Gold nanoparticles (AuNPs) with strong red fluorescence (peaking at 657 nm under 365 nm excitation) were synthesized with the assistance of a bifunctional peptide. The peptide was rationally designed with two functional regions: region 1 (CCY) for synthesizing AuNPs and region 2 (MLRAALSTARRGPRLSRLL) for targeting mitochondria. The resulting AuNPs show excellent stability, low toxicity, good biocompatibility, as can target mitochondria. The AuNPs exhibit a temperature dependent fluorescence with high sensitivity and good reversibility. Fluorescence intensity drops to 56% of its initial value on elevating temperature from 20 to 55 °C, while the quantum yield drops from 7.1% to 3.9% and fluorescence lifetime (which is 12.2 μs at 20 °C) drops to 8.96 μs at 55 °C. The AuNPs are shown to be viable mitochondrial thermometers for use in HeLa cells.

•AgPt DNFs were fabricated by a one-pot successive co-reduction aqueous method.•Apzc was used as a structure-directing agent.•The growth mechanism of AgPt DNFs was investigated in some detail.•The hierarchical structures displayed significant SERS enhancement for 4-NTP as a typical Raman probe.•AgPt DNFs demonstrated improved SERS performance for the detection of 4-NTP.With the purpose to search novel surface-enhanced Raman scattering (SERS) substrates, uniform multi-branched AgPt alloyed dendritic nanoflowers (AgPt DNFs) are fabricated with the assistance of 3-aminopyrazine-2-carboxylic acid (Apzc) as a structure-director via a one-pot successive aqueous co-reduction strategy. The formation mechanism of AgPt DNFs is investigated in details. Their morphology, structure, size, and composition are confirmed by a series of characterization technique. The hierarchical nanostructures exhibit strong SERS enhancement and excellent stability by using 4-nitrothiophenolate (4-NTP) as a typical Raman probe. The improved SERS performance for 4-NTP is mainly attributed to the synergistic effects between the bimetals, together with the enriched hot spots at the sharp corners and/or edges of the architectures. This synthetic strategy provided a facile and environment-friendly method to prepare other metallic architectures with novel properties.Download high-res image (169KB)Download full-size image

•Hierarchical AuPd nanochain networks were synthesized by a single-step aqueous method.•Theophylline-7-acetic acid was used as a new capping agent.•The architectures were utilized to construct a sandwich-like immunosensor for ultrasensitive detection of CA15-3.•The immunosensor showed wide linear range, low detection limit, high reproducibility and stability.A novel ultra-sensitive enzyme-free sandwich-like electrochemical immunosensor was fabricated based on hierarchical AuPd nanochain networks (NCNs). The architectures were firstly synthesized by a single-step seedless aqueous method with theophylline-7-acetic acid (T7AA) as a new capping agent. The obtained AuPd NCNs were used for the antibody immobilization and signal amplification. The immunosensor for carbohydrate antigen 15-3 had a good linearity within the concentration range from 0.001 pg mL−1 to 100 ng mL−1, with the low detection limit of 0.35 fg mL−1 (S/N = 3). It showed good reproducibility, high sensitivity and stability, which provided a promising platform for the clinical immunoassay of carbohydrate antigen 15-3.Download high-res image (141KB)Download full-size image

A facile one-pot coreduction strategy was developed to synthesize composition-tunable cross-linked AgPt aerogels, where ionic liquid (1-aminopropyl-3-methylimidazolium bromide, [APMIm]Br) played a significant role in controlling the morphology and structure. During the synthesis progress, Br− easily reacted with Ag+ to form AgBr precipitate and consequently slowed down the reducing rate of Ag+, as well as acting as a capping agent to promote the anisotropic growth of AgPt aerogels, as mainly demonstrated by the electronic microscopy, Brunauer-Emmett-Teller, X-ray diffraction and X-ray photoelectron spectroscopy analysis. The architectures showed superior catalytic activity and enhanced durability toward ethanol oxidation reaction (EOR) and ethylene glycol oxidation reaction (EGOR) in contrast with commercial Pt black, owing to the tailored composition, morphology and electronic structure of the prepared AgPt aerogels.Download high-res image (69KB)Download full-size image

Herein, a rapid and straightforward coreduction aqueous approach was developed for preparation of support-free trimetallic Pt53Ru39Ni8 nanosponges with clean surface. Plenty of hydrogen bubbles were in situ formed via the oxidation and hydrolysis of the reductant (sodium borohydride), which served as the dynamic template in the fabrication of the porous sponge-like structures. The shape, size, crystal structure, and composition of the products were characterized by a set of characterization techniques. The obtained Pt53Ru39Ni8 nanosponges displayed dramatically highly electrocatalytic performances for hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HOR) outperformed home-made PtNi nanoparticles (PtNi NPs), RuNi NPs and commercial PtRu black (50 wt.%). The present route provides new insights for facile synthesis of other bi-, tri- and even multi-metallic nanocatalysts for potential applications in catalysis, energy conversion and storage.Download high-res image (160KB)Download full-size image

In this paper, growth hormone releasing peptide-6 (GHRP-6) is a bioactive polypeptide and acts as the reducing agent and capping ligand for synthesis of bright green fluorescent gold nanoclusters (GHRP-6-Au NCs) by a simple and environmental-friendly aqueous method, with the assistance of NaBr as the fluorescent sensitizer. The obtained GHRP-6-Au NCs had high fluorescent quantum yield (10.7%), and the fluorescence was strongly quenched by the existence of trace Fe3+. Thus, a new and highly sensitive sensor for the assay of Fe3+ was constructed based on the analyte-induced fluorescent quenching mechanism. The sensor had a low detection limit of 1.4 µM (S/N = 3) and a wide linear range of 2–1000 µM. Besides, GHRP-6-Au NCs exhibited low cytotoxicity and high biocompatibility for cell imaging.Download high-res image (156KB)Download full-size image

In this work, well-defined dendrite-like PtAg alloyed nanocrystals were prepared by a facile one-pot l-hydroxyproline-assisted successive coreduction approach on a large scale, where no any template or seed involved. l-Hydroxyproline was employed as a green structuring director. The formation mechanism of the alloyed dendritic nanocrystals was investigated in details. The as-prepared frameworks exhibited boosted electrocatalytic activity, improved stability and enhanced tolerance toward oxygen reduction reaction (ORR) and ethylene glycol oxidation reaction (EGOR) in alkaline media in contrast with commercial Pt black catalyst. The developed method provides novel strategy for preparing other shape-controlled nanocatalysts with superior catalytic activity and durability.Download high-res image (85KB)Download full-size image

•Alloyed PdCu NCs were prepared by a one-pot solvothermal method.•KBr was used as the capping agent in the synthetic process.•HDPC are used as the capping agent and surfactant to avoid the aggregation.•The architectures showed enlarged ECSA and improved electrocatalysis towards GOR.•PdCu NCs exhibited enhanced catalytic performance for HER in acid media.The catalytic capability of bimetallic nanocatalysts is closely correlated with their size, shape, and crystal structures. Herein, a facile one-pot solvothermal strategy is designed to fabricate uniform spherical PdCu nanocrystals (NCs) assembled by many smaller grains. Oeylamine (OAm) is acted as the reaction solvent and reductant. KBr and hexadecylpyridinium chloride monohydrate (HDPC) are used as the capping agent and surfactant to avoid the aggregation, respectively. The architectures possess larger electrochemically active surface area (ECSA) of 13.6 m2 g−1 than commercial Pd black (4.4 m2 g−1), showing the improved catalytic ability for glycerol oxidation reaction (GOR) in alkaline electrolyte in contrast with Pd black. Besides, the obtained catalyst exhibits more positive onset potential (−56 mV) and Tafel slope (51 mV decade−1) toward hydrogen evolution reaction (HER) in acidic media relative to commercial Pd/C, albeit with their performance bellow commercial Pt/C catalyst.Download high-res image (260KB)Download full-size image

•AgPt HANS were obtained by a one-pot aqueous method.•Cytosine served as the eco-friendly growth-directing agent.•The hollow structure showed the enlarged electrochemically active surface area.•The architectures displayed superior catalytic activity and better stability for EGOR and HER.Herein, a simple one-pot aqueous method was developed for synthesis of AgPt hollow alloyed nanostructures (AgPt HANS) with polyvinylpyrrolidone (PVP) and cytosine as the dispersing agent and eco-friendly growth-director, respectively. The synthesized architectures displayed the improved catalytic performance toward ethylene glycol oxidation reaction (EGOR) relative to commercial Pt black in alkaline media. Meanwhile, the catalyst exhibited the enhanced catalytic activity for hydrogen evolution reaction (HER) with the positive onset potential (Eonset, −39 mV) and a small Tafel slope (40 mV dec−1) relative to commercial Pt/C (20 wt%, −31 mV, 33 mV dec−1) in 0.5 M H2SO4, along with the more positive Eonset (−34 mV) and a smaller Tafel slope (59 mV dec−1) in 0.5 M KOH compared with Pt/C (−35 mV, 85 mV dec−1).Download high-res image (210KB)Download full-size image

•AuAg HNCs were prepared by a simple one-pot aqueous method.•PCA was used as the green growth-directing agent.•The architectures served as the carrier and catalyst for CA199 and ORR, respectively.•The immunosensor was constructed by virtue of the enlarged ORR signals.•The resulted immunosensor showed improved analytical performance for the detection of CA199.Herein, bimetallic alloyed AuAg hollow nanocrystals (AuAg HNCs) were prepared by a simple one-pot aqueous method using polycytidysic acid (PCA) as the green growth-directing agent. The novel immunosensor for carbohydrate antigen 199 (CA199) was further constructed based on the enhanced catalytic currents of oxygen reduction reaction (ORR) by AuAg HNCs. By virtue of the good biocompatibility and catalytic activity of AuAg HNCs, the immunosensor exhibited superior analytical performance for the assay of CA199 under the optimal experimental conditions, the ORR signals linearly decreased with the increased CA199 concentrations in the range of 1 ~ 30 U mL–1, with the low detection limit of 0.228 U mL–1, improved stability, reproducibility and selectivity.

