Efficient treatment of organic pollutants in water by a facile and green technique is a great challenge for environmental remediation. In this study, we report a simple and low-energy strategy for catalytic reduction of organic pollutants in water by continuous-flow flash nanoprecipitation. The one-step processing technique integrates rapid metal@polymer nanoparticle production and catalytic reaction in a continuous-flow fashion. Such a concept is successfully demonstrated for simultaneous formation of Au@polymer nanospheres and catalytic reduction of organic pollutants (e.g., methylene blue and 4-nitrophenol) in water. Furthermore, the catalytic reaction rate could be easily tuned by varying the processing parameters (e.g., feeding concentration). The activity of the nanocatalyst was demonstrated in five recycles without any detectable loss. The characteristics of continuous-flow mode make the one-step process scalable, promising processing methodology for wastewater treatment.

•Carbon-Fe3O4 core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization.•Polydopamine and Fe(NO3)3 are precursors for N-doped carbon source and Fe3O4 nanoparticles, respectively.•The nanocomposites exhibit high electrochemical activity in ORR.•The nanocomposites effectively adsorb organic dyes with magnetic recovery and good recycle property.We present the synthesis and multifunctional utilization of core-satellite carbon-Fe3O4 nanoparticles to serve as the enabling platform for a range of applications including oxygen reduction reaction (ORR) and magnetic adsorbent. Starting from polydopamine (PDA) nanoparticles and Fe(NO3)3, carbon-Fe3O4 core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization. The synergistic combination of Fe3O4 and N-doped carbon endows the nanocomposite with high electrochemical activity in ORR and mainly four electrons transferred in reaction process. Furthermore, carbon-Fe3O4 nanoparticles used as magnetic adsorbent exhibit the efficient removal of Rhodamine B from an aqueous solution. The recovery and reuse of the adsorbent is demonstrated 5 times without any detectible loss in activity.Starting from polydopamine (PDA) nanoparticles and Fe(NO3)3, carbon-Fe3O4 core–satellite nanospheres are synthesized through successive steps of impregnation, ammoniation and carbonization. The nanocomposites serve as the enabling platform for a range of applications including oxygen reduction reaction (ORR) and magnetic adsorbent.

In this paper, we report a simple and low-energy strategy for the preparation of silver decorated polymer colloids. The reported constrained-volume synthesis integrates polymer nanoprecipitation and metal deposition in a one-step continuous-flow fashion. The deposition of Ag nanoparticles (NPs) associated with different optical properties is easily controlled by varying processing parameters. The as-synthesized colloidal NPs have good antimicrobial properties. In addition, the sensitivity of the colloids towards hydrogen peroxide exhibits a linear response over a wide concentration range with a detection limit of 0.03 μM.

•Ultrathin NiO nanosheets were coated on hollow N-doped carbon spheres with the assistance of polydopamine.•The hierarchical hollow nanostructures have high surface area and uniform pore size distribution.•HNCS-NiO nanocomposites exhibit high capacitance of 550.4 F g− 1 at the current density of 0.5 A g− 1.The polydopamine-assisted hierarchical composites of ultrathin NiO nanosheets uniformly coating on the surface of hollow nitrogen-doped carbon spheres (HNCS-NiO) were successfully fabricated via a facile synthesis method. The hierarchical HNCS-NiO composites as electrode materials for supercapacitors exhibit high capacitance of 550.4 F g− 1 (880.6 mF cm− 2) at the current density of 0.5 A g− 1 (0.8 mA cm− 2), and present a good rate capability. The composites display excellent improved electrochemical properties not only because their hierarchical hollow nanostructures can provide enough space to buffer the volume expansion during the reversible intercalation/deintercalation processes, but also because their larger specific surface areas can provide adequate active sites for the redox electrochemical reaction.The polydopamine-assisted hierarchical composites of ultrathin NiO nanosheets uniformly coating on the surface of hollow nitrogen-doped carbon spheres were fabricated, which exhibit excellent electrochemical properties as electrode materials for supercapacitors.Download high-res image (113KB)Download full-size image

Nitrogen-doped graphene/carbon nanohorns composite (NGLC) was prepared by one-step co-pyrolysis of graphene oxide, carbon nanohorns (CNHs), urea, and lignosulfonate. CNHs as spacers were inserted into graphene nanosheets. The introduction of CNHs and the loosened nano-structure of NGLC make it achieve a high specific capacitance of 363 F g−1 at a discharge current density of 1 A g−1, and NGLC exhibits an ultrahigh stability of 93.5% capacitance retention ratio after 5000 cycles. The outstanding comprehensive electrochemical performance of NGLC could meet the need of the future acted as an efficient supercapacitor electrode material.

