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The macro-invertebrate is an important part of the aquatic food web of urban rivers, and it is of great significance in understanding its ecological suitability for the stability of river ecosystems. Previous studies, such as those that have conducted suitability index and canonical correspondence analyses (CCAs), have widely used a macro-invertebrate suitability analysis; however, these studies can only confirm a few coupling relationships between the environment and macro-invertebrates. In our study, one-way ANOVA, HCA, PCA and GAM models were used to explain the differences in the spatial and temporal distribution of environmental factors, as well as to reduce data redundancy. A response curve of the critical environmental factors and macro-invertebrates was constructed, and the nonlinear relationship between these factors and benthic animals was quantified to analyze the ecological threshold of the macro-invertebrates. The study area was the Majiagou River, Harbin, China. The results show that COD had significant seasonal differences due to complex hydrological conditions, and most of the water quality factors had spatial differences. The GAM model explained 60% of the Margalef diversity index (MDI) variance. The relationship between chlorophyll-a and MDI was unimodal, and MDI and NH4+-N essentially showed a negative correlation; when the total nitrogen (TN) value reached 5.8 mg/L, MDI reached its peak. When MDI was higher than the mean value, the chlorophyll-a range was 18.1 μg/L~83 μg/L. The NH4+-N was less than 1.8 mg/L, and TN was 1.8~6.8 mg/L. This study provides a reference for the comprehensive management of urban river ecosystems.

Graphdiyne (GDY) has been considered as an appealing electrode material for electrochemical sensing because of its alkyne-rich structure and high degrees of π-conjugation, which shows great affinity to heavy metal ions and pollutant molecules via d−π and π–π interactions. However, the low surface area and poor conductivity of bulk GDY limit its electrochemical performance. Herein, a two-dimensional ultrathin GDY/graphene (GDY/G) nanostructure was synthesized and used as an electrode material for electrochemical sensing. Graphene plays the role of an epitaxy template for few-layered GDY growth and conductive layers. The formed few-layered GDY with a high surface area possesses abundant affinity sites toward heavy metal ions (Cd2+, Pb2+) and toxic molecules, for example, nitrobenzene and 4-nitrophenol, via d−π and π–π interactions, respectively. Moreover, hemin as a key part of the enzyme catalytic motif was immobilized on GDY/G via π–π interactions. The artificial enzyme mimic hemin/GDY/G-modified electrode exhibited promising ascorbic acid and uric acid detection performance with excellent sensitivity and selectivity, a good linear range, and reproducibility. More importantly, real sample detection and the feasibility of this electrochemical sensor as a wearable biosensor were demonstrated.

The abuse of conventional antibiotics leads to increasing bacterial resistance. Nanozyme is a new kind of ultra-efficient and safe nanomaterial with intrinsic enzyme-like activities, showing remarkable potential as a next generation nanobactericide. Graphdiyne (GDY) is a burgeoning two-dimensional (2D) carbon allotrope with intriguing physicochemical properties, holding a great promise as a metal-free nanozyme. In this study, a boron doped GDY nanosheet (B-GDY) was constructed to simulate the performance of peroxidase (POD). By promoting the decomposition of H2O2 to produce reactive oxygen species (ROS), the bactericidal efficacies against both Gram-positive and Gram-negative bacteria were substantially enhanced attributed to the extremely high catalytic activity of B-GDY. In-depth density functional theory (DFT) calculations illuminate that doping of boron can introduce more active B-defect sites as well as lower Gibbs free energy during the H2O2 decomposition reaction. Notably, B-GDY contributes to significant wound healing and excellent biocompatibility, reducing the biological burden. The design of this nanozyme opens a new avenue for the development of alternative antibiotics.

A novel Schiff base fluorescent probe for rare earth ion Lu3+ is reported. Emission intensity of the probe is intrinsically non-fluorescent, which is due to isomerization of the C=N bond in the excited-state proton transfer (ESPT) of phenolic protons of the salicylic amide moiety. In the presence of Lu3+, fluorescence intensifies significantly due to inhibition of the C=N isomerization and ESPT. The Schiff base is characterized by high sensitivity and selectivity towards Lu3+. The fluorescence turn-on mechanism of Lu[L]2 system is proposed.