A simple and facile method is described for the morphology-controlled synthesis of bimetallic Au–Pd alloyed nanochain networks (NNCs) that show high catalytic performance for the Ullmann intermolecular homocoupling of aromatic or alkyl halides (X = I, Br, Cl) in aqueous media and can be reused at least five times, which can also be applied to intramolecular homocoupling.

•3D porous PtAg HNCNs were prepared by a one-pot co-reduction aqueous method.•3-APDH acted as a structure-director in the current synthesis.•The hierarchical architectures showed significantly enlarged ECSA.•The frameworks showed effective catalytic activity and high durability for ORR.With the purpose to develop low-cost, highly active and durable electrocatalysts in fuel cells, three-dimensional (3D) freestanding porous PtAg hollow nanochain networks (HNCNs) with tunable compositions were large-scaled prepared by a one-pot co-reduction method. 3-Aminopyrrolidine dihydrochloride (3-APDH) served as the structure director in the synthetic process, while no other specific additives such as surfactant, polymer, seed and template were involved. The structure, morphology, and composition of the architectures were examined by a series of characterizations. PtAg HNCNs showed larger electrochemically active surface area (ECSA) due to the specific 3D hollow porous structure. Moreover, PtAg HNCNs with high Pt content (i.e., Pt75Ag25 HNCNs) exhibited significantly improved durability and enhanced mass activity of 0.37 mA mg−1 at 0.81 V (vs. RHE) in contrast with commercial Pt/C for oxygen reduction reaction (ORR), owing to the specific structures and synergetic effects of the bimetals. This strategy can be explored to fabricate other novel metallic nanocatalysts in fuel cells.Download high-res image (190KB)Download full-size image

•Hierarchical Au dendrites are facilely prepared by a one-pot wet-chemical method.•Poly(ionic liquid) is employed as the stabilizing agent and structure director.•The architectures show enhanced SERS performance for the adsorbed 4-MBA.•Au dendrites are applied for the assay of other molecules as highly active SERS substrates.In this work, high-quality hyperbranched Au dendrites were synthesized by a fast, straightforward, scalable and cost-effective one-pot strategy with the assistance of poly(ionic liquid) poly(1-vinyl-3-ethylimidazolium bromide) (PVEIB) as the stabilizing agent and structure director. PVEIB plays the key role in the formation of the dendritic architectures that are composed of a trunk, secondary and tertiary branches. The as-prepared Au nanodendrites exhibited surface-enhanced Raman scattering (SERS) performance for the detection of 4-mercaptobenzoic acid (4-MBA) with a linear range of 0.5–10 μM and a detection limit of 0.02 μM, owing to their rough surfaces and parallel branches. Taking advantage of its facile fabrication and highly SERS signals, Au NDs were further explored for the assay of other molecules (e.g., 4-nitrobenzenethiol, 4-aminothiophenol, 1,4-benzenedithiol, and 4-mercaptophenyl boronic acid) with improved performances.

•Dendritic Pt–Au core–shell alloy nanocrystals are prepared facilely on a large scale.•The atomic ratios of Pt to Au in the core and shell are 4:1 and 2:3, respectively.•A simple one-pot successive coreduction method is developed.•Polyinosinic acid is firstly used as a capping agent.•The hybrid crystals display enhanced electrocatalytic performance for MOR.In this work, well-defined dendritic Pt–Au core–shell alloy nanocrystals (Pt–Au CSANCs) are synthesized on a large scale via a simple one-pot oligonucleotide-assisted successive coreduction route. The atomic ratios of Pt to Au in the core and shell of Pt–Au CSANCs are 4:1 and 2:3, respectively. Polyinosinic acid (PIA), a commercially available oligonucleotide, is employed as a capping agent. Control experiments demonstrate that the dosage of PIA and the successive coreduction are essential to form dendritic Pt–Au CSANCs. The as-synthesized architectures show enhanced electrocatalytic activity and improved stability for methanol oxidation in alkaline media by comparison with PtAu nanocrystals and commercial Pt black catalysts.

•RGO-PtPd nanoflowers are facilely prepared by a simple one-pot aqueous approach.•L-histidine is used as the structure-directing agent.•There is no any seed, template, special apparatus or organic solvent involved.•The nanocomposites show improved electrocatalytic performance for EGOR.Amino acids with intrinsic affinity to metallic ions can be employed for controllable synthesis of metal nanocrystals with tunable size and morphology, as well as less toxicity. In this work, L-histidine was exploited as a structure-director for in situ controlled growth of bimetallic PtPd alloyed nanoflowers on reduced graphene oxide (RGO-PtPd nanoflowers) by a simple one-pot aqueous approach at room temperature. There was no seed, template, special apparatus or organic solvent involved in the synthetic process. The as-synthesized nanocomposites displayed improved electrocatalytic ability and durability for ethylene glycol oxidation reaction (EGOR) as compared to Pt-RGO, Pd-RGO, commercial PtRu/C, Pt black and Pt/C catalysts.Pt-Pd alloy nanoflowers were uniformly supported on reduced graphene oxide by a facile L-histidine-assisted wet-chemical method. The as-synthesized nanocomposites displayed enhanced electrocatalytic activity and better stability for EGOR.

•PdAu NWs were facilely prepared by a rapid wet-chemical approach via oriented attachment growth.•4-Aminopyridine was used as the growth director and weak stabilizing agent.•PdAu NWs had enlarged electrochemically active surface area.•The architectures exhibited enhanced catalytic performance for MOR.Herein, a facile 4-aminopyridine-assisted one-pot approach was developed for synthesis of bimetallic PdAu alloyed nanowires (NWs) on a large scale, without using any pre-made seed, surfactant or polymer. Their formation mechanism was discussed based on the oriented attachment growth. The as-synthesized architectures have enlarged electrochemically active surface area and enhanced mass activity relative to commercial Pd black catalyst, revealing the improved catalytic activity, durability, and tolerance to carbonaceous species poisoning toward methanol oxidation reaction (MOR). This is attributed to their unique wire-like nanostructures, along with the synergetic effects between Pd and Au.A rapid 4-aminopyridine-assisted approach was developed for large-scaled synthesis of bimetallic PdAu nanowires via oriented attachment growth. The as-obtained architectures showed the enhanced catalytic performance toward MOR.

Well-defined bimetallic yolk–shell nanostructures of Ni@PtNi nanocrystals with porous shells were uniformly deposited on reduced graphene oxide (Ni@PtNi NCs-rGO) under hydrothermal conditions. The physical characterization was systematically investigated by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The as-fabricated products exhibited improved catalytic performance toward the reduction of p-nitrophenol in comparison with commercial Pt/C (50 wt%), monometallic Pt nanoparticles/rGO and Ni nanoparticles/rGO catalysts.

•AuPt NDs were facilely prepared by a single-step wet-chemical method.•5-Aminouracil-6-carboxylic acid was used as the capping agent and weak stabilizer.•The electrochemically active surface area of AuPt NDs is about 29.67 m2 g−1.•The architectures showed superior electrocatalytic activity for ORR and HER in acid and alkaline media.Herein, well-dispersed porous AuPt alloy nanodendrites (AuPt NDs) were facilely synthesized by a single-step seedless approach by using 5-aminouracil-6-carboxylic acid (AUCA) as the capping agent and weak stabilizer. The architectures showed large electrochemically active surface area (29.67 m2 g−1), and enhanced catalytic performances for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) both in acid and alkaline media. Specifically, the mass activity and specific activity of the as-made catalyst were 31.55 mA mg−1 and 2.65 mA cm−2 (0.1 M HClO4), 29.49 mA mg−1 and 2.5 mA cm−2 (0.1 M KOH) for ORR, respectively, along with a notably low Tafel slope of 34 mV dec−1 (0.5 M H2SO4) and 55 mV dec−1 (0.1 M KOH) towards HER. This synthetic approach can be explored to fabricate other catalysts with improved catalytic performances in fuel cells and renewable energy.

