Facile Synthesis of Ag/Pd NanoparticleLoaded Poly(ethylene imine) Composite Hydrogels with Highly Efficient Catalytic Reduction of 4-Nitrophenol

Poly(ethylene imine) (PEI) has abundant amino groups in a macromolecular chain and can be used as a graft source for metal nanocomposites, which shows excellent ability to form stable complexes with heavy metal ions. In this work, a simple and convenient method was used to make PEI into a stable hydrogel with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-N-hydroxysuccinimide and subsequently coprecipitate with silver nitrate solution or palladium chloride solution to form metal-loaded composite hydrogels. In addition, the characterizations of composite hydrogels were investigated by scanning electron microscopy, specific surface area tests (Brunauer-Emmett-Teller), X-ray photoelectron spectroscopy, and ultraviolet spectroscopy. The properties of composite hydrogels on the catalytic reduction of 4-nitrophenol were studied. The results showed that the composite hydrogels could be easily separated from the water environment, which indicated the large-scale potential application in organic catalytic degradation and wastewater treatment.

Facile Preparation and Highly Efficient Catalytic Performances of Pd-Cu Bimetallic Catalyst Synthesized via Seed-Mediated Method

With the rapid development of industry, the problem of environmental pollution has become increasingly prominent. Exploring and preparing green, efficient, and low cost catalysts has become the key challenge for scientists. However, some conventional preparation methods are limited by conditions, such as cumbersome operation, high energy consumption, and high pollution. Here, a simple and efficient seed-mediated method was designed and proposed to synthesize a highly efficient bimetallic catalyst for catalyzing nitro compounds. A Pd-Cu bimetallic composite (BCM) can be prepared by synthesizing the original seed crystal of precious metal palladium, then growing the mature nanocrystalline palladium and supporting the transition metal copper. Importantly, after eight consecutive catalytic cycles, the conversion of the catalyzed 2-NA was 84%, while the conversion of the catalyzed 4-NP was still 72%. And the catalytic first order rates of 2-NA and 4-NP constants were 0.015 s-1, and 0.069 s-1, respectively. Therefore, current research of nanocomposites catalyst showed great significance for serious environmental pollution problems and the protection of living environment, providing a new idea for the preparation of new bimetallic catalytic materials.

Facile Preparation and Enhanced Catalytic Properties of Self-Assembled Pd Nanoparticle-Loaded Nanocomposite Films Synthesized via the Electrospun Approach

In recent years, people pay more attention to environmental pollution and the treatment of sewage has become the focus of recent research. Palladium nanoparticles have good catalytic properties but are easy to agglomerate. Therefore, we used the electrospinning technology to prepare a uniform composite nanofiber film based on polyacrylic acid (PAA) and polyvinyl alcohol (PVA), which demonstrated that they are good carriers of palladium nanoparticles to make the nanoparticles well dispersed. Furthermore, carbon nanotubes (CNTs) were added to increase the specific surface area of the composite nanofiber film and improve its mechanical properties. The successfully synthesized PAA/PVA/CNT-COOH@palladium nanoparticle (PdNP) composite fiber films were characterized by scanning electron microscopy, transmission electron microscopy, and thermogravimetry analysis. p-Nitrophenol and 2-nitroaniline were utilized as typical pollutants to further evaluate the catalytic performance of PAA/PVA/CNT-COOH@PdNP composite fiber films. The PAA/PVA/CNT-COOH@PdNP composite fiber films exhibited enhanced catalytic performance and could be reused for eight consecutive cycles. This work provided new clues for the preparation and application of composite electrospun film materials.

