These images show the completed triple layer nanowires. Image: KAUST. By combining multiple nanomaterials into a single structure, researchers at the King Abdullah University of Science & Technology (KAUST) in Saudi Arabia have been able to create hybrid materials that incorporate the best properties of each component and outperform any single substance.
The researchers have developed a controlled method for making triple-layered hollow nanostructures consisting of a conductive organic core sandwiched between layers of electrocatalytically active metals. The potential uses for these nanostructures, which are reported in a paper in Nature Communications , range from better battery electrodes to renewable fuel production.
Although several methods exist to create two-layer nanomaterials, making three-layered nanostructures has proven much more difficult, says Peng Wang from KAUST’s Water Desalination and Reuse Center. Wang co-led the current research with Yu Han, a member of the Advanced Membranes and Porous Materials Center at KAUST. This difficulty inspired the researchers to develop a new, dual-template approach, explains Sifei Zhuo, a postdoctoral member of Wang's team.
The researchers grew their hybrid nanomaterial directly on carbon paper – a mat of electrically conductive carbon fibers. They first produced a bristling forest of nickel cobalt hydroxyl carbonate (NiCoHC) nanowires on the surface of each carbon fiber. Each tiny inorganic bristle was coated with an organic layer called hydrogen-substituted graphdiyne (HsGDY).
Next came the key dual-template step. When the team added a chemical mixture that reacts with the inner NiCoHC, the HsGDY acted as a partial barrier. Some nickel and cobalt ions from the inner layer diffused outward, where they reacted with thiomolybdate from the surrounding solution to form an outer nickel- and cobalt-co-doped molybdenum disulfide (Ni,Co-MoS2 ) layer. Meanwhile, some sulfur ions from the added chemicals diffused inwards to react with the remaining nickel and cobalt. The resulting substance had the structure Co9 S8 , Ni3 S2 @HsGDY@Ni,Co-MoS2 , in which the conductive organic HsGDY layer is sandwiched between two inorganic layers.
This triple layer material showed good ability at electrocatalytically splitting water molecules to generate hydrogen, a potential renewable fuel. The researchers also created other triple-layer materials using the same dual-template approach.
"These triple-layered nanostructures hold great potential in energy conversion and storage," says Zhuo. "We believe it could be extended to serve as a promising electrode in many electrochemical applications, such as in supercapacitors and sodium-/lithium-ion batteries, and for use in water desalination."
This story is adapted from material from KAUST , with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source .