A hydrogen evolution-assisted one-pot aqueous approach was developed for facile synthesis of trimetallic PdNiRu alloy nanochain-like networks (PdNiRu NCNs) by only using KBH4 as the reductant, without any specific additive (e.g. surfactant, polymer, template or seed). The products were mainly investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The hierarchical architectures were formed by the oriented assembly growth and the diffusion-controlled deposition in the presence of many in-situ generated hydrogen bubbles. The architectures had the largest electrochemically active surface area (ECSA) of 84.32 m2 g–1Pd than PdNi nanoparticles (NPs, 65.23 m2 g–1Pd), PdRu NPs (23.12 m2 g–1Pd), NiRu NPs (nearly zero), and commercial Pd black (6.01 m2 g–1Pd), outperforming the referenced catalysts regarding the catalytic characters for hydrazine oxygen reaction (HOR). The synthetic route provides new insight into the preparation of other trimetallic nanocatalysts in fuel cells.Hierarchical PdNiRu alloyed nanochain-like networks are prepared using in-situ generated hydrogen bubbles as dynamic templates based on the diffusion-controlled metallic deposition. Download high-res image (219KB)Download full-size image

Herein, a simple one-pot aqueous method was developed for the fabrication of uniform hollow bimetallic AgPt alloyed nanocrystals (H-AgPt NCs) by using 5-aminoorotic acid (5-amino-2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid) as a growth-directing agent, without any seed, organic solvent or template involved. The prepared H-AgPt NCs displayed enhanced electrocatalytic activity for hydrogen evolution reaction (HER) with a more positive onset overpotential (ηonset) of −28 mV and a smaller Tafel slope of 40 mV dec−1 relative to commercial Pt black (−34 mV, 50 mV dec−1) and Pt/C (20 wt.%, −33 mV, 33 mV dec−1) in 0.5 M H2SO4. Meanwhile, the obtained catalyst exhibited improved catalytic features toward oxygen reduction reaction (ORR) with a positive ηonset (0.916 V) and enhanced kinetic current density (243.23 mA mg−1Pt) in 0.1 M HClO4 at 0.850 V compared with Pt black (0.876 V, 25.85 mA mg−1Pt).Download high-res image (165KB)Download full-size image

In this work, bimetallic platinum-palladium sheet-assembled alloy networks (PtPd SAANs) were facilely synthesized by an eco-friendly one-pot aqueous approach under the guidance of l-glutamic acid at room temperature, without any additive, seed, toxic or organic solvent involved. l-Glutamic acid was served as the green shape-director and weak-stabilizing agent. A series of characterization techniques were employed to examine the morphology, structure and formation mechanism of the product. The architectures exhibited improved electrocatalytic activity and durable ability toward methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) in contrast with commercial Pt black and Pd black catalysts. This is ascribed to the unique structures of the obtained PtPd SAANs and the synergistic effects of the bimetals. These results demonstrate the potential application of the prepared catalyst in fuel cells.Download high-res image (197KB)Download full-size image

•A fast one-step co-reduction method was developed for synthesis of PtCoNi FNs.•The alloyed catalyst showed boosted catalytic characters for HER in acid and alkaline electrolytes.•The catalyst exhibited more positive onset potential and faster kinetics toward ORR.AbstractA fast one-step co-reduction method was developed to synthesize trimetallic PtCoNi alloyed flower-like networks (PtCoNi FNs) in an ice-bath only using KBH4 as the reductant, while no any polymer, seed, organic or surfactant was involved. The morphology, structure and composition of the product were characterized by microscopic analysis, X-ray diffraction and X-ray photoelectron spectroscopy. The architectures exhibited boosted electrocatalytic activity and stability for hydrogen evolution reaction (HER) in acidic and alkaline media. The overpotential of PtCoNi FNs for HER is smaller than the contrast materials (PtCo NPs, PtNi NCs, Pt black and Pt/C) at the fixed current density of 10 mA cm−2, and the correlative exchange current density is significantly enlarged compared with commercial Pt black while comparable to commercial Pt/C (20 wt%). Besides, the catalyst showed the highly boosted catalytic characters for oxygen reduction reaction (ORR) with the more positive onset potential and faster kinetics.Download high-res image (273KB)Download full-size image

•Uniform flower-like Au@AuPd NCs were prepared by a facile one-pot co-reduction method.•DAHP was acted as a new structure-directing agent.•The flower-like architectures had enlarged ECSA.•The catalyst showed enhanced catalytic performances for FAOR and HER.Herein, a one-pot co-reduction method was developed to prepare flower-like Au@AuPd core-shell nanocrystals (Au@AuPd NCs) under the guidance of 2,4-diamino-6-hydroxypyrimidine (DAHP). The product was mainly characterized by microscopic measurements, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis, and its formation mechanism was discussed in details. The architectures showed much larger electrochemical active surface area (62.68 m2 g−1Pd) than commercial Pd black (8.23 m2 g−1 Pd), together with the higher mass activity (1250 mA mg−1) for formic acid oxidation reaction (FAOR). Besides, the catalyst displayed improved catalytic features for hydrogen evolution reaction (HER) relative to Pd black and Pt/C catalysts. These indicate the potential applications of the catalyst in energy storage and transformation.Download high-res image (344KB)Download full-size image

