Cytotoxic activity of greener synthesis of cerium oxide nanoparticles using carrageenan towards a WEHI 164 cancer cell line

Carrageenan hydrogel as a “greener” and a vegetable-based stabilizing agent has the potential for many biosyntheses of different nanoparticles by sol-gel method. Herein, we describe for the first time an economic and eco-friendly preparation of cerium oxide nanoparticles (CeO₂-NPs) using carrageenan. When carrageenan hydrogel comes in contact with a cerium nitrate solution, cerium ions anchor themselves to the –SO₃^- groups into the carrageenan and after the gelation process, have fewer opportunities escaping from the polymeric network. The CeO₂-NPs were well-prepared and successfully characterized by PXRD, FTIR, FESEM, UV–Vis, and TGA-DTA. The calcined CeO₂-NPs showed strong UV absorption (λ_max = 328?nm) with the calculated band gap of 2.69?eV. The results obtained from FESEM images indicate that CeO₂-NPs obtained at 600?°C ranges from 18 to 60?nm and have a mean diameter of ~34?nm. The in vitro cytotoxicity study on WEHI 164 cell line has mentioned low toxic and non-toxic CeO₂-NPs in a range of concentrations (0.97–250?μg/ml), thus, we reckon that the greener synthesized CeO₂-NPs will have persistent utilization in various fields of medical applications.     

Plant-based synthesis of cerium oxide nanoparticles as a drug delivery system in improving the anticancer effects of free temozolomide in glioblastoma (U87) cells

Nowadays, nanocarriers were proven to contain the potential of improving cancer treatments and are utilized to carry anticancer medications to tumors. In this study, cerium oxide nanoparticles (CeO₂-NPs) were synthesized by using Caccinia macranthera leaf extract as the stabilizer and reducer agent, as well as cerium nitrate salt as the supplier source of cerium. The synthesized CeO₂-NPs were analyzed through different procedures such as UV–Vis, FTIR, FESEM/EDX/PSA, XRD, XPS, and TGA/DTA. The outcomes of XRD and FTIR analyses con?rmed the synthesis of pure and crystalline structures of CeO₂-NPs. The average size and zeta potential of our nanoparticles were about 30 nm and ?18.5 mV, respectively. According to the results of XPS analysis, the percentage of Ce⁴⁺ was more than that of the Ce³⁺ oxidation state in synthesized NPs. The CeO₂-NPs were loaded with Temozolomide (TMZ) as an anti-cancer drug through electrostatic interaction and the produced nano-drug (CeO₂-TMZ) was delivered to glioblastoma multiforme (GBM) tumor cells. In conformity to the observations, the drug loading content (DLC) and drug loading efficiency (DLE) of CeO₂-TMZ were about 89.10 and 20.29, respectively. In comparison to the TMZ drug, the in vitro assay exhibited the exertion of higher antiproliferative activities, cell cycle arrest, apoptosis, and expression of p53 by CeO₂-TMZ, which proves the promising capability of this drug as a remedial factor for cancer treatment.     

Size-Controlled Synthesis of Colloidal Gold Nanoparticles at Room Temperature Under the Influence of Glow Discharge

Highly dispersed colloidal gold (Au) nanoparticles were synthesized at room temperature using glow discharge plasma within only 5 min. The prepared Au colloids were characterized with UV–visible absorption spectra (UV–vis), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) equipped with an energy dispersion X-ray spectrometer (EDX). UV–vis, XPS and EDX results confirmed that Au³⁺ ions in HAuCl₄ solution could be effectively reduced into the metallic state at room temperature with the glow discharge plasma. TEM images showed that Au nanoparticles were highly dispersed. The size of colloidal Au nanoparticles could be easily tuned in the nanometer range by adjusting the initial concentration of HAuCl₄ solution. Moreover, the as-synthesized Au colloids (d _av = 3.64 nm) exhibited good catalytic activity for glucose oxidation. The nucleation and growth of colloidal Au particles under the influence of the plasma was closely related with the high-energy electrons generated by glow discharge plasma.     

