploidization process. Results The similarities of the 5S rDNA coding region (class I, class II and class III) between RCC and 3nG were 98.3%, 100% and 99.1%, respectively, and the similarities of the 5S rDNA coding region (class IV, class V and class VI) between 2nCC and 3nCC were 97.5%, 100% and 100%, respectively. Fluorescence in situ hybridization (FISH) with 5S rDNA as probe indicated that the expected numbers of maternal chromosomal loci were found in 3nG and 3nCC, respectively. Conclusions These observations indicate that autotriploidization has little influence on the divergence of 5S rDNA family in Carassius auratus.

Nearly monodisperse Zinc oxide (ZnO) quantum dots (QDs) displayed yellow fluorescence were synthesized using urea as dispersant. In this paper, urea-ZnO QDs were used as fluorescent probe to detect Cr

The fluorescence intensity of N, S co-doped graphene quantum dots (N, S-GQDs) can be quenched by Fe3+ and Hg2+. Density functional theory (DFT) simulation and experimental studies indicate that the fluorescence quenching mechanisms for Fe3+ and Hg2+ detection are mainly attributed to the inner filter effect (IFE) and dynamic quenching process, respectively. The electronegativity difference between C and doped atoms (N, S) in favor to introduce negative charge sites on the surface of N, S-GQDs leads to charge redistribution. Those negative charge sites facilitate the adsorption of cations on the N, S-GQDs&rsquo, surface. Atomic population analysis results show that some charge transfer from Fe3+ and Hg2+ to N, S-GQDs, which relate to the fluorescent quenching of N, S-GQDs. In addition, negative adsorption energy indicates the adsorption of Hg2+ and Fe2+ is energetically favorable, which also contributes to the adsorption of quencher ions. Blue fluorescent N, S-GQDs were synthesized by a facile one-pot hydrothermal treatment. Fluorescent lifetime and UV-vis measurements further validate the fluorescent quenching mechanism is related to the electron transfer dynamic quenching and IFE quenching. The as-synthesized N, S-GQDs were applied as a fluorescent probe for Fe3+ and Hg2+ detection. Results indicate that N, S-GQDs have good sensitivity and selectivity on Fe3+ and Hg2+ with a detection limit as low as 2.88 and 0.27 nM, respectively.

Polyploidization can significantly alter the size of animal gametes. Autotetraploid fish (RRRR, 4nRR = 200) (4nRR) possessing four sets of chromosomes were derived from whole-genome duplication in red crucian carp (RR, 2n = 100) (RCC). The diploid eggs of the 4nRR fish were significantly larger than the eggs of RCC. To explore the differences between the ovaries of these two ploidies of fishes at the molecular level, we compared the ovary transcriptome profiles of 4nRR fish and RCC and identified differentially expressed genes (DEGs). A total of 19,015 unigenes were differentially expressed between 4nRR fish and RCC, including 12,591 upregulated and 6,424 downregulated unigenes in 4nRR fish. Functional analyses revealed that eight genes (CDKL1, AHCY, ARHGEF3, TGFβ, WNT11, CYP27A, GDF7, and CKB) were involved in the regulation of cell proliferation, cell division, gene transcription, ovary development and energy metabolism, suggesting that these eight genes were related to egg size in 4nRR fish and RCC. We validated the expression levels of these eight DEGs in 4nRR fish and RCC using quantitative PCR. The study results provided insights into the regulatory mechanisms underlying the differences in crucian carp egg sizes.

View of the negative influence of metal ions on natural environment and human health, fast and quantitative detection of metals ions in water systems is significant. Ultra-small grain size CdS quantum dots (QDs) modified with N-acetyl-L-cysteines (NALC) (NALC-CdS QDs) are successfully prepared via a facile hydrothermal route. Based on the changes of fluorescence intensity of NALC-CdS QDs solution after adding metal ions, the fluorescence probe made from the NALC-CdS QDs is developed to detect metal ions in water systems. Among various metal ions, the fluorescence of NALC-CdS QDs effectively quenched by the addition of Cu2+, the probe shows high sensitivity and selectivity for detecting Cu2+in other interferential metal ions coexisted system. Importantly, the fluorescence intensity of NALC-CdS QDs changes upon the concentration of Cu2+, the probe displays an excellent linear relationship between the fluorescence quenching rate and the concentration of Cu2+in ranging from 1 to 25μM. Besides, the detected limitation of the probe towards Cu2+as low as 0.48μM. The measurement of Cu2+in real water sample is also carried out using the probe. The results indicate that NALC-CdS QDs fluorescence probe may be a promising candidate for quantitative Cu2+detection in practical application.