•Uniform Pt2.6Co1 nanoflowers were prepared by a simple solvothermal method.•Glucose and CTAC were used as the green reductant and structure director, respectively.•The architectures had the enlarged ECSA.•The architectures exhibited excellent catalytic performances for HER in acid and alkaline media.•The architectures showed highly catalytic performances for ORR in acid media.Herein, uniform Pt2.6Co1 nanoflowers (NFs) were synthesized in oleylamine by a one-pot solvothermal method, using cetyltrimethylammonium chloride (CTAC) and glucose as the capping agent and green reducing agent. The samples were mainly characterized by transmission electron microscopy (TEM), high angle annular dark-field scanning TEM (HAADF-STEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The architectures had larger electrochemically active surface area (ECSA) of 23.84 m2 g−1Pt than Pt1.2Co1 nanocrystals (NCs, 14.96 m2 g−1Pt), Pt3.7Co1 NCs (16.96 m2 g−1Pt) and commercial Pt black (20.35 m2 g−1Pt). And the as-obtained Pt2.6Co1 catalyst displayed superior catalytic performance and better durability for hydrogen evolution reaction (HER) as compared to Pt1.2Co1 NCs, Pt3.7Co1 NCs, commercial 50% Pt/C and Pt black catalysts in acid and alkaline media. Meanwhile, the electrocatalytic performance of Pt2.6Co1 NFs for oxygen reduction reaction (ORR) is better in acid media as compared with that in alkaline media. It indicates the great potential applications of the as-prepared catalyst in fuel cells.Download high-res image (189KB)Download full-size image

Despite increasing research studies in the past few decades, it is still a challenge to find highly efficient catalysts for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). Herein, a one-pot solvothermal method was developed for constructing Pt76Co24 nanomyriapods (NMs) with abundant active sites, where L-glutamic acid and cetyltrimethylammonium chloride (CTAC) were used as the green reductant and structure directing agent, respectively. The architecture had a larger electrochemically active surface area (ECSA) of 24.49 m2 g−1 than Pt49Co51 nanoparticles (NPs, 15.17 m2 g−1), Pt80Co20 NPs (16.71 m2 g−1) and commercial Pt black (20.35 m2 g−1), and exhibited superior catalytic performances for ORR and HER. The mass activity of Pt76Co24 NMs (105.26 mA mgPt−1) for ORR was twice as high as Pt black (47.35 mA mgPt−1). And the Pt76Co24 NM catalyst exhibited better durability in acid media relative to Pt black and/or Pt/C (20 wt%). This work would have practical applications in catalysis, and energy storage and conversion.

•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.

In this work, AuPd@Pd core–shell nanocrystals (AuPd@Pd NCs) were fabricated by a one-pot co-reduction approach, where theophylline-7-acetic acid (TAA) acted as a new structure-directing agent. The crystal structure and composition were mainly characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), together with X-ray photoelectron spectroscopy (XPS). The growth mechanism of AuPd@Pd NCs was investigated in detail. The obtained AuPd@Pd NCs exhibited superior catalytic characters for formic acid oxidation reaction (FAOR) and glycerol oxidation reaction (GOR) in contrast with commercial Pd black in alkaline media.Download high-res image (123KB)Download full-size image

•Ag1Pt2 NCs were facilely prepared by a one-pot wet-chemical method.•l-Arginine was used as the eco-friendly shape-directing agent.•The architectures showed significantly enhanced SERS signals for 4-NTP and 4-MBA.•The SERS-active substrate was explored for the assay of 4-NTP and 4-MBA.The hierarchical multi-branched Ag1Pt2 nanocorallines (NCs) were prepared in a large scale by a rapid aqueous method, using l-arginine as the eco-friendly shape-directing agent. The product was mainly characterized by microscopy measurements, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The architectures exhibited superior surface-enhanced Raman scattering (SERS) with 4-nitrothiophenol (4-NTP), the enhancement factor (EF) of 1.3 × 105, a wide linear range of 10–100 μM and a low detection limit of 0.01 μM. Meanwhile, the SERS-active substrate was explored for the assay of 4-mercaptobenzoic acid (4-MBA) with significantly enhanced SERS performance. It means Ag1Pt2 NCs as a good Raman-active platform for sensing in food and environment analysis, owing to their rough surfaces and unique multi-branched structures.Download high-res image (263KB)Download full-size image

•AuPd NCs/rGO is facilely prepared by a simple one-pot aqueous method.•AHPP is used as the reductant, stabilizing agent, and structure-director.•The nanocomposites display larger ECSA and improved catalytic performance for ORR and HER relative to other catalysts.Herein, we develop a simple one-pot aqueous method to prepare AuPd alloy nanocrystals on reduced graphene oxide (AuPd NCs/rGO), by using 1-acetyl-4-(p-hydroxyphenyl) piperazine (AHPP) as the reductant, stabilizing agent and structure-director, without any other additives (e.g., seed, surfactant or polymer). The product is mainly characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and thermogravimetric analysis. The obtained AuPd NCs/rGO displays enlarged electrochemically active surface area and superior catalytic performances toward oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) relative to Pt/C, Pd/C, Pd/rGO and Au/rGO catalysts, showing promising applications in energy storage and conversion.Download high-res image (116KB)Download full-size image

•Uniform AuPt NDs are facilely prepared by a simple bio-inspired method.•Folic acid is used as the structure director and stabilizing agent.•The alloyed architectures have large electrochemically active surface area.•The nanocrystals display improved catalytic activity and stability for MOR and EOR.Folic acid (FA), as an important biomolecule in cell division and growth, is firstly employed as the structure director and stabilizing agent for controlled synthesis of uniform Au65Pt35 nanodendrites (NDs) by a one-pot wet-chemical bio-inspired route at room temperature. No pre-seed, template, organic solvent, polymer, surfactant or complex instrument is involved. The products are mainly characterized by transmission electron microscopy (TEM), high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), and X-Ray photoelectron spectroscopy (XPS). The architectures have enlarged electrochemically active surface area (60.6 m2 gPt−1), enhanced catalytic activity and durability for methanol and ethanol oxidation in contrast with commercial Pt black and the other AuPt alloys by tuning the molar ratios of Au to Pt (e.g., Au31Pt69 and Au82Pt18 nanoparticles). This strategy would be applied to fabricate other bimetallic nanocatalysts in fuel cells.

