scholarly journals Green Synthesis of Ag Nanoparticles by Celery Leaf Extract Supported on Magnetic Carbon-Based Biochar Substrate, as a Green Catalyst for Reduction Reactions

2021 ◽  
Author(s):  
Sahar Taheri ◽  
Majid M Heravi ◽  
Pourya Mohammadi
Keyword(s):  
Electron Microscopy ◽  
Green Synthesis ◽  
Ag Nanoparticles ◽  
Leaf Extract ◽  
Structural Integrity ◽  
Catalytic Performance ◽  
Research Area ◽  
Magnetic Nanocatalyst ◽  
X Ray ◽  
Carbon Based

Abstract Green synthesis of a noble metal such as Ag nanoparticles is an enormously developed research area. In this study, biochar/Fe3O4-Ag magnetic nanocatalyst was produced via a green path by using Celery stalk as a carbon-based substrate, and Celery leaf extract as reducing and stabilizing agents to construct Ag nanoparticles. The synthesized nanocatalyst was determined using various techniques, such as UV-Vis, FT-IR spectroscopy, XRD (X-ray diffraction), SEM/EDX spectroscopy (scanning electron microscopy/energy-dispersive X-ray), TEM (transmission electron microscopy), and VSM (vibrating sample magnetometer). To survey the catalytic action of the biochar/Fe3O4-Ag nanocatalyst, it was used in the reduction reaction of disparate nitroaromatics, aldehydes, and ketones. This catalyst has demonstrated premier characteristics in terms of the amount, reusability, recoverability, activity, and structural integrity of the catalyst during the reaction. In addition, biochar/Fe3O4-Ag could be detached magnetically and recycled multiple times without significantly reducing its catalytic performance.

scholarly journals The Effect of Mg and Zn Dopants on Pt/Al2O3 for the Dehydrogenation of Perhydrodibenzyltoluene

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 490
Author(s):  
Rudaviro Garidzirai ◽  
Phillimon Modisha ◽  
Innocent Shuro ◽  
Jacobus Visagie ◽  
Pieter van Helden ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
Flow Reactor ◽  
Plug Flow ◽  
Optical Emission ◽  
Catalytic Performance ◽  
Emission Spectrometry ◽  
Hydrogen Yield ◽  
X Ray ◽  
Temperature Programmed

The effects of Mg and Zn dopants on the catalytic performance of Pt/Al2O3 catalyst were investigated for dehydrogenation of perhydrodibenzyltoluene (H18-DBT) as a liquid organic hydrogen carrier. Al2O3 supports were modified with Mg and Zn to produce Mg-Al2O3 and Zn-Al2O3 with a target loading of 3.8 wt.% for dopants. The modified supports were impregnated with chloroplatinic acid solution to produce the catalysts Pt/Al2O3, Pt/Mg-Al2O3 and Pt/Zn-Al2O3 of 0.5 wt.% Pt loading. Thereafter, the catalysts were characterised using inductively coupled plasma- optical emission spectrometry, scanning electron microscopy-energy dispersive X-ray spectroscopy, hydrogen temperature-programmed reduction, carbon-monoxide pulse chemisorption, ammonia temperature-programmed desorption, X-ray diffraction and transmission electron microscopy. The dehydrogenation experiments were performed using a horizontal plug flow reactor system and the catalyst time-on-stream was 22 h. Pt/Mg-Al2O3 showed the highest average hydrogen flowrate of 29 nL/h, while an average of 27 nL/h was obtained for both Pt/Al2O3 and Pt/Zn-Al2O3. This has resulted in a hydrogen yield of 80% for Pt/Mg-Al2O3, 71% for Pt/Zn-Al2O3 and 73% for Pt/Al2O3. In addition, the conversion of H18-DBT ranges from 99% to 92%, Pt 97–90% and 96–90% for Pt/Mg-Al2O3, Pt/Zn-Al2O3 and Pt/Al2O3, respectively. Following the latter catalyst order, the selectivity to dibenzyltoluene (H0-DBT) ranges from 78% to 57%, 75–51% and 71–45%. Therefore, Pt/Mg-Al2O3 showed improved catalytic performance towards dehydrogenation of H18-DBT.

scholarly journals Enhanced Photocatalytic Activity of Cu2O Cabbage/RGO Nanocomposites under Visible Light Irradiation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1712
Author(s):  
Appusamy Muthukrishnaraj ◽  
Salma Ahmed Al-Zahrani ◽  
Ahmed Al Otaibi ◽  
Semmedu Selvaraj Kalaivani ◽  
Ayyar Manikandan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermo Gravimetric Analysis ◽  
Visible Region ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Pollutants ◽  
Transmission Electron