Due to the poor conductivity of Fe based, Cu based and Co based electrode materials commonly used in the electrochemical detection of glucose, and the uneven stirring and poor conductivity of the traditional preparation method based on glassy carbon electrode. In order to solve the above problems, in this work, CdIn2O4with high electrical conductivity was directly grown on three-dimensional (3D) Ni foam to prepare electrode materials for non-enzymatic glucose sensors. CdIn2O4nanoparticles is prepared from cadmium acetate and indium nitrate hydrate in benzyl alcohol by non-aqueous sol-gel method. The electrocatalytic oxidation performances of CdIn2O4electrode material for non-enzymatic glucose are studied. The results show that the proposed CdIn2O4electrode material has good electrochemical properties and sensing performance for glucose detection. The electrochemical response of CdIn2O4electrode material to glucose is recorded that calibration plot for glucose concentrations ranging from 1.0μM to 1.0 mM (R2 = 0.99), a limit detection of 0.08μM, an excellent sensitivity of 3.2925 mA.mM-1.cm-2, a rapid response time of 1.58 s, a good selectivity and a good long-term stability. These demonstrate the significant potential of CdIn2O4electrode material based on 3D Ni foam as non-enzymatic glucose sensors, which makes it possible to use it as a practical glucose detector. This work could introduce a new concept of nanoparticles modified electrode material grown directly on 3D Ni foam, thus a simple and reliable electrochemical glucose sensor platform is realized. This study was completed in 2019 in the school of materials and energy, Yunnan University.

In this work, an efficient and stable fluorescent probe for Al3+was established. The fluorescent probe based on the fluorescence 'turn-on' mode of zinc sulfide crystal composite zinc oxide quantum dots (ZnS/ZnO QDs). The ZnS/ZnO QDs were synthesized via two-step method using L-Cysteine (L-Cys) as a sulfur source and stabilizer. In the synthesis of ZnS/ZnO QDs, the fluorescence of zinc oxide quantum dots (ZnO QDs) decreased and its stability increased in aqueous solution after the addition of L-Cys. In addition, the as-synthesized ZnS/ZnO QDs shows fluorescent enhancement to Al3+. The ZnS/ZnO QDs based fluorescence 'turn-on' probe presented wide linear ranges (1 nM-8μM and 8-100μM). The availability of as-established sensing probe was also estimated by real water sample tests. Furthermore, the fluorescent enhancing mechanism was carried out by recording the fluorescent lifetime of samples, which might be related to the QDs dispersion and charge transfer weaken.

Distant hybridization is an important technique and a useful strategy to obtain new germplasm resources. In this study, we obtained a new type of hybrid bream (BBTB) by two rounds of backcrossing from an established hybrid lineage of blunt snout bream (Megalobrama amblycephala, 2n = 48, BSB, ♀) × topmouth culter (Culter alburnus, 2n = 48, TC, ♂). The DNA content, chromosomal number, morphological traits, gonad histology, genetic composition, and muscle composition of BBTB were investigated. The determined DNA content, chromosomal number, and gonad histology showed that BBTB was a bisexual fertile diploid hybrid fish with 48 chromosomes. Analyses of the genetic composition revealed that the 5S rDNA and HoxD10a of BBTB were inherited from the two genomes of the original parents (BSB and TC). Analysis of muscle composition showed that BBTB possessed higher muscle protein levels and lower muscle carbohydrate levels than BSB. The newly obtained BBTB has the potential to establish a new diploid hybrid lineage and is highly significant for fish genetic breeding.

Cerium oxide nanoparticles/multi-wall carbon nanotubes (MWCNTs) composites are synthesized by a facile hydrothermal method without any surfactant or template. The morphology and microstructure of samples are examined by scanning electron microscopy (SEM), transition electron microscopy (TEM), X-ray diffraction (XRD), Raman spectrum and X-ray photoelectron spectroscopy (XPS). Electrochemical properties of the MWCNTs, the pure CeO2, and the CeO2/MWCNTs nanocomposites electrodes are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GDC) and electrochemical impedance spectroscopy (EIS) measurements. The CeO2/MWCNTs nanocomposite (at the mole ratio of 1:1) electrode exhibits much larger specific capacitance compared with both the MWCNTs electrode and the pure CeO2 electrode and significantly improves cycling stability compared to the pure CeO2 electrode. The CeO2/MWCNTs nanocomposite (at the mole ratio of 1:1) achieves a specific capacitance of 455.6 F g−1 at the current density of 1 A g−1. Therefore, the as prepared CeO2/MWCNTs nanocomposite is a promising electrode material for high-performance supercapacitors.