Facile Preparation of Carbon Nanotube-Cu2O Nanocomposites as New Catalyst Materials for Reduction of P-Nitrophenol

The effective synthesis and self-assembly of nanocomposites were of key importance for a broad range of nanomaterial applications. In this work, new carbon nanotube (CNT)-Cu2O nanocomposites were successfully synthesized via a facile approach. CNT was selected as the anchoring substrate to load Cu2O nanoparticles to prepare composite catalysts with well stability and good reusability. It is discovered that the prepared CNT-Cu2O nanocomposite materials could be effectively controlled via regulating preparation temperature and time without the use of any stabilizing agents. The nanostructures of synthesized composites were well characterized by many techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). And the prepared CNT-Cu2O nanocomposites with optimized preparation conditions as new catalyst displayed excellent catalytic performance on the reduction reaction of p-nitrophenol, demonstrating potential applications for environmental governance and composite materials.

Facile Preparation of Self-Assembled Polydopamine-Modified Electrospun Fibers for Highly Effective Removal of Organic Dyes

Polydopamine (PDA) nanoparticles can be used as an adsorbent with excellent adsorption capacity. However, nanosized adsorbents are prone to aggregation and thus are severely limited in the field of adsorption. In order to solve this problem, we utilized polydopamine in-situ oxidation self-polymerization on the surface of polycaprolactone (PCL)/polyethylene oxide (PEO) electrospun fiber after solvent vapor annealing (SVA) treatment, and successfully designed and prepared a PCL/PEO@PDA composite membrane. The SVA treatment regulated the microscopic morphology of smooth PCL/PEO electrospun fibers that exhibited a pleated microstructure, increasing the specific surface area, and providing abundant active sites for the anchoring of PDA nanoparticles. The PCL/PEO@PDA composite obtained by chemical modification of PDA demonstrated numerous active sites for the adsorption of methylene (MB) and methyl orange (MO). In addition, the PCL/PEO@PDA composites were reusable several times with good reutilization as adsorbents. Therefore, we have developed a highly efficient and non-agglomerated dye adsorbent that exhibits potential large-scale application in dye removal and wastewater purification.

Facile solvothermal preparation of Fe3O4–Ag nanocomposite with excellent catalytic performance

Functional nanocomposites demonstrate excellent comprehensive properties and outstanding characteristics for numerous applications. Magnetic nanocomposites are an important type of composite materials, due to their applications in optics, medicine and catalysis. In this report, a new Fe₃O₄-loaded silver (Fe₃O₄–Ag) nanocomposite has been successfully synthesized via a simple solvothermal method and in situ growth of silver nanowires. The silver nanowires were prepared via the reduction of silver vanadate with the addition of uniformly dispersed Fe₃O₄ nanoparticles. Structural and morphological characterizations of the obtained Fe₃O₄–Ag nanocomposite were carried out using many characterization methods. As a new composite catalyst, the synthesized magnetic Fe₃O₄–Ag nanocomposite displayed a high utilization rate of catalytically active sites in catalytic reaction medium and showed good separation and recovery using an external magnetic field. The facile preparation and good catalytic performance of this Fe₃O₄–Ag nanocomposite material demonstrate its potential applications in catalytic treatment and composite materials.

A new Fe₃O₄–Ag nanocomposite was prepared via solvothermal method, demonstrating potential application in catalytic degradation of wastewater treatment and composite materials.

Preparation of MoS2-based polydopamine-modified core–shell nanocomposites with elevated adsorption performances

New molybdenum disulfide (MoS₂)-based core–shell nanocomposite materials were successfully prepared through the self-assembly of mussel-inspired chemistry. Characterization by Fourier transform infrared, thermogravimetric analysis, scanning electron microscope and transmission electron microscopy revealed that the surface of the flaked MoS₂ was homogeneously coated with a thin layer of polydopamine (PDA). Dye adsorption performances of the synthesized MoS₂–PDA nanocomposites were investigated at different pH values and reaction times. Compared with pure MoS₂ nanosheets, the obtained core–shell nanocomposites showed elevated adsorption performances and high stability, indicating their potential applications in wastewater treatment and composite materials.

New core–shell MoS₂–PDA nanocomposites are prepared via mussel-inspired chemistry and a simple interfacial self-assembly process, demonstrating potential applications in wastewater treatment and self-assembled core–shell composite materials.