•Pd@Pt DNC/rGO is prepared via a facile and seed-less single-step route.•PEO is employed as the structure-director and stabilizing agent.•The nanocomposite has large electrochemically active surface area (114.15 m2gmetal−1).•The nanocomposite exhibits enhanced electrocatalytic performances for MOR and EOR.In this report, a facile, seed-less and single-step method is developed for large-scale synthesis of core–shell Pd@Pt dendritic nanocrystals anchored on reduced graphene oxide (Pd@Pt DNC/rGO) under mild conditions. Poly(ethylene oxide) is employed as a structure-directing and stabilizing agent. Compared with commercial Pt/C (20 wt%) and Pd/C (20 wt%) catalysts, the as-obtained nanocomposite has large electrochemically active surface area (114.15 m2gmetal−1), and shows superior catalytic activity and stability with the mass activities of 1210.0 and 1128.5 mAmgmetal−1 for methanol and ethanol oxidation, respectively. The improved catalytic activity is mainly the consequence of the synergistic effects between Pd and Pt of the dendritic structures, as well as rGO as a support.

•Uniform PtPd@Pt nanocrystals are well-dispersed on rGO.•Formic acid is employed as the reducing agent, without using any additive.•The one-pot wet-chemical method is simple and environmentally friendly.•The nanocomposites show highly catalytic performance for EGOR in acidic and alkaline media.Bimetallic core-shell PtPd@Pt nanocrystals were uniformly supported on reduced graphene oxide (PtPd@Pt NCs/rGO) through a facile and green wet-chemical procedure. Formic acid was employed here as the reducing agent, without using any additive (e.g., surfactant, polymer, seed, or template). The as-prepared nanocomposites displayed enlarged electrochemically active surface area, enhanced catalytic activity, high stability and tolerance toward ethylene glycol oxidation reaction (EGOR) in acidic and alkaline media as compared with commercial Pd/C and Pt/C catalysts. This strategy opens an environmentally friendly way to fabricate other bimetallic catalysts with improved catalytic activity and stability in direct alcohol fuel cells.

Herein, a facile and straightforward green-assembly approach was developed for preparation of nitrogen and sulphur co-doped three-dimensional (3D) graphene hydrogels (N/S-GHs) with the assistance of glutathione. Specifically, graphene oxide is reduced and assembled into 3D porous nanostructures with glutathione as the reducing agent and modifier for its intrinsic structure, along with the nitrogen and sulphur sources in the synthetic process. As expected, the as-obtained N/S-GHs demonstrated superior adsorption performances for organic dyes (e.g., methylene blue, malachite green, and crystal violet) in aqueous media. This work provides new insight for the green-assembly of 3D porous nanomaterials as adsorbent and their promising applications in water treatment.A facile green-assembly method was developed for synthesis of porous N/S-GHs with the assistance of glutathione. The as-obtained porous nanocomposites N/S-GHs showed the improved adsorption ability for organic dyes.

Neuron-like gold-palladium (AuPd) alloy nanostructures were synthesized by simultaneous reduction of AuCl4− and PdCl42− with ascorbic acid, using N-methylimidazole as the structure-director and stabilizing agent. The synthesis method was simple and seedless, without any template or polymer. The architectures strongly depended on the concentration of N-methylimidazole, reaction temperature and time, and hence the formation mechanism was described in detail. The as-obtained architectures exhibited superior electrocatalytic activity for ethanol oxidation and surface-enhanced Raman scattering (SERS) responses, owing to their unique nanostructures with high density of steps, edges, and corners on their branches, along with the synergetic functions between Au and Pd.

•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.

•AuPt NWNs are facilely prepared with tunable compositions.•In-situ formed hydrogen bubbles are used as a dynamic template.•The wet-chemical method is simple, rapid, convenient, mild and green.•The strategy is exempt from pressuring, heating, and special apparatus.•AuPt NWNs show improved catalytic activity and stability for EOR and ORR.Herein, we present an ultra-simple one-pot wet-chemistry method for large-scaled synthesis of surface-clean and self-supported bimetallic AuPt nanowire networks (AuPt NWNs) with tunable compositions by using hydrogen bubble as a dynamic template. Hydrogen bubbles are in situ generated from the hydrolysis and oxidation of sodium borohydride which are rapid pouring into the metal precursor solutions. The strategy is very convenient, mild and green, exempted from pressuring, heating, and special apparatus. The resulting AuPt NWNs have clean surfaces, because the gas bubbles do not need to use additional acid/base or organic solvent to remove. Moreover, the as-prepared AuPt NWNs display excellent electrocatalytic activity and durability toward ethanol oxidation and oxygen reduction reactions.

•PtAu ANFs were facilely prepared by a one-pot successive co-reduction approach.•Methotrexate was served as the shape-regulator and stabilizer.•The porous nanocrystals show large electrochemically active surface area.•The nanocrystals showed enhanced catalytic performances for EOR and ORR.Well-defined porous PtAu alloyed nanoflowers (PtAu ANFs) were fabricated by a one-pot surfactant-free successive co-reduction approach. Methotrexate, an antimetabolite and antifolate drug, was employed here as the shape-regulator and stabilizer for the first time, while no any seed, polymer, or surfactant was involved during the synthetic process. The as-prepared architectures were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction in details. The as-synthesized hybrid nanocrystals exhibited improved catalytic performances for ethanol oxidation and oxygen reduction in contrast with PtAu-10 NCs, PtAu-50 NPs, and commercial Pt black catalysts, demonstrating their promising applications in fuel cells.A facile surfactant-free successive co-reduction approach was developed for synthesis of porous PtAu alloy nanoflowers only with assistance of methotrexate.

