APTES-functionalized Fe 3 O 4 microspheres supported Cu atom-clusters with superior catalytic activity towards 4-nitrophenol reduction

Adsorption behavior of Mo(VI) from aqueous solutions using tungstate-modified magnetic nanoparticle

A new magnetic nanoparticle modified with sodium tungstate (Mnp-Si-W) was synthesized and employed for the sorption of molybdenum from aqueous solutions. The prepared nanoparticles (Mnp-Si-W) were characterized by different advanced techniques. Different parameters that influenced the adsorption percent of Mo(VI) were investigated using a batch process. Based on a systematic investigation of the adsorption isotherms and kinetics models, Mo(VI) adsorption follows the Langmuir model and pseudo-second-order kinetics. According to the Langmuir isotherm model, the Mnp-Si-W nanoparticles exhibited a maximum adsorption capacity of 182.03 mg g-1 for Mo(VI) at pH 2.0. The effect of competing ions showed that the prepared nanoparticles have a high selectivity for the sorption of molybdenum. Moreover, the effect of some interfering anions on Mo(VI) ion sorption is found in the following order: phosphate < sulfate < chromate. Finally, the nanoparticle (Mnp-Si-W) can be successfully reused five times.

A Highly NIR Emissive Cu16 Pd1 Nanocluster

The construction of stable copper nanoclusters (Cu-NCs) with near-infrared (NIR) emission that can be used for catalysis is highly desired, yet remains a challenge. Herein, an atomically precise bimetallic Cu/Pd NC with a molecular formula of Cu16 Pd1 L10 (PPh3 )2 (Pz)6 (Pz = 3,5-(CF3 )2 Pyrazolate, L = 4-CH3 OPhC≡C- ), abbreviated as Cu16 Pd1 , is synthesized. Single-crystal X-ray crystallographic analysis of Cu16 Pd1 reveals a Cu10 Pd1 kernel with pseudo-gyroelongated square bipyramid confirmation surrounded by other 6 Cu(I) ions and protected ligands. Interestingly, it exhibits strong NIR emission with the highest photoluminescence quantum yield (PLQY) among all the Cu NCs/Cu alloys (λem  > 800 nm) in the solid-state, and also displays NIR emission in solution. Experimental results and theoretical calculations suggest that the impressive NIR emission is attributed to abundant supramolecular interactions in the solid-state, including intramolecular metal-metal and intermolecular interactions. Of note, the bimetallic Cu16 Pd1 can catalyze the reduction of 4-nitrophenol. This work provides a novel method for synthesizing Cu/Pd NCs and reminds that the less studied Cu/Pd NC can serve as outstanding luminescent material, which is seldom noticed in atomically precise nanoclusters.

Magnetic alginate-carboxymethyl cellulose to immobilize copper nanoparticles as a green and sustainable catalyst for 4-nitrophenol reduction

In the present work, sustainable green catalysts with high activity, and excellent stability were prepared and thoroughly characterized by XRD, FT-IR, BET, VSM, SEM, EDX, HR-TEM, and TGA techniques. The combined sodium alginate (SA) and carboxymethyl cellulose (CMC) biopolymers were functionalized with Fe₃O₄ nanoparticles to immobilize copper nanoparticles to form Fe₃O₄@SA-CMC-CuNP nanocomposites in batch experiments. Furthermore, the Fe₃O₄@SA-CMC-CuNP nanocomposites were utilized as the heterogeneous catalyst for 4-nitrophenol (4-NP) reduction to 4-aminophenol (4-AP) in the presence of NaBH₄, and the progress of the catalytic reaction was monitored using UV-visible spectrophotometry. The Fe₃O₄@SA-CMC-CuNP nanocomposite exhibited much higher catalytic activity for the 4-nitrophenol reduction reaction than individual components Fe₃O₄ and Fe₃O₄@SA-CMC. The effect of parameters such as the amount of catalyst was evaluated and 30 mg of the catalyst amount with a 95.0% reduction of 4-nitrophenol for 1.5 min was obtained. The effect of reaction temperature was also investigated to find out the activation energy. The analyses of kinetics and thermodynamics were carried out to understand the catalytic behavior. Furthermore, the catalyst can be separated from the reaction system through the usage of a magnet and recycled up to five times without any loss of activity. Therefore, the development of sustainable green catalyst biopolymer-based nanocomposites is promising for new catalysts in the future for treating organic wastewater.