Facile fabrication of porous hollow CeO2 microspheres using polystyrene spheres as templates

Porous hollow CeO₂ microspheres were fabricated using negative-charged PS microspheres as templates by a facile method. The hollow CeO₂ microspheres were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and N₂ adsorption?Cdesorption. The results showed that the as-synthesized hollow CeO₂ microspheres are well monodisperse and uniform in size. The porous shells of hollow microspheres are relatively rough and composed of tiny nanoparticles. The external diameter, internal diameter, and shell thickness of hollow CeO₂ microspheres are about 190, 160, and 15?nm, respectively. A possible mechanism for the formation of hollow CeO₂ spheres was also discussed.     

A convenient approach to synthesize stable silver nanoparticles and silver/polystyrene nanocomposite particles

In this study, silver nanoparticles were prepared by the reduction of silver nitrate in SDS+ isopentanol/styrene/H₂O reverse microemulsion system using sodium citrate as reducing agent. The Ag/PS nanocomposite particles were prepared by in situ emulsion polymerization of the styrene system containing silver nanoparticles that did not separate from the reaction solution. The polymerization dynamic characteristic was studied, at the same time, silver nanparticles and the encapsulation of composite particles were characterized by Fourier‐transform‐infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X‐ray diffraction (XRD) measurement, UV–vis diffuse reflectance spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The results of TEM and UV–vis absorption spectra showed that well‐dispersed silver nanoparticles have a narrow size distribution. XRD showed that Ag and Ag/PS nanocomposite particles were less than 10 and 20 nm in size, which is similar to those observed by TEM. The results of XPS spectra revealed that the microemulsion system can stabilize the silver nanoparticles from aggregation and provided supporting evidence for the polystyrene encapsulated silver nanoparticle structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

Preparation of silver supported porous 4A-zeolite through hard template agent combined with heat treatment and study on its catalytic performance

A simple and novel scheme for preparing hierarchical porous 4A-zeolite was introduced in this study. By Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), X-Ray Powder Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Simultaneous Thermal Analysis (STA), Transmission Electron Microscopy (TEM), CO₂ adsorption–desorption (BET and BJH) and UV–vis spectra, the silver nanoparticles supported samples of microporous-macroporous hierarchical 4A-zeolite (Ag/P-4A-zeolite) were proven to be successfully synthesized. TEM and CO₂ adsorption–desorption images indicated the presence of microporous and the formation of macroporous. XRD, ICP-AES and UV–vis spectra indicated that obtained P-4A-zeolite possess silver nanoparticles. In addition, the catalytic results showed that the silver loaded hierarchical porous 4A-zeolite (Ag/P-4A-zeolite) composite catalyst had catalytic performance in hydrogenation of 4-nitrophenol (4-NP) and epoxidation of styrene.     

Polymer-assisted freeze-drying synthesis of Ag-doped ZnO nanoparticles with enhanced photocatalytic activity

Ag-doped ZnO nanoparticles with high and stable photocatalytic activity were prepared by polymer-assisted freeze-drying method with simple process and without organic solvents used. The structural morphology and optical properties of Ag-doped ZnO nanoparticles were characterized by X-ray Diffraction (XRD), Inductive Coupled Plasma Optical Emission Spectrometry (ICP-OES), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM) and high resolution TEM (HRTEM) with energy dispersive X-ray spectroscopy, Ultraviolet-visible Diffuse Reflectance Spectroscopy (UV–vis DRS), X-ray Photoelectron Spectroscopy (XPS) and Fourier Transmission Infrared Spectroscopy (FTIR). Moreover, the thermoanalytical measurements (TGA–DTG) analysis is carried out for proper calcination temperature. XRD results show that Ag nanoparticles were successfully doped into ZnO lattice, and UV–vis DRS results indicate that the doped Ag nanoparticles result in ZnO exhibiting enhanced light trapping capability in the 400?nm and 600?nm range. The photocatalytic activity of Ag-doped ZnO was examined by analyzing the degradation of methyl orange (MO) and methylene blue (MB) dyes under UV light and solar light irradiation, and the results show that all Ag-doped ZnO nanoparticles exhibit better photocatalytic activity than those of pure ZnO nanoparticles at the same degradation conditions; especially the synthesized Ag-ZnO nanoparticles are easy to be recycled and have high photocatalytic stability. Based on the experimental results, the photocatalytic electron transfer path and the photocatalytic mechanism of Ag-ZnO nanoparticles under UV and solar irradiation conditions are explained and clarified.     