Nanozymes are promising new-generation antibacterial agents owing to their low cost, high stability, broad-spectrum activity, and minimal antimicrobial resistance. However, the inherent low catalytic activity of nanozymes tends to limit their antibacterial efficacy. Herein, a heterostructure of zinc oxide nanorod@graphdiyne nanosheets (ZnO@GDY NR) with unparallel piezocatalytic enzyme mimic activity is reported, which concurrently possesses intrinsic peroxidase-like activity and strong piezoelectric responses and effectively promotes the decomposition of hydrogen peroxide (H

The burbot (Lota lota) is the only member of the order Gadiformes adapted solely to freshwater. This species has the widest longitudinal range among freshwater fish worldwide. Burbot serves as a good model for studies on adaptive genome evolution from marine to freshwater environments. However, a high-quality reference genome of burbot has not yet been released. Here, the first chromosome-level genome of burbot was constructed using PacBio long sequencing and Hi-C technology. A total of 95.24 Gb polished PacBio sequences were generated, and the preliminary genome assembly was 575.83 Mb in size with a contig N50 size of 2.15 Mb. The assembled sequences were anchored to 22 pseudochromosomes by using Hi-C data. The final assembled genome after Hi-C correction was 575.92 Mb, with a contig N50 of 2.01 Mb and a scaffold N50 of 22.10 Mb. A total of 22,067 protein-coding genes were predicted, 94.82% of which were functionally annotated. Phylogenetic analyses indicated that burbot diverged with the Atlantic cod approximately 43.8 million years ago. In addition, 377 putative genes that appear to be under positive selection in burbot were identified. These positively selected genes might be involved in the adaptation to the freshwater environment. These genome data provide an invaluable resource for the ecological and evolutionary study of the order Gadiformes.

Pd-based nanostructures have high catalytic activity and good light trapping ability for photothermal catalysis. In this work, PdFe nanosheets (NSs) were synthesized through a hydrothermal method and efficiently catalyzed ethylene glycol electrooxidation reaction (EGOR). Under the irradiation of light, the mass activity of EGOR enhanced 1.78 times (from 4.02 to 7.17 A mg−1) comparing with no light, which was 18 times higher than commercial Pd/C. The high activity is attributed to the combination of high photothermal conversion efficiency and the exposure of high energy facet (111) of PdFe NSs. The effects of Pd/Fe ratio, light intensity, and wavelength were investigated.

The high savings of Chinese families is a widely concerned issue. This paper attempts to explain the high savings of Chinese families from the perspective of female labor participation. Firstly, the relationship between female labor participation and household savings rate is theoretically discussed, and then an empirical test is conducted using the 2017 China Household Financial Survey data. In order to overcome the endogenous influence, the labor participation rate of other married women in the same community and the same age group is used as a tool variable for labor participation of married women in the family, and the influence of labor participation of married women on household savings rate is empirically tested. The results of the study show that labor participation of married women significantly increases household savings rates. Heterogeneity analysis found that married women’s labor participation had a significant impact on the 20- to 30-year-old female family, university and higher education levels, and the savings rate of families who would like be with two children. Further research found that married women’s labor participation in promoting the increase in household savings rate is due to a significant increase in household income levels, while household consumption levels have not changed significantly. At the same time, the current female labor participation did not significantly reduce the family’s preventive saving motivation, but further increased the household savings rate. This paper provides a new perspective for understanding the high savings of Chinese families and can provide a reference for future policy development.

Effective electronic interactions between molecular catalysts and supports are critical for heterogeneous enzyme mimics, yet they are frequently neglected in most catalyst designs. Taking the enzyme mimics of hemin immobilized on graphdiyne (Hemin-GDY) as an example, we explicate for the first time the underlying role of GDY as a co-catalyst. Based on the robust conjugation between GDY and hemin, the delocalized π-electrons in GDY act as a ligand for Fe ions so that the orbital interactions including electron transport from GDY → Fe can induce the formation of an electron-rich Fe center and an electron-deficient π-electron conjugated system. This mechanism was validated by electron paramagnetic resonance (EPR), Raman spectroscopy, and DFT calculations. Moreover, both EPR spetra and Lineweaver-Burk plots revealed that Hemin-GDY could efficiently catalyze the decomposition of hydrogen peroxide (H2O2) to produce hydroxyl radical (•OH) and superoxide anion (O2•–) by a ping-pong type catalytic mechanism, and particularly, the catalytic activity was increased by 2.3-fold comparing to that of hemin immobilized on graphene (Hemin-GR). In addition, Hemin-GDY with the exceptional activity and stability was demonstrated for efficient catalytic degradation of organic pollutants under acidic conditions. Collectively, this work provides a theoretical basis for the design of GDY supported catalysts and renders great promises of the GDY based enzyme mimics.