•Au–Pd@Pd NCs are prepared via one-step wet-chemical co-reduction.•It is simple, without using any seed, organic solvent, polymer or surfactant.•Allantoin is employed as a structure-directing agent.•The nanocrystals show highly catalytic performance for EGOR.Herein, uniform core–shell Au–Pd@Pd nanocrystals (Au–Pd@Pd NCs) were prepared by a simple and eco-friendly one-step wet-chemical co-reduction method using allantoin as a structure-directing agent, without using any pre-made seed, toxic organic solvent, surfactant or polymer. Their characterizations were determined by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The possible growth mechanism was also discussed in details. The as-fabricated architecture showed enhanced electrocatalytic ability and stability toward ethylene glycol oxidation reaction (EGOR) as compared to Au nanocrystals and commercial Pd black catalysts in alkaline media.

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.

In this work, uniform oxygen and sulfur co-doped graphitic carbon nitride quantum dots (OS-GCNQDs) have been prepared by thermal treatment of citric acid and thiourea. The as-obtained OS-GCNQDs show strong blue photoluminescence (PL) with a relatively high quantum yield of 14.5%. Furthermore, OS-GCNQDs exhibit stable and specific concentration-dependent PL intensities in the presence of mercury(II) ions in the range of 0.001–20.0 μM, with a detection limit of 0.37 nM (3S/N). More importantly, OS-GCNQDs were explored for cell imaging with satisfactory biocompatibility, and so are a potential fluorescent probe in biosensing and bioimaging applications.

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.

In this work, a general strategy was developed for the facile synthesis of bimetallic AuM (M = Pt or Pd) alloyed flowerlike-assembly nanochains (FANs) with the assistance of diprophylline as a structure-directing and stabilizing agent. The morphologies, crystal structures, and compositions of AuPt and AuPd FANs were investigated primarily by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The formation mechanism was discussed in some detail by varying the concentration of diprophylline. The as-prepared AuM FANs displayed improved catalytic activities and better stabilities for oxygen reduction reaction (ORR) compared to commercial E-TEK Pt/C, Pt black and Pd black.

A simple and facile one-pot wet-chemical co-reduction method was developed for the synthesis of reduced graphene oxide supported porous PtAu alloyed nanoflowers (PtAu-nanoflowers/rGO). p-Aminopyridine was employed as a structure-directing agent and a stabilizing agent. No seed, template, surfactant, or polymer was involved in the synthesis process. It was found that the reaction temperature and the dosage of p-aminopyridine were essential for the final product. Furthermore, the as-prepared nanocomposites showed improved catalytic activity for the reduction of 4-nitrophenol in contrast to monometallic Pt nanocrystals/rGO, Au nanocrystals/rGO, and commercial Pt/C (50 wt%).

•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.

•AuPt nanochains were rapidly prepared by a simple one-pot method.•Metformin was employed as a structure-director.•The alloyed nanocrystals had enlarged electrochemical active surface area.•The nanocrystals showed highly electrocatalytic performances for MOR and EOR.In this work, a simple and rapid one-pot wet-chemical approach was developed for large-scale synthesis of bimetallic AuPt alloyed nanochains with hierarchical structures. Metformin was employed as a structure-director in the synthetic process. There was no any premade seed, organic solvent, polymer or special apparatus involved. The characterization techniques included X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), and transmission electron microscopy (TEM). The as-fabricated nanocrystals had enlarged electrochemical active surface area (ECSA, 43.87 m2 gPt−1), and exhibited improved electrocatalytic activity and durability for ethanol oxidation reaction (EOR) and methanol oxidation reaction (MOR) using Pt nanochains and commercial Pt black as contrasts.A facile metformin-mediated one-pot method was developed for preparing AuPt alloyed nanochains. The as-prepared nanocrystals showed enhanced electrocatalytic activity and improved stability for methanol and ethanol oxidation as compared with Pt nanochains and commercial Pt black.

•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.

Porous bimetallic alloyed palladium silver (PdAg) nanoflowers supported on reduced graphene oxide (PdAg NFs/rGO) were prepared via a facile and simple in situ reduction process, with the assistance of cetyltrimethylammonium bromide as a structure directing agent. The as-prepared nanocomposite modified glassy carbon electrode (PdAg NFs/rGO/GCE) showed enhanced catalytic currents and enlarged peak potential separations for the oxidation of ascorbic acid (AA), dopamine (DA), and uric acid (UA) as compared to those of PdAg/GCE, rGO/GCE, commercial Pd/C/GCE, and bare GCE. The as-developed sensor can selectively detect AA, DA, and UA with a good anti-interference ability, wide concentration ranges of 1.0 μM–2.1 mM, 0.4–96.0 μM, and 1.0–150.0 μM, respectively, together with low detection limits of 0.057, 0.048, and 0.081 μM (S/N = 3), respectively. For simultaneous detection of AA, DA, and UA, the linear current–concentration responses were observed from 1.0 μM–4.1 mM, 0.05–112.0 μM, and 3.0–186.0 μM, with the detection limits of 0.185, 0.017, and 0.654 μM (S/N = 3), respectively.

In this work, monodispersed core–shell AuPt@Au nanocrystals supported on reduced graphene oxide (AuPt@Au NCs/rGO) were fabricated by a one-step wet-chemical approach using melamine as a structure-director and stabilizing agent. Transmission electron microscopy (TEM), high-angle annular dark-field scanning TEM (HAADF-STEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were employed to examine their structure and morphology. The as-synthesized nanocomposites displayed better catalytic activity for p-nitrophenol reduction and improved reusability as compared with monometallic Au/rGO, Pt/rGO and commercial Pt/C catalysts.