Facile synthesis of CdS nanoparticles photocatalyst with high performance

A simple one-step solid-state reaction has been introduced to synthesize CdS nanoparticles. The as-prepared CdS product was characterized by X-ray powder diffraction (XRD), BET surface area measurement, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), particle size distribution (PSD) and UV–vis absorption spectrum. The experiment results reveal that the CdS product was composed of nanoparticles about 60 nm in diameter, of which specific surface area is 78.02 m²/g. The photocatalysis results indicate that the CdS nanoparticles exhibit excellent photocatalytic activity for the degradation of rhodamine B under UV irradiation. Nearly 95% of rhodamine B was degraded after 60 min of irradiation, higher than that of P25, which is due to the large specific surface area and mesoporous structure.     

Characterization of surface-modified ceria oxide nanoparticles synthesized continuously in supercritical methanol

Surface-modified ceria oxide (CeO₂) nanoparticles were synthesized continuously in supercritical methanol at 400 °C, 30 MPa and a residence time of ∼40 s using a flow type reactor system. Oleic acid and decanoic acid were used as the surface modifiers. Transmission electron microscopy (TEM) showed that the surface modifiers changed drastically the shape and size of the nanoparticles. When 0.3 M of the surface modifiers were used, primary particles with diameter of 2–3 nm loosely aggregated and formed secondary particles with size of 30–50 nm. Wide angle X-ray diffraction (WAXD) analysis revealed that the surface-modified nanoparticles retained CeO₂ crystalline structure. The surface-modified CeO₂ nanoparticles had a very high surface area (140–193 m²/g) compared to the unmodified CeO₂ particles synthesized in supercritical water (8.5 m²/g). Fourier transform infrared (FT-IR) and thermogravimetric analysis (TGA) indicated that aliphatic, carboxylate and hydroxyl groups were chemically bounded on the surface of CeO₂ nanoparticles. Dispersability test using ultraviolet transmittance showed that most of the surface-modified CeO₂ nanoparticles were dispersed in ethylene glycol for 30 days while the unmodified CeO₂ particles synthesized in supercritical water or in supercritical methanol were precipitated after 7–15 days.     

Biosynthesized Ag–ZnO nanohybrids exhibit strong antibacterial activity by inducing oxidative stress

We report facile biosynthesis of Ag–ZnO nanohybrids consisting of Ag nanoparticles decorated ZnO nanobullets prepared by decorating wet chemically synthesized ZnO nanobullets with Ag nanoparticles through bioreduction of Ag ⁺ ions with aqueous extract of Piper nigrum fruits. The prepared nanomaterials were well characterized by FESEM, TEM, HRTEM, EDX, XRD, XPS, PL and UV–vis spectroscopy. FESEM and TEM analyses on the nanohybrids revealed ∼18 nm Ag nanoparticles decorating ZnO nanobullets with average size ∼48 nm. XRD results revealed hexagonal wurtzite ZnO with 22.4 nm crystallite size and FCC Ag with 18.7 nm crystalline size. Ag–ZnO nanohybrids exhibited strong antibacterial action against Escherichia coli, Bacillus oceanisediminis and Pseudomonas entomophila and efficiently inhibited their growth at 100 μg/mL, 50 μg/mL and 125 μg/mL, respectively. The molecular basis of antibacterial action of Ag–ZnO nanohybrids against E. coli was investigated using different biochemical and molecular assays. Addition of antioxidant histidine suppressed the antibacterial action of Ag–ZnO nanohybrids towards E. coli due to its ROS scavenging action. Bradford assay results showed enhanced protein leakage from Ag–ZnO nanohybrids treated E. coli, while TBARS assay results confirmed lipid peroxidation triggered by ROS. SEM on Ag–ZnO nanohybrids treated E. coli confirmed significant damage to the cell wall leading to morphology change. The antibacterial activity of Ag–ZnO nanohybrids against E. coli is mainly due to the ROS-induced oxidative stress, which caused enhanced lipid peroxidation, cell wall damage leading to significant protein leakage and DNA fragmentation.     

