Simultaneous excellent catalytic performances toward hydrogenation reduction of 4-nitrophenol and reduction of Cr(VI) in water by novel designing of Cu-CoO/N-doped carbon nanocatalysts

Surface Coordination Decouples Hydrogenation Catalysis on Supported Metal Catalysts

In this paper, a facile route has been developed to prepare magnetic trimetallic Au-Ag-γ-Fe2O3/rGO nanocomposites. The impact of the preparation method (the intensity of reductant) on the catalytic performance was investigated. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The prepared nanocomposites show fine catalytic activity towards the reduction reaction of 4-nitrophenol (4-NP). The nanocomposites also have superparamagnetism at room temperature, which can be easily separated from the reaction systems by applying an external magnetic field.

Incorporating Sulfur Atoms into Palladium Catalysts by Reactive Metal–Support Interaction for Selective Hydrogenation

Ultrafine PdRu Nanoparticles Immobilized in Metal–Organic Frameworks for Efficient Fluorophenol Hydrodefluorination under Mild Aqueous Conditions

Effect of acidity and porosity changes of dealuminated mordenite on n-pentane, n-hexane and light naphtha isomerization

Novel bio-mediated Ag/Co3O4 nanocomposites of different weight ratios using aqueous neem leaf extract: Catalytic and microbial behaviour

Self-Assembly Ultrathin Fe-Terephthalic Acid as Synergistic Catalytic Platforms for Selective Hydrogenation

β-Cu2V2O7 nanoparticles were prepared using a solution-combustion method using two different fuels, which are: Urea and Glycine. The as-prepared catalysts were characterized using X-ray diffraction, Fourier transform infrared spectra, scanning electron microscopy, Brunauer–Emmett–Teller Method, and UV–Vis diffusive reflectance spectroscopy. The photocatalytic activity of copper vanadate was investigated by degradation of cationic dye crystal violet in an aqueous solution under UV and visible light irradiation. The effect of selected parameters such as catalyst mass, dye concentration, and solution pH on the catalytic performances has been discussed. On the other hand, the reuse tests of β-Cu2V2O7 displayed high-performance stability after five cycles.

The present study explores synthesis of spinel copper aluminate nanocomposites (CuAl2O4 NCs) for electrochemical applications and solvent-free synthesis of xanthanedione derivatives. CuAl2O4 NCs were synthesized from copper nitrate and aluminum nitrate with/without use of sodium dodecyl sulfate (SDS) by aqueous precipitation and microwave-assisted (MW) technique. As-synthesized CuAl2O4 NCs were characterized structurally and morphologically using X-ray diffraction (XRD) analysis, Fourier-transform infrared (FT-IR) spectroscopy, diffuse reflectance spectroscopy (DRS), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Formation of cubic spinel structure after calcination at 900 °C was confirmed by XRD analysis, while Raman, XPS, and EDS validated the composition and purity. TEM revealed that the particles had uniform nanosphere shape with average size of 10 nm for microwave-assisted with surfactant (MWS-CuAl2O4), while aqueous precipitation with surfactant (APS-CuAl2O4) NCs exhibited nanograins with particle size of 17 nm. AFM revealed higher surface roughness for MWS-CuAl2O4 NCs than APS-CuAl2O4 NCs. The electrochemical performance of the CuAl2O4 NCs was examined in aqueous Na2SO4 (1 M) as electrolyte using cyclic voltammetry (CV), revealing that the MWS-CuAl2O4 NCs demonstrated high specific capacitance (125 F g−1 at current density of 0.5 mA cm−2). Furthermore, one-pot, facile, eco-friendly MWS-CuAl2O4 NC-catalyzed synthesis of xanthanediones was developed, exhibiting excellent yield and reusability with negligible reduction in efficiency even after four consecutive cycles. MWS-CuAl2O4 NCs showed enhanced electrochemical and catalytic performance.