Porous gold nanosheets modified glassy carbon electrode (GCE) was facilely prepared by one-step electrodeposition, using N-methylimidazole as a growth-directing agent. The porous gold nanosheets modified GCE was characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction spectroscopy. The modified electrode displayed improved sensitivity for individual and simultaneous differential pulse voltammetric determination of dopamine (DA; at 180 mV) and acetaminophen (AC; at 450 mV vs. Ag/AgCl) even in the presence of ascorbic acid. The oxidation peak currents linearly increased with the concentrations of DA and AC in the ranges from 2.0 to 298.0 μM and 3.0 to 320.0 μM, respectively, and the detection limits are 0.28 μM for DA and 0.23 μM for AC. The relative standard deviations (n = 20) are 1.5 % for DA and 0.4 % for AC.

1.A facile, simple, low-cost, and green method was developed for synthesis of fluorescent NSCDs.2.The fluorescent intensity can be significantly quenched by MTX via FRET recognition.3.The as-prepared NSCDs were employed for highly sensitive and selective detection of MTX in human serum.In this report, N, S-codoped fluorescent carbon nanodots (NSCDs) were prepared by a facile, simple, low-cost, and green thermal treatment of ammonium persulfate, glucose, and ethylenediamine. The as-prepared NSCDs displayed bright blue emission with a relatively high fluorescent quantum yield of 21.6%, good water solubility, uniform morphology, and excellent chemical stability, compared to pure CDs. The fluorescence of NSCDs can be significantly quenched by methotrexate (MTX) via fluorescence resonance energy transfer (FRET) between NSCDs and MTX, which was used for highly selective and sensitive detection of MTX with a wide linear range up to 50.0 μM and a low detection limit of 0.33 nM (S/N=3). Moreover, this method was explored for practical detection of MTX in human serum with satisfied results.

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.

Herein, a simple, one-step seedless wet-chemical method was developed for synthesis of well-dispersed gold@palladium core–shell nanoflowers supported on reduced graphene oxide (Au@Pd/rGO) with the assistance of melamine as a linking agent and using poly(vinylpyrrolidone) as a structure-directing agent. The as-prepared Au@Pd/rGO exhibited enhanced electrocatalytic activity and improved stability for oxygen reduction reaction (ORR) and ethylene glycol (EG) oxidation in alkaline media compared with Pd/rGO, Au/rGO, and Pd black. This method can be extended to easily prepare core–shell nanostructures with designed compositions and desired catalytic properties.

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 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 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.

•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.

•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.

•Well-defined Pt–Pd nanoflowers supported on RGOs are prepared by a facile wet-chemical strategy.•This approach is simple, without any seed, template, organic solvent, or special apparatus.•NaNO2 and PVP are essential to the formation of flower-like Pt–Pd nanostructures.•The nanocomposites display the enhanced electrocatalytic activity and long-term stability for ORR.A simple and rapid one-pot wet-chemical method is developed for large-scale preparation of reduced graphene oxide nanosheets supporting Pt–Pd nanoflowers (Pt–Pd NFs/RGOs) using hydrazine hydrate as a reducing agent, without any seed, template, organic solvent, or special apparatus. The coexistence of sodium nitrite (NaNO2) and poly(vinyl pyrrolidone) (PVP), and their amounts are essential for synthesis of flower-like nanostructures. Besides, Pt–Pd NFs/RGOs have higher catalytic activity and better durability for oxygen reduction reaction, compared with commercial Pt–C (50 wt %).Well-defined Pt–Pd nanoflowers supported on RGOs are prepared by a simple wet-chemical approach, without using any seed, template, organic solvent, or special apparatus. The nanocomposites show the improved electrocatalytic activity and long-term stability towards oxygen reduction reaction.

•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.

•Uniform porous Pt–Pd nanospheres supported on reduced graphene oxide were prepared.•NP-40 was employed as a soft template, without any seed, organic solvent or special apparatus.•This wet-chemical strategy is simple, facile, and effective.•The composites exhibit high electrocatalytic activity and long-term stability.In this study, a simple, facile, and effective wet-chemical strategy was developed in the synthesis of uniform porous Pt–Pd nanospheres (Pt–Pd NSs) supported on reduced graphene oxide nanosheets (RGOs) under ambient temperature, where octylphenoxypolye thoxyethanol (NP–40) is used as a soft template, without any seed, organic solvent or special instruments. The as-prepared nanocomposites display enhanced electrocatalytic activity and good stability toward methanol oxidation, compared with commercial Pd/C and Pt/C catalysts. This strategy may open a new route to design and prepare advanced electrocatalysts for fuel cells.In this work, we report a simple and facile wet-chemical route for preparation of uniform porous Pt–Pd nanospheres supported on reduced graphene oxide nanosheets under ambient temperature, without the need of premade seed, organic solvents or special apparatus. The as-prepared hybrid composites displayed enhanced electrocatalytic activity and better stability toward methanol oxidation.

•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.

•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.

•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.

•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.

•Pt@Pd/RGO is synthesized by a wet-chemical co-reduction method.•This method is simple and facile, without any seed, template, or organic solvent.•Caffeine is served herein as a structure-directing agent and a capping agent.•The as-prepared Pt@Pd/RGO shows the enhanced catalytic activity for MOR.A facile, rapid, and wet-chemical co-reduction method is developed for synthesis of platinum@palladium core-shell nanoparticles supported on reduced graphene oxide (denoted as Pt@Pd/RGO) with the assistance of caffeine, without any seed or template. Caffeine is used here as a structure-directing agent and a capping agent, which is critical to the formation of Pt@Pd core-shell nanoparticles. Furthermore, the as-synthesized Pt@Pd/RGO shows the enlarged electrochemically active surface area, remarkably enhanced catalytic activity, and improved stability for methanol oxidation reaction (MOR), compared to Pt/RGO, Pd/RGO, commercial Pt black and Pd black.A facile, rapid, and wet-chemical co-reduction method is developed for synthesis of Pt@Pd/RGO with the help of caffeine, without any seed or template. The as-prepared nanocomposite exhibits the enhanced electrocatalytic activity and improved stability for MOR, compared with Pt/RGO, Pd/RGO, commercial Pt black and Pd black.