Investigation of optical and thermally stimulated properties of SiO2 nanoparticles‐filled polycarbonate

Polycarbonate nanocomposite containing silicon oxide nanoparticles average size of 5 nm at different weight ratio has been prepared by solution mixing method. The dispersion of nanoparticles in polymer matrix was studied by transmission electron microscopy (TEM). The optical and thermally stimulated behavior of nanocomposites were analyzed by energy dispersive X‐ray spectra (EDX), X‐ray diffraction pattern (XRD), UV–vis spectroscopy, differential scanning calorimetry (DSC), and thermally stimulated discharge current (TSDC). TEM images show the dispersion and size of the nanoparticles, however, EDX indicate the presence of SiO₂ on the surface of the nanocomposite film. An XRD result reveals that the crystallinity increases with increase in concentration of SiO₂ nanoparticles in polymer matrix. The direct and indirect optical energy band gaps decreased and number of carbon atom increased with concentration of SiO₂ nanoparticles. We have observed that the increase of SiO₂ nanoparticles in PC significantly reduces the refractive index. DSC and TSDC show that glass transition temperature increases according to SiO₂ weight ratio. The TSDC of nanocomposites samples could be understand in terms of non‐Debye theory of charge relaxation and co‐tunneling mechanism of charge transport. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Mangrove-mediated synthesis of silver nanoparticles using native Avicennia marina plant extract from southern Iran

The development of eco-friendly and nontoxic processes for the synthesis of nanoparticles is one of the most important discussed issues in nanotechnology science. This study reports the green synthesis of silver nanoparticles (AgNPs) using aqueous extract of leaf, stem, and root of Avicennia marina, the native and dominant mangrove plant in southern Iran. Among the different plant parts, the extract of leaves yielded the maximum synthesis of AgNPs. Synthesized AgNPs were investigated using UV–visible spectrophotometry, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and Fourier transform infrared (FTIR) spectroscopy. Absorption spectrum in 420?nm confirmed the synthesis of AgNPs. TEM images revealed that the synthesized AgNPs had the same spherical morphology with a size range between 0 and 75?nm. The distribution size histogram indicated that the most frequent particles were in the range of 10–15?nm and the mean size of nanoparticles was 17.30?nm. The results of SEM image showed nanoparticles with a size range between 15 and 43?nm. XRD pattern indicated the crystalline nature of synthesized nanoparticles. EDS results confirmed the presence of elements like silver, carbon, chlorine, nitrogen, and oxygen in the nanoparticles produced from leaf extract. Silver had the maximum percentage of formation, 51.6%. FTIR indicated the presence of different functional groups such as amines, alcohol, alkanes, phenol, alkyl halides, and aromatic loops in the synthesis process. Green biosynthesis of AgNPs using aqueous extract of native A. marina appears rapid, reliable, nontoxic, and eco-friendly.     

Synthesis,characterization and enhanced visible-light photocatalytic activity of Zn2SnO4/C nanocomposites with truncated octahedron morphology

Novel Zn₂SnO₄/C nanocomposites with truncated octahedron morphology were constructed using a two-step hydrothermal synthesis route combined with subsequent calcination. The as-prepared samples were characterized by X–ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR), Raman spectroscopy, field–emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflection spectroscopy, photoluminescence spectroscopy (PL), and Brunauer–Emmett–Teller surface area measurements. The result of FESEM showed that the as-prepared Zn₂SnO₄/C nanocomposites are composed of numerous uniform nanoparticles with regular truncated octahedron morphology. Raman spectral characterization combined with HRTEM result revealed that a thin layer of carbon was attached on the surface of Zn₂SnO₄. Using rhodamine B (RhB) as a model organic pollutant, the visible-light photocatalytic activities of the as-prepared samples were investigated, and the photocatalytic mechanism was discussed. Compared with pure Zn₂SnO₄, Zn₂SnO₄/C nanocomposites exhibited much better visible-light photocatalytic activity. The increase in the photocatalytic activity of Zn₂SnO₄/C nanocomposites was mainly attributed to the enhancement of the optical absorption capability and efficient separation of photogenerated electron-hole pairs.     