In this study, a series of spherical poly(styrene-co-acrylonitrile) (P(St-co-AN)) nanoparticles were prepared using flash nanoprecipitation method. TEM images illustrated the controllability of grain sizes by adjusting the feeding initial concentration of copolymer. The as obtained nanoparticles were followed with the amidoximation with hydroxylamine. The amidoximated P(St-co-AN) copolymer nanoparticles showed a good uranium adsorption capacity of 37.67 mg g−1 at pH 1.5.

•Fe3O4@PDA and Fe3O4@C core–shell nanoparticles effectively adsorb organic dyes.•Each core–shell nanoparticle performs differently in adsorption for cationic and anionic dyes.•Surface charge determines the adsorption capability.•The electrostatic attraction plays main role for adsorption.Magnetic core–shell structured nanoparticles (NPs) have recently attracted great attention as adsorbents because of their excellent adsorption property and easy separation. In this work, Fe3O4@polydopamine core–shell NPs are synthesized by coating a layer of polydopamine (PDA) onto the surface of magnetic Fe3O4 NPs and Fe3O4@carbon NPs are obtained after carbonization of Fe3O4@PDA. Both core–shell NPs are tested as magnetic adsorbents for cationic and anionic dyes. The results show that Fe3O4@PDA NPs have good adsorption property toward methylene blue while Fe3O4@C NPs exhibit excellent performance for methyl orange adsorption. The adsorption behavior performs differently after switch of surface charge for both adsorbents. The adsorption mechanism shows that the adsorption capacity of both Fe3O4@PDA and Fe3O4@C is mainly determined by the electrostatic interaction between adsorbents and dyes.Download high-res image (165KB)Download full-size image

We present the use of silica-polydopamine (SiO2@PDA) core–shell nanoparticles (NPs) as self-confined templates for the fabrication of ultra-stable hollow Pt anchored N-doped carbon nanospheres (Pt/HN-C). SiO2@PDA nanospheres were fabricated by a facile one-pot process, followed by the deposition of Pt NPs onto the outer shell layer. The confinement and adhesion of the PDA framework ensured the distribution and stability of Pt NPs after carbonization at the carbon shell layer. The converted Pt/HN-C exhibited excellent catalytic performance and durability for the oxygen reduction reaction (ORR).

Herein, we report a novel route to construct a hierarchical three-dimensional porous carbon (3DC) through a copolymer-silica assembly. In the synthesis, silica acts as a hard template and leads to the formation of an interconnected 3D macropore, whereas styrene-co-acrylonitrile polymer has been used as both a carbon source and a soft template for micro- and meso-pores. The obtained 3DC materials possess a large surface area (∼550.5 m2 g−1), which facilitates high dispersion of Pt nanoparticles on the carbon support. The 3DC-supported Pt electrocatalyst shows excellent performance in the oxygen reduction reaction (ORR). The easy processing ability along with the characteristics of hierarchical porosity offers a new strategy for the preparation of carbon nanomaterials for energy application.

Core–shell nanoparticles (NPs) have emerged as a type of important nanomaterial for various applications. The challenge in the preparation of core–shell NPs is to find a simple, cost-effective and less time-consuming strategy with minimum environmental impact. The consolidation of multiple preparation steps into one step represents a new green synthesis pathway in chemistry and materials science. In this review, we provide an overview of the recent developments in the fabrication of core–shell NPs through one-step/pot methodologies. A variety of one-step/pot preparation methods are presented, discussed and compared, followed by the summary and outlook of this emerging area.

Core–shell nanoparticles (NPs) have emerged as a type of important nanomaterial for various applications. The challenge in the preparation of core–shell NPs is to find a simple, cost-effective and less time-consuming strategy with minimum environmental impact. The consolidation of multiple preparation steps into one step represents a new green synthesis pathway in chemistry and materials science. In this review, we provide an overview of the recent developments in the fabrication of core–shell NPs through one-step/pot methodologies. A variety of one-step/pot preparation methods are presented, discussed and compared, followed by the summary and outlook of this emerging area.

Herein, we report a novel route to construct a hierarchical three-dimensional porous carbon (3DC) through a copolymer-silica assembly. In the synthesis, silica acts as a hard template and leads to the formation of an interconnected 3D macropore, whereas styrene-co-acrylonitrile polymer has been used as both a carbon source and a soft template for micro- and meso-pores. The obtained 3DC materials possess a large surface area (∼550.5 m2 g−1), which facilitates high dispersion of Pt nanoparticles on the carbon support. The 3DC-supported Pt electrocatalyst shows excellent performance in the oxygen reduction reaction (ORR). The easy processing ability along with the characteristics of hierarchical porosity offers a new strategy for the preparation of carbon nanomaterials for energy application.