Green synthesis of metal nanoparticles using plants

Silver nanoparticles are nanoparticles of silver which are in the range of 1 and 100 nm in size. Silver nanoparticles have unique properties which help in molecular diagnostics, in therapies, as well as in devices that are used in several medical procedures. The major methods used for silver nanoparticle synthesis are the physical and chemical methods. The problem with the chemical and physical methods is that the synthesis is expensive and can also have toxic substances absorbed onto them. To overcome this, the biological method provides a feasible alternative. The major biological systems involved in this are bacteria, fungi, and plant extracts. The major applications of silver nanoparticles in the medical field include diagnostic applications and therapeutic applications. In most of the therapeutic applications, it is the antimicrobial property that is being majorly explored, though the anti-inflammatory property has its fair share of applications. Though silver nanoparticles are rampantly used in many medical procedures and devices as well as in various biological fields, they have their drawbacks due to nanotoxicity. This review provides a comprehensive view on the mechanism of action, production, applications in the medical field, and the health and environmental concerns that are allegedly caused due to these nanoparticles. The focus is on effective and efficient synthesis of silver nanoparticles while exploring their various prospective applications besides trying to understand the current scenario in the debates on the toxicity concerns these nanoparticles pose.

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Silver nanoparticles: mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects

Zinc oxide can be called a multifunctional material thanks to its unique physical and chemical properties. The first part of this paper presents the most important methods of preparation of ZnO divided into metallurgical and chemical methods. The mechanochemical process, controlled precipitation, sol-gel method, solvothermal and hydrothermal method, method using emulsion and microemulsion enviroment and other methods of obtaining zinc oxide were classified as chemical methods. In the next part of this review, the modification methods of ZnO were characterized. The modification with organic (carboxylic acid, silanes) and inroganic (metal oxides) compounds, and polymer matrices were mainly described. Finally, we present possible applications in various branches of industry: rubber, pharmaceutical, cosmetics, textile, electronic and electrotechnology, photocatalysis were introduced. This review provides useful information for specialist dealings with zinc oxide.

Zinc Oxide-From Synthesis to Application: A Review.

Synthesis of metallic nanoparticles using plant extracts.

Nanoparticulate material delivery to plants

Spherical, triangular (prismatic) and square plate shaped gold nanoparticles have been synthesised from HAuCl4 · 3H2O solution using the aqueous leaf extract of Cocculus hirsutus. Nanoparticles are characterised using higher resolution transmission electron microscope, X-ray diffraction and UV–Vis absorption spectroscopic study. FT-IR analysis reveals that the gold nanostructures are mostly stabilised by the carbonyl and amide groups present in the active component of C. hirsutus leaf extract. Formation of gold nanostructures of variable morphologies has been explained due to slow reduction of gold ions by the mild reducing ascorbic acid present within the extract and this controlled reduction assists the preferential deposition of Au atom on different lesser-protected faces of initially grown gold nanostructure.

Synthesis of gold nanoparticles of variable morphologies using aqueous leaf extracts ofCocculus hirsutus

Solution-phase synthesis of silver nanodiscs in HPMC-matrix and simulation of UV-vis extinction spectra using DDA based method.

Photocatalytic metal‐free carboxylation of olefins offers an environment‐friendly approach for resolving the increasing energy issue as well as mitigating the dilemma caused by the greenhouse effect. Carboxylation of styrene and its derivatives by photocatalytic CO2 reduction reaction shows great potential for sustainable utilization of greenhouse gas CO2 into valuable chemicals. Herein, we have constructed a highly crystalline and thermally stable 2D porous covalent organic framework (COF) having very low band‐gap energy, 1.8 eV and it shows efficient photocatalytic activity towards the carboxylation of aryl‐alkenes in good yields in presence of p‐terphenyl as a co‐catalyst at ambient temperature under visible light irradiation and 1 atmospheric CO2 pressure which facilitates to overcome the current transition metal catalyzed approaches. In addition, TR‐OT COF is a proficient and highly selective catalyst with outstanding recyclability. This suggests that this COF material is a novel photocatalyst for CO2 reduction towards α, β‐carboxylation of styrene and its derivatives under 20 W light‐emitting diode (LED) light.

Visible Light‐Driven Carboxylation of Olefins by Using 2D Metal‐Free Covalent Organic Framework as Intrinsic Photocatalyst: A Sustainable Approach for CO2 Utilization

Priyanka Sarkar

Papers

Synthesis of gold nanoparticles of variable morphologies using aqueous leaf extracts ofCocculus hirsutus

Solution-phase synthesis of silver nanodiscs in HPMC-matrix and simulation of UV-vis extinction spectra using DDA based method.

Visible Light‐Driven Carboxylation of Olefins by Using 2D Metal‐Free Covalent Organic Framework as Intrinsic Photocatalyst: A Sustainable Approach for CO2 Utilization