Ni-Pd-Incorporated Fe3O4 Yolk-Shelled Nanospheres as Efficient Magnetically Recyclable Catalysts for Reduction of N-Containing Unsaturated Compounds

The use of metal-based heterogeneous catalysts for the degradation of N-containing organic dyes has attracted much attention due to their excellent treatment efficiency and capability. Here, we report the synthesis of heterometals (Ni and Pd)-incorporated Fe3O4 (Ni-Pd/Fe3O4) yolk-shelled nanospheres for the catalytic reduction of N-containing organic dyes using a facile combination of solvothermal treatment and high-temperature annealing steps. Benefiting from the magnetic properties and the yolk-shelled structure of the Fe3O4 support, as well as the uniformly dispersed active heterometals incorporated in the shell and yolk of spherical Fe3O4 nanoparticles, the as-prepared Ni-Pd/Fe3O4 composite shows excellent recyclability and enhanced catalytic activity for three N-containing organic dyes (e.g., 4-nitrophenol, Congo red, and methyl orange) compared with its mono metal counterparts (e.g., Ni/Fe3O4 and Pd/Fe3O4). In the 4-nitrophenol reduction reaction, the catalytic activity of Ni-Pd/Fe3O4 was superior to many Fe3O4-supported nanocatalysts reported within the last five years. This work provides an effective strategy to boost the activity of iron oxide-based catalytic materials via dual or even multiple heterometallic incorporation strategy and sheds new light on environmental catalysis.

Single-Step Synthesized Functionalized Copper Carboxylate Framework Meshes as Hierarchical Catalysts for Enhanced Reduction of Nitrogen-Containing Phenolic Contaminants

Nitrogen-containing phenolic contaminants (NCPCs) represent typical pollutants of industrial wastewaters. As catalytic reduction of NCPCs is a useful technique and Cu is an efficient metal catalyst, Cu-carboxylate frameworks (CuCF) are favorable materials. However, they are in powder form, making them difficult to use; thus, in this study, CuCF was grown on macroscale supports. Herein, we present a facile approach to develop such a CuCF composite by directly using a Cu mesh to grow CuCF on the mesh through a single-step electrochemical synthesis method, forming CuCF mesh (CFM). CFM could be further modified to afford CuCF mesh with amines (NH2) (CFNM), and CuCF mesh with carboxylates (COOH) (CFCM). These CuCF meshes are compared to investigate how their physical and chemical characteristics influenced their catalytic behaviors for reduction/hydrogenation of NPCPs, including nitrophenols (NPs) and dyes. Their nanostructures and surface properties influence their behaviors in catalytic reactions. In particular, CFCM appears to be the most efficient mesh for catalyzing 4-NP, with a much higher rate constant. CFCM also shows a significantly lower Ea (28.1 kJ/mol). CFCM is employed for many consecutive cycles, as well as convenient filtration-type 4-NP reduction. These CuCF meshes can also be employed for decolorization of methylene blue and methyl orange dyes via catalytic hydrogenation.

Fabrication and catalytic application of tandem reactor module using Au nanoparticles-coated glass beads as packing materials

A tandem reactor module using Au nanoparticles (NPs)-coated glass beads as packing materials is designed and fabricated for the catalytic reduction of 4-NP. Au NPs-coated glass beads are firstly prepared...

Magnetic Nanoparticle Composites: Synergistic Effects and Applications

Composite materials are made from two or more constituent materials with distinct physical or chemical properties that, when combined, produce a material with characteristics which are at least to some degree different from its individual components. Nanocomposite materials are composed of different materials of which at least one has nanoscale dimensions. Common types of nanocomposites consist of a combination of two different elements, with a nanoparticle that is linked to, or surrounded by, another organic or inorganic material, for example in a core-shell or heterostructure configuration. A general family of nanoparticle composites concerns the coating of a nanoscale material by a polymer, SiO2 or carbon. Other materials, such as graphene or graphene oxide (GO), are used as supports forming composites when nanoscale materials are deposited onto them. In this Review we focus on magnetic nanocomposites, describing their synthetic methods, physical properties and applications. Several types of nanocomposites are presented, according to their composition, morphology or surface functionalization. Their applications are largely due to the synergistic effects that appear thanks to the co-existence of two different materials and to their interface, resulting in properties often better than those of their single-phase components. Applications discussed concern magnetically separable catalysts, water treatment, diagnostics-sensing and biomedicine.

Macroporous polymer resin with conjugated side-chains: an efficient Ag nanoparticle support for preparing a photocatalyst

Ag NPs loaded on macroporous resin with conjugated side-chains can absorb broad wavelength light, transfer electrons to Ag and immobilize “Ag” by amino groups, all of which facilitate the photocatalytic activity and stability for 4-NP reduction.