Towards the utilization of Cu2O nanomaterial for the degradation of industrial dye pollutants such as methylene blue and methyl orange, the graphene-incorporated Cu2O nanocomposites (GCC) were developed via a precipitation method. Using Hummers method, the grapheme oxide (GO) was initially synthesized. The varying weight percentages (1–4 wt %) of GO was incorporated along with the precipitation of Cu2O catalyst. Various characterization techniques such as Fourier-transform infra-red (FT-IR), X-ray diffraction (XRD), UV–visible diffused reflectance (UV-DRS), Raman spectroscopy, thermo gravimetric analysis (TGA), energy-dispersive X-ray analysis (EDX), and electro chemical impedance (EIS) were followed for characterization. The cabbage-like morphology of the developed Cu2O and its composites were ascertained from field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, the growth mechanism was also proposed. The results infer that 2 wt % GO-incorporated Cu2O composites shows the highest value of degradation efficiency (97.9% and 96.1%) for MB and MO at 160 and 220 min, respectively. Further, its catalytic performance over visible region (red shift) was also enhanced to an appreciable extent, when compared with that of other samples.

Optimization of Green Synthesis Approach of Silver Nanoparticles Using Indonesian Wild Honey

2021 ◽  
Vol 891 ◽  
pp. 111-115
Author(s):  
Maradhana Agung Marsudi ◽  
Farah Fitria Sari ◽  
Pandu Mauliddin Wicaksono ◽  
Adinda Asmoro ◽  
Arif Basuki ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Particle Count ◽  
Transmission Electron ◽  
Nitrate Precursor ◽  
Synthesis Approach

In this work, silver nanoparticles have been successfully synthesized using simple and environmentally friendly ‘green synthesis’ method using Indonesian wild honey as mediator. Particle count and size can be optimized by varying the silver nitrate precursor and honey concentration, with the help of sodium hydroxide as pH regulator. Based on X-ray diffraction (XRD) result, crystalline structure of Ag has been confirmed in sample with impurities from AgCl. Based on dynamic light scattering (DLS) and transmission electron microscopy (TEM) results, it was found that the smallest average particles size of AgNPs (117.5 nm from DLS and 11.1 nm from TEM) was obtained at sample with 5% w/v of honey and 0.5 mM of AgNO3.

BIOSYNTHESIZED SILVER NANOPARTICLES USING CATHARANTHUS ROSEUS AND THEIR ANTIBACTERIAL EFFICACY IN SYNERGY WITH ANTIBIOTICS; A FUTURE ADVANCEMENT IN NANOMEDICINE

2021 ◽  
pp. 116-124
Author(s):  
MONIKA GUPTA
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Catharanthus Roseus ◽  
Leaf Extract ◽  
Research Work ◽  
Resistant Bacteria ◽  
Surface Plasmon Resonance Peak ◽  
Plasmon Resonance Peak ◽  
X Ray ◽  
Uniform Dispersion

Objective: This research work develops an approach to synthesize silver nanoparticles (AgNPs) by reduction of leaf extract of Catharanthus roseus plant. This study produces synthesized nanoparticles that have process-controlled attributes which make their antibiotic action highly efficient. These attributes include smaller size, proper morphology, uniform dispersion, metal ion content, and formation of functional groups. By optimizing the reduction process parameters, AgNPs gain the desired properties.  Methods: The biosynthesis of AgNPs process was performed using reaction of 10% (w/v) C. roseus leaf extract with AgNO3. The optimum conditions and concentration used for synthesis of nanoparticles were: 1 mM AgNO3, pH 5, and temperature 80°C with an incubation time of 72 h. All the above parameters were analyzed by ultraviolet-visible spectrophotometer with the surface plasmon resonance peak obtained at 440 nm. Results: Various characterization techniques were performed, namely, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, photoluminescence study, X-ray diffraction spectroscopy, Fourier transform infrared, dynamic light scattering, and atomic force microscopy. The results obtained from characterization confirmed the spherical morphology of the nanoparticles with size between 50 and 87 nm. In the current investigation, the antimicrobial activity of biosynthesized AgNPs was also determined using minimum inhibitory concentration and zone of inhibition methods against six different bacteria at different doses of AgNPs (100, 150, and 200 μg/ml) alone and also in combination with antibiotic-streptomycin. Conclusion: The results revealed that high concentration of AgNPs inhibits the bacterial growth. Furthermore, AgNPs revealed much stronger antibacterial action in synergy with streptomycin against antibiotic-resistant bacteria.

