Green synthesis of silver nanoparticles using Terminalia cuneata and its catalytic action in reduction of direct yellow-12 dye

Facile green synthesis of silver nanoparticles (AgNPs) using aqueous bark extract of Terminalia cuneata has been reported in this article. The effects of concentration of the extract, reaction time and pH were studied by UV-Vis spectroscopy. Appearance of yellow color with λmax around ~420 nm suggested the formation of AgNPs. The stable AgNPs were further characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) with zeta potential and high resolution transmission electron microscopy (HR-TEM) with energy dispersive X-ray spectroscopy (EDS) analysis. The synthesized AgNPs were in the size range of 25-50 nm with a distorted spherical shape identified from HR-TEM analysis. The catalytic activity of AgNPs on the reduction of direct yellow-12 using NaBH4 was analyzed using a UV-Vis spectrophotometer. This study showed the efficacy of biogenic AgNPs in catalyzing the reduction of direct yellow-12.

Facile preparation of a hierarchically porous metal–organic nanocomposite with excellent catalytic performance

A hierarchical porous MOF nanocrystal, hpCuL (L = 2,4,6-tris(3,5-dicarboxylatephenylamino)-1,3,5-triazine) was prepared via a facile gel-aging process. This nanocomposite exhibits high catalytic activity and stability for the reduction of 4-nitrophenol.

Thermosensitive antibacterial Ag nanocomposite hydrogels made by a one-step green synthesis strategy

Clay nanosheets act as a catalyst and stabilizing agent for rapid in situ synthesis of silver nanoparticles in a hydrogel matrix.

In situ formation of gold nanoparticles on magnetic halloysite nanotubes via polydopamine chemistry for highly effective and recyclable catalysis

A simple and green approach to fabricate magnetic halloysite nanotubes supported Au nanoparticles composite from bio-inspired polydopamine chemistry was demonstrated for highly effective and recyclable catalysis.

The preparation of a recyclable catalyst of silver nanoparticles dispersed in a mesoporous silica nanofiber matrix

A recyclable catalyst of sliver nanoparticles well dispersed in mesoporous silica was successfully synthesized via a straight-forward strategy combining an electrospinning technique with post-calcination.

In situ and facile synthesis of silver nanoparticles on baby wipes and their applications in catalysis and SERS

Silver nanoparticles were immobilized on fibers to create composite materials. The composites are shown to be efficient heterogeneous catalyst with very good recyclability. These composite materials are also proven to be good SERS substrates.

E. N. Fabrication of a versatile chitosan nanocomposite hydrogel impregnated with biosynthesized silver nanoparticles using Sapindus mukorossi: characterization and applications

A biological and eco-friendly method has been adopted for the synthesis of silver nanoparticles, which can be used for a number of applications.

Tannic acid functionalized graphene hydrogel for entrapping gold nanoparticles with high catalytic performance toward dye reduction

In this work, a simple, cost-effective, and environmental-friendly strategy was developed to synthesize gold nanoparticles (Au NPs) decorated graphene hydrogel with the use of tannic acid. This facile route involved the reduction of graphene oxide (GO) in the presence of tannic acid to form tannic acid functionalized graphene hydrogel, followed by loading and in situ reduction of AuCl4(-) ions in the graphene hydrogel network benefiting from the abundant phenol groups of tannic acid. Tannic acid (TA), a typical plant polyphenol widely present in woods, not only reduced GO and induced the self-assembly of reduced graphene oxide into graphene hydrogel, but also served as the reducing agent and stabilizer for the synthesis and immobilization of Au NPs, avoiding extra chemical reagent and any stabilizer. The obtained Au NPs decorated graphene hydrogel (Au@TA-GH) was fully characterized and exhibited much higher catalytic activities than the unsupported and other polymer-supported Au NPs toward the reduction of methylene blue (MB). In addition, the high catalytic activity of Au@TA-GH could withhold in different pH solution conditions. Another distinct advantage of Au@TA-GH as catalysts is that it can be easily recovered and reused for five cycles.