•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 %).

•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.

•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.

•Uniform porous Cu2O nanospheres were facilely prepared with the assistance of ionic liquid crystal [C16MMIm]Br.•The as-prepared Cu2O spheres were well dispersed on RGOs via ultrasonciation.•The RGOs-Cu2O nanocomposites showed excellent electrocatalytic activity toward glucose oxidation.•The as-constructed non-enzymatic sensor had a low detection limit, wide linear range, and fast response.In this work, well-defined monodisperse porous Cu2O nanospheres were facilely synthesized, using ionic liquid crystal 1-hexadecyl-2,3-dimethylimidazolium bromide ([C16MMIm]Br) as a soft template. The as-prepared Cu2O nanospheres were successfully anchored on the reduced graphene oxide nanosheets (RGOs) by simple ultrasonication. The RGOs-Cu2O nanocomposites showed high electrocatalytic activity toward glucose oxidation. Thus, a non-enzymatic amperometric glucose sensor was constructed with a wide linear range from 0.01 to 6 mM, low detection limit of 0.05 μM (S/N = 3), high selectivity (185 μA mM−1), and fast response (within 3 s). This strategy opens a new facile and simple chemical route to prepare porous metal oxides supported on RGOs with novel properties.In this work, uniform porous Cu2O nanospheres were facilely prepared using ionic liquid crystal [C16MMIm]Br) as a soft template. The Cu2O nanospheres were uniformly distributed on RGOs by ultrasonciation. The RGOs-Cu2O nanocomposites showed superior electrocatalytic activity toward glucose oxidation and were further applied for the construction of non-enzymatic glucose sensor with good performance.

A simple, facile and green hydrothermal method was developed in the synthesis of water-soluble nitrogen-doped carbon dots (N-CDs) from streptomycin. The as-prepared N-CDs displayed bright blue fluorescence under the irradiation of UV light, together with a high quantum yield of 7.6% and good biocompatibility as demonstrated by the cell viability assay. Thus, the N-CDs can be used as fluorescent probes for cell imaging, which have potential applications in bioimaging and related fields. This strategy opens a new way for the preparation of fluorescent carbon nanomaterials using small molecules as carbon sources.

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).

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.

•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.

In this report, ultrathin worm-like Au nanowires were constructed with the assistance of L-glutamic acid as a structure-directing agent and a weak stabilizing agent. The morphology of the Au products was found to be strongly dependent on the experimental parameters such as the amount of L-glutamic acid, as well as the reaction temperature. This synthesis was a seedless process, without using any template, surfactant, or toxic organic agent. Furthermore, the as-prepared Au nanowires were applied to facilely fabricate porous Au films with controllable thickness via simple gravity settling. The Au films showed high surface-enhanced Raman scattering (SERS) enhancement, using 4-mercaptobenzoic acid as a model probe. The Au films may be promising candidates for SERS sensing. This strategy provides an environmental friendly way for the preparation of various metal nanostructures with novel morphologies and useful applications.

•Well-defined Pd nanodendrites supported on reduced graphene oxide is prepared at room temperature.•NP-40 plays an important role as a soft template in the formation of the Pd nanodendrites.•The synthesis process is simple, fast, green, without any seed, organic solvent, or special apparatus.•The as-prepared nanocomposites exhibit the enhanced catalytic activity toward ethylene glycol and glycerol electrooxidation.In this paper, a simple, fast, and green method is developed for preparation of uniform Pd nanodendrites anchored on reduced graphene oxide (Pd/RGO) at room temperature, with the assistance of octylphenoxypolye thoxyethanol (NP-40) as a soft template, while no seed, organic solvent, or special apparatus involved. The as-prepared nanocomposites show the improved CO tolerance, enhanced catalytic activity, and better stability for ethylene glycol (EG) and glycerol (Gly) electrooxidation in alkaline media, compared with commercial Pd black and Pd/C catalysts. The synthetic strategy can be extended to fabricate other electrocatalysts in direct alcohol fuel cells.In this paper, we demonstrate a simple, rapid, and facile wet-chemical approach to synthesize uniform Pd nanodendrites supported on reduced graphene oxide at room temperature, without any seed, organic solvent or special apparatus. The novel nanocomposite shows superior electrocatalytic activity, high CO-poisoning tolerance and stability for the electrooxidation of ethylene glycol and glycerol.

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.

Bimetallic alloyed Pd–Au nanochain networks supported on reduced graphene oxide (Pd–Au NNs/RGO) were prepared by a one-pot wet-chemical co-reduction method with the assistance of caffeine as a capping agent and a structure directing agent, while no seed, template, or surfactant was involved. It was found that the dosage of caffeine and the concentrations of the precursors (i.e. PdCl42− + AuCl4−) played essential roles in the formation of Pd–Au NNs. Moreover, the as-prepared nanocomposites exhibited much better electrocatalytic performance than those of conventional Pd black and Pd–C toward oxygen reduction reaction (ORR) in alkaline media in terms of the onset potential, limiting current, and stability.

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.

A simple method was developed for synthesis of network-like gold nanochains and gold nanoflowers in the presence of cytosine by reduction of tetrachloroauric acid with sodium borohydride and ascorbic acid, respectively. The resulting gold nanocrystals were coated with microperoxidase-11 via electrostatic interactions. Electrodes modified with protein-coated gold nanochains or nanoflowers display well-defined and quasireversible redox peaks and enhanced high electrocatalytic activity toward the reduction of H2O2 that is due to direct electron transfer to the protein. The effects were exploited for the amperometric detection of H2O2 with a linear response from 0.5 μM to 0.13 mM (for the gold nanochains) and from1.0 μM to 0.11 mM (for the gold nanoflowers), respectively. The sensor shows lower detection limit and faster response time than sensors based on the use of spherical gold nanoparticles.

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 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.