A novel coordination polymer, {[Cd4(Ccbp)3(dpe)4·4H2O]·(ClO4)5·4H2O} (CP 1) (Ccbp = 3-carboxy-1-(3-carboxybenzyl)pyridin-1-ium, dpe = 1,2-di(pyridin-4-yl)ethane), was synthesized under hydrothermal conditions by a zwitterionic organic ligand and dipyridine ligand, and was fully characterized. This CP 1 with a pyridine cation basic skeleton can be used as the first potential dual-function luminescence sensing material for the selective, sensitive and recyclable sensing of acetone molecules in aqueous phase and for the quantitative detection of ultra-low temperatures of 10 to 70 K.

Au@AgPt yolk-shell nanoparticles (Y-SNPs) with Au core and porous Ag/Pt alloy shell were prepared via a double-template method. This synthesis employed Au@Ag core-shell nanoparticles as a hard-template to obtain Au@AgPt Y-SNPs by a galvanic replacement reaction between PtCl62− and Ag. Brij-58 surfactant micelles served as a soft-template to prepare dendritic and porous shell. The thus-synthesized Au@AgPt Y-SNPs exhibited enhanced catalytic performance (889 mA mgPt−1) and stability for methanol oxidation reaction (MOR) at room temperature, which is 5 times as high as the commercial Pt/C (20 wt% Pt). The enhanced electrocatalytic activity is attributed to following aspects: electronic effect between Pt and Au, synergism between Pt and Ag, and nanoreactor confinement effect in the cavity between the Au core and the shell. The present work provides a simple strategy for the formation of ternary metallic Y-SNPs, which exhibit promising applications in electrocatalysis, energy conversion and sensing.

Sun Island Bund Wetland (SIBW) is a river floodplain wetland located at the south part of Heilongjiang Province in Northeast China. An investigation of the influence of habitat type on macroinvertebrates assemblages structure was conducted in July 2016. Nine (9) sampling sites were selected based on sediment type, water condition, and aquatic vegetation type. Macroinvertebrates attributes including density, biomass, and four diversity indices (Simpson diversity index, Margalef richness index, Shannon-Weiner index, and Pielou evenness index) were assessed. A total of 53 taxa were collected during the study period, with the highest density dominated being from aquatic insects and gastropods.Bellamya purificataandExopalaemon annandaleiwere the most dominant among all the species. The results showed that the assemblages structure of macroinvertebrates in different habitats was significantly different. Also, the results with PCA showed that the higher values of invertebrates density, biomass, diversity indices, and species richness had a greater association with the habitat types of silt-humus sediment, closed lentic area, and submerged-flouting-emergent vegetation.

Supported ultrafine palladium nanoparticles with uniform distribution exhibit remarkable catalytic capabilities in various applications. Obtaining size-controlled Pd nanoparticles on a support remains challenging and here we present a one-step in situ route to well-defined Pd nanoparticles through reduction of a Pd-containing chalcogel (Pd/Sn/S) with tunable size distribution. The spacings of the Pd nanoparticles on the chalcogel can be controlled by using antimony-containing chalcogels (Pd–Sb/Sn/S). The catalytic performance of Pd nanoparticles supported on the chalcogel surface was assessed in 4-nitrophenol reduction and the Suzuki–Miyaura coupling reaction, and found to exhibit good activities and robust stability. This in situ and one-step synthetic method could be further extended to synthesize a series of noble metal nanoparticles for a variety of applications.