Monodisperse ZnFe2O4 nanospheres were succesuffully synthesized via a nonaqueous route in benzyl alcohol at low temperaure of 200 °C. It was found that the ZnFe2O4 is 7–16 nm in diameter with a large surface area of 87.40 m2/g. The gas sensor based on ZnFe2O4 nanospheres shows a high pontential for detecting low-ppm-level toluene, exhibiting a good linearity ranging from 1 to 100 ppm with a high response (100 ppm:9.98) and excellent selectivity.

Beta-manganese dioxide (β-MnO2) microrods were hydrothermally synthesized from ammonium persulfate [(NH)4S2O8] solution using manganese sulfate (MnSO4) as reductant at 180 °C for 3 h. The characterizations, including X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, showed that the crystallinity and morphology of the as-synthesized samples were well-defined β-MnO2 microrods with the diameters of about 100 nm and lengths of about 2–4 μm. To explore the optimal degradation conditions, the as-synthesized β-MnO2 microrods were employed into the degradation of methyl orange dye solution with the concentration of 20 mg/L in the presence of H+ with pH values equalling 1.0, 1.5, 2.0, 3.0, 5.0, and 7.0, respectively. The results indicate that the degradation efficiency could reach 98% after 9 min at the pH value of 1.0 or 2.0. Also, the lower the pH value, the higher the degradation efficiency. Based on these experimental results, a proper mechanism of the degradation process of methyl orange is proposed and the rationality of the mechanism is further investigated through the scientific control tests.

A facile, cost-effective, template-free chemical method was developed for the synthesis of β -Co(OH) 2 nanoplatelets under the different preparation conditions. The morphology and microstructure of as-synthesized samples were examined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS), respectively. The observations revealed the formation of a single phase of the hexagonal brucite-like β -Co(OH) 2 , which had an irregular hexagonal disk with angles of adjacent edges of 120°, edge lengths ranging from 200 to 300 nm, and thicknesses of 20–40 nm. When investigated as catalyst for CO oxidation, the β -Co(OH) 2 nanoplatelets exhibited good catalytic activity for CO. Among β -Co(OH) 2 nanoplatelets, the sample prepared at 100 °C for 8 h performed the best, giving the T 100% (the temperature required for achieving a CO of 100%) of 120 °C for the oxidation of CO. There are good correlations of Co 3+ /Co 2+ , the absorbed O x − ions and surface OH group with catalytic activity of the samples for CO oxidation.

Tin oxide microspheres were successfully obtained through a facile hydrothermal method without any polymer templates or surfactant. The as-synthesized SnO 2 microspheres are composed of large amount of small spheres with average diameters of about 250 nm, and every small sphere consists of numerous primary nanocrystallites with average sizes of about 8 nm. The resultant product was used as sensing material for gas sensor to detect the formaldehyde (HCHO) gas. The gas response, response and recovery time, selectivity and stability were carefully studied. It was found that the response value of the sensor to 100 ppm HCHO was 38.3 at the operating temperature of 200 °C. The gas sensor based on SnO 2 microspheres has excellent gas response, good response-recovery properties, linear dependence, repeatability and selectivity, making it to be a promising candidate for practical detectors for HCHO.

Nanoporous titanium dioxide was synthesized by a hydrothermal method without using of surfactant or template. The structure, morphology, surface chemical states and specific surface area were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N2 adsorption-desorption isotherms, respectively. The as-synthesized products are anatase-TiO2 with small grain size (about 12.27 nm) and high surface area (147.17 m2 g−1). The as-synthesized porous TiO2 powder was used to fabricate indirect-heating gas sensor whose gas-sensing characteristics toward acetone were investigated. At its optimal operation temperature, the sensor possesses a good sensitivity, selectivity, linear dependence, low detection limitation, and response/recovery, repeatability as well as long-term stability. Especially for the high sensitivity and fast response/recovery, its response reaches 25.97 for 500 ppm acetone, which is several times higher that of the reported TiO2-based sensors. The response and recovery times are only 13 and 8 s, respectively. Those values demonstrate the potential of using as-synthesized TiO2 for acetone gas detection, particularly in the dynamic monitoring. Apart from these, the mechanism related to the advanced properties was also investigated and presented.