A Sustainable Approach to Fabricating Ag Nanoparticles/PVA Hybrid Nanofiber and Its Catalytic Activity

Ag nanoparticles were synthesized by using Ficus altissimaBlume leaf extract as a reducing agent at room temperature. The resulting Ag nanoparticles/PVA mixture was employed to create Ag nanoparticles/PVA (polyvinyl alcohol) hybrid nanofibers via an electrospinning technique. The obtained nanofibers were confirmed by means of UV-Vis spectroscopy, The X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and then tested to catalyze KBH₄ reduction of methylene blue (MB). The catalytic results demonstrate that the MB can be reduced completely within 15 min. In addition, the Ag nanoparticles/PVA hybrid nanofibers show reusability for three cycles with no obvious losses in degradation ratio of the MB.

An autonomic and “off–on–off”-switchable polymer microreactor

An autonomic “off–on–off” polymer microreactor containing the switchable domains of molecular chains is reported. The switching of molecular chains acted as a molecular switch for regulating access to the encapsulated metal nanoparticles.

A porous aerogel nanocomposite of silver nanoparticles-functionalized cellulose nanofibrils for SERS detection and catalytic degradation of rhodamine B

Herein, cellulose nanofibrils (CNFs) were functionalised with silver nanoparticles (AgNPs) via a green in situ hydrothermal synthesis approach. The produced nanocomposites were used for the detection and catalytic degradation of rhodamine B.

Alginate fibers embedded with silver nanoparticles as efficient catalysts for reduction of 4-nitrophenol

Silver nanoparticles (AgNPs) have attracted much attention as promising catalysts in various electron transfer reactions due to their high catalytic efficiency.

Amidic C–N bond cleavage of isatin: chemoselective synthesis of pyrrolo[2,3,4-kl]acridin-1-ones using Ag NPs decorated rGO composite as an efficient and recoverable catalyst under microwave irradiation

A facile route for the chemo-selective synthesis of pyrrolo[2,3,4-kl]acridin-1-ones via ring-opening or amidic C–N bond cleavage of isatin under microwave irradiation using Ag NPs/rGO composite as an effective and robust catalyst has been described.

Highly regenerable mussel-inspired Fe₃O₄@polydopamine-Ag core-shell microspheres as catalyst and adsorbent for methylene blue removal

We report a facile method to synthesize Fe3O4@polydopamine (PDA)-Ag core-shell microspheres. Ag nanoparticles (NPs) are deposited on PDA surfaces via in situ reduction by mussel-inspired PDA layers. High catalytic activity and fast adsorption of a model dye methylene blue (MB) at different pH values are achieved mainly due to the presence of monodisperse Ag NPs and electrostatic interactions between PDA and MB. The as-prepared Fe3O4@PDA-Ag microspheres also show high cyclic stability (>27 cycles), good acid stability, and fast regeneration ability, which can be achieved efficiently within several minutes by using NaBH4 as the desorption agent, showing great potentials in a wide range of applications.

A one-step green route to synthesize copper nanocrystals and their applications in catalysis and surface enhanced Raman scattering

A nontoxic, simple, inexpensive, and reproducible strategy, which meets the standard of green chemistry, is introduced for the synthesis of copper nanocrystals (Cu NCs) with olive oil as both reducing agent and capping agent. By changing the reaction parameters, the shape, size and surface structure of the Cu NCs can be well controlled. The obtained Cu nanocubes show excellent catalytic properties for the catalytic reduction of dyes and CO oxidation. Moreover, the prepared Cu nanocubes as substrates exhibit surface enhanced Raman scattering (SERS) activity for 4-mercaptopyridine (4-Mpy). Therefore, this facile route provides a useful platform for the fabrication of Cu NCs which have the potential to replace noble metals for certain applications.