•Bimetallic AuPd nanoclusters are well distributed on graphitic carbon nitride sheets.•The one-pot aqueous method is simple and rapid, without any specific additives involved.•The nanocomposites display enlarged electrochemically active surface area.•The nanocomposites show enhanced electrocatalytic performances for ORR and HER.Herein, we developed a facile one-pot aqueous method to fabricate well-distributed bimetallic AuPd nanoclusters supported on graphitic carbon nitride (AuPd NCs/g-C3N4). The method is simple, rapid, without using any specific additives. The nanocomposites displayed enlarged electrochemically active surface area. The obtained nanocatalyst exhibited the more positive onset and half-wave potentials at 1.09 and 0.98 V (vs. NHE) for oxygen reduction reaction, respectively, along with the enhanced kinetic current density of 1.86 mA cm−2. Meanwhile, the catalyst showed the improved catalytic activity for hydrogen evolution reaction with the onset potential of −29 mV (vs. NHE) and small Tafel slope of 47 mV dec−1. These results demonstrated the improved electrocatalytic performance of the catalyst in contrast with commercial Pt/C (50%) and Pd/C (20%) catalysts.

•Hierarchical PtAu alloy nanodendrites are prepared by a facile one-pot method.•Poly(ionic liquid) is employed as the green shape-regulator and stabilizer.•The nanostructures have enlarged electrochemically active surface area.•The architectures show enhanced catalytic performances for EGOR and ORR.Herein, a facile one-pot method is developed to prepare three-dimensional (3D) hierarchical AuPt alloy nanodendrites (AuPt NDs) with the assistance of poly(ionic liquid) as the green shape-regulator and stabilizer. The as-synthesized architectures show enlarged electrochemically active surface area, and enhanced maximum mass activity (3616 mA mg−1) for ethylene glycol oxidation reaction (EGOR) in alkaline media. Furthermore, the as-synthesized AuPt NDs exhibit superior catalytic activity and more positive onset potential (0.89 V vs. RHE) toward oxygen reduction reaction (ORR) in 0.1 M HClO4 via the four-electron pathway, owing to the unique nanostructures as well as the synergistic effects between Au and Pt.

•Fluorescent Au/Ag NCs were prepared by a simple and green method.•Lipoic acid acted as a reducing and stabilizing agent.•Fluorescent Au/Ag NCs were explored as temperature and Fe3+ sensors.•Au/Ag NCs displayed low cytotoxicity for intracellular Fe3+ imaging in HeLa cells.Herein, we demonstrate a facile, straightforward and green method for synthesis of highly red-emitting fluorescent bimetallic Au/Ag nanoclusters (NCs) employing lipoic acid as both a reducing agent and a protecting agent. The as-prepared Au/Ag NCs exhibited bright red emission with a strong peak centered at 630 nm (quantum yield measured as 6.4%), and showed excellent stability and remarkable temperature-dependent fluorescent property. The fluorescence responses were reversible and linear to the environment temperature from 20 to 65 °C with a resolution as high as 1.34 °C, which allows its potential application as a fluorescent nanothermometer. Moreover, Au/Ag NCs were also explored for selective and sensitive determination of Fe3+ based on the specific quenching of the fluorescence by Fe3+, and explored for fluorescence imaging Fe3+ in living HeLa cells thanks to their very low cytotoxicity.

•Bright green fluorescent GCNQDs doped with oxygen and sulfur were prepared.•The microwave synthesis method was simple, rapid, economical and eco-friendly.•The fluorescent quantum yield was up to 31.67%.•The GCNQDs with low cytotoxicity were used for vitro bioimaging of HeLa cells.Herein, bright green luminescent graphitic carbon nitride quantum dots (GCNQDs) doped with oxygen and sulfur are prepared simply by microwave treatment of citric acid and thiourea. The as-obtained GCNQDs show excitation wavelength and pH dependent luminescence behaviors in the visible range. Besides, the GCNQDs exhibit high fluorescence quantum yield (31.67%), strong resistance to the interference of high ionic strength environment, and good biocompatibility as demonstrated by the cell viability assay. Thus, the resulting GCNQDs can be used as a promising fluorescent probe for HeLa cell imaging with low cytotoxicity, and have great potential in bioanalysis and related fields.Bright green fluorescent GCNQDs were facilely prepared by a simple, rapid and eco-friendly microwave synthesis method. The GCNQDs with low cytotoxicity were used for vitro bioimaging of HeLa cells.

•Water-soluble bright blue fluorescent Au NCs were prepared by a simple and green method.•l-Carnosine was served as a weak reducing agent and a protecting ligand.•The resulting Au NCs with low cytotoxicity were explored for cellular imaging.Herein, a simple and green method was developed for the construction of water soluble fluorescent gold nanoclusters (Au NCs) with the assistance of l-carnosine as both a protecting ligand and a weak reducing agent. The as-prepared Au NCs, with the smaller size (2.31 nm) and longer fluorescence lifetime (7.48 ns), exhibited bright blue photoluminescence under UV light (365 nm) with a quantum yield of 3.4%, excellent stability, and low toxicity for cancer HeLa cell imaging.A simple and green method was developed for synthesis of water-soluble fluorescent Au NCs with l-carnosine, which were explored for bioimaging of HeLa cells.

•Au/Ag nanoclusters exhibit good stability and excellent fluorescence performance.•Detection strategy based on a photoinduced election transfer pathway was designed.•A sensitive assay for tyrosinase activity based on Au/Ag nanoclusters was developed.•This work broadens the application of bimetallic nanoclusters in the bioanalysis.Due to the vital role of tyrosinase in melanin biosynthesis and its function as an important biomarker for melanoma cancer, highly sensitive detection of its activity using biocompatible materials is in urgent demand. Herein we report a convenient and highly sensitive fluorometric biosensor for tyrosinase activity detection based on biocompatible dopamine-functionalized Au/Ag nanoclusters (Dopa-Au/Ag NCs). Dopamine with redox property was covalently linked to Au/Ag NCs surface and formed a Dopa-Au/Ag NCs bioconjugate with strong blue fluorescence. Dopamine is readily oxidized by molecular oxygen under the catalysis of tyrosinase. After dopamine is transformed to o-dopaquinone, an intraparticle photoinduced election transfer (PET) process occurs between Au/Ag NCs and o-dopaquinone moiety, leading to the fluorescence quenching of the Dopa-Au/Ag NCs bioconjugate. Thus, this biosensor was utilized for sensitive and selective detection of tyrosinase in terms of the relationship between fluorescence quenching efficiency and tyrosinase activity. This study discovers that Au/Ag NCs and dopaquinone can serve as a good electron acceptor and donor pair which results in an efficient intraparticle photoinduced electron transfer process, and also provides another alternative way for tyrosinase activity monitoring.

In this work, porous bimetallic palladium–silver (Pd63Ag37) alloy nanocorals were synthesized by a simple and facile one-pot polyol method. The composition and morphology of the nanocrystals were well controlled by changing the concentrations of the precursors. The obtained nanocrystals were mainly characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and the Brunauer–Emmett–Teller method. Porous Pd63Ag37 nanocorals had an enlarged electrochemically active surface area (55.85 m2 g−1), and exhibited enhanced electrocatalytic activity and improved stability for glycerol oxidation reaction as compared to commercial Pd black, owing to the unique porous coral-like nanostructures and synergistic interactions of the alloyed bimetals.

In this work, a facile, convenient and effective one-pot wet-chemical method was developed for preparation of well-dispersed porous bimetallic Pt–Au alloyed nanodendrites uniformly supported on reduced graphene oxide nanosheets (Pt–Au pNDs/RGOs) at room temperature. The fabrication strategy was efficient and green owing to the use of cytosine as a structure-directing agent and weak stabilizing agent, without employing any organic solvent, template, seed, surfactant, or complicated apparatus. The as-synthesized Pt–Au pNDs/RGOs exhibited significantly enhanced catalytic performance toward the reduction of 4-nitrophenol, as compared to commercial Pt black and home-made Au nanocrystals.

A facile one-pot solvothermal method was developed for the fabrication of well-defined three-dimensional highly branched Pt–Pd alloyed multipods, using ethylene glycol as a solvent and a reducing agent, along with N-methylimidazole as a structure-directing agent, without any seed, template, or surfactant. The as-prepared nanocrystals exhibited a relatively large electrochemically active surface area, improved electrocatalytic activity and superior stability for ethylene glycol oxidation in alkaline media, compared with commercial Pt black and Pd black, making them promising electrocatalysts in fuel cells.

•Bimetallic Au–Pt nanochains/RGO is prepared by a simple one-pot wet-chemical co-reduction method.•Caffeine, a natural alkaloid, is employed as a capping agent and a structure-directing agent.•There is no any seed, template, surfactant or polymer involved.•The as-prepared nanocomposites exhibit highly electrocatalytic performances for methanol and EG oxidation reactions.In this work, a simple, rapid and facile one-pot wet-chemical co-reduction method is developed for synthesis of bimetallic Au–Pt alloyed nanochains supported on reduced graphene oxide (Au–Pt NCs/RGO), in which caffeine is acted as a capping agent and a structure-directing agent, while no any seed, template, surfactant or polymer involved. The as-prepared nanocomposites display enlarged electrochemical active surface area, significantly enhanced catalytic activity and better stability for methanol and ethylene glycol oxidation, compared with commercial Pt–C (Pt 50 wt%), PtRu–C (Pt 30 wt% and Ru 15 wt%) and Pt black.A simple, rapid, and facile one-pot wet-chemical co-reduction method is developed for the synthesis of bimetallic Au–Pt nanochains networks supported on reduced graphene oxide (RGO). The as-prepared nanocomposites show highly electrocatalytic activity and stability toward methanol and EG oxidation.