scholarly journals Green Synthesis and Catalytic Activity of Silver Nanoparticles Based on Piper chaba Stem Extracts

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1777 ◽  
Author(s):  
Md. Mahiuddin ◽  
Prianka Saha ◽  
Bungo Ochiai
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Ftir Spectroscopy ◽  
Visual Observation ◽  
Face Centered Cubic ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Face Centered ◽  
Average Size

A green synthesis of silver nanoparticles (AgNPs) was conducted using the stem extract of Piper chaba, which is a plant abundantly growing in South and Southeast Asia. The synthesis was carried out at different reaction conditions, i.e., reaction temperature, concentrations of the extract and silver nitrate, reaction time, and pH. The synthesized AgNPs were characterized by visual observation, ultraviolet–visible (UV-vis) spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), energy dispersive x-ray (EDX), and Fourier transform infrared (FTIR) spectroscopy. The characterization results revealed that AgNPs were uniformly dispersed and exhibited a moderate size distribution. They were mostly spherical crystals with face-centered cubic structures and an average size of 19 nm. The FTIR spectroscopy and DLS analysis indicated that the phytochemicals capping the surface of AgNPs stabilize the dispersion through anionic repulsion. The synthesized AgNPs effectively catalyzed the reduction of 4-nitrophenol (4-NP) and degradation of methylene blue (MB) in the presence of sodium borohydride.

Ultra-sonication enhanced green synthesis of silver nanoparticles using Barleria buxifolia leaf extract and its possible application

2021 ◽  
Author(s):  
Vanaraj sekar
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Leaf Extract ◽  
Cancer Cell Line ◽  
Xrd Analysis ◽  
Blue Dye ◽  
Multiple Use ◽  
Uniform Size ◽  
X Ray ◽  
Vis Spectroscopy

Abstract A simple and eco-friendly method for the green synthesis of silver nanoparticles (AgNPs) by ultrasound-assisted strategy using Barleria buxifolia leaf extract as a reducing and capping agent was established in this study. The obtained AgNPs were characterized. UV-vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning and transmission electron microscopy (SEM and TEM), Energy Dispersive X-Ray Analyzer (EDX), X-ray diffraction, dynamic light scattering (DLS) analysis showed that the obtained AgNPs were mono dispersed spheres with uniform size of 80 nm. UV-vis spectroscopy, FTIR, and XRD analysis indicated that the surface of the obtained AgNPs was covered with organic molecules in plant extracts. The results of ABTS assays showed that high antioxidant activity was seen in the obtained AgNPs. Green synthesized AgNPs showed potent antibacterial and anti-biofilm activity against tested pathogens. Cytotoxicity assay showed that the obtained AgNPs were significantly cytotoxic to cancer cell line (MCF-7). In addition, the AgNPs synthesized in this paper can also photo catalytically degrade methylene blue dye under visible light. The potent bioactivity exhibited by the green synthesized silver nanoparticles leads towards the multiple use as antioxidant, antibacterial, anti-biofilm, cytotoxic as well as photo catalytic agent.

SYNTHESIS AND CHARACTERIZATION OF NEEM-BASED ZINC OXIDE PHOTOCATALYST

2021 ◽  
Vol 36 (1) ◽  
pp. 9-15
Author(s):  
I.N Gana ◽  
V.U Ohageria ◽  
U.G Akpan ◽  
I.J Ani
Keyword(s):  
Zinc Oxide ◽  
Green Synthesis ◽  
Surface Area ◽  
Leaf Extract ◽  
Zinc Acetate Dihydrate ◽  
Sol Gel ◽  
Sem Analysis ◽  
X Ray ◽  
Bet Analysis ◽  
Neem Leaf Extract