As a new methanol sensing material, the composite of palladium-platinum-In 2 O 3 composited nanocrystalline SnO 2 was successfully obtained by a solid-phase reaction method. The phase composition and the unique structure of as-prepared SnO 2 -Pd-Pt-In 2 O 3 composite were comprehensively characterized using the techniques such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The results of gas sensing properties indicate that the sensor based on the as-prepared SnO 2 -Pd-Pt-In 2 O 3 composite shows the ultra-high response to methanol at an optimal operating temperature of 160 °C when the mass ratio of SnO 2 , Pd, Pt and In 2 O 3 is 100:0.8:2:30. The gas response toward 100 ppm of methanol reaches as high as 320.73. The detection limit of the sensor is estimated to be 0.1 ppm. The sensor also exhibited good response-recovery properties, selectivity, remarkable repeatability and stability, suggesting its greatly promising application in gas sensing. This work could stimulate an effective means to fabricate methanol sensor with superior performance. At the same time, a possible sensing mechanism of the SnO 2 -Pd-Pt-In 2 O 3 composite is discussed.

ZnO hollow spheres with high crystallinity were prepared successfully via a simple template process using ZnCl 2 , carbamide and polystyrene spheres (PSS) as raw materials. The structural and morphological characterizations of the samples were carried out by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. Indirect-heating sensor using ZnO hollow spheres as sensing materials was fabricated on an alumina tube with Au electrodes and Pt wires. The gas sensing properties of the as-synthesized ZnO hollow spheres for n -butanol were investigated. It is shown that the sensor exhibited good sensing performances, characterized by high response, very short response time, and stability to n -butanol gas at operating temperature of 385 °C. These results indicate that the ZnO hollow spheres are highly promising candidates for practical detectors for n -butanol.

Macro-/nanoporous Al-doping ZnO powders with enhanced gas sensing properties are prepared by a solution combustion method using Zn(CH 3 COO) 2 ·2H 2 O, Zn(NO 3 ) 2 ·6H 2 O, Al(NO 3 ) 3 ·9H 2 O, N 2 H 4 ·H 2 O and C 2 H 5 NO 2 as precursors. Characterization by TEM, SEM and BET techniques demonstrates that the Al-doping ZnO powders have a coral-like morphology with a hierarchically porous structure from macro pores, with the wall containing smaller mesopores. The gas-sensing characteristics of the ZnO samples with different Al-doping concentrations are investigated and the results indicate that the gas sensor prepared from 2.5 at% Al doping ZnO powders shows the highest gas sensitivity and selectivity towards n -butanol. A maximum gas response of 751.95 towards 100 ppm n -butanol is achieved at the operating temperature of 300 °C. The mechanisms of responses are also proposed considering the unique material structure.

Hierarchically porous Mn3O4 has been synthesized via a facile solution combustion synthesis using Mn(NO3)2 · 4H2O as an oxidizer and ethylene glycolc (EG) as a fuel. The thermal analysis indicated that the combustion reaction can be initiated at a low temperature (126–140 °C). The obtained Mn3O4 appeared as a hierarchical network with well-connected poroes. At room temperature, the porous Mn3O4 was found to be highly effective for catalytic degradation of methyl orange (MO) in the presence of acid.

A series of NiO/RGO composites based on NiO nanoparticles anchored on layered RGO surfaces were proposed by the same hydrothermal method combined with different calcination temperatures (250, 300, 400 and 500 °C). The effects of calcination temperatures on the capacitive behaviors have been discussed by investigating the components, morphologies, surface conditions of the NiO/RGO composites. The specific capacitance values of NiO/RGO composites calcined at 250, 300, 400 and 500 °C are 950, 553, 375 and 205 F/g at the current density of 1 A/g and the corresponding capacitance retention are 91.3%, 83.9%, 71.9% and 67.3% after 1000 cycles at the current density of 10 A/g. The results suggest the calcination temperature plays an important role in the electrochemical performances of NiO/RGO composites and the electrochemical performances were deteriorated with the increasing calcination temperatures.