•Pt–Pd–Co alloyed nanoflowers were prepared by a facile one-pot solvothermal method.•Oleylamine was used as the solvent, surfactant and reducing agents.•CPC was employed as the co-surfactant and shape-directing agents.•Pt–Pd–Co nanocrystals exhibited improved electrocatalytic activity and high stability for EG oxidation.In this work, three-dimensional trimetallic Pt–Pd–Co alloyed nanoflowers are fabricated by a facile one-pot solvothermal strategy, with the assistance of oleylamine as the solvent, surfactant, and reducing agents, along with cetylpyridinium chloride (CPC) as the co-surfactant and shape-directing agents. Their morphology and crystal structure were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning transmission electron microscope (STEM), and X-ray photoelectron spectra (XPS) in details. The respective electrochemically active surface area (ECSA) is estimated to be 32.53 m2 g−1, and current density is 132.91 mA cm−2 for the electrooxidation of ethylene glycol (EG). These values are much higher than those of PtPdCo nanoparticles, PtPd nanoparticles, commercial Pt black, and Pd black under the identical conditions, showing the improved catalytic activity of Pt–Pd–Co nanoflowers. The excellent performances are attributed to the specific structure and synergistic interactions of the trimetallic alloy. The as-prepared nanoflowers can serve as a promising electrocatalyst in fuel cells.A facile one-pot solvothermal method was developed for synthesis of Pt–Pd–Co alloyed nanoflowers using oleylamine as the solvent, surfactant and reducing agents, along with cetylpyridinium chloride (CPC) as the co-surfactant and shape-directing agents. The nanocrystals displayed highly electrocatalytic activity and stability toward EG oxidation.

•Well-defined urchin-like Pd nanoparticles with clean surfaces were prepared by one-step electrodeposition.•Nitrite ions were acted as the growth directing agent.•There was no any organic solvent, template, surfactant, seed, or complex apparatus involved in the present synthesis.•Urchin-like Pd nanoparticles showed improved electrocatalytic performance toward methanol oxidation.A simple, facile, green, and controlled one-step electrodeposition method was developed for preparation of well-defined urchin-like Pd nanoparticles on a glassy carbon electrode, using nitrite ions as the growth directing agent. No any organic solvent, template, surfactant, seed, or complex apparatus was involved. The as-prepared Pd nanostructures had “clean” surfaces because of the surfactant-free formation process. The obtained Pd deposits were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The experimental parameters including deposition potential, the dosage of H2PdCl4 and nitrite ions, and deposition time were investigated in details. The urchin-like Pd nanoparticles demonstrated better tolerance, enhanced electrocatalytic activity, and superior stability toward methanol oxidation in alkaline media.Well-defined urchin-like Pd nanoparticles with clean surfaces were prepared by a simple, green, and controlled electrodeposition method, using nitrite ions as the growth directing agent. The as-prepared urchin-like Pd nanoparticles displayed enhanced electrocatalytic activity and better stability toward methanol oxidation compared with spherical Pd nanoparticles.

Correction for ‘Facile preparation of reduced graphene oxide supported PtNi alloyed nanosnowflakes with high catalytic activity’ by Pei Song et al., RSC Adv., 2015, 5, 35551–35557.

A facile hydrothermal strategy was designed for the preparation of alloyed PtNi nanosnowflakes supported on reduced graphene oxide (PtNi nanosnowflakes/RGO), with the assistance of N,N-dimethylformamide (DMF) as the solvent and reductant, and ethylenediamine as the surfactant and capping agent. The as-obtained nanocomposites were mainly characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, which showed enhanced catalytic activity and better stability over commercial Pt/C (10 wt%) in the catalytic reduction of p-nitrophenol to p-aminophenol.

In this work, bimetallic Au–Pt alloyed nanowire networks (AuPt NNs) were facilely synthesized by a simple and rapid one-pot wet-chemical method on a large-scale, using N-methylimidazole as a structure-directing agent and a weak stabilizing agent. The surface of AuPt NNs was clean owing to the easy removal of the adsorbed N-methylimidazole. The control experiments demonstrated that the morphologies of AuPt NNs were strongly correlated with the amount of N-methylimidazole and reaction temperature. The formation mechanism included the four-stage growth processes: rapid nucleation, selective adsorption, π–π induced assembly, and oriented attachment growth. The as-synthesized AuPt NNs exhibited enhanced electrocatalytic activity and improved stability for methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) as compared to commercial Pt black and individual Pt nanoparticles.

A nanocomposite consisting of coral-like gold nanostructures on reduced graphene oxide (RGO) was synthesized with the assistance of dimethylbiguanide (DMBG). It was then fabricated on a glassy carbon electrode, coating with cysteamine in order to enable the immobilization of acetylcholinesterase (AChE) as a model enzyme whose activity of hydrolyzing the substrate of acetylthiocholine is inhibited by the pesticide triazophos. The biosensor has response to acetylthiocholine in the 0.3 ~ 300 μM concentration range at 0.65 V (vs. SCE). The inhibition of the enzyme by triazophos can be determined in concentrations of up to 210 ppb, with a detection limit of 0.35 ppb of triazophos (S/N = 3). The biosensor is highly reproducible and acceptably stable.

We describe a simple solvothermal method for preparation of reduced graphene oxide nanosheets decorated with uniform Cu2O nanoclusters by using poly(vinyl pyrrolidone)-poly(methacrylamide)-poly(vinyl imidazole) triblock co-polymer as a shape-directing agent and L-glutamic acid as a reducing agent. The resulting nanocomposite was deposited on a glassy carbon electrode where it displays improved electrocatalytic activity toward glucose oxidation in 0.5 M NaOH. This observation was exploited to construct a non-enzymatic amperometric sensor for glucose. It has a detection limit as low as 1.0 μM, high sensitivity (23.058 μA mM−1), and a dynamic (analytical) range that extends from 5.0 to 9595 μM at a working potential of 600 mV (vs. SCE).

A simple and facile method is developed for one-pot preparation of hierarchical dendritic PtPd nanogarlands supported on reduced graphene oxide (PtPd/RGO) at room temperature, without using any seed, organic solvent, or complex apparatus. It is found that octylphenoxypolyethoxyethanol (NP-40) as a soft template and its amount are critical to the formation of PtPd garlands. The as-prepared nanocomposites are further applied to methanol and ethanol oxidation with significantly enhanced electrocatalytic activity and better stability in alkaline media.

In this work, a facile general strategy is developed for preparation of palladium-based bimetallic alloyed nanodendrites (PdM NDs, M = Pt, Co, and Ni) via coreduction of Pd(II) acetylacetonate and M(II/III) acetylacetonate salts with oleylamine. Hexadecylpyridinium chloride monohydrate (HDPC) is used as a co-surfactant for preventing the aggregation of nanodendrites. Control experiments varying the precursors and reaction time demonstrate that the dendritic nanocrystals are formed via aggregation-based crystal growth. The as-prepared hybrid nanocrystals display improved electrocatalytic activity and better stability for methanol and ethylene glycol (EG) oxidation, compared with home-made Pd NDs and commercial Pd black catalysts. The developed method provides a novel platform for synthesis of novel electrocatalysts in fuel cells.

In this study, a simple, facile and one-pot solvothermal method was developed for preparation of reduced graphene oxide (RGO) supported hollow Ag@Pt core–shell nanospheres (hAg@Pt), using ethylene glycol (EG) as a reducing agent and sodium dodecyl sulfate (SDS) as a soft template. Control experiments demonstrated that the molar ratios of the Pt–Ag precursors, the amount of SDS, the presence of RGO, and the reaction temperature were critical to the final nanocomposites. The as-prepared hAg@Pt–RGO showed the improved electrocatalytic activity and durability toward ethylene glycol oxidation, which can serve as a promising potential electrocatalyst in direct alcohol fuel cells.

In this report, well-dispersed porous Pt–Pd nanodendrites (Pt–Pd NDs) were synthesized at high yield by a simple, one-pot, wet chemical method without using any seed, template, or toxic organic solvent. Poly(vinylpyrrolidone) (PVP) and urea were employed as the co-stabilizing and co-structure-directing agents. It was found that the reaction temperature, the amount of PVP and urea, the Pt/Pd molar ratio, and the pH value of the reaction media greatly affected the size and shape of the Pt–Pd product. The as-prepared Pt–Pd nanocrystals had a larger active surface area, superior catalytic activity, and better stability for the electrooxidation of methanol and ethylene glycol (EG), compared with the commercial Pt-black and Pd-black catalysts.

Popcorn-like PtAu nanoparticles were fabricated by a facile and green one-pot wet-chemical method, where H2PtCl4 and HAuCl4 were simultaneously reduced by glucosamine in alkaline media. The PtAu nanoparticles were further supported on reduced graphene oxide by simple ultrasonication. The nanocomposites showed an enhanced catalytic performance toward oxygen reduction reaction (ORR), dominated by a four-electron pathway, in comparison with Pt–rGO and commercial 10% Pt/C catalysts. Meanwhile, the nanocomposites displayed improved electrocatalytic properties and better stability for methanol oxidation over Pt–rGO and commercial Pt/C catalysts.