Graphdiyne quantum dots (GDQDs) have attracted increasing attentions due to its unique electronic, optical, and electrochemical properties. However, the low conductivity and quantum yield of GDQDs limit their application. Here, nitrogen-doped graphdiyne dots (N-GDQDs) are firstly synthesized by a simple, friendly and one-step hydrothermal method. The N-GDQDs show a maximum emission at 410 nm under the excitation wavelength of 319 nm. The doping N modifies the surface defect of N-GDQDs and further greatly improves their quantum yield (from 14.6% to 48.6%). In addition, the doping N induces a strong electron transport ability and good conductivity of N-GDQDs. Subsequently, the prepared N-GDQDs are used for constructing an optical-electrochemical nanosensor for sensitive and selective detection of dopamine (DA). DA can quench the fluorescence of N-GDQDs by forming a ground-state non-fluorescent complex between phenoxy anions (in PBS solution) in DA and pyridinic N sites of N-GDQDs, which leads to a highly sensitive and selective detection of DA with a limit of detection (LOD) of 0.14 μM and a linear range of 0.32–500 μM. In the electrochemical detection, DA can be oxidized to DA-quinone under the electric field through N-GDQDs/GCE, which shows a big affinity to N-GDQDs. The LOD for DA is 0.02 μM with a linear range of 0.05–240 μM. Finally, the spiked application for DA detection in human serum samples is investigated, the results show that the method has high accuracy. Our work provides a new carbon quantum dots based sensing platform, which shows great potential in practical application.

Some cold-water fishes are particularly sensitive to the water temperature increasing caused by current global warming. However, the alterations in the physiology and behavior of infraspecific populations living in heterogeneous landscapes in response to water temperature increasing were significantly different. Consequently, understanding the impact of temperature increasing on different populations may be crucial for the conservation of cold-water fishes in the context of global warming. The burbot is the only freshwater specie in Gadiformes. To better understand the differences of different populations of burbot under similar thermal stress, Lota lota was selected as the research objects. Firstly, RNA-seq was applied to identify the transcriptomic responses of Heilongjiang population exposed to three temperature gradients (0 °C, 18 °C and 28 °C). Compared with 0 °C, 4216 and 12,657 genes were significantly differentially expressed at 18 °C and 28 °C, respectively. Meanwhile, 49 genes were significantly differentially expressed in three temperature pairs and these genes were presumed to involve in stress response process, immunologic process, reproductive process, development process, material metabolism process, signal transduction process, spermatogenesis process and cell apoptosis process. The response differences of two L. lota populations to similar thermal stress were compared and the results showed that they have different gene expression responses (the number of differentially expression genes and biological processes). The lower annual temperature of the Heilongjiang River might make it more sensitive to temperature increasing. Based on the comparative transcriptome analyses, 12 orthologous genes were considered as the potential regulators of L. lota preference for cold-water environment and these genes are potentially related to the immunologic process, reproductive process, development process, signal transduction process, and cell apoptosis process. Those results can provide basic information for the rational development of conservation strategies of different L. lota populations under the background of global warming.

In this paper, the panel data of China from 2003 to 2012 and stochastic frontier and threshold regression models were used to analyze the impact of government’s fund and enterprises’ research and development (RD enterprises’ R&D investment can promote innovation efficiency, meaning "market failure" phenomenon will be less. The optimal interval of investment intensity is 0.288 or above and the optimal interval of R&D investing intensity coefficient is between 0.688 and 0.775. Key words: Government R&D fund, enterprise R&D investment, innovation efficiency.

Multifunctional enzymatic nanomaterials (nanozymes) with good biocompatibility, strong enzymatic activity, and substrate specificity are the desired alternatives to natural enzymes. Here, the design of a peroxidase mimetic nanozyme capable of detecting and depleting glutathione (GSH) in the bacterial cells is presented. The nanozyme palladium-iron nanostructure decorated graphdiyne nanosheet (PdFe/GDY) was prepared by a facile hydrothermal approach. It can efficiently catalyze the decomposition of H2O2 to produce •OH by a peroxidase-like mechanism. Surprisingly, the PdFe/GDY nanozymes can detect GSH in bacteria with excellent specificity and ultra-low detection limit of 24.45 nM. Moreover, the PdFe/GDY nanozymes can consume GSH for bacterial disinfection with killing efficacy > 99.99%, promote wound healing and do not cause significant toxicity in vitro and in vivo. To our knowledge, this is the first example of a GDY-based nanozyme biosensor and antibacterial agent. Collectively, this work would be indicative to construct GDY-based nanozymes in clinical diagnosis and sterilization.