MnO 2 was self-grown on carbon fiber paper (CFP) via a facile redox reaction, which is constructed by interconnected ultrathin nanosheets array. The CFP acts as both a supporting scaffold and a reducing agent for MnO 2 growth. The obtained MnO 2 /CFP composite was directly used as electrodes for supercapacitors, delivering a high specific capacitance of 713.7 F/g (0.5 A/g). Cyclic stability testing of the MnO 2 /CFP electrode reveals 86.8% retention in specific capacitance after 1200 cycles at 5.0 A/g. The nanosheet morphology of the MnO 2 on CFP brings about more efficient electroactive sites and facilitates the electrolyte penetration, allowing greater access for ions to active reaction sites. Hence, the attractive electrochemical performances exhibited by this MnO 2 /CFP electrode endow them potentially promising candidates for supercapacitors.

Mesoporous Co3O4 nanosheets were synthesized via a facile chemical coprecipitation method without using of surfactant or template. Mesoporous Co3O4 material was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) to examine the morphology and microstructure to find out the cause for the highly sensitive sensing behavior. SEM and TEM analyses reveal that the Co3O4 nanosheets consisting of nanoparticles prepared here are porous in nature, with average pore sizes of approximately 50 nm or smaller. The sensor based on porous Co3O4 nanaosheets was used for detecting the volatile organic compounds (VOCs) including ethanol, methanol, acetone, isopropanol, formaldehyde and n-butanol. The results demonstrate that the sensor shows potential for detecting VOCs. The significant improvement of sensitivity is attributed to the porous structure, good contact and relatively small crystal size. The gas sensor shows high response values, fast response and recovery times towards VOCs. So, porous Co3O4 nanosheets are considered as promising sensor material for detecting VOCs.

Hydrazine electro-oxidation takes an important role in direct hydrazine fuel cells (DHFCs) and hydrazine electrochemical sensor, but the high cost of precious metal electrode hinders the practical applications of hydrazine electro-oxidation. In this study, an inexpensive 3D electrode of Ni 3 S 2 @Ni foam was obtained through a hydrothermal condition using sodium sulfide as corrodent and Ni foam as both substrate and Ni source. The formation mechanism of this Ni 3 S 2 layer was studied through a process analysis based on physical chemistry with assistant of the results from characterizations. The obtained Ni 3 S 2 @Ni foam was used as electrode to test its hydrazine electro-oxidation properties in terms of DHFCs and electrochemical sensor. It is found Ni 3 S 2 @Ni foam possesses the ability to electro-oxidize hydrazine and Ni 3 S 2 layer leads to increased activity including lower onset potential and higher current. In the aspect of hydrazine electrochemical sensor, the fabricated Ni 3 S 2 layer leads to increased sensitivity and dynamic response property. The results indicate that as-prepared Ni 3 S 2 @Ni foam possesses a potential for practical application in hydrazine electro-oxidation, and Ni 3 S 2 is a very promising substitute material for noble metals in hydrazine electro-oxidation. At the same time, with the characterization of the as-prepared Ni 3 S 2 @Ni foam electrode on structure, morphology and surface chemical states, the mechanism of the corrosion method as well as enhanced properties were investigated.

MnO 2 hollow microspheres consisted of nanoribbons were successfully fabricated via a facile hydrothermal method with SiO 2 sphere templates. The crystal structure, morphology and microwave absorption properties in X and Ku band of the as-synthesized samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and a vector network analyzer. The results show that the three-dimensional (3D) hollow microspheres are assembled by ultra thin and narrow one-dimensional (1D) nanoribbons. A rational process for the formation of hollow microspheres is proposed. The 3D MnO 2 hollow microspheres possess improved dielectric and magnetic properties than the 1D nanoribbons prepared by the same procedures with the absence of SiO 2 hard templates, which are closely related to their special nanostructures. The MnO 2 microspheres also show much better microwave absorption properties in X (8–12 GHz) and Ku (12–18 GHz) microwave band compared with 1D MnO 2 nanoribbons. The minimum reflection loss of −40 dB for hollow microsphere can be observed at 14.2 GHz and reflection loss below −10 dB is 3.5 GHz with a thickness of only 4 mm. The possible mechanism for the enhanced microwave absorption properties is also discussed.