•Pt3Co nanoflowers are prepared by a simple solvolthermal method.•Pt3Co nanoflowers display the enhanced electrocatalytic activity for ORR dominated by a four-electron pathway.•Pt3Co nanoflowers show the improved electrocatalytic property and high stability towards MOR.Herein, a simple one-pot approach is developed for preparation of Pt3Co nanoflowers by co-reduction of Pt (II) acetylacetonate (Pt(acac)2) and Co (III) acetylacetonate (Co(acac)3) in oleylamine, without any seed or template. It is found that hexadecylpyridinium chloride monohydrate (HDPC) is served as both the stabilizing and structuring-directing agent that plays an important role in the formation of well-dispersed flower-like Pt3Co nanoparticles. The as-prepared Pt3Co nanoflowers show the enhanced catalytic performance for oxygen reduction reaction (ORR) in comparison with solid Pt3Co nanoparticles and commercial Pt black catalysts, dominated by a four-electron pathway based on the Koutecky–Levich equation. Meanwhile, Pt3Co nanoflowers exhibit the improved catalytic activity and long-term stability towards methanol oxidation reaction (MOR), using solid Pt3Co nanoparticles and commercial Pt black catalysts as references. The improved catalytic features of Pt3Co nanoflowers are mainly attributed to the porous three-dimensionally interconnected structures, enlarged specific surface area, ligand effect and bifunctional mechanism between Pt and Co. The as-developed method provides a promising pathway for preparation of highly efficient electrocatalysts for ORR and MOR.Pt3Co nanoflowers are prepared by a simple solvolthermal method. The as-prepared nanostructures show the enhanced electrocatalytic performance for oxygen reduction and methanol oxidation.

•A facile strategy is developed for one-pot synthesis PtRu nanodendrites supported on RGO.•HDPC as a shape-directing agent plays a vital role in formation of PtRu nanodendrites.•The porous nanostructures show high electrochemically active surface area.•The nanocomposites display excellent electrocatalytic performance towards EG oxidation.In this report, a simple and facile solvothermal method is developed for fabrication of platinum–ruthenium (PtRu) nanodendrites supported on reduced graphene oxide (PtRu-RGO) in the ethylene glycol (EG) system, using hexadecylpyridinium chloride (HDPC) as a shape-directing agent. The as-prepared nanocomposites show the superior catalytic activity and better stability towards EG oxidation, compared with RGO-supported Pt nanoparticles and commercial PtRu/C (Pt 30 wt. %, Ru 15 wt. %) catalysts. This strategy may open a new route to design and prepare advanced electrocatalysts in direct EG fuel cells.A facile strategy is developed for synthesis of porous PtRu nanodendrites supported on RGO, using HDPC as a shape-directing agent. The as-prepared nanocomposites show the excellent electrocatalytic performance towards EG oxidation.

•PtPd@Pd core–shell nanospheres are synthesized by a one-step co-reduction method.•This method is simple and facile, without any seed, template, or organic solvent.•The nanocrystals exhibit the improved electrocatalytic activity towards ORR.•The nanocrystals show the enhanced electrocatalytic activity for methanol and EG oxidation.Well-defined platinum–palladium@palladium core–shell nanospheres (PtPd@Pd NSs) are synthesized by a facile one-pot solution approach using N-methylimidazole and poly(vinyl pyrrolidone) (PVP) as directing and capping agents, respectively, without using any seed, template, or organic solvent. The coexistence of the precursors, N-methylimidazole, PVP, and reaction temperature has great effects on the final morphology. Thus-prepared nanocomposites display an improved electrocatalytic activity for oxygen reduction reaction (ORR) in acidic media, methanol and ethylene glycol oxidation reaction in alkaline media, compared with Pt nanoparticles, Pd nanoparticles, commercial Pt black and Pd black catalysts. This method may direct a general orientation for shape control synthesis of functional bimetallic nanocrystals as promising electrocatalysts in direct alcohol fuel cells (DAFCs).A simple, facile, and one-step co-reduction route was developed for preparation of PtPd@Pd core–shell nanospheres, without using any seed, template, or organic solvent. The as-prepared nanocrystals display the enhanced electrocatalytic activity and stability for oxygen reduction reaction in acidic media, methanol and ethylene glycol oxidation reaction in alkaline media.

•AuPd@Pd nanocrystals are prepared by a simple and green wet-chemical method.•HEPES is used as a reducing and a shape-directing agent.•The AuPd@Pd nanocrystals are dispersed on graphene by ultrasonication.•The nanocomposites show high electrocatalytic activity toward ORR and MOR in alkaline media.Well-defined core–shell gold–palladium@palladium nanocrystals (AuPd@Pd) are facilely prepared by a simple and green wet-chemical method at 25 °C. A Good's buffer, 2-[4-(2-hydroxyethyl)-1-piperazinyl] ethanesulfonic acid (HEPES), is used as a reducing agent and a shape-directing agent, while there is no template, seed, organic solvent, or surfactant involved. The AuPd@Pd nanocrystals are uniformly dispersed on graphene nanosheets by ultrasonication, resulting in the formation of graphene supported AuPd@Pd (G-AuPd@Pd). The as-prepared nanocomposites exhibit the improved catalytic activity, good tolerance, and better stability for oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) in alkaline media, compared with the G-Pd and commercial Pd black catalysts. The as-developed method may provide a promising pathway for large-scale fabrication of AuPd-based catalysts.We have developed a simple and green wet-chemical route for large-scale synthesis of core–shell AuPd@Pd nanocrystals, without using any template, seed, organic solvent, or surfactant. HEPES is used here as a reducing agent and a shape-directing agent. The as-prepared nanocrystals were uniformly dispersed on graphene nanosheets (G) by simple ultrasonication. The resulting G-AuPd@Pd displayed the enhanced catalytic activity for oxygen reduction reaction and methanol oxidation reaction in alkaline media, compared with the G-Pd and commercial Pd black catalysts.

•A rapid and simple method was developed for large-scale preparation of Pt–Pd hollow nanospheres supported on RGO nanosheets.•No surfactant, seed, or template was involved during the mild synthetic process.•The as-prepared nanocomposites displayed the enhanced electrocatalytic activity and stability for methanol oxidation.Shape-controlled synthesis of bimetallic catalysts attracts increasing attention, because their catalytic performance is closely correlated with the size, shape and crystal structure. In this report, a rapid and simple route is developed for large-scale synthesis of Pt–Pd hollow nanospheres (Pt–Pd HNSs) supported on reduced graphene oxide nanosheets (RGOs) under mild conditions, while no surfactant, seed, or template is involved. The as-prepared nanocomposites display the improved electrocatalytic activity and better stability for methanol oxidation in alkaline media, compared with commercial Pt black and Pd black catalysts. This work may open a new route for construction of Pt-based bimetallic catalysts in fuel cells.In this work, a simple and rapid method was developed for large-scale preparation of Pt–Pd hollow nanospheres supported on reduced graphene oxide nanosheets (RGOs/Pt–Pd HNSs) under mild conditions, without using any surfactant, seed, or template. The as-prepared RGOs/Pt–Pd HNSs displayed the improved electrocatalytic activity and better stability toward methanol oxidation, compared with commercially Pd black and Pt black catalysts.

•Well-defined flower-like Pt arrays were prepared via one-step electrodeposition, assisted with urea as a growth directing agent.•This method is simple, facile, and controllable, without using any template, seed or surfactant.•The Pt arrays show an enhanced electrocatalytic activity toward ethylene glycol and methanol oxidation.In this paper, well-defined flower-like Pt arrays were prepared on the glassy carbon electrode by one-step electrodeposition at–0.3 V for 600 s in 0.5 M H2SO4 containing 5 mM H2PtCl6 and 150 mM urea. This method is simple, facile, and controllable, without using any template, seed or surfactant. The experimental parameters were investigated and found urea acted as a growth directing agent. The as-prepared Pt nanocrystals were preferentially growing along the (111) directions, which were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX). Moreover, the flower-like Pt nanoarrays exhibited a large effective surface area (EASA) and enhanced performance toward the oxidation of ethylene glycol and methanol in acid media, compared with Pt nanoparticles and commercial Pt black catalysts. This strategy can be extended to prepare other noble metal nanostructures as good electrocatalysts in fuel cells.A simple, facile, and controllable method was developed for preparation of well-defined flower-like Pt arrays via one-step electrodeposition, assisted with urea as a growth directing agent. The as-prepared Pt nanocrystals have a larger electroactive surface area and higher electrocatalytic activity toward ethylene glycol and methanol oxidation in acid media, compared with Pt nanoparticles and commercial Pt black catalysts.

•Flower-like PtAg nanostructures were uniformly supported on reduced graphene oxide by a facile one-pot solvothermal method.•Ionic liquid crystal [C16MMIm]Br was used as a capping agent and a structure directing agent.•The as-prepared nanocomposites showed the enhanced electrocatalytic activity toward oxygen reduction reaction.A simple and facile one-pot solvothermal method is developed for preparation of flower-like PtAg alloys uniformly supported on reduced graphene oxide nanosheets (flower-like PtAg/RGOs). Ionic liquid crystal (1-hexadecyl-2,3-dimethylimidazolium bromide, [C16MMIm]Br) is used as a capping agent and a structure directing agent. The as-prepared nanocomposites show the larger electrochemically active surface area, better catalytic activity, higher methanol tolerant activity, and longer-term durability for oxygen reduction reaction, compared with commercial Pt black, Pt-C (10 wt %), and RGOs catalysts.