•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.

•Using gelatin as a biotemplate, ZnO nanostars were prepared under hydrothermal conditions.•The ZnO nanostars are assembled by some nanorods growing along the [0 0 0 1] directions.•The ZnO nanostars show good performance to the degradation of methyl orange under UV irradiation.Biotemplate-assisted approach is simple and friendly to the environment. With the assistance of gelatin as a soft biotemplate and a structure-directing agent, star-like zinc oxide (ZnO) nanostructures have been prepared by assembly of well-defined nanorods under hydrothermal conditions. Their morphology and structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The growth mechanism of the ZnO nanostars is also investigated. The as-prepared ZnO nanostars display high photocatalytic activity toward the degradation of methyl orange (MO) under ultraviolet (UV) irradiation.Graphical abstract

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.

In this report, flower-like Au nanochains were facilely prepared by a one-step synthesis with the assistance of caffeine as a structure directing and weak stabilizing agent. It was found that the reaction temperature and the ratio of [caffeine]/[HAuCl4] were the key factors during the synthesis process, and their growth mechanism was discussed in some detail. The as-prepared Au superstructures displayed an excellent catalytic ability towards the reduction of p-nitrophenol, which showed potential applications in the construction of optical and catalytic devices.

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%).

Water–soluble fluorescent silver nanoclusters (Ag NCs) were prepared with the assistance of commercially available polyinosinic acid (PI) or polycytidylic acid (PC). The fluorescence of the Ag NCs is effectively quenched by trace mercury(II) ions, which can be applied for their detection. The response of the Ag NCs prepared with PI to Hg(II) ion is linear in the Hg(II) concentration range from 0.05 to 1.0 μM (R2 = 0.9873), and from 0.5 to 10 μM of Hg(II) (R2 = 0.9971) for Ag NCs prepared with PC. The detection limits are 3.0 nM and 9.0 nM (at an S/N of 3), respectively. The method is simple, sensitive and fairly selective.

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).

In this paper, monodisperse polydopamine (PDA)–Ag hybrid hollow microspheres were synthesized by self-polymerization of dopamine on ZnO microspheres as sacrificial templates. The templates were dissolved in basic media and in situ reduced the incorporated Ag+ ion with ascorbic acid. The as-prepared PDA–Ag composites modified glassy carbon electrode exhibited a broad linear range of 0.092–20 mM for H2O2 determination, with a remarkable sensitivity of 6.79 μA mM−1, a detection limit of 1.97 μM (S/N = 3), and rapid response (within 5 s). Moreover, the electrode showed good reproducibility, anti-interferant ability and long-term stability.Graphical abstract. In this work, well-defined polydopamine (PDA)–Ag hollow microspheres were synthesized by self-polymerization of dopamine and using ZnO microspheres as sacrificial templates in basic media. Meanwhile, the Ag+ ion grafted onto the PDA shells, was in situ reduced by ascorbic acid and formed Ag nanoparticles. The resulting products exhibited enhanced electrocatalytic ability towards the reduction of H2O2.Highlights► Well-defined ZnO microspheres were prepared in large scale by a novel hydrothermal method. ► The ZnO microspheres were used as sacrificial templates for polydopamine (PDA)–Ag hollow microspheres in basic media. ► Ag nanoparticles were obtained via in situ reduction of the incorporated Ag+ ion on PDA surface by ascorbic acid. ► The PDA–Ag hollow microspheres showed high electrocatalytic ability towards H2O2.

Without any template or surfactant, a facile d-penicillamine assisted solvothermal method was developed for large-scale synthesis of hierarchical PbS microstars with octa-symmetric-dendritic arms along the ⟨111⟩ direction in the water/ethanolamine (EA) solution. In this process, d-penicillamine was used as both a sulfur source and a chelating agent. The parameters, including the molar ratio of the precursors, the volume ratio of the binary solvents, and the reaction temperature and time, have great effects on the morphology of the final products. Additionally, the possible growth mechanism was proposed to explain the formation of these architectures. This facile d-penicillamine-assisted technique provides a new way for shape-controlled synthesis of other superstructured materials.

Ultra-long Cu microdendrites (MDs) were prepared by one-step electrodeposition on a glassy carbon electrode. The results demonstrated that the reduction potential, pH, and temperature of the electrolysis solution, as well as the amount of Cu2+ and citrate ions, play important roles in the formation of the Cu MDs. Notably, the X-ray diffraction experiments confirmed that the aggregations of the Cu nanocrystals preferred to grow along (111) direction. In addition, the resulting Cu MDs-modified electrode showed good electrochemical performance as a non-enzyme glucose sensor in alkaline media.

•PtAu PNCs were large-scaled synthesized by a one-pot bio-inspired aqueous method.•l-histidine was used as the structure director, without any template or seed.•The as-synthesized architectures had enlarged ECSA.•PtAu PNCs showed superior catalytic and durable capability for MOR and ORR.Porous Pt-based bimetallic nanocatalysts receive significant interest in fuel cells. Herein, amino acid-assisted strategy was designed to construct uniform dendrite-like PtAu porous nanoclusters (PtAu PNCs) by a simple wet-chemical method, where l-histidine served as the structure director and poly (vinylpyrrolidone) (PVP) as the dispersing agent. We mainly investigated the structure, composition, formation mechanism and electrocatalytic performance of PtAu PNCs. By virtue of the bimetallic synergetic effects and unique structures, the architectures exhibited enhanced catalytic activity and durability for methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) in contrast with non-porous PtAu nanocrystals, Au nanocrystals, porous Pt nanoparticles and commercial Pt black catalysts.