Hollow CuO fibers were successfully fabricated using a facile solution combustion method by incorporating cotton fibers as biotemplate. XRD patterns along with Rietveld refinement confirm the formation of CuO with monoclinic phase. The length of the as-synthesized CuO fibers is at micrometer scale, and the average fiber diameter ranges from several nanometers up to order of micrometers. After combustion reaction, a large amount of coalescent particles left on the surface of the cotton fibers to form porous walls of CuO. By totally removing cotton body at 600 °C, hollow CuO fibers were obtained. A possible growth mechanism of hollow CuO fibers using cotton fibers as templates was given based on experimental data. When used as a sensing material in gas sensor, it exhibited a superior sensitivity and good selectivity toward low-ppm-level (1–100 ppm) n-propanol. Theses findings not only provide a novel approach to fabricate hollow CuO fibers via a solution combustion route, but also explore a promising gas sensor toward n-propanol.

Cd doped porous Co 3 O 4 nanosheets were successfully synthesized via a facile chemical coprecipitation method without using of surfactant or template. The samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption/desorption isotherms (BET) and X-ray photoelectron spectrum (XPS) for their composition, structure/morphology, and BET surface area, respectively. The nanosheets consisting of nanoparticles prepared here are porous in nature, with average pore sizes of approximately 50 nm or smaller. The electrochemical properties of the Cd doped porous Co 3 O 4 nanosheets were investigated by cyclic voltammetry (CV), galvanostatic charge–discharge, electrochemical impedance spectroscopy (EIS) in 6 mol/L KOH solution. The 5% Cd doped porous Co 3 O 4 nanosheets electrode shows the maximum specific capacitance as high as 737 F/g at the current density of 1 A/g, which is 69% higher than that of the undoped porous Co 3 O 4 nanosheets electrode. Furthermore, it has good specific capacitance retention of ca. 96% after 1000 continuous charge–discharge cycles. It shows a better cyclic stability than undoped porous Co 3 O 4 nanosheets electrode, indicating that the Cd doped porous Co 3 O 4 nanosheets is a promising electroactive material for supercapacitor.

Reduced graphene oxide/cryptomelane (RGO/KMn8O16) composites are successfully synthesized from α-MnO2 nanorods and GO using a water-bathing precipitation method. The unique structure of KMn8O16 nanorods, with a length of 2–4 μm, dispersed on the surface of RGO leads to a much enhanced electrical conductivity and ionic transport, finally achieving composites with an improved electrochemical performance. Electrochemical measurement results show a specific capacitance of 222.3 F/g at a current density of 0.2 A/g, much higher than that of the original α-MnO2. After 500 cycles at 2.0 A/g, the RGO/KMn8O16 composite electrode still retains 92.6% of its initial specific capacitance. The excellent electrochemical performance and durability observed for this composite electrode suggest its potential application for electrochemical capacitors.

In this work, Ag-functionalized In 2 O 3 /ZnO (IZO) nanocomposites with various contents were successfully fabricated by a nonaqueous route. The ZnO and In 2 O 3 showed separated phases and different sizes deriving from the faster growth of ZnO than In 2 O 3 using benzyl alcohol as the oxygen supplying agent. To demonstrate the usage of such Ag-functionalized IZO, the gas sensors have been fabricated and investigated for formaldehyde (HCHO) detection. The results reveal that the as-synthesized 3 wt% Ag-functionalized IZO samples exhibit high response of about 842.9 towards 2000 ppm HCHO at operating temperature of 300 °C. All sensors show rapid response and recovery. The highly sensing properties are attributed to the synergistic effects arising from the presence of these multiple functional materials, i.e. the special structure of IZO nanocomposites, the formation of the heterojunctions, the influence of Ag nanoparticles, and the mutual doping effect.

