Solid-state self carbo-passivation for refurbishing colloidal dispersity of catalytic silica nanoreactors.

Silica-based nanostructures are among the most utilized materials. However, a persistent challenge is their irreversible agglomeration upon drying and heat treatments, restricting their homogeneous colloidal re-dispersion - a mandatory requirement for diverse bio-applications. We address this bottleneck by developing a self carbo-passivation (SCP) strategy: silica nanoparticles (NPs), pre-included with the catalytic metal precursors and organosilanes undergo thermochemical conversion with highly controlled interior-to-surface segregation of nanometer-scale "carbonaceous skin patches".

Control of sensitivity in metal oxide electrolyte gated field-effect transistor-based glucose sensor by electronegativity modulation.

In this study, the sensitivity of electrolyte-gated field-effect transistor-based glucose sensors using oxide semiconductor materials was controlled via electronegativity modulation. By controlling the enzymatic reaction between glucose and glucose oxidase, which is affected by the surface potential, the sensitivity of the glucose sensor can be effectively adjusted. To evaluate the sensitivity characteristics of the glucose sensor according to electronegativity control, devices were fabricated based on InO through Ga and Zn doping.

Cation-eutaxy-enabled III-V-derived van der Waals crystals as memristive semiconductors.

Novel two-dimensional semiconductor crystals can exhibit diverse physical properties beyond their inherent semiconducting attributes, making their pursuit paramount. Memristive properties, as exemplars of these attributes, are predominantly manifested in wide-bandgap materials. However, simultaneously harnessing semiconductor properties alongside memristive characteristics to produce memtransistors is challenging.

MoO@MoS Core-Shell Structured Hybrid Anode Materials for Lithium-Ion Batteries.

We explore a phase engineering strategy to improve the electrochemical performance of transition metal sulfides (TMSs) in anode materials for lithium-ion batteries (LIBs). A one-pot hydrothermal approach has been employed to synthesize MoS nanostructures. MoS and MoO phases can be readily controlled by straightforward calcination in the (200-300) °C temperature range.

Development of a highly active FeNC catalyst with the preferential formation of atomic iron sites for oxygen reduction in alkaline and acidic electrolytes.

Nitrogen-doped porous carbons containing atomically dispersed iron are prime candidates for substituting platinum-based catalysts for oxygen reduction reaction (ORR) in fuel cells. These carbon catalysts are classically synthesizedviacomplicated routes involving multiple heat-treatment steps to form the desired Fe-N sites. We herein developed a highly active FeNC catalyst comprising of exclusive Fe-N sites by a simplified solid-state synthesis protocol involving only a single heat-treatment.

Curved Structure of Si by Improving Etching Direction Controllability in Magnetically Guided Metal-Assisted Chemical Etching.

Metal-assisted chemical etching (MACE) is widely used to fabricate micro-/nano-structured Si owing to its simplicity and cost-effectiveness. The technique of magnetically guided MACE, involving MACE with a tri-layer metal catalyst, was developed to improve etching speed as well as to adjust the etching direction using an external magnetic field. However, the controllability of the etching direction diminishes with an increase in the etching dimension, owing to the corrosion of Fe due to the etching solution; this impedes the wider application of this approach for the fabrication of complex micro Si structures.

Characterization of Cr (VI) - Containing solid phase particles in dry dust deposition in Daejeon, South Korea.

Solid phase speciation of chromium in dry dust deposition and road paint was determined using transmission electron microscopy (TEM) and X-ray absorption spectroscopy (XAS). Spherical black carbon aggregates in dry dust deposition contained discrete nano-sized lead chromate (PbCrO) and zinc chromate (ZnCrO), which likely originated from yellow traffic paint and zinc chromate primer (corrosion resistant pigment), respectively based on their main applications. Road marking paint samples from auto roads included lead chromate particles whose size, shape, composition and crystal structure were similar to those in dry dust deposition.

Density control and wettability enhancement by functionalizing carbon nanotubes with nickel oxide in aluminum-carbon nanotube system.

Excellent mechanical properties of carbon nanotubes (CNTs) make them ideal reinforcements for synthesizing light weight, high strength metal matrix composite. Aluminum is attractive matrix due to its light weight and Al/CNT composites are promising materials for various industrial applications. Powder metallurgy and casting techniques are normally used for bulk fabrications of composites.

Enhanced morphological and thermal stabilities of nickel germanide with an ultrathin tantalum layer studied by ex situ and in situ transmission electron microscopy.

The formation and morphological evolution of germanides formed in a ternary Ni/Ta-interlayer/Ge system were examined by ex situ and in situ annealing experiments. The Ni germanide film formed in the Ni/Ta-interlayer/Ge system maintained continuity up to 550°C, whereas agglomeration of the Ni germanide occurred in the Ni/Ge system without Ta-interlayer. Through microstructural and chemical analysis of the Ni/Ta-interlayer/Ge system during and after in situ annealing in a transmission electron microscope, it was confirmed that the Ta atoms remained uniformly on the top of the newly formed Ni germanide layer during the diffusion reaction.

Fabrication of CdTe/Te hetero-nanostructures by vapor-solid process.

CdTe/Te core-shell heterostructures were fabricated by the vapor phase synthesis at low temperatures using a quartz tube furnace. Two step vapor-solid processes were employed. First, various tellurium structures such as nanowires, nanorods, nanoneedles, microtubes and microrods were synthesized under different deposition conditions.

Mechanism of Pt loading on multi-walled carbon nanotubes.

Microwave treatment of multi-walled carbon nanotubes (MWCNTs) with nitric acid (HNO3) and 0.2 M sodium chlorate (NaClO3) can generate and enhance defects on the surfaces of MWCNTs. These defects are the important sites to load Pt nanoparticles (NPs).