We report a sensitive sensing strategy based on metal-enhanced fluorescence (MEF) and hybridization chain reaction (HCR). Hg2+ aptamers were immobilized on magnetic nanoparticles (NPs) and HCR process happened without Hg2+, forming long DNA chains and allowing fluorescent indicator (SYBR Green) intercalated in the double helix. After magnetic separation from test solution, positively charged Ag@SiO2 NPs were added, they were electrostatically absorbed on negatively charged DNA chains, acting as “smart dust” to enhance fluorescence signal. This design was used for Hg2+ detection and it showed high sensitivity with a limit of detection down to 25 pM. This method also exhibited good selectivity over other metal ions and was successfully applied in real water sample analyses.

Hollow dendritic Ag/Pt alloy nanoparticles were synthesized by a double template method: Ag nanoparticles as the hard template to obtain hollow spheres by a galvanic replacement reaction between PtCl62− and metallic Ag and surfactant micelles (Brij58) as the soft template to generate porous dendrites. The formation of a Ag/Pt alloy phase was confirmed by XRD and HRTEM. Elemental mapping and line scanning revealed the formation of the hollow architecture. We studied the effects of the Ag/Pt ratio, surfactant and reaction temperature on the morphology. In addition, we explored the formation process of hollow dendritic Ag/Pt nanoparticles by tracking the morphologies of the nanostructures formed at different stages. In order to improve the electrocatalytic property, we controlled the size of the nanoparticles and the thickness of the shell by adjusting the amount of the precursor. We found that these Ag/Pt alloy nanoparticles exhibited high activity (440 mA mg−1) and stability as an electrocatalyst for catalyzing methanol oxidation.

Plasmonic metal nanocatalysts have excellent light trapping properties and high chemical reactivity. Impressively, Au nanostructures can absorb a wide array of visible light by tuning their morphology. In this work, spherical gold nanoparticles (Au NSs), multi-branched gold nanoparticles (Au NMs) and gold nanorods (Au NRs) were successfully synthesized; the shape- and size-dependences of these gold nanocatalysts on the methanol oxidation reaction (MOR) under light irradiation were studied. It is worth mentioning that Au NRs have the highest anode peak current density under dark conditions due to the exposure of highly active facets. A similar enhancement effect was obtained for Au NSs and Au NMs under visible light irradiation, which is due to the generation of a high concentration of energetic charge carriers on these Au nanostructures. The size dependences of Au NSs on the MOR showed that a larger electrochemically active surface area (ECSA) was obtained for small nanoparticles, which is due to the surface effect. In addition, the catalytic performance, durability and anti-CO stripping of these Au nanocatalysts under visible light irradiation, as well as the effect of light intensity and wavelength were described in detail. This work provides an insight into the mechanism of plasmon enhanced electrocatalysis by Au nanostructures with different sizes and shapes.

Etched PtCu nanowires (NWs) were synthesized by a hydrothermal reaction and chemical etching process. The NWs are shown to be viable peroxidase (POx) mimics capable of catalyzing the oxidation of the substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to form a blue-green coloration. The mechanism of catalysis was investigated and the results demonstrated that H2O2 is decomposed to form hydroxyl radicals which oxidize TMB in the presence of the NWs. Under optimized conditions, a steady-state kinetic analysis revealed that the NWs possess a stronger affinity for H2O2 and TMB compared to the enzyme horseradish POx. Based on the high POx-like activity, a colorimetric assay for H2O2 was established. Absorbance at 652 nm increases linearly in the 0.1–300 μM H2O2 concentration range, and the detection limit is 0.06 μM (at S/N = 3). The assay was successfully applied to the determination of H2O2 in (spiked) milk and contact lens solution. Furthermore, a highly sensitive test strip was designed which represents a low cost and fast alternative for the visual determination of H2O2.

