46 research outputs found
Interaction of the Helium, Hydrogen, Air, Argon, and Nitrogen Bubbles with Graphite Surface in Water
No full textThe interaction of the confined gas with solid surface immersed in water is a common theme of many important fields such as self-cleaning surface, gas storage, and sensing. For that reason, we investigated the gas-graphite interaction in the water medium. The graphite surface was prepared by mechanical exfoliation of highly oriented pyrolytic graphite (HOPG). The surface chemistry and morphology were studied by X-ray photoelectron spectroscopy, profilometry, and atomic force microscopy. The surface energy of HOPG was estimated by contact angle measurements using the Owens-Wendt method. The interaction of gases (Ar, He, H2, N2, and air) with graphite was studied by a captive bubble method, in which the gas bubble was in contact with the exfoliated graphite surface in water media. The experimental data were corroborated by molecular dynamics simulations and density functional theory calculations. The surface energy of HOPG equaled to 52.8 mJ/m(2) and more of 95% of the surface energy was attributed to dispersion interactions. The results on gas-surface interaction indicated that HOPG surface had gasphilic behavior for helium and hydrogen, while gasphobic behavior for argon and nitrogen. The results showed that the variation of the gas contact angle was related to the balance between the gas-surface and gas-gas interaction potentials. For helium and hydrogen the gas-surface interaction was particularly high compared to gas-gas interaction and this promoted the favorable interaction with graphite surface
Thermodynamics and kinetics of early stages of carbon dot formation: a case of citric acid and ethylenediamine reaction
No full textOwing to their extraordinary photophysical properties, carbon dots (CDs) have found applications across various fields, including bioimaging, sensing, and environmental research. Despite huge application potential, the fabrication of CDs still lacks the desired control at the molecular level, and precise structural regulation towards property-tailored CDs remains elusive. The mechanistic details of nucleation, growth, and carbonization processes leading to CDs are still unknown, with key thermodynamic and kinetic parameters yet to be revealed. Herein, we performed quantum chemical calculations of explicitly micro-hydrated reaction systems to thoroughly explore the mechanism of a prototypical reaction of citric acid and ethylenediamine. The theoretical results showed activation barriers and thermodynamics along the reaction pathway, thus helping identify key heterocyclic intermediates and cyclization products. The cyclization and condensation reactions were further simulated via a reactive molecular dynamics protocol, suggesting potential growth scenarios and generating plausible structures for further exploration of the polymerization and carbonization processes. The theoretical calculations were cross-validated with NMR and MALDI-TOF measurements. The data obtained provide a comprehensive deterministic insight into the initial stages of CD formation, revealing new reaction intermediates and pathways, and rationally predicting the formation of specific structural arrangements of premature CDs. The presented deterministic approach represents an important step towards rational bottom-up design of these unique fluorescence systems
Laser-induced MXene-functionalized graphene nanoarchitectonics-based microsupercapacitor for health monitoring application
No full textMicrosupercapacitors (micro-SCs) with mechanical flexibility have the potential to complement or even replace microbatteries in the portable electronics sector, particularly for portable biomonitoring devices. The real-time biomonitoring of the human body's physical status using lightweight, flexible, and wearable micro-SCs is important to consider, but the main limitation is, however, the low energy density of micro-SCs as compared to microbatteries. Here using a temporally and spatially controlled picosecond pulsed laser, we developed high-energy-density micro-SCs integrated with a force sensing device to monitor a human body's radial artery pulses. The photochemically synthesized spherical laser-induced MXene (Ti3C2T x )-derived oxide nanoparticles uniformly attached to laser-induced graphene (LIG) act as active electrode materials for micro-SCs. The molecular dynamics simulations and detailed spectroscopic analysis reveal the synergistic