Algicidal Effects of Green Synthesized Silver Nanoparticles using Tinospora cordifolia on Chlamydomonas reinhardtii

Eco-friendly anti-algal agents are in demand for preventing the growth of unwanted algae. Green synthesized nanoparticles exhibit antimicrobial properties and have been used as a better alternative against chemical and physical processes. In the present study, treatment of silver nitrate with leaf extracts (5% w/v) of Tinospora cordifolia, a plant with proven antimicrobial effects, exhibited UV-visible absorption maxima between 440-460 nm after 1h indicating bioreduction of silver to nanoparticles. The green synthesised silver nanoparticles (5 mgl-1) exhibited inhibition zones against Chlamydomonas reinhardtii in in vitro agar assays. Treatment with green synthesised silver nanoparticles during exponential phase of algal growth resulted in significant reduction in algal population, carbohydrate, protein and chlorophyll contents confirming the anti-algal potential. This is the first report on the growth inhibitory potential of green synthesised silver nanoparticles against green algae

Tunable optical features from self-organized rhodium nanostructures

Manipulating the surface to tune plasmonic emission is an exciting fundamental challenge and here we report on the development of unique morphology-dependant optical features of Rh nanostructures prepared by an equilibrium procedure. The emergence of surface plasmon peaks at 375 nm and 474 nm, respectively, is ascribed to truncated and smooth surface of nanospheres in contrast to the absence of surface plasmon for bulk Rh(0) in the visible range. Smaller sized, high surface area domains with well developed, faceted organization are responsible for the promising characteristics of these Rh nanospheres which might be especially useful for potential catalytic, field emission and magnetic applications

Enhanced electrocatalytic performance of interconnected Rh nano-chains towards formic acid oxidation

A chain-like assembly of rhodium nanoparticles (5–7 nm mean diameter) has been synthesized from rhodium chloride with the help of polydentate molecules like tartaric and ascorbic acids (1 : 3 in mM scale) as capping agents at room temperature. Subsequent characterization using transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy reveals a unique inter-connected network like features, while their electrochemical behavior using cyclic voltammetry and current–time transient suggests potential applications as electrocatalysts in fuel cells. A significant negative shift in the onset potential as well as higher anodic peak current density for formic acid oxidation on Rh- tartaric acid (Rh-TA) as compared to that of bulk Rh metal confirms their higher electrocatalytic activity. Interestingly, the enhancement factor (R) with respect to that of bulk metallic Rh towards formic acid oxidation ranges up to 2000% for Rh-TA and 1200% for Rh-AA (Rh-ascorbic acid) respectively. The composition of Rh nano-chains has been further analyzed with thermogravimetry and Fourier transform infra-red spectroscopy to demonstrate the importance of controlling the chain topology using polyfunctional organic molecules. These findings open up new possibilities for tailoring nanostructured electrodes with potential benefits since the development of a better electrocatalysts for many fuel cell reactions continues to be an important challenge

High aspect ratio nanoscale multifunctional materials derived from hollow carbon nanofiber by polymer insertion and metal decoration

A novel high aspect ratio material which can simultaneously display multiple functions such as proton and electron conductivity and electrocatalytic activity has been developed by incorporating both platinum nanoparticles and phosphoric acid doped polybenzimidazole along the inner and outer surfaces of a hollow carbon nanofibe