Probing of Ni-Encapsulated Ferromagnetic Boron Nitride Nanotubes by Time-Resolved and Steady-State Photoluminescence Spectroscopy

Here we report the synthesis of multifunctional Ni-encapsulated boron nitride nanotubes (BNNTs), with average diameter and length measuring ∼30 nm and ∼25 μm, by a facile ball-milling–chemical vapor deposition route. The resulting BNNTs exhibit an intense blue emission peaking at ∼480 nm upon ∼365 nm excitation, and the time-resolved emission spectroscopy shows a photoluminescence decay lifetime of picoseconds. The SQUID magnetization measurements show an enhanced coercivity of 140 Oe. Obtained collective optical and magnetic properties of BNNT suggest that it could be an exceptional choice for future optomagnetic-based sensor devices, biomedical therapy, and bioimaging applications

Three-Dimensionally Engineered Porous Silicon Electrodes for Li Ion Batteries

The ultimate goal of Li ion battery design should consist of fully accessible metallic current collectors, possibly of nanoscale dimensions, intimately in contact with high capacity stable electrode materials. Here we engineer three-dimensional porous nickel based current collector coated conformally with layers of silicon, which typically suffers from poor cycle life, to form high-capacity electrodes. These binder/conductive additive free silicon electrodes show excellent electrode adhesion resulting in superior cyclic stability and rate capability. The nickel current collector design also allows for an increase in silicon loading per unit area leading to high areal discharge capacities of up to 0.8 mAh/cm² without significant loss in rate capability. An excellent electrode utilization (∼85%) and improved cyclic stability for the metal/silicon system is attributed to reduced internal stresses/fracture upon electrode expansion during cycling and shorter ionic/electronic diffusion pathways that help in improving the rate capability of thicker silicon layers

Conversion of Industrial Bio-Waste into Useful Nanomaterials

Chromium-complexed collagen is generated as waste during processing of skin into leather. Here, we report a simple heat treatment process to convert this hazardous industrial waste into core–shell chromium–carbon nanomaterials having a chromium-based nanoparticle core encapsulated by partially graphitized nanocarbon layers that are self-doped with oxygen and nitrogen functionalities. We demonstrate that these core–shell nanomaterials can be potentially utilized in electromagnetic interference (EMI) shielding application or as a catalyst in aza-Michael addition reaction. The results show the ability to convert industrial bio-waste into useful nanomaterials, suggesting new scalable and simple approaches to improve environmental sustainability in industrial processes

Carbon Nanotube–Nanocup Hybrid Structures for High Power Supercapacitor Applications

Here, we design and develop high-power electric double-layer capacitors (EDLCs) using carbon-based three dimensional (3-D) hybrid nanostructured electrodes. 3-D hybrid nanostructured electrodes consisting of vertically aligned carbon nanotubes (CNTs) on highly porous carbon nanocups (CNCs) were synthesized by a combination of anodization and chemical vapor deposition techniques. A 3-D electrode-based supercapacitor showed enhanced areal capacitance by accommodating more charges in a given footprint area than that of a conventional CNC-based device