interfacial interaction mechanism of Ti-O-C covalent bonding between MXene and LIG. The incorporation of MXene nanosheets improves the graphene sheet alignment and ion transport while minimizing self-restacking. Furthermore, the micro-SCs based on a nano-MXene-LIG hybrid demonstrate high mechanical flexibility, durability, ultrahigh energy density (21.16 x 10(-3) mWh cm(-2)), and excellent capacitance (similar to 100 mF cm(-2) @ 10 mV s(-1)) with long cycle life (91% retention after 10 000 cycles). Such a single-step roll-to-roll highly reproducible manufacturing technique using a picosecond pulsed laser to induce MXene-derived spherical oxide nanoparticles (size of quantum dots) attached uniformly to laser-induced graphene for biomedical device fabrication is expected to find a wide range of applications.Microsupercapacitors (micro-SCs) with mechanical flexibility have the potential to complement or even replace microbatteries in the portable electronics sector, particularly for portable biomonitoring devices. The real-time biomonitoring of the human body's physical status using lightweight, flexible, and wearable micro-SCs is important to consider, but the main limitation is, however, the low energy density of micro-SCs as compared to microbatteries. Here using a temporally and spatially controlled picosecond pulsed laser, we developed high-energy-density micro-SCs integrated with a force sensing device to monitor a human body's radial artery pulses. The photochemically synthesized spherical laser-induced MXene (Ti3C2T x )-derived oxide nanoparticles uniformly attached to laser-induced graphene (LIG) act as active electrode materials for micro-SCs. The molecular dynamics simulations and detailed spectroscopic analysis reveal the synergistic interfacial interaction mechanism of Ti-O-C covalent bonding between MXene and LIG. The incorporation of MXene nanosheets improves the graphene sheet alignment and ion transport while minimizing self-restacking. Furthermore, the micro-SCs based on a nano-MXene-LIG hybrid demonstrate high mechanical flexibility, durability, ultrahigh energy density (21.16 x 10(-3) mWh cm(-2)), and excellent capacitance (similar to 100 mF cm(-2) @ 10 mV s(-1)) with long cycle life (91% retention after 10 000 cycles). Such a single-step roll-to-roll highly reproducible manufacturing technique using a picosecond pulsed laser to induce MXene-derived spherical oxide nanoparticles (size of quantum dots) attached uniformly to laser-induced graphene for biomedical device fabrication is expected to find a wide range of applications
Role of the puckered anisotropic surface in the surface and adsorption properties of black phosphorus
No full textThe structure of phosphorene resembles the honeycomb arrangement of graphene, but its layers are buckled and highly anisotropic.</p
Covalently functionalized graphene as a supercapacitor electrode material
No full textThe need for efficient, lightweight, flexible, stable and eco-friendly portable electric power delivery has placed research on supercapacitor electrode materials at the forefront of endeavors to provide future energy storage. Graphene-based materials and composites have been shown to be promising materials toward this goal. In this review, we describe recent progress in the development of electrode materials by the covalent functionalization of graphene. Covalent graphene derivatives are an emerging and potentially large class of very efficient materials, whose structural and physicochemical properties can be tailored according to the specific needs of capacitive charge storage. They also open doors to new composites and hybrids, which may further advance the field-encoding properties and other features as yet unexplored
Role of the puckered anisotropic surface in the surface and adsorption properties of black phosphorus
No full textNanomaterials have a high surface-to-mass ratio and their surface properties significantly affect their features and application potential. Phosphorene, a single layer of black phosphorus (BP), was the first homoatomic two-dimensional material to be prepared after the discovery of graphene. The structure of phosphorene resembles the honeycomb arrangement of graphene, but its layers are buckled and highly anisotropic. We studied how this difference affects the surface properties of BP, namely the free surface energy and adsorption affinity of various organic molecules. Using inverse gas chromatography, we measured the total surface free energy of BP powder to be 90 mJ m−2 and showed that it was dominantly determined by dispersion forces, but, unlike on graphene, with a notable contribution from specific acid–base interactions. We further measured adsorption enthalpies of volatile organic compounds on BP and rationalized them using density functional theory calculations. Polar molecules showed an increased affinity due to a significant contribution of dipole–dipole interactions to the molecule–surface bonding, because the buckled surface of BP causes higher diffusion barriers than those on graphene, hinders molecular in-plane motion and supports mutual orientation of molecular dipoles over longer distances, in contrast to graphene