The use of chemicals for the synthesis of photocatalyts poses threat to the environment. In this study, an active photocatalyst, Dalbejiya Dongoyaro (Azadirachta indica)-based zinc oxide (ZnO) was biosynthesized from zinc acetate dihydrate using sol gel and precipitation methods. The synthesized samples were characterized using Fourier Transfer InfraRed (FTIR), X-Ray Diffractometry (XRD), Brunauer Emmet Teller (BET), Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) characterization techniques. The XRD and SEM analysis of the green synthesized and non-green synthesized ZnO demonstrated the formation of hexagonal wurtzite crystalline structure and agglomerated morphology. EDX analysis demonstrated the existence of Zn and O as the major constituents of the as-synthesized nanoparticles with traces of carbon which could be attributed to the carbon tape of the sample holder. The BET analysis displayed that the surface area of the ZnO nanoparticles increased from 23.75 to 97.08 cm3/g after the green synthesis. Based on the surface area values, it can be derived that neem leaf extract enhanced the surface area of the green synthesized sample. Green synthesis is a promising route for the synthesis of photocatalyst nanoparticle which is environmentally friendly and sustainable method. Keywords: Zinc oxide, Neem leaf extract, Photocatalyt, Degradation, Bio-synthesis

scholarly journals Synthesis of Hollow Flower-Like Fe3O4/MnO2/Mn3O4 Magnetically Separable Microspheres with Valence Heterostructure for Dye Degradation

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 589 ◽  
Author(s):  
Mingliang Ma ◽  
Yuying Yang ◽  
Yan Chen ◽  
Fei Wu ◽  
Wenting Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Organic Contaminants ◽  
Dye Degradation ◽  
Catalytic Performance ◽  
X Ray ◽  
Composite Microspheres ◽  
Magnetically Separable ◽  
Mno2 Nanosheet

In this manuscript, hollow flower-like ferric oxide/manganese dioxide/trimanganese tetraoxide (Fe3O4/MnO2/Mn3O4) magnetically separable microspheres were prepared by combining a simple hydrothermal method and reduction method. As the MnO2 nanoflower working as precursor was partially reduced, Mn3O4 nanoparticles were in situ grown from the MnO2 nanosheet. The composite microspheres were characterized in detail by employing scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), vibration sample magnetometer (VSM) and UV–visible spectrophotometer (UV–vis). Under visible light conditions, the test for degrading rhodamine B (RhB) was used to verify the photocatalytic activity of the photocatalyst. The results showed that the efficiency of the Fe3O4/MnO2/Mn3O4 photocatalyst in visible light for 130 min is 94.5%. The catalytic activity of photocatalyst far exceeded that of the Fe3O4/MnO2 component, and after four cycles, the catalytic performance of the catalyst remained at 78.4%. The superior properties of the photocatalyst came from improved surface area, enhanced light absorption, and efficient charge separation of the MnO2/Mn3O4 heterostructure. This study constructed a green and efficient valence heterostructure composite that created a promising photocatalyst for degrading organic contaminants in aqueous environments.

scholarly journals Preparation of pod-shaped TiO 2 and Ag@TiO 2 nano burst tubes and their photocatalytic activity

2019 ◽  
Vol 6 (9) ◽  
pp. 191019 ◽  
Author(s):  
Shang Wang ◽  
Zhaolian Han ◽  
Tingting Di ◽  
Rui Li ◽  
Siyuan Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Oxalic Acid ◽  
Ultraviolet Light ◽  
Photoelectron Spectroscopy ◽  
Degradation Process ◽  
Catalytic Performance ◽  
Tetrabutyl Titanate ◽  
Order Kinetic ◽  
X Ray

The pod-shaped TiO 2 nano burst tubes (TiO 2 NBTs) were prepared by the combination of electrospinning and impregnation calcination with oxalic acid (H 2 C 2 O 4 ), polystyrene (PS) and tetrabutyl titanate. The silver nanoparticles (AgNPs) were loaded onto the surface of TiO 2 NBTs by ultraviolet light reduction method to prepare pod-shaped Ag@TiO 2 NBTs. In this work, we analysed the effect of the amount of oxalic acid on the cracking degree of TiO 2 NBTs; the effect of the concentration of AgNO 3 solution on the particle size and loading of AgNPs on the surface of TiO 2 NBTs. Scanning electron microscopy and transmission electron microscopy investigated the surface morphology of samples. X-ray diffraction and X-ray photoelectron spectroscopy characterized the structure and composition of samples. Rhodamine B (RhB) solution was used to evaluate the photocatalytic activity of pod-shaped TiO 2 NBTs and Ag@TiO 2 NBTs. The results showed that TiO 2 NBTs degraded 91.0% of RhB under ultraviolet light, Ag@TiO 2 NBTs degraded 95.5% under visible light for 75 and 60 min, respectively. The degradation process of both samples was consistent with the Langmuir–Hinshelwood first-order kinetic equation. Therefore, the catalytic performance of the sample is: Ag@TiO 2 NBTs > TiO 2 NBTs > TiO 2 nanotubes.

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