•PdAu NSFs were prepared by a single-step wet-chemical method.•PVEIB was employed as the stabilizing agent and structure director.•The architectures showed enhanced catalytic performances for EOR and EGOR.•The best utilization of Pd was demonstrated in the case of Pd1Au3 NSFs.In this work, snowflake-like bimetallic PdAu alloy nanostructures with tunable composition and size were large-scaled synthesized at room temperature via a facile wet-chemical strategy. Their morphology and size depend on the composition and concentration of poly(1-vinyl-3-ethylimidazolium bromide) (PVEIB) as the stabilizing agent and structure director. The as-prepared architectures exhibit excellent electrocatalytic activity and stability towards ethanol and ethylene glycol oxidation in alkaline media. And snowflake-like Pd1Au3 nanostructures display the best catalytic performance. This is due to the unique snowflake-like structures, alloy nature, and tunable composition and size, along with effectively avoiding the support corrosion usually occurred on commercial catalysts.

In this work, solid-core@porous-shell alloyed PtAg nanocrystals (PtAg NCs) were fabricated via a simple one-pot co-reduction wet-chemical method on a large scale. Diprophylline (DPP) was employed as the stabilizing agent and shape-directing agent, without any surfactant, polymer, seed or template. The products were mainly analyzed by a series of characterization technique. The hierarchical architectures had enhanced stability and improved electrocatalytic activity for hydrogen evolution reaction (HER) and glycerol oxidation reaction (GOR) in contrast with commercial available Pt/C and Pt black catalysts. For the prepared PtAg NCs catalyst, the Tafel slope is 40 mV dec−1 toward HER in 0.5 M H2SO4, coupled with the specific activity and mass activity of 77.91 mA cm−2 and 1303 mA mg−1Pt toward GOR, respectively.Figure optionsDownload full-size imageDownload high-quality image (130 K)Download as PowerPoint slide

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.

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 work, uniform oxygen and sulfur co-doped graphitic carbon nitride quantum dots (OS-GCNQDs) have been prepared by thermal treatment of citric acid and thiourea. The as-obtained OS-GCNQDs show strong blue photoluminescence (PL) with a relatively high quantum yield of 14.5%. Furthermore, OS-GCNQDs exhibit stable and specific concentration-dependent PL intensities in the presence of mercury(II) ions in the range of 0.001–20.0 μM, with a detection limit of 0.37 nM (3S/N). More importantly, OS-GCNQDs were explored for cell imaging with satisfactory biocompatibility, and so are a potential fluorescent probe in biosensing and bioimaging applications.

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 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 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.

A simple and facile one-pot wet-chemical co-reduction method was developed for the synthesis of reduced graphene oxide supported porous PtAu alloyed nanoflowers (PtAu-nanoflowers/rGO). p-Aminopyridine was employed as a structure-directing agent and a stabilizing agent. No seed, template, surfactant, or polymer was involved in the synthesis process. It was found that the reaction temperature and the dosage of p-aminopyridine were essential for the final product. Furthermore, the as-prepared nanocomposites showed improved catalytic activity for the reduction of 4-nitrophenol in contrast to monometallic Pt nanocrystals/rGO, Au nanocrystals/rGO, and commercial Pt/C (50 wt%).

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.

Fluorescent graphene-like carbon nitrides (FL GCNs) are emerging as a new kind of graphene-like two-dimensional (2D) layered nanomaterials in bioimaging, sensing, drug delivery, cancer therapy, photocatalysis, solar energy and optoelectronic devices, owing to their excellent optoelectronic properties, high specific surface areas, good biocompatibility and low toxicity. In this review, we firstly introduced the synthetic methods for FL GCNs such as the “top-down” and “bottom-up” strategies, followed by systematically addressing the unique properties of FL GCNs. Then, the current applications of FL GCNs were discussed in detail, and finally an outlook on their possible and potential developments was roughly described.

Despite increasing research studies in the past few decades, it is still a challenge to find highly efficient catalysts for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). Herein, a one-pot solvothermal method was developed for constructing Pt76Co24 nanomyriapods (NMs) with abundant active sites, where L-glutamic acid and cetyltrimethylammonium chloride (CTAC) were used as the green reductant and structure directing agent, respectively. The architecture had a larger electrochemically active surface area (ECSA) of 24.49 m2 g−1 than Pt49Co51 nanoparticles (NPs, 15.17 m2 g−1), Pt80Co20 NPs (16.71 m2 g−1) and commercial Pt black (20.35 m2 g−1), and exhibited superior catalytic performances for ORR and HER. The mass activity of Pt76Co24 NMs (105.26 mA mgPt−1) for ORR was twice as high as Pt black (47.35 mA mgPt−1). And the Pt76Co24 NM catalyst exhibited better durability in acid media relative to Pt black and/or Pt/C (20 wt%). This work would have practical applications in catalysis, and energy storage and conversion.

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.

Herein, a simple, one-step seedless wet-chemical method was developed for synthesis of well-dispersed gold@palladium core–shell nanoflowers supported on reduced graphene oxide (Au@Pd/rGO) with the assistance of melamine as a linking agent and using poly(vinylpyrrolidone) as a structure-directing agent. The as-prepared Au@Pd/rGO exhibited enhanced electrocatalytic activity and improved stability for oxygen reduction reaction (ORR) and ethylene glycol (EG) oxidation in alkaline media compared with Pd/rGO, Au/rGO, and Pd black. This method can be extended to easily prepare core–shell nanostructures with designed compositions and desired catalytic properties.

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 work, a general strategy was developed for the facile synthesis of bimetallic AuM (M = Pt or Pd) alloyed flowerlike-assembly nanochains (FANs) with the assistance of diprophylline as a structure-directing and stabilizing agent. The morphologies, crystal structures, and compositions of AuPt and AuPd FANs were investigated primarily by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The formation mechanism was discussed in some detail by varying the concentration of diprophylline. The as-prepared AuM FANs displayed improved catalytic activities and better stabilities for oxygen reduction reaction (ORR) compared to commercial E-TEK Pt/C, Pt black and Pd black.