Researchers have developed a new separation membrane with 2D layered transition metal dichalcogenides (tungsten disulfide) for size-selective separation of small molecules of about 3 nm. The as-prepared WS2 membranes exhibit 5 times higher water permeance than graphene oxide membranes with similar rejection. To further improve the water permeance, they team employed ultrathin metal hydroxide nanostrands to create more fluidic channels while keeping the rejection rate of specific molecules unchanged.
A growing body of medical nanotechnology research deals with the development of antibacterial applications, ranging from nanotechnology-based approaches for diagnosing superbugs to antimicrobial surface coatings and wound treatment with antibacterial nanomaterials. Especially silver nanomaterials have been used effectively against different bacteria, fungi and viruses but also carbon nanomaterials like nanotubes and graphene. In new work, researchers have now designed an antibacterial system combining graphene quantum dots with a low dose of a common medical reagent, hydrogen peroxide H2O2.
Renewable and high-capacity energy systems like fuel cells and metal-air batteries are key components in any scenario on future energy systems free of fossil fuels. The performance of fuel cells largely depends on the oxygen reduction reaction - the process that breaks the bonds of the oxygen molecules - which is substantially affected by the activity of the cathode catalyst. Researchers have now demonstrated the synthesis of a novel N-doped graphene/single-walled carbon nanotube hybrid material by a facile and cost-favorable one-step CVD method.
Over the past few years, researchers have developed numerous methods for synthesizing graphene. The synthesis of high-quality graphene is usually prepared by a complex and costly process - epitaxial growth on transition metal surfaces via chemical vapor deposition using high-purity hydrocarbons as precursors. In new work, researchers demonstrate graphene synthesis by liquid precursor deposition, a process that may give access to a wider range of substrate materials for graphene growth.
Most nanomotors designs are powered by quantum or, in most cases, catalytic chemical processes, the nanoscale equivalent of conventional internal heat engines that are so prevalent in our daily life has been missing. Researchers have now suggested a new type of ultrathin graphene engine which mimics an internal combustion engine system. This graphene engine consists of only a few parts - functionalized graphene, laser light, and substrate, which would make it simple to work with.
The nanotechnology-enabled detection of a change in individual cells, for instance cell surface charge, presents a new alternative and complementary method for disease detection and diagnosis. Since diseased cells, such as cancer cells, frequently carry information that distinguishes them from normal cells, accurate probing of these cells is critical for early detection of a disease. For this purpose, researchers have now designed a graphene-based optical refractive index sensor.
Much hope (and hype) rides on graphene as a 'post-silicon' material for fabricating next-generation nanoelectronic devices. However, graphene's Achilles heel is its lack of an energy band gap. Therefore, graphene must be modified to produce a band gap, if it is to be used in electronic devices. Using a new approach, researchers now have demonstrated the operation of an all two-dimensional transistor, using a transition metal dichalcogenides channel material, hexagonal boron nitride gate dielectric, and graphene source/drain and gate contacts.
The way graphene sheets are produced in solution, by exfoliation, is an original process, still not completely understood. The exfoliation of a 2D object from a 3D bulk material is a process spanning from the nano- to meso-scale due to bubble cavitation, intercalation and disruptive fragmentation. When characterizing these 2D sheet solutions, their average size and size standard deviation are commonly reported, often assuming that their size follows a 'normal' distribution. Experimental data shows that this is not the case.