Testing of photocatalytic potential of silver nanoparticles produced through nonthermal plasma reduction reaction and stabilized with saccharides

In this study, silver nanoparticles (AgNPs) were produced through an atmospheric pressure plasma reduction reaction and tested for photodegradation of methyl blue (MB) under sunlight exposure. The argon plasma born reactive species were used to reduce silver ions to AgNPs in the solution. Glucose, fructose and sucrose were also added in the solution to stabilize the growth process. The glucose stabilized reaction produced the smallest nanoparticles of 12 nm, while sucrose stabilized reaction produced relatively larger nanoparticles (14 nm). The nanoparticles exhibited rough morphology and narrow diameter distribution regardless of stabilizer type. The narrow diameter distribution and small band gap helped activating majority of nanoparticles at a single wavelength of light spectrum. The band gap energy of AgNPs varied from 2.22 eV to 2.41 eV, depending on the saccharide type. The photoluminescence spectroscopy of AgNPs produced emission peaks at 413 nm, 415 nm, and 418 nm. The photocatalytic potential of AgNP samples was checked by degrading MB dye under sunlight. The degradation reaction reached a saturation level of 98% after 60 min of light exposure.

Fabricated narrow diameter distribution nanofiber for an air filtration membrane using a double rings slit spinneret

A needleless electrospinning setup called “Needleless Double Rings Slit Electrospinning” was proposed for the first time. The control pump transports solution to the double rings slits through an insulated infusion tube. High voltage is applied to the metal ring and electric force exceeds the surface tension and viscosity, and multiple jets are spontaneously formed on the top of solution surface. Different spinning process parameters, including solution concentration, applied voltage, collection distance and spinning time, have an influence on nanofiber diameter distribution. The morphology of nanofibers has been observed using scanning electron microscopy. It is worth noting that narrow diameter distribution nanofibers have been fabricated using a novel double rings slit spinneret. Nanofiber diameter distribution has determined the mean pore diameter, pore diameter distribution, filtration efficiency and filtration resistance. The final results show that the pore size and filtration property for nanofiber membranes are significantly related with nanofiber diameter distribution. Narrow diameter nanofibers have contributed to the improvement of filtration properties for nanofiber membranes.

Synthesis of single-walled carbon nanotubes on graphene layers

Single-walled carbon nanotubes with a narrow diameter distribution are grown on graphene layers via chemical vapor deposition.

Growth of Single-Walled Carbon Nanotubes from Well-Defined POSS Nanoclusters Structure

High-quality single-walled carbon nanotubes (SWNTs) with narrow diameter distribution can be generated from well-defined Si 8 O 12 nanoclusters structure which form from thermal decomposition of chemically modified polyhedral oligomeric silsesquioxane (POSS). The nanosized Si x O y particles were proved to be responsible for the SWNT growth and believed to be the reason for the narrow diameter distribution of the as-grown SWNTs. This could be extended to other POSS. The SWNTs grown from the nanosized Si x O y particles were found to be semiconducting enriched SWNTs (s-SWNTs). A facile patterning technology, direct photolithography, was developed for generating SWNT pattern, which is compatible to industrial-level fabrication of SWNTs pattern for device applications. The metal-free growth together with preferential growth of s-SWNTs and patterning in large scale from the structure-defined silicon oxide nanoclusters not only represent a big step toward the control growth of SWNTs and fabrication of devices for applications particularly in nanoelectronics and biomedicine but also provide a system for further studying and understanding the growth mechanism of SWNTs from nanosized materials and the relationship between the structure of SWNT and nonmetal catalysts.