We report on one-step hybridization of silver, gold and palladium nanoparticles from solution onto exfoliated two-dimensional (2D) Ti₃C₂ titanium carbide (MXene) nanosheets. The produced hybrid materials can be used as substrates for surface-enhanced Raman spectroscopy (SERS). An approximate analytical approach is also developed for the calculation of the surface plasmon resonance (SPR) frequency of nanoparticles immersed in a medium, near the interface of two dielectric media with different dielectric constants. We obtained a good match with the experimental data for SPR wavelengths, 440 nm and 558 nm, respectively for silver and gold nanoparticles. In the case of palladium, our calculated SPR wavelength for the planar geometry was 160 nm, demonstrating that non-spherical palladium nanoparticles coupled with 2D MXene yield a broad, significanlty red-shifted SPR band with a peak at 230 nm. We propose a possible mechanism of the plasmonic hybridization of nanoparticles with MXene. The as-prepared noble metal nanoparticles on MXene show a highly sensitive SERS detection of methylene blue (MB) with calculated enhancement factors on the order of 10⁵. These findings open a pathway for extending visible-range SERS applications of novel 2D hybrid materials in sensors, catalysis, and biomedical applications.

This study demonstrates a facile, mild and environmentally-friendly sustainable (soft processing) approach for the efficient electrochemical exfoliation of graphite using a sodium hydroxide/hydrogen peroxide/water (NaOH/H₂O₂/H₂O) system that can produce high-quality, anodic few-layer graphene nanosheets in 95% yield at ambient reaction conditions. The control experiment conducted using NaOH/H₂O revealed the crucial role of H₂O₂ in the exfoliation of graphite. A possible exfoliation mechanism is proposed. The reaction of H₂O₂ with hydroxyl ions (HO⁻) leads to the formation of highly nucleophilic peroxide ions (O₂²⁻), which play a crucial role in the exfoliation of graphite via electrochemical-potential-assisted intercalation and strong expansion of graphite sheets.

Formation of reduced and functionalized graphene oxide (r-FGO) at ambient temperature and pressure is demonstrated by generating liquid plasma submerged in acetonitrile and graphene oxide solution. The partial restoration of conjugation (sp² domain) and insertion of fluorophores such as nitrile and amine in r-FGO displays enhanced fluorescence property. Presence of nitrile and amine in r-FGO are confirmed by X-ray photoelectron spectroscopy and Fourier transforms infrared spectroscopy. Morphology and optical property of r-FGO are studied with transmission electron microscopy, scanning tunneling microscopy and Ultraviolet–visible spectroscopy measurements. The nitrile and amine present in r-FGO undergo a surface-controlled reversible redox reaction and sp²- enriched r-FGO acts as an electrical double layer, providing additional hybrid capacitance or pseudocapacitance. r-FGO shows high cyclic stability with a specific capacitance value of 349 F/g at the scan rate of 10 mV/s. Only marginal reduction of specific capacitance (<10% reduction) is observed at the end of 1000 cycles.

Here, we introduce a 2D metal-organic framework (MOF) into the poly(vinylidene fluoride) (PVDF) matrix, which has been comparatively less explored in this field. Highly 2D Ni-MOF has been synthesized in this regard via hydrothermal route and has been incorporated into PVDF matrix via solvent casting technique with ultralow filler (0.5 wt%) loading. The polar phase percentage of 0.5 wt% Ni-MOF loaded PVDF film (NPVDF) has been found to be increased to ~85% from a value of ~55% for neat PVDF. The ultralow filler loading has inhibited the easy breakdown path along with increased dielectric permittivity and hence has enhanced the energy storage performance. On the other hand, significantly enriched polarity and Young’s Modulus has helped in improving its mechanical energy harvesting performance, thereby enhancing the human motion interactive sensing activities. The piezoelectric and piezo-tribo hybrid devices made up of NPVDF film have shown improved output power density of ~3.26 and 31 μW/cm² compared to those of the piezoelectric and piezo-tribo hybrid devices comprising of neat PVDF (output power density ~0.6 and 17 μW/cm², respectively). The developed composite can thus be considered an excellent candidate for multifunctional applications.

In this study, micro-plasma discharge is produced by applying a high electric potential between graphite and Pt electrodes in acetonitrile solvent. The electrons generated in the micro-plasma discharge collide with acetonitrile and produce ˙H and ˙CH₂CN radicals. The radicalized graphene layer exfoliated from the graphite electrode reacts with nascent hydrogen (˙H) and acetonitrile (˙CH₂CN) radicals and partially restores its aromaticity and conjugation. Raman spectra of the product confirm the synthesis of nitrogen-functionalized graphene (N-FG), which has a marginal increase in disorderness compared to that of pure graphite and remarkable dispersibility in both hydrophilic and hydrophobic solvents. The excellent fluorescence properties of N-FG confirm the presence of fluorophores such as –NH and –NC– at the radicalized graphene sites, as supported by ultraviolet-visible spectroscopy and X-ray photoelectron spectroscopy studies. The functional groups present in N-FG lead to excellent electrochemical performance, with distinct redox peaks in cyclic voltammetry and a high specific capacitance of 291 F g⁻¹ at a scan rate of 5 mV s⁻¹. N-FG exhibits excellent cycling stability, with a marginal reduction of specific capacitance (<10% reduction) at the end of 1000 cycles.