Inspired by the multiple water purification mechanisms of water hyacinth, a group of researchers has combined different decontamination techniques - adsorption, photocatalytic degradation, distillation - into a single paper-based composite system for water purification by using solar light as the clean energy input. Compared with water treatment with a single mechanism, the multifunctional composite reported in this work could significantly enhance the clean water generation efficiency and maximize the use of the broad-spectrum solar light in a facile and effective way.
Using multilayer graphene as an electrically reconfigurable optical medium, researchers have demonstrated an optoelectronic framework compatible with conventional printing paper. The device consist of two multilayer graphene layers transfer-printed on both sides of the paper. In this configuration, multilayer graphene simultaneously operates as the electrically reconfigurable optical medium and electrically conductive electrodes. In addition, the paper substrate yields a flexible and foldable mechanical support for the graphene layers and it holds the electrolyte in the network of hydrophilic cellulose fibers.
The latest example of a graphene-based wireless sensor that could make 24-hour healthcare easier to achieve by enabling wireless monitoring of various biomedical events in order to gain a more comprehensive assessment of the wearer's healthcare status. This novel device, which detects chemical/molecular agents and lengths of exposure, can be used as lightweight and transparent wearable or bio-implantable electronic sensor. It may provide an inexpensive way to detect in real-time the biomedical of interest.
High-temperature heaters, such as furnaces, are widely used in chemical reactions, materials synthesis and device processing. The limitations of these heating devices often are their bulky size, weight, low maximum heating temperatures and slow ramp rates. To overcome these limitations, and to provide a heating element with a high temperature range to the target object in a micro- and nanoscale environment, researchers have developed a 3D-printable high-temperature, high-rate heater that can be applied to a wide range of nanomanufacturing when precise temperature control in time, placement, and the ramping rate is important.
When inkjet printing graphene, achieving satisfactory results it is a trade-off between the sizes of the graphene sheets and the chosen printing strategies. Direct ink writing offers an attractive way to break the routine and meet the printability with the demanding sheet sizes. The nozzles' diameters range from sub micrometer to millimeter scale to accommodate the inks. More importantly, the extrusion-based procedure plays a crucial role in directing the orientation of graphene sheets to pass through the nozzle during printing.
Lithium-sulfur (Li-S) batteries, which employ sulfur as cathode and metallic lithium as anode materials, have been extensively studied as promising alternatives to the widely used lithium-ion batteries because - theoretically - they can render 3-6 times higher energy density. In practice, though, it has proven challenging to approach that theoretical value. Specifically, the rapid capacity fading, low Coulombic efficiency, and irreversible loss of active materials have impeded large-scale commercial use of Li-S batteries. Researchers now have shown that trapping lithium polysulfide species on (nanoscale) host materials is an effective way to overcome these challenges.
The scaling up of nanomaterials in the broader context of materials science and engineering is the topic of a Perspective article, where the authors construct a roadmap for assembling nanoscale building blocks into bulk nanostructured materials, and define some of the critical challenges and goals. Two-dimenisonal sheets are uniquely well-suited in this roadmap for constructing dense, bulk-sized samples with scalable material performance or interesting emergent properties. But no matter what structures are used, when nanostructures with better-than-bulk material performances are used in bulk form, it is critical that those extraordinary nanoscale properties can be scaled to the macroscopic level.
Hierarchical porous carbon/graphene (HPC/HPG) materials have been intensively investigated over the past decades. These materials are demonstrated as promising electrode materials for various systems, such as lithium-ion batteries, lithium-sulfur batteries, supercapacitors, and fuel cells, with a remarkable capacity, high efficiency, long stability, and excellent rate capability. Researchers have now proposed the employment of hierarchical porous calcium oxide (CaO) particles as effective catalytic template for the facile CVD growth of graphene.