Application of In Situ Surface-Enhanced Raman Spectroscopy (SERS) to the Study of Citrate Oxidation on Silica-Supported Silver Nanoparticles

Surface-enhanced Raman spectroscopy (SERS) was used to characterize citrate anions adsorbed on nanometer-sized particles of Ag supported on SiO₂. The magnitude of the surface-enhancement effect was determined to be ～3 × 10² on the as-prepared samples of Ag/SiO₂. Upon heating in air above 373 K, the citrate anions undergo oxidation to uni- and bidentate carbonate species and then decomposition to CO₂ and adsorbed O atoms. In the SERS of Ag/SiO₂, a very strong enhancement of the ν(C=O) signal for the bidentate CO₃ species was observed for temperatures between 398 and 448 K, which is accompanied by an increase in the UV–vis absorbance of the sample at the frequency of the laser line used for Raman spectroscopy. This phenomenon is attributed to an increase in the surface-enhancement effect caused by clustering of the Ag nanoparticles as they sinter at elevated temperatures. The present investigation shows that the proper interpretation of in situ SERS spectra requires an understanding of the changes occurring in the UV–vis spectrum of the sample.     

Nanostructured CeO2 for selective-sensing and smart photocatalytic applications

Well crystalline CeO₂ nanoparticles have been successfully synthesized via solution combustion synthesis (SCS) using (NH₄)₂[Ce(NO₃)₆] and C₄H₆O₆ as oxidizer and fuel. The structural characteristics of as-synthesized material were investigated in terms of FESEM, HRTEM, EDS, XRD, FTIR and UV–Vis spectroscopy techniques. The surface area of synthesized CeO₂ nanoscale material was obtained from BET plot. Results showed a pure, well-crystallized, flake-like mesoporous material to be formed with crystallite size of 18.86?nm. The focus of this study was to investigate the application of as-synthesized CeO₂ nanomaterial for sensing and photocatalytic degradation of picric acid (PA) in its aqueous solution. It was found to be highly selective for PA detection in aqueous solution when compared with other aromatic compounds. Detection limit (0.52?µM) for PA when compared with earlier studies was found to be much better. In addition, 0.05?gm of as-synthesized CeO₂ nanomaterial is found to be optimum amount ensuring maximum catalytic photodegradation of 10?ppm PA in aqueous solution. These experimental findings point out that as-synthesized CeO₂ nanomaterial can be efficiently used as an effective chemical sensor and photocatalyst.     

A novel one-pot biosynthesis of pure alpha aluminum oxide nanoparticles using the macroalgae Sargassum ilicifolium: A green marine approach

A novel biological method is proposed for producing ceramic alpha aluminum oxide nanoparticles using an extract of the algae Sargassum ilicifolium. The algal extract functions as a bioreducing as well as a stabilizer agent. The presence of an absorption peak at 227?nm, confirmed the formation of the aluminum oxide nanoparticles using a UV–visible spectroscopy. FTIR analysis indicated that bioreduction of aluminum ions and nanoparticle stabilization probably occurred by interactions between aluminum and the biofunctional groups of algal extract. The XRD pattern revealed that after calcination at ~ 1200?°C, the Al₂O₃ nanoparticles were alpha crystalline in nature with a diameter of 35?nm and had a rhombohedral structure. TEM indicated that the alumina nanoparticles were well-dispersed and spherical in shape with an average size of 20?±?2.1?nm. EDX spectroscopy revealed that the sample contained only aluminum (46.31%) and oxygen (53.69%), confirming the high purity of the alumina nanopowder. The results demonstrated that alpha alumina NPs has an optical band gap of 5.46?eV.     