Microwave Assisted Biosynthesis of Silver Nanoparticles Using the Rhizome Extract of Alpinia galanga and Evaluation of Their Catalytic and Antimicrobial Activities

Biomediated methods are considered to be a safer alternative to conventional physicochemical methods for the fabrication of nanomaterials due to their eco-friendly nature. In the present study, silver nanoparticles (AgNPs) were synthesized by microwave irradiation using aqueous rhizome extract of the medicinal plant Alpinia galanga. The nanoparticles were also synthesized under ambient condition without the assistance of microwave radiation and the former method was found to be much faster than the latter. The silver nanoparticles were characterized by UV-vis., FTIR, XRD, and HR-TEM analysis. UV-vis. spectroscopic studies provided ample evidences for the formation of nanoparticles. The FTIR spectrum confirmed the presence of plant phytochemicals as stabilizing agent around the AgNPs. XRD and HR-TEM analyses clearly proved the crystalline nature of the nanoparticles. From the TEM images, the nanoparticles were found to be roughly spherical in shape with an average diameter of 20.82 ± 1.8 nm. The nanoparticles showed outstanding catalytic activity for the reduction of methyl orange by NaBH4. The AgNPs were also evaluated for their antimicrobial activity by well diffusion method against S. aureus, B. subtilis, V. cholera, S. paratyphi, and A. niger. They were found to be highly toxic against all the tested pathogenic strains.

Facile in situ synthesis of silver nanoparticles on procyanidin-grafted eggshell membrane and their catalytic properties

Facile, efficient, and robust immobilization of metal nanostructures on porous bioscaffolds is an interesting topic in materials chemistry and heterogeneous catalysis. This study reports a facile in situ method for the synthesis and immobilization of small silver nanoparticles (AgNPs) at room temperature on natural eggshell membrane (ESM), which presents interwoven fibrous structure and can be used as a unique protein-based biotemplate. Procyanidin (Pro), a typical plant polyphenol extracted from grape seeds and skins, was first grafted onto ESM fibers to serve as both reductant and stabilizer during the synthesis process. As a result, the AgNPs were facilely synthesized and robustly immobilized on the ESM fibers without additional chemical reductant or physical treatments. The morphology and microstructure of the as-prepared AgNPs@Pro-ESM composites were characterized by combined microscopy and spectroscopy technologies. The results indicate that small AgNPs with mean diameter of 2.46 nm were successfully prepared on the Pro-ESM biotemplate. The composites exhibited good catalytic activity toward the reduction of 4-nitrophenol (4-NP). More importantly, these composite catalysts can be easily recovered and reused for more than eight cycles because of their high stability.

Highly versatile p(MAc)–M (M: Cu, Co, Ni) microgel composite catalyst for individual and simultaneous catalytic reduction of nitro compounds and dyes

Poly(methacrylic acid) (p(MAc)) microgels were synthesized by inverse suspension polymerization and used as a template for copper, nickel, and cobalt nanoparticle preparation.

Towards intelligent bioreactor systems: triggering the release and mixing of compounds based on DNA-functionalized hybrid hydrogel

We have designed and synthesized an intelligent DNA-functionalized hydrogel bioreactor system that can be controlled by external stimuli.

Synthesis and Characterization of Silver/Titanium dioxide Core-Shell Nanoparticles

Silver nanoparticles (AgNPs) with mean diameter of 150 nm were synthesized by using an aqueous-basedreduction method. Ascorbic acid and sodium hydroxide (NaOH) were used as a reducing agent and as acatalyst, respectively. These AgNPs were subsequently coated with a layer of TiO2 to form Ag/TiO2 core-shellnanoparticles by using a sol-gel method. The particle sizes and morphology of Ag/TiO2 core-shellnanoparticles were characterized using scanning electron microscopy (SEM) and transition electronmicroscopy (TEM). The photocatalytic activity of the Ag/TiO2 core-shell nanoparticles were evaluated basedon the degradation of methylene blue (MB) as the model reaction. The TiO2 coating has resulted in theenhanced photocatalytic activity of Ag nanoparticles as compared to bare Ag nanoparticles.