A facile method to prepare Pt-Cu nanowires (NWs) was introduced. Structural characterization such as high-resolution transmission electron microscope (HR-TEM), selected-area electron diffraction (SAED), EDS element mapping, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and inductively coupled plasma mass spectrometry (ICP-MS) showed the formation of Pt-Cu alloy, with a width of 4.5 nm on average. The formation process of Pt-Cu NWs was studied; it was found that bromine ion, who has preferential adsorption on Pt (100) face, served as a growth-directing agent; Brij58 not only served as a protector but also played an important role in forming Pt-Cu NWs; the mechanism was proposed. Their electrocatalytic activity towards methanol oxidation was investigated; we found that the current density of Pt-Cu NWs was 295 mA·mg-1 when the ratio of Pt/Cu is 1 : 1, which is 11.5 and 2.35 times higher than that of pure Pt (26 mA·mg-1) and commercial Pt/C (126 mA·mg-1). The high electrocatalytic activity is attributed to the presence of abundant structural defects and surface active sites on the synthesized Pt-Cu NWs.

In this work, the PtCu electrocatalyst supported on graphdiyne (PtCu/GDY) nanocomposite was synthesized for methanol oxidation reaction (MOR). The results demonstrated that the obtained PtCu/GDY catalyst has a good dispersion on graphdiyne. The electrochemical experiments indicated that the PtCu/GDY displayed a superior electrocatalytic activity towards MOR with a high mass activity of 336 mA mg−1. Furthermore, the presence of GDY can significantly improve the CO tolerance property of PtCu for MOR, which facilitating OHads generation from H2O decomposition. Therefore, the PtCu/GDY electrocatalyst offers an exciting opportunity to be commercialization of direct methanol fuel cells.

The chapter elaborates on the business angel (BA) market in China, which has developed significantly since its emergence at the end of the 1990s. The increasing numbers of successful cashed-out entrepreneurs emerging from the Internet and high-tech has resulted in the emergence of angel investment. Currently, there are numerous angel groups and matchmaking services that have served to enhance the market. The authors show that the investment behavior of Chinese BAs is very similar to that in western countries, but Chinese BAs are younger, invest more infrequently and lack an understanding of BA investing. The authors also emphasize the need to understand the role of the government in the BA market in improving the regulation and environment of BA investments.

We describe a colorimetric assay for mercury(II) ion. It is based on a hybridization chain reaction (HCR) and the use of Fe3O4@Au nanoparticles (NPs). Aptamers specific for Hg(II) were immobilized on the surface of the Fe3O4@AuNPs. The presence of Hg(II) inhibits the HCR process and this enables less Methylene Blue (MB) to intercalate into the dsDNA structure. After magnetic separation of the DNA-loaded NPs carrying Hg(II), the change in the absorbance of the residual MB solution is measured at 663 nm. The respective calibration plot is linear in the 1 to 300 nM concentration range, with a 0.7 nM detection limit (at a signal-to-noise ratio of 3). The method displays excellent selectivity over other metal ions. It was applied to the analysis of Hg(II) in spiked river water.

Graphene oxide/ferroferric oxide/polyethylenimine (GO/Fe3O4/PEI) nanocomposites were synthesized by an in situ growth of Fe3O4 nanoparticles on GO sheets, and then modified by PEI. The GO/Fe3O4/PEI nanocomposites showed extremely high removal efficiency for anionic dye Congo Red (CR) due to the positively charged PEI molecules (methylene blue was also tested but with low adsorption capacity due to its cationic property). The CR removal capacity was 574.7 mg g−1, higher than most of reported results. The adsorption kinetics could be well described by a pseudo-second-order model. Furthermore, GO/Fe3O4/PEI nanocomposites could be easily recycled by magnetic separation. The removal efficiency remained above 70% after five cycles.

A sensitive “on-off” fluorescent protocol for thrombin detection is demonstrated. Firstly, thrombin aptamers which hybridize with labeled help DNA were immobilized on the surface of Ag@SiO2 nanoparticles (NPs). The silver core causes the label Cy5 to display strong metal-enhanced fluorescence. On addition of thrombin and graphene oxide (GO), thrombin (with its high affinity for the aptamers) displaces the Cy5-labeled help DNA which then binds to the surface of GO via π-stacking, causing fluorescence quenching of Cy5. The findings were used to design a thrombin assay that has a 0.05 nM detection limit and excellent selectivity. It was applied to the quantification of thrombin in spiked serum samples where is showed recoveries ranging from 97 % to 107 %, with relative standard deviations between 2.2 and 4.5 %.