Synthesis of heterostructured Bi2O3–CeO2–ZnO photocatalyst with enhanced sunlight photocatalytic activity

The development of heterostructured semiconductor photocatalysts makes a noteworthy advancement in environmental purification technology. In this work, a novel heterostructured Bi₂O₃−CeO₂−ZnO, fabricated by a combination of microwave-assisted hydrothermal and thermal decomposition methods, showed an enhanced photocatalytic activity for Rhodamine B (RhB) degradation under sunlight, as compared to pristine ZnO, Bi₂O₃, CeO₂, and commercial Degussa TiO₂-P25. The obtained products were thoroughly characterized by various techniques including X- ray powder diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), elemental color mapping, energy-dispersive X-ray spectroscopy (EDAX), Raman spectrometry, Fourier transform infrared (FT-IR) spectroscopy, UV–visible diffuse reflectance spectroscopy (UV–vis DRS), and photoluminescence (PL) spectroscopy. PXRD analysis reveals that the heterostructure has the monoclinic lattice phase of α-Bi₂O₃, the cubic phase of CeO₂ and the hexagonal wurtzite phase of ZnO. FE-SEM images show that Bi₂O₃−CeO₂−ZnO has an ordered mixture of nanorod and nanochain structures. EDAX, elemental color mapping, Raman and FT-IR analyses confirm the successful formation of the heterostructured Bi₂O₃−CeO₂−ZnO. The UV–Vis DRS results demonstrate that Bi₂O₃−CeO₂−ZnO exhibits wide visible-light photoabsorption in 400–780 nm range. Moreover, the reduction in PL intensity of the heterostructured Bi₂O₃−CeO₂−ZnO, when compared to the pristine Bi₂O₃, CeO₂, and ZnO, indicates enhanced charge separation. The study on the mechanism displayed that the improved photocatalytic activity of Bi₂O₃−CeO₂−ZnO could be attributed to (1) the efficient separation of photoinduced electrons and holes of the photocatalysts, caused by the vectorial transfer of electrons and holes among ZnO, CeO₂ and Bi₂O₃, and (2) the wide visible-light photoabsorption range. This study introduces a new class of promising sunlight-driven photocatalysts.     

Physicochemical and catalytic properties of nanosized Au/CeO2 catalysts for eco-friendly oxidation of benzyl alcohol

In this work, benzyl alcohol oxidation was investigated over Au/CeO₂-homogeneous deposition–precipitation (ACH) and Au/CeO₂-direct anionic-exchange (ACD) catalysts. Various characterization techniques were employed to study their physicochemical properties. TEM images revealed presence of 5.3 and 7.4 nm Au nanoparticles in ACH and ACD catalysts, respectively. Raman studies showed that only ACH sample exhibits oxygen deficiency (0.0574). Amongst, the ACH catalyst exhibited better catalytic performance owing to smaller gold nanoparticles and abundant oxygen vacancies. The alcohol conversion and product selectivity were strongly dependent on temperature and time-on-stream conditions. The catalytic activity decreased after repeated use due to aggregation of Au nanoparticles.     

Biopolymer-assisted green synthesis and characterization of calcium hydroxide nanoparticles

The use of biopolymers in the synthesis of different nanostructures can be a cost effective and eco-friendly approach. In the present study, a facile and “green” sol–gel method was employed for preparing calcium hydroxide nanoparticles (Ca(OH)₂-NPs) in gelatin matrix as a bio-template. Prepared nanoparticles were characterized by different instruments such as powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR). The PXRD analysis revealed hexagonal Ca(OH)₂-NPs with preferential orientation in (101) reflection plane. They are hexagonal in shape with a mean particle size of approximately 42 nm in thickness. The synthesized Ca(OH)₂-NPs using gelatin were found to be comparable to those obtained from conventional methods using hazardous capping/stabilizing polymeric agents or surfactants and this route can be an excellent alternative for the synthesis of Ca(OH)₂-NPs using biomaterials.     

Au–Pt nanoparticles in amine functionalized MCM-41: Catalytic evaluation in hydrogenation reactions

Nano-sized Au–Pt nanoparticles (Au–Pt-bi-MNPs) have been synthesized by the simultaneous reduction of HAuCl₄ and HPtCl₆ by NaBH₄ inside the channels of amine functionalized Si-MCM-41 (NH₂–Si-MCM-41) at ambient conditions. These materials were characterized using chemical analysis, UV–vis, XPS, XRD, FT-IR, Surface area and TEM analysis. The size of these alloyed nanoparticles (bi-MNPs) were found in the range of 2–4 nm. These nanoparticles were evaluated to study their catalytic activities towards hydrogenation of aromatic nitro compounds. The catalytic activity of the Au–Pt bi-MNPs was found to be superior to monometallic Au nanoparticles.