Laser-Induced MXene-Functionalized Graphene Nanoarchitectonics-Based Microsupercapacitor for Health Monitoring Application
No full textMicrosupercapacitors (micro-SCs) with mechanical flexibility
have
the potential to complement or even replace microbatteries in the
portable electronics sector, particularly for portable biomonitoring
devices. The real-time biomonitoring of the human body’s physical
status using lightweight, flexible, and wearable micro-SCs is important
to consider, but the main limitation is, however, the low energy density
of micro-SCs as compared to microbatteries. Here using a temporally
and spatially controlled picosecond pulsed laser, we developed high-energy-density
micro-SCs integrated with a force sensing device to monitor a human
body’s radial artery pulses. The photochemically synthesized
spherical laser-induced MXene (Ti3C2Tx)-derived oxide nanoparticles uniformly attached
to laser-induced graphene (LIG) act as active electrode materials
for micro-SCs. The molecular dynamics simulations and detailed spectroscopic
analysis reveal the synergistic interfacial interaction mechanism
of Ti–O–C covalent bonding between MXene and LIG. The
incorporation of MXene nanosheets improves the graphene sheet alignment
and ion transport while minimizing self-restacking. Furthermore, the
micro-SCs based on a nano-MXene-LIG hybrid demonstrate high mechanical
flexibility, durability, ultrahigh energy density (21.16 × 10–3 mWh cm–2), and excellent capacitance
(∼100 mF cm–2 @ 10 mV s–1) with long cycle life (91% retention after 10 000 cycles).
Such a single-step roll-to-roll highly reproducible manufacturing
technique using a picosecond pulsed laser to induce MXene-derived
spherical oxide nanoparticles (size of quantum dots) attached uniformly
to laser-induced graphene for biomedical device fabrication is expected
to find a wide range of applications
Accessibility of grafted functional groups limits reactivity of covalent graphene derivatives
No full textLaser-Induced MXene-Functionalized Graphene Nanoarchitectonics-Based Microsupercapacitor for Health Monitoring Application
No full textMicrosupercapacitors (micro-SCs) with mechanical flexibility
have
the potential to complement or even replace microbatteries in the
portable electronics sector, particularly for portable biomonitoring
devices. The real-time biomonitoring of the human body’s physical
status using lightweight, flexible, and wearable micro-SCs is important
to consider, but the main limitation is, however, the low energy density
of micro-SCs as compared to microbatteries. Here using a temporally
and spatially controlled picosecond pulsed laser, we developed high-energy-density
micro-SCs integrated with a force sensing device to monitor a human
body’s radial artery pulses. The photochemically synthesized
spherical laser-induced MXene (Ti3C2Tx)-derived oxide nanoparticles uniformly attached
to laser-induced graphene (LIG) act as active electrode materials
for micro-SCs. The molecular dynamics simulations and detailed spectroscopic
analysis reveal the synergistic interfacial interaction mechanism
of Ti–O–C covalent bonding between MXene and LIG. The
incorporation of MXene nanosheets improves the graphene sheet alignment
and ion transport while minimizing self-restacking. Furthermore, the
micro-SCs based on a nano-MXene-LIG hybrid demonstrate high mechanical
flexibility, durability, ultrahigh energy density (21.16 × 10–3 mWh cm–2), and excellent capacitance
(∼100 mF cm–2 @ 10 mV s–1) with long cycle life (91% retention after 10 000 cycles).
Such a single-step roll-to-roll highly reproducible manufacturing
technique using a picosecond pulsed laser to induce MXene-derived
spherical oxide nanoparticles (size of quantum dots) attached uniformly
to laser-induced graphene for biomedical device fabrication is expected
to find a wide range of applications