•Well-defined Pd-on-Cu nanocrystals were uniformly supported on RGO by a solvothermal method.•CTAB was served as a structure-directing agent in the present synthesis.•The as-prepared nanocomposites displayed the enhanced electrocatalytic activity and better stability for ethanol oxidation.A simple, facile, and one-pot solvothermal strategy was developed to prepare Pd-on-Cu nanoparticles evenly distributed on reduced graphene oxide (Pd-on-Cu/RGO) in ethylene glycol systems, using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent. Control experiments were demonstrated the critical role of CTAB and GO to the final morphology. The as-prepared nanocomposites exhibited the enlarged surface area of 64.98 m2 g−1 Pd, improved electrocatalytic activity, and better stability for ethanol oxidation in alkaline media, which can serve as promising anode catalysts in direct alcohol fuel cells.A simple one-pot solvothermal route was designed to prepare well-defined Pd-on-Cu nanostructures supported on reduced graphene oxide in ethylene glycol systems, using CTAB as a structure-directing agent. The as-prepared nanocomposites demonstrated the superior electrocatalytic activity for ethanol oxidation.

•Bimetallic alloyed Pt-Pd nanocubes/RGOs were prepared by a simple one-pot solvothermal co-reduction method.•KI and PVP were used as a structure-directing agent and a capping agent, respectively.•The as-prepared nanocomposites display high electrocatalytic performance for ethanol oxidation and oxygen reduction reactions.In this work, a one-pot solvothermal method was developed for large-scaled synthesis of well-defined bimetallic alloyed Pt-Pd nanocubes uniformly supported on reduced graphene oxide nanosheets (Pt-Pd nanocubes/RGOs). Herein, poly(vinylpyrrolidone) (PVP) and KI were employed as a capping agent and a structure-directing additive, respectively, and N, N-dimethylformamide (DMF) is used as a solvent and a reducing agent. The as-prepared Pt-Pd nanocubes/RGOs exhibited the enlarged electrochemically active surface area, enhanced electrocatalytic activity, and improved stability for ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR), compared with commercial Pt-C (10 wt %).A facile one-pot solvothermal method was developed for preparation of bimetallic alloyed Pt-Pd nanocubes/RGOs. The as-prepared nanocomposites had larger electrochemically active surface area and enhanced electrocatalytic properties for EOR and ORR oxidation, compared with commercial Pt-C (10 wt %).

•Pt/reduced graphene oxide nanocomposite was prepared by in situ chemical reduction.•Pt nanoparticles were well-dispersed on reduced graphene oxide sheets.•The as-prepared nanocomposite displayed high electrocatalytic activity.•It was used to simultaneous determination of dopamine and uric acid in the presence of ascorbic acid with high sensitivity.In this paper, a Pt/reduced graphene oxide (Pt/RGO) modified glassy carbon electrode was prepared for the detection of dopamine (DA) and uric acid (UA) in the presence of high concentration of ascorbic acid (AA). The electrochemical behavior of the Pt/RGO modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry, which showed good performance toward individual detection of DA and UA and even their simultaneous detection in the presence of 1.0 mM AA. Evidently, the electro-oxidation peak currents displayed linear relationship with the associated DA and UA concentrations in the range of 10.0-170.0 μM and 10.0-130.0 μM, respectively, with the detection limits of 0.25 μM for DA and 0.45 μM for UA at three folds of the signal-to-noise ratio. The good performance of the Pt/RGO modified electrode provided a promising alternative in routine sensing applications.In this work, Pt/reduced graphene oxide nanocomposite (Pt/RGO) was prepared by in situ chemical reduction. The Pt/RGO modified glassy carbon electrode exhibited excellent catalytic activity towards the oxidation of dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA). Differential pulse voltammetry (DPV) was used to simultaneous determination of DA and UA with high sensitivity.

A simple and green approach was developed for the preparation of fluorescent Cu nanoclusters (NCs) using the artificial peptide CLEDNN as a template. The as-synthesized Cu NCs exhibited a high fluorescence quantum yield (7.3%) and good stability, along with excitation and temperature dependent fluorescent properties, which could be employed for temperature sensing. Further investigations demonstrated low toxicity of Cu NCs for cellular imaging.

Hierarchical MnO2–Ag hollow microspheres (HMs) with sheet-like subunits were facilely prepared through an in situ redox reaction and spontaneously self-assembled orientation via Ostwald ripening in a urea solution under a lower hydrothermal temperature (130 °C), without using any seed, template or capping agent. The as-prepared samples display an excellent electrocatalytic ability by the typical amperometric detection of H2O2 as a model system. The as-formed H2O2 sensor has a wide linear range from 1.31 μM to 36.71 mM (R = 0.9997), low detection limit (1.31 μM), high sensitivity (8.46 μA mM−1), and fast response (<5 s).

•Uniform PtAg nanoflowers are well-distributed on reduced graphene oxide.•Ethylene glycol is used as a reducing agent because of its low toxic and benign to environment.•The one-pot solvothermal method is simple and facile, without using any seed.•The Pt–Ag nanoflowers have high electrochemically active surface area.•The as-prepared nanocomposites exhibit improved electrocatalytic activity and stability.In this work, a simple and facile method is developed in the synthesis of well-dispersed PtAg nanoflowers on reduced graphene oxide nanosheets (PtAg/RGOs) under solvothermal conditions, using ethylene glycol as a reducing agent and hexadecyl trimethyl ammonium bromide (CTAB) as capping and stabilizing agents. The as-prepared nanocomposites show a superior electrocatalytic activity, good tolerance, and better stability toward the oxidation of formic acid and ethylene glycol in alkaline media, compared with the commercial Pt/C (10 wt%) catalyst. For the oxidation of formic acid, the PtAg nanoflowers own thirty times higher of the catalytic currents than those of the commercial Pt/C catalyst. Meanwhile, for the oxidation of ethylene glycol, the ratio of forward current (jF) to reverse current (jR) is high up to 8.4, which is almost four times higher than that of the commercial Pt/C catalyst. This strategy provides a promising platform for direct formic acid and ethylene glycol fuel cells.In this work, a facile one-pot solvothermal method is developed in the synthesis of well-dispersed PtAg nanoflowers supported on reduced graphene oxide nanosheets (PtAg/RGOs) with the assistance of CTAB. The as-prepared composites display enhanced electrocatalytic activity and stability toward the oxidation of formic acid and ethylene glycol.

Here, a simple, green, and economic method was developed for the synthesis of fluorescent carbon nanoparticles (CPs) by one-step hydrothermal treatment of grape juice, without any additives (e.g. salts, acids, bases, and organic solvents). The as-prepared CPs showed bright blue fluorescence under the irradiation of UV light, with a high quantum yield of 13.5%, good water solubility, excellent stability, and low toxicity, which can be used as an excellent fluorescent probe for cellular imaging.

A simple, green, and solvent-free method was developed for large-scale preparation of fluorescent nitrogen–sulfur-codoped carbon nanoparticles (NSCPs) by direct thermal treatment of gentamycin sulfate at 200 °C. The as-prepared NSCPs displayed high water-solubility, long lifetime (14.01 ns), high quantum yield (27.2%), excellent stability, and low cytotoxicity, and can be used as a probe for cellular imaging.

Fluorescent carbon quantum dots (CQDs) were synthesized by one-step hydrothermal treatment with apple juice as raw material. The result indicated that the fluorescence could be quenched by Hg2+ with high specificity. Based on this phenomenon, a selective and sensitive sensor was constructed for the detection of Hg2+ in phosphate solutions (pH 7.0). The fluorescence intensity showed linear responses with Hg2+ concentration ranging from 5.0 to 100.0 nM and 1.0 to 50.0 μM, with the detection limit of 2.3 nM (S/N = 3). The as-fabricated sensor was further extended for the determination of Hg2+ in real water samples.Fluorescent CQDs were synthesized with apple juice under hydrothermal conditions, which exhibited clear yellow in visible light but a bright blue fluorescence under UV light. CQDs displayed an excitation dependent emission, accompanied by the decrease of the fluorescence intensity.

In this study, a facile strategy was developed for the synthesis of fluorescent gold nanoparticles (Au NPs) with wavelength-tunable emissions using different short-peptides as templates. Thus formed Au NPs displayed excellent characteristics such as large Stokes shift, long fluorescence lifetime and good stability. Moreover, the Au NPs emitted at 611 nm can act as sensitive and selective probes for the detection of Hg2+ with a wide range from 50 nM to 25 μM and a low detection limit of 5 nM.

A facile method was developed for large-scale preparation of porous worm-like Pd nanotubes based on the reduction of PdO nanotubes, which were obtained by calcining the complex precipitate of [Pd(dimethylglyoxime)2]n. The Pd catalyst showed excellent electrocatalytic activity and stability towards ethylene glycol oxidation.