Allotetraploids play central roles in the field of polyploid breeding of freshwater fishes. The molecular basis underlying distant hybridization and individual differences between allotetraploids and their parents is largely unknown. In this study, we performed quantitative proteomics profiling in gonad and liver tissues between allotetraploid and its parents Red Crucian Carp (♀) and Common Carp (♂) respectively. Thousands of proteins were identified and quantified. Species and tissue specific analysis revealed that a large number of causal proteins are specifically regulated in gonad or liver tissue in allotetraploid and its parents respectively. Subsequently, integrative bioinformatics analyses including functional enrichment, pathway and network analyses were conducted. The results suggested a series of gonad and liver specifically regulated proteins such as LSM3, LSM7, PABPC1B and ALDH3A1, EHHADHB, ACAT2 play crucial roles in reproduction-related and metabolism-related pathways including "DNA replication", "Spliceosome" and "Metabolic pathways", "Biosynthesis of antibiotics". Meanwhile, species specifically regulated proteins such as FMR1, MAO are involved in "RNA transport", "Glycine, serine and threonine metabolism". Herein, we established the first comprehensive proteomics knowledgebase for particular freshwater fishes. It may shed light on the molecular mechanisms underlying polyploidy breeding and individual differences and serve as an indispensable reference for further studies. SIGNIFICANCE: The molecular basis underlying distant hybridization and individual differences between allotetraploid and their parents Red Crucian Carp and Common Carp is largely unknown. Quantitative proteomics profiling integrated with multiple bioinformatics analysis revealed that a large number of causal proteins are specifically expressed in gonad or liver tissue in allotetraploid and its parents. Herein, we established the first comprehensive proteomics knowledgebase for particular freshwater fishes. It may shed light on the molecular mechanisms underlying polyploidy breeding and individual differences and serve as an indispensable reference for further associated studies.

A simple, rapid and high stability analytical method development for determination ascorbic acid (AA) is using the glassy carbon electrode (GCE) embellished with mesoporous CuCo2O4 rods as a nonenzymatic amperometric sensor. The mesoporous CuCo2O4 rods were prepared by hydrothermal method adopting NH4F as a surfactant to synthesize triumphantly are employed. The sample is pure spinel CuCo2O4 rods with mesoporous structure. It is excellent electrocatalytic performances for AA is measured by I-t curve. The sensitivity of the mesoporous CuCo2O4 rods sensor is up to 9.482 mA mM−1 cm−2 within linearity range of AA concentration (1–100 μM) and 2.474 mA mM−1 cm−2 within linearity range of AA concentration (100–1000 μM), respectively. The detection limit is down to 0.21 μM with correlation coefficient R2 = 0.99. The CuCo2O4/GCE AA sensor exhibits excellent electrochemical stability, repeatability and selectivity, and actual measurement for vitamin C tablets.

To improve the electrochemical performance and overcome the disadvantages of layered double hydroxides (LDHs), designing the three-dimensional structure may be an effective way. Based on this strategy, we successfully synthesized multi-sized nanosheets cobalt-iron layered double hydroxides (Co-Fe LDHs) on Ni foam by a facile hydrothermal reaction. The poor conductivity of LDHs can be improved by directly grown on Ni foam which can be used as conductive skeleton. The sample has a unique three-dimensional structure with multi-sized nanosheets observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The elements and structure are confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrodes show a great specific capacitance of 3340 mF cm−2 (1670 C cm−2) at 1 mA cm−2 and good cycling stability which keeps the capacitance retention at 85.1% after 4000 cycles. The improved performances may be due to the unique structure with multi-sized nanosheets and the Ni foam used as conductive skeleton to reduce agglomeration and strengthen conductivity. The results indicate the Co-Fe LDHs grown on Ni Foam have a promising future as supercapacitor electrodes.

CeO2 nanocomposites modified by CuO are successfully synthesized by a facile hydrothermal method. The influence of different Cu contents on the crystal structure, morphology, surface element valence, specific surface area, and material reduction temperature has been characterized by many different technical characterization means of XRD, SEM, TEM, Raman, XPS, specific surface area measurement and temperature programmed control under hydrogen, respectively. With the increasing of Cu metal content, the grain size tends to decrease and specific surface area of the sample tends to increase. The CO catalytic oxidation performance of CuO–CeO2 nanocomposites is studied by gas chromatography. Compared with pure CeO2, the CuO–CeO2 nanocomposite catalysts showed more active catalytic performance. The temperature with catalyst rate of 50% in all CuO–CeO2 nanocomposite catalysts for CO conversion is relatively low (77

