Influence of shock waves on bifunctional nickel particles: Enhancing magnetic properties and supercapacitor applications.

In the present study, shock-wave impact experiments were conducted to investigate the structural properties of nickel metal powder when exposed to shock waves. Both X-ray diffractometry and scanning electron microscopy were used to evaluate the structural and surface morphological changes in the shock-loaded samples. Notably, the experimental results revealed variations in lattice parameters and cell structures as a function of the number of shock pulses and the increasing volume. The transition occurred from P2 (100 shocks) to P3 (200 shocks). Remarkably, P5 (400 shocks) exhibited attempts to return to its initial state, and intriguingly, P4 displayed characteristics reminiscent of the pre-shock condition. Additionally, significant morphological changes were observed with an increase in shock pulses. Magnetic measurements revealed an increase in magnetic moment for P2, P3, and P4, but a return to the original state was observed for P5. Moreover, the capacitance exhibited an upward trend with increasing shock pulses, except for P5, where it experienced a decline. These findings underscore the significant impact of even mild shock waves on the physical and chemical characteristics of bifunctional nickel particles. This research sheds light on the potential applications of shock wave-induced structural changes in enhancing the magnetic properties and supercapacitor performance of nickel particles.

CdTe QD-decorated GO nanosheet heterojunction for efficient photocurrent generation and photocatalytic activity.

Cadmium telluride quantum dot (CdTe QD)-decorated graphene oxide (GO) nanosheets are promising heterojunctions for the environmental remediation of organic pollutants in water. However, assembling these two materials is a challenge. For this purpose, we have developed a one-step approach for the decoration of QDs onto the surface of GO nanosheets/intercalation of QDs into GO nanosheets through self-assembly, resulting in the formation of sandwiched hybrid heterojunctions. After synthesis, the samples were analysed for variations in their structural, morphological, compositional, optical and photoelectrochemical characteristics using various analytical tools. Interlinking QDs and GO nanosheets enhanced the photocurrent generation (∼5.8 µA cm-2), resulting in faster electron transfer by delaying the decay time (58.25 ms). A higher rate constant value (k = 0.135 min-1) was obtained for degrading 93% MB dye in 20 min. This work demonstrates a cost-effective strategy for constructing CdTe QDs/GO nanosheet hybrid heterojunctions for potential application in the field of photocatalysis.

Enhanced charge carrier transfer process in nickel titanate nanostructures for environmental remediation of industrial dye.

The effective charge carrier transfer process in one-dimensional (1D) NiTiO3 nanofibers and NiTiO3 nanoparticles was demonstrated experimentally, showcasing an effective photocatalytic enhancement under visible light ambience. The rhombohedral crystal structure of NiTiO3 nanostructures was confirmed using X-ray diffractometer (XRD). The morphology and optical characteristics of the synthesized nanostructures were characterized using scanning electron microscopy (SEM) and UV-visible spectroscopy (UV-Vis). Nitrogen adsorption-desorption analysis corresponding to NiTiO3 nanofibers showcased porous structures with an average pore size of ~3.9 nm. The photoelectrochemical (PEC) measurement studies revealed an enhanced photocurrent for the NiTiO3 nanostructures, confirming enhanced charge carriers transportation in fibers than in particles due to the delocalized electrons in the conduction band, thereby hindering the photoexcited charge carrier's recombination. The photodegradation efficiency of methylene blue (MB) dye under the visible light irradiation revealed an enhancement in the rate of degradation for NiTiO3 nanofibers when compared to NiTiO3 nanoparticles.

CuO-NiO binary transition metal oxide nanoparticle anchored on rGO nanosheets as high-performance electrocatalyst for the oxygen reduction reaction.

To replace the existing noble-metal-based catalysts, developing highly efficient, stable electrocatalysts for oxygen reduction reactions for the increased current generation with lower overpotential is a demanding undertaking. In the present work, CuO-NiO/rGO nanocomposites were prepared using simple, cost-effective Co-precipitation methods. They act as highly effective electrocatalysts for oxygen reduction reactions in an alkaline medium. The structural characterizations demonstrate that prepared nanoparticles (≈13 nm) are tightly and effectively organized on reduced graphene oxide sheets. The electrochemical properties of the CuO, NiO nanoparticles and CuO-NiO, CuO-NiO/rGO nanocomposites were investigated. The results of the CuO-NiO/rGO nanocomposites revealed the high current density (2.9 × 10-4 mA cm-2), lower Tafel slope (72 mV dec-1) and low hydrogen peroxide yield (15%) when compared to other prepared materials (CuO, NiO, and CuO-NiO). The reduced graphene oxide increases an electron transfer during the ORR process, while the CuO-NiO has variable oxidation states that promote electro-rich features. With the combination of CuO-NiO and rGO, the hybrid electrocatalysts specific surface area and charge transfer rate drastically increase. The investigations of the rotating ring-disk electrodes experiments indicate that the oxygen reduction process takes place on CuO-NiO/rGO through an efficient four-electron pathway. Our results propose a new approach to creating highly efficient and long-lasting electrocatalysts.