The metal complex effect on the hydrogenation of chlorobenzene over a poly(N-vinyl-2-pyrrolidone)-stabilized platinum colloidal nanocatalyst (PVP-Pt) has been studied under 298 K and atmospheric pressure. The introduction of metal complexes and ligands exhibited great effect on the activity and the selectivity of the nanocatalyst. It is evidently manifested that the modification of metal complexes is not the simple sum of those of the metal central ions and the corresponding ligands.

Dendritic Pt–Cu nanoparticles were synthesized by a facile one-step method with the help of surfactant Brij58 at room temperature, and we also studied the effects of different Pt–Cu ratios on the morphology and size of nanoparticles. In addition, we further tuned the morphology of the Pt–Cu nanostructures by introducing bromide ions, eventually leading to the appearance of some tripod-like structures. Compared with dendritic Pt–Cu and commercial Pt black, these tripod-like Pt–Cu nanostructures exhibited higher electrocatalytic activity and CO tolerance for catalyzing methanol oxidation.

Fe3O4 nanoparticles were synthesized on graphene oxide (GO), then mixed with polyethylenimine to obtain GO/Fe3O4/PEI nanocomposites. Due to the high surface area of GO, superparamagnetism of Fe3O4, and excellent complex ability of PEI, the nanocomposites showed extremely high Cu2+ removal efficiency. The Cu2+ removal capacity was 157 mg g−1, which is higher than most reported results. The adsorption kinetics could be best described by a pseudo-second-order model. Moreover, GO/Fe3O4/PEI nanocomposites could be easily recycled by magnetic separation. After five cycles, the removal efficiency remained 84%.

Au nanoparticles (AuNPs) dispersed in water were stabilized by tripolyphosphate (P3O105-). When Cr2O72- (Cr(VI)) was present, the AuNPs did not change; when Cr3+ (Cr(III)) was present, the AuNPs would aggregate because of cooperative metal-ligand reaction. Aggregated AuNPs showed different color from the non-aggregated ones. Thus, a simple colorimetric assay was made using AuNPs-Cr(VI) to detect ascorbic acid (AA). Upon introducing AA to the AuNPs-Cr(VI) system, Cr(VI) was reduced to Cr(III), and the aggregation of AuNPs occurred. This colorimetric assay performed high selectivity and a linear concentration response in the range of 0.2 to 10 μM; its limit of detection was 0.15 μM.

A biosensing platform using Ag@SiO2-DNA-fluorophore nanostructure was designed for metal ions and small organic molecules detection. DNA hybridization occurred in the presence of the targets through the formation of base–target–base complex; accordingly, the fluorophore (Cy3) was brought to the surface of Ag@SiO2 core/shell nanostructures. Through controlling the thickness of the silica shell on the Ag nanoparticle, the fluorescence of Cy3 could be enhanced by the surface plasmon resonance of Ag nanoparticle for up to 2.5 folds. This metal-enhanced fluorescence (MEF) sensor provided high sensitivity and selectivity for the detection of Hg2+, Ag+, and coralyne. It may be developed as a new class of MEF biosensors for other metal ions and organic molecules analysis.

Colloidal platinum–ruthenium bimetallic nanoparticles with 2.3 nm were synthesized in solution and then immobilized on tin dioxide powder to make a supported nanocatalyst (Pt–Ru/SnO 2 ). The immobilized bimetallic nanoparticles had the same size and size distribution as the solution dispersed ones. Selective hydrogenation of o -chloronitrobenzene to o -chloroaniline was performed over the as-prepared Pt–Ru/SnO 2 nanocatalyst without using any solvent; 99.5% selectivity to o -chloroaniline at ∼100% conversion was achieved.

The effect of metal ions on the hydrogenation of chlorobenzene over poly(vinylpyrrolidone)-stabilized platinum (PVP-Pt) colloidal catalysts was studied in methanol at 298 K and atmospheric pressure. It showed that some metal cations significantly affected the catalytic performances of the colloidal nanocatalysts. Almost all the metal cations studied decreased both the activity and the selectivity to cyclohexane, which might be due to the electron-deficient state of the surface Pt atoms resulting from the adsorbed metal ions. It is therefore essential to remove some metal ions, especially Sn2+, Cu2+, Zn2+, and Mn2+ from wastewaters for efficient catalytic hydrodechlorination.