Idiopathic pulmonary fibrosis (IPF), whose early diagnosis and effective treatment still remain the focus of clinical studies, is a chronic, irreversible and finally fatal pulmonary disease. Glutamyl transpeptidase (GGT) has a potential relationship with the occurrence and development of IPF. Therefore, explore whether GGT can be applied as a biological indicator for the clinical identification and diagnosis of IPF, sensitive and accurate detection of GGT under physiological conditions is necessary. In this research, a new fluorescent probe Cy-GGT was exhibited for detecting GGT concentrations in pulmonary fibrosis cell and mice models. Cy-GGT was capable of rapidly and selectively detecting GGT in vitro. The probe was successfully applied for visualizing GGT in oxidative stress cell models, pulmonary fibrosis cells and mice models. The results revealed that intracellular GGT increased in the cells and mice models of pulmonary fibrosis. GGT plays a significant part in pulmonary fibrosis, and the GGT level abnormally expressed in the lung tissue may be employed as a potential biological indicator to diagnose IPF lesions. Furthermore, the discovery of the close relationship between IPF and GGT will provide a new idea for effective therapy of IPF in the future.

Developing dinotefuran (DNF) sensing probe is crucial for the monitoring of DNF residues. A dual-emission ratiometric fluorescent probe of sulfur-doped carbon quantum dots (S-CQDs) and copper nanoclusters (CuNCs) hybrid (S-CQDs/CuNCs) were developed for sensitive and selective detection of DNF. The fluorescent signals of CuNCs were quenched in the presence of DNF, while the fluorescent signals of S-CQDs enhanced after the addition of DNF. The ratiometric fluorescent performance of as-developed probe was mainly based on the inner filter effect (IFE) between S-CQDs and CuNCs. Interestingly, the aggregation of CuNCs occurred after the addition of DNF, reducing the IFE effect between S-CQDs and CuNCs, leading to the fluorescent intensity of S-CQDs recovered and CuNCs fluorescence decayed. The ratiometric fluorescent performance of S-CQDs/CuNCs illustrated a good sensitivity and selectivity ranging from 10 μM and 500 μM, with a low detection limit of 7.04 μM. Importantly, real samples investigations implied the good application potential of S-CQDs/CuNCs in DNF monitoring.

Based on the production of an allotetraploid fish line (4nAL, 4n = 200, AABB, F3-F28) derived from a cross between female Carassius auratus var. red (RCC, 2n = 100, AA) and male Cyprinus carpio (COC, 2n = 100, BB) and an autotetraploid fish line (4nAU, 4n = 200, AAAA, F2-F14) derived from a cross between female RCC and male Megalobrama amblycephala (BSB, 2n = 48), we obtained a new tetraploid hybrid (4nNT, 4n = 200, AAAB) by crossing 4nAU females with 4nAL males. The aim of this study was to comparatively investigate the biological characteristics of 4nNT fish and their parents. The results regarding the DNA content and chromosome numbers indicated that 4nNT were tetraploid with three sets of RCC-derived chromosomes and one set of COC-derived chromosomes. Histological sectioning showed that female and male 4nNT individuals had normal ovarian and testis development, respectively. Analyses of 5S rDNA molecular organization revealed that the 5S rDNA of 4nNT was inherited from the original parents and contained obvious base variations and sequence insertions or deletions. The newly produced 4nNT hybrid has the potential to establish a new tetraploid fish line, and it also provides an ideal model for studying the genomic structure and genetic expression variation in polyploid hybrid fish.

Copper, as an essential element in human body, can have adverse impact on environment and healthy individuals if it is excessive. So it is necessary to establish a rapid and effective method for detecting Cu2+. In this work, we describe a method for determination of Cu2+ based on water-soluble ZnO quantum dots (QDs) modified with (3-aminopropyl)triethoxysilane (APTEs). The ZnO QDs functionalized with APTEs (NH2–ZnO QDs) synthesized by a simple sol-gel method and displayed strong yellow-green fluorescence with a peak at 535 nm under 350 nm excitation. High-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, luminescence, and UV–visible absorption spectroscopy were used to characterize the NH2–ZnO QDs. In addition, the emission from NH2–ZnO QDs was selectively quenched upon addition of Cu2+. Therefore, this finding was used to design a fluorescent probe based on NH2–ZnO QDs to detect Cu2+ in water solution, and the linear relationships were 2–20 nM and 1–100 μM respectively, with detection limit for Cu2+ at 1.72 nM (on the basis of 3σ/slope criterion). This fluorescent probe had also been applied in real water sample to testify its availability in drinking water. Furthermore, the quenching mechanism was studied by measurements of UV–visible absorption spectra and fluorescent lifetime of ZnO QDs, which may be attributed to the aggregation induced by Cu2+ and the dynamic quenching existing energy transfer between QDs and Cu2+.