A highly loaded Ni@SiO2 core–shell catalyst for CO methanation

Development of a Ce–Zr–La modified Pt/γ-Al2O3 TWCs’ washcoat: Effect of synthesis procedure on catalytic behaviour and thermal durability

The development of efficient heterogeneous catalysts for reductive conversion of 4-nitrophenol (4-NP) is of vital significance for environmental remediation, dyestuff industry, pharmaceutical industry. We reported that Au@D201, a polymer gold nanocomposite of gold nanoparticles loaded on D201 resin, was prepared using macroporous styrenic ion exchange resin D201 as carrier, chloroauric acid as gold source and sodium borohydride as reducing agent. The average diameter of gold nanoparticles in Au@D201 composites is 5 nm, which has excellent catalytic properties for the reduction of 4-nitrophenol. The Au@D201 was characterized by ultraviolet–visible spectroscopy, X-ray diffraction, mercury injection instrument, transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). The results reveal that some of the gold nanoparticles were loaded on the surface of the resin, and most of the gold nanoparticles were in the resin pores. A strong chemical interaction, between the gold nanoparticles and the resin, is similar to the cross-linking action of the macromolecules. The gold nanoparticles provide a new cross-linking point for the resin, increasing the degree of cross-linking of the resin and causing some degree of resin ordering to occur. XPS shows that the electron density of the outer layer of the gold atom increases, indicating that there are some conjugated interactions between the resin and gold atoms. Conjugated interactions and the gold quantum size effect are the main reasons for improving the catalytic effect of the composite material. When the gold nano-loading amount is 0.1%, it still has an excellent catalytic effect on the reduction reaction of 4-nitrophenol.

This study describes the synthesis of Ag nanoparticles using DNA templates with polymorphic structures including the G-quadruplex, the I-motif, and the Duplex and their application for the catalytic reduction of 4-nitrophenol by NaBH4. Interactions between Ag+ and polymorphic DNA were studied through circular dichroism, polyacrylamide gels, and UV spectroscopy. Ag nanoparticles with narrow size distributions were prepared through the reduction of Ag+ by NaBH4 under different DNA templates and Ag+/base ratios. These DNA-templated Ag nanoparticles demonstrated excellent catalytic performance in the reduction reaction of 4-nitrophenol. The rate constants depended on the structure of DNA template, with the decreasing order: I-motif-Ag > G-quadruplex-Ag > Duplex-Ag. The results obtained here suggest a promising pathway to adjust physical–chemical properties of metal nanoparticles through the template of polymorphic DNA.

Green synthesis of predominant (1 1 1) facet CuO nanoparticles: Heterogeneous and recyclable catalyst for N-arylation of indoles

Noble and precious metal catalysts are sought for their remarkable efficiency in catalyzing numerous reactions in heterogeneous phase. However, they are costly and require the development of high-surface-area supports that favor their strong immobilization, dispersion, and stability. Toward this end, mesoporous silica-based materials can be regarded as unique supports for nanometric-sized noble metal catalysts provided they are functionalized with appropriate ligands. In this work, mesoporous silica SBA-15 was prepared and modified with 3-azidopropyltriethoxysilane and then clicked with alkyne derivatives of 1,3,5-triazine complex ligand. The resulting hybrid material contains triazole and triazine moieties covalently bound to the mesoporous silica network. The triazole/triazine minidendron was immobilized through a 1,3-dipolar cycloaddition click reaction, which was monitored by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The heterocyclic ligand-functionalized SBA-15 material served as a hybrid reactive platform for in situ deposition of palladium nanoparticles whose size is 3.154 ± 0.49 nm as assessed by X-ray diffraction and confirmed by transmission electron microscopy. The catalytic performance of the final palladium-decorated hybrid triazole/triazine-functionalized SBA-15 support was evaluated in the model reduction of 4-nitrophenol to 4-aminophenol by catalytic hydrogenation and stoichiometric reduction. Excellent catalytic performances were achieved, with reduction rate constant (Kapp) of 16.8 × 10-3 s-1 for this model reaction. Moreover, the hybrid catalyst can be produced in high yield and recycled.