In this work, we developed a low-cost, facile, sensitive, and selective colorimetric method for the quantitative determination of dopamine, based on 4-amino-3-hydrazino-5-mercapto-1,2,4-triazol (AHMT) functionalized gold nanoparticles (AHMP-AuNPs) as a model probe. Dopamine could induce the aggregation of the AHMT-AuNPs through hydrogen-bonding interactions, which caused the colloidal solution changed from red to blue. And the color change was in situ monitored for the quantitative determination of dopamine in human serum and urine samples. The developed approach is simple, without using complex financial instruments and adding other metal salts or ions for improving sensitivity.Keywords: 4-amino-3-hydrazino-5-mercapto-1,2,4-triazol; dopamine; gold nanoparticles; hydrogen-bonding interactions;

•Au porous textile-like sheet arrays (AuPTSAs) were prepared by one-step electrodeposition.•N-methylimidazole play an important role in formation of AuPTSAs.•This approach is simple and facile, without any seeds, templates, or surfactants.•The AuPTSAs show high electrocatalytic activity toward methanol oxidation in alkaline media.Au porous textile-like sheet arrays (AuPTSAs) have been facilely prepared on a glassy carbon electrode (GCE) by one-step electrodeposition, which are performed at -0.4 V for 600 s in the electrolysis solution containing 10 mM HAuCl4, 1.25 M N-methylimdazole and 0.5 M H2SO4. N-methylimdazole plays an important role in the formation of the gold nanostructures. This approach is simple and facile, whereas no additional issues such as seeds, templates, and surfactants are required. Thus prepared AuPTSAs are perpendicular to the electrode surface and growing in the (1 1 1) directions and their growth mechanism is discussed in some detail. The AuPTSAs show enhanced electrocatalytic activity with better stability toward methanol oxidation in alkaline media, compared with those of polycrystalline Au nanoparticles.Au porous textile-like sheet arrays (AuPTSAs) were facilely prepared by one-step electrodeposition with the assistance of N-methylimidazole. This approach is simple and facile, whereas no additional issues such as seeds, templates, or surfactants are involved. The AuPTSAs show enhanced electrocatalytic activity and good stability toward methanol oxidation in alkaline media, compared with those of Au dendrites and nanoparticles.

•Functionalized RGO was obtained by previously coating with PDA.•Pt nanoparticles were uniformly immobilized on the PDA/RGO nanocomposites.•The as-prepared composites have high electrochemically active surface area.•The Pt/PDA/RGO composites show high electrocatalytic activity.In this report, a facile and general approach was developed to prepare uniform Pt nanoparticles (NPs) on reduced graphene oxide (RGO) nanosheets, previously coated with a layer of polydopamine (PDA). The novel composites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), and electrochemical technique, which had high electrochemically active surface area of 63.3 m2 g−1 and high electrocatalytic activity toward the reduction of O2. Furthermore, the Pt/PDA/RGO modified electrode exhibited a low detection limit of 0.4 μM (S/N = 3) and a high sensitivity of 13.3 μA μM−1 cm−2 for the detection of H2O2 as a model analyte.In this report, Pt nanoparticles (NPs) were uniformly deposited on the reduced graphene oxide (RGO), previously coated with a layer of polydopamine (PDA). The novel composites have high electrochemically active surface area and high electrocatalytic activity toward the reduction of H2O2 with a low detection limit and a high sensitivity.

•Au hierarchical dendrites (HDs) were prepared by one-step electrodeposition as Raman-active substrates.•Cytosine plays an important role in the formation of Au HDs.•This approach is simple, fast, feasible and controllable, without any seed, template or surfactant.•The Au HDs were applied for SERS amplification detection of Pb2+ with high sensitivity.In this work, a facile, feasible and controlled electrochemical route was developed to prepare well-defined three-dimensional (3D) gold hierarchical dendrites (Au HDs) on a glassy carbon electrode by one-step electrodeposition, using the applied potential of 0.0 V for 600 s in the electrolyte containing 20 mM HAuCl4, 150 mM cytosine and 0.5 M H2SO4. Cytosine played important roles in the synthesis of the Au HDs, while no seed, template or surfactant involved. The corresponding growth mechanism was discussed in some detail. The as-prepared Au nanocrystals were applied as Raman-active substrates for surface-enhanced Raman scattering (SERS) amplification detection of Pb2+ with high sensitivity.In this work, Au hierarchical dendrites (HDs) were prepared by one-step electrodeposition with the assistance of cytosine. This approach is simple, fast, feasible, controllable and cost-effective, without any template or surfactant. The as-prepared Au nanocrystals were applied for SERS amplification detection of Pb2+ with high sensitivity.

•Well-defined urchin-like Au arrays were facilely prepared by one-step electrodeposition.•Iron(III) ions serve as catalysts and growth directing agents.•This approach is simple, controllable and convenient, without any template, seed or surfactant.•The Au nanocrystals display high electrocatalytic activity toward the oxidation of ethylene glycol and glycerol.In this study, well-defined urchin-like gold arrays were prepared on glassy carbon electrodes by one-step electrodeposition at the potential of 0.2 V for 600 s in the electrolyte containing 3.5 mM HAuCl4, 100 mM FeCl3 and 0.5 M HCl, preferentially growing along the (1 1 1) directions with high purity. Their growth mechanism were discussed in some detail, by investigating the control experiments such as the concentration of FeCl3 and HAuCl4, applied potential and electrodeposition time. It is found that iron(III) ions (mainly existed in the form of FeCl4−) here serve as catalysts and growth directing agents. The as-prepared Au nanocrystals display high electrochemically active surface areas toward the electrooxidation of ethylene glycol and glycerol. This approach is simple, controllable and convenient, whereas no additional seed, template, and surfactant are involved.In this work, a simple, controllable and convenient method was developed for the preparation of well-defined urchin-like Au arrays by one-step electrodeposition, without any template, seed and surfactant, using iron(III) ions as catalysts and growth directing agents. The as-prepared Au nanocrystals display high electrocatalytic activity toward the oxidation of ethylene glycol and glycerol.

Herein, a simple, green, and low-cost way was developed in the synthesis of fluorescent nitrogen-doped carbon nanoparticles (FNCPs) with nitrogen content of 6.88%, using one-pot hydrothermal treatment of strawberry juice. The as-prepared FNCPs exhibited a maximum emission at 427 nm with a quantum yield of 6.3%, which could be specifically quenched by Hg2+. This phenomenon was used to develop a fluorescent method for facile detection of Hg2+ with a linear range from 10 nM to 50 μM and a detection limit of 3 nM (S/N = 3), and further extended to measure environmental water samples with satisfactory recovery. This study provides a green strategy in the synthesis of FNCPs to detect Hg2+ with good performance.

Water-soluble fluorescent Ag nanoclusters (NCs) were prepared with the assistance of commercially available polyinosinic acid (PI) as a template, which can be greatly quenched by trace biological thiols such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH). The developed PI–Ag NCs were used for highly sensitive and selective detection of the thiols with the linear ranges of 0.1–5 μM (R2 = 0.9962) for Cys, 0.5–4 μM (R2 = 0.9967) for Hcy, and 0.05–6 μM (R2 = 0.9958) for GSH, respectively. This method was extended for the detection of total thiols in human plasma samples with acceptable recovery from 95.21% to 101.60% and satisfactory relative standard deviations (<5%).

•Single crystalline flower-like Bi2S3 nanostructures were synthesized•D-penicillamine played an important role in the nanostructures•The possible growth mechanism has been discussed•The as-prepared Bi2S3 nanoflowers show good hydrogen storage abilitySingle crystalline flower-like Bi2S3 nanostructures were successfully synthesized via a simple, facile and green hydrothermal method, with the assistance of D-penicillamine. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and found their morphologies mainly depend on the ratios of Bi3 + to D-penicillamine, as well as the reaction temperature and time. And the possible growth mechanism has been discussed in some detail. In addition, the as-prepared Bi2S3 nanoflowers show good hydrogen storage ability. This strategy can be potentially expanded to prepare other metal chalcogenides materials.In this study, a simple and facile hydrothermal method was developed for the construction of single crystalline flower-like Bi2S3 nanostructures with the assistance of D-penicillamine. The as-prepared Bi2S3 nanoflowers show good hydrogen storage ability.

In our work, a simple, facile, and green method was developed for the synthesis of water-soluble and well-dispersed fluorescent gold nanoparticles (Au NPs) within 5 min, using captopril as a capping agent. The as-prepared Au NPs showed strong emission at 414 nm, with a quantum yield of 5.5%. The fluorescence of the Au NPs can be strongly quenched by mercury (II) ion (Hg2 +) due to the stronger interactions between thiolates (RS−) and Hg2 +. It was applied to the detection of Hg2 + in water samples in the linear ranges of 0.033–0.133 μM and 0.167–2.500 μM, with a detection limit of 0.017 μM. Therefore, the as-prepared Au NPs can meet the requirement for monitoring Hg2 + in environmental samples.In this work, we developed a simple, fast and facile method for the preparation of water-soluble and fluorescent gold nanoparticles (Au NPs). The trace existence of Hg2 + could strongly quench the fluorescence of the Au NPs. The Au NPs were used to detect highly toxic Hg2 + in water samples with high sensitivity and selectivity.Highlights► Water-soluble fluorescent Au NPs stabilized by captopril ► The synthesis procedure was simple, fast and facile. ► The fluorescence of the Au NPs can be strongly quenched by Hg2 +. ► The Au NPs were used to the assay of Hg2 + in water samples with high sensitivity and selectivity.

We have developed a method for in-situ construction of a porous network-like silver film on the surface of a glassy carbon electrode (GCE). It is based on a galvanic replacement reaction where a layer of copper nanoparticles is first electrodeposited as a sacrificial template. The silver film formed possesses a porous network-like structure and consists of an assembly of numerous nanoparticles with an average size of 200 nm. The electrode displays excellent electrocatalytic activity, good stability, and fast response (within 2 s) toward the reduction of nitrate at a working potential of −0.9 V. The catalytic currents linearly increase with the nitrate concentrations in the range of 0.08–6.52 mM, with a detection limit of 3.5 μM (S/N = 3) and a repeatability of 3.4 % (n = 5).

•Well-defined AuPt NDs are facilely prepared by a one-pot ultrasonication-assisted method.•4-amino-2,6-dihydroxypyrimidine is used as the structure-director and dispersing agent.•The architectures show enhanced catalytic properties toward ORR and HER.Herein, we present an ultrasonication-assisted wet-chemical method for facile synthesis of uniform bimetallic AuPt alloy nanodendrites (NDs), using 4-amino-2,6-dihydroxypyrimidine as the structure-directing and dispersing agents, without any template, seed, organic solvent or polymer. The structure, morphology, size, and composition of the as-obtained nanocrystals are examined by a series of characterization techniques. The architectures display remarkable catalytic performances toward oxygen reduction and hydrogen generation in comparison with commercial Pt black and Pt/C catalysts, through the polarization, chronoamperometry, and durability measurements. This is due to the special dendritic nanostructures with rich surface defects, porous features and the synergistic effects between Pt and Au in the alloy. In combination with the simple, easily controllable, and time-saving synthetic strategy, AuPt NDs may find potential applications and shed some light on the construction of other bimetallic nanocatalysts in fuel cells.

•A facile and efficient one-pot wet chemical method was developed to synthesize Pd-Cu nanowires (NWs) using octylphenoxypolyethoxyethanol as structure-directing and stabilizing agents.•The Pd-Cu NWs shows prominent catalytic ability and durability for the Suzuki cross coupling reaction under mild conditions.•Pd-Cu NWs is stable and reusable for the reaction.The construction and design of nanomaterials are important for improving their performance. Here we present a simple one-pot wet-chemical method for the preparation of alloyed Pd-Cu nanowires using octylphenoxypolyethoxyethanol (NP-40) as structure-directing and stabilizing agents. The obtained nanocrystals display outstanding catalytic activity for ligand-free Suzuki cross coupling reaction under mild conditions, and can be easily recovered and reused for at least 5 consecutive cycles without showing significant loss of catalytic activity.Pd-Cu nanowires were facilely synthesized by a simple one-pot wet-chemical method. The nanocrystals show remarkable catalytic performance toward ligand-free Suzuki cross coupling reaction under mild conditions.Download high-res image (243KB)Download full-size image

Theophylline as a naturally alkaloid is commonly employed to treat asthma and chronic obstructive pulmonary disorder. Herein, a facile theophylline-assisted green approach was firstly developed for synthesis of PtAu nanospheres/reduced graphene oxide (PtAu NSs/rGO), without any surfactant, polymer, or seed involved. The obtained nanocomposites were applied for the catalytic reduction and removal of highly toxic chromium (VI) using formic acid as a model reductant at 50 °C, showing the significantly enhanced catalytic activity and improved recyclability when compared with commercial Pt/C (50%) and home-made Au nanocrystals supported rGO (Au NCs/rGO). It demonstrates great potential applications of the catalyst in wastewater treatment and environmental protection. The eco-friendly route provides a new platform to fabricate other catalysts with enhanced catalytic activity.

In this work, a facile one-pot wet-chemical method was developed for the self-assembly of PdPt@Pt nanorings via in situ reduction of [PdCl4]2– and [PtCl6]2– at room temperature, which are simultaneously dispersed on reduced graphene oxide (rGO; denoted as PdPt@Pt/rGO). Hexadecylpyridinium chloride was demonstrated as a shape-directing agent and formic acid as a reducing agent during the reaction process. The as-prepared PdPt@Pt/rGO exhibited enhanced electrocatalytic activity and better stability for oxygen reduction reaction and ethanol oxidation reaction in acid media, compared with PtPd/rGO, Pt/rGO, Pd/rGO, Pt black, and Pt/C catalysts.

Water-soluble fluorescent Ag nanoclusters (NCs) were prepared with the assistance of commercially available polyinosinic acid (PI) as a template, which can be greatly quenched by trace biological thiols such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH). The developed PI–Ag NCs were used for highly sensitive and selective detection of the thiols with the linear ranges of 0.1–5 μM (R2 = 0.9962) for Cys, 0.5–4 μM (R2 = 0.9967) for Hcy, and 0.05–6 μM (R2 = 0.9958) for GSH, respectively. This method was extended for the detection of total thiols in human plasma samples with acceptable recovery from 95.21% to 101.60% and satisfactory relative standard deviations (<5%).

In this report, well-dispersed porous Pt–Pd nanodendrites (Pt–Pd NDs) were synthesized at high yield by a simple, one-pot, wet chemical method without using any seed, template, or toxic organic solvent. Poly(vinylpyrrolidone) (PVP) and urea were employed as the co-stabilizing and co-structure-directing agents. It was found that the reaction temperature, the amount of PVP and urea, the Pt/Pd molar ratio, and the pH value of the reaction media greatly affected the size and shape of the Pt–Pd product. The as-prepared Pt–Pd nanocrystals had a larger active surface area, superior catalytic activity, and better stability for the electrooxidation of methanol and ethylene glycol (EG), compared with the commercial Pt-black and Pd-black catalysts.

In this study, a facile strategy was developed for the synthesis of fluorescent gold nanoparticles (Au NPs) with wavelength-tunable emissions using different short-peptides as templates. Thus formed Au NPs displayed excellent characteristics such as large Stokes shift, long fluorescence lifetime and good stability. Moreover, the Au NPs emitted at 611 nm can act as sensitive and selective probes for the detection of Hg2+ with a wide range from 50 nM to 25 μM and a low detection limit of 5 nM.

In this work, a facile general strategy is developed for preparation of palladium-based bimetallic alloyed nanodendrites (PdM NDs, M = Pt, Co, and Ni) via coreduction of Pd(II) acetylacetonate and M(II/III) acetylacetonate salts with oleylamine. Hexadecylpyridinium chloride monohydrate (HDPC) is used as a co-surfactant for preventing the aggregation of nanodendrites. Control experiments varying the precursors and reaction time demonstrate that the dendritic nanocrystals are formed via aggregation-based crystal growth. The as-prepared hybrid nanocrystals display improved electrocatalytic activity and better stability for methanol and ethylene glycol (EG) oxidation, compared with home-made Pd NDs and commercial Pd black catalysts. The developed method provides a novel platform for synthesis of novel electrocatalysts in fuel cells.

Popcorn-like PtAu nanoparticles were fabricated by a facile and green one-pot wet-chemical method, where H2PtCl4 and HAuCl4 were simultaneously reduced by glucosamine in alkaline media. The PtAu nanoparticles were further supported on reduced graphene oxide by simple ultrasonication. The nanocomposites showed an enhanced catalytic performance toward oxygen reduction reaction (ORR), dominated by a four-electron pathway, in comparison with Pt–rGO and commercial 10% Pt/C catalysts. Meanwhile, the nanocomposites displayed improved electrocatalytic properties and better stability for methanol oxidation over Pt–rGO and commercial Pt/C catalysts.

In this study, a simple, facile and one-pot solvothermal method was developed for preparation of reduced graphene oxide (RGO) supported hollow Ag@Pt core–shell nanospheres (hAg@Pt), using ethylene glycol (EG) as a reducing agent and sodium dodecyl sulfate (SDS) as a soft template. Control experiments demonstrated that the molar ratios of the Pt–Ag precursors, the amount of SDS, the presence of RGO, and the reaction temperature were critical to the final nanocomposites. The as-prepared hAg@Pt–RGO showed the improved electrocatalytic activity and durability toward ethylene glycol oxidation, which can serve as a promising potential electrocatalyst in direct alcohol fuel cells.

In this work, porous bimetallic palladium–silver (Pd63Ag37) alloy nanocorals were synthesized by a simple and facile one-pot polyol method. The composition and morphology of the nanocrystals were well controlled by changing the concentrations of the precursors. The obtained nanocrystals were mainly characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and the Brunauer–Emmett–Teller method. Porous Pd63Ag37 nanocorals had an enlarged electrochemically active surface area (55.85 m2 g−1), and exhibited enhanced electrocatalytic activity and improved stability for glycerol oxidation reaction as compared to commercial Pd black, owing to the unique porous coral-like nanostructures and synergistic interactions of the alloyed bimetals.

In this work, a facile, convenient and effective one-pot wet-chemical method was developed for preparation of well-dispersed porous bimetallic Pt–Au alloyed nanodendrites uniformly supported on reduced graphene oxide nanosheets (Pt–Au pNDs/RGOs) at room temperature. The fabrication strategy was efficient and green owing to the use of cytosine as a structure-directing agent and weak stabilizing agent, without employing any organic solvent, template, seed, surfactant, or complicated apparatus. The as-synthesized Pt–Au pNDs/RGOs exhibited significantly enhanced catalytic performance toward the reduction of 4-nitrophenol, as compared to commercial Pt black and home-made Au nanocrystals.