Candle Soot derived Fractal-like Carbon Nanoparticles Network as High-Rate Lithium Ion Battery Anode Material

Dendrite-free Zn anode enabled by combining carbon nanoparticles hydrophobic layer with crystal face reconstruction toward high-performance Zn-ion battery

Aqueous zinc ion batteries (ZIBs) have been considered promising energy storage systems due to their excellent electrochemical performance, environmental toxicity, high safety and low cost. However, uncontrolled dendrite growth and side reactions at the zinc anode have seriously hindered the development of ZIBs. Herein, we prepared the carbon nanoparticles layer coated zinc anode with (103) crystal plane preferential oriented crystal structure (denoted as C@RZn) by a facile one-step vapor deposition method. The preferential crystallographic orientation of (103) crystal plane promotes zinc deposition at a slight angle, effectively preventing the formation of Zn dendrites on the surface. In addition, the hydrophobic layer of carbon layer used as an inert physical barrier to prevent corrosion reaction and a buffer during volume changes, thus improving the reversibility of the zinc anode. As a result. the C@RZn anode achieves a stable cycle performance of more than 3000 h at 1 mA cm-2 with CE of 99.77 % at 5 mA cm-2. The full battery with C@RZn anode and Mn-doped V6O13 (MVO) cathode show stability for 5000 cycles at the current density of 5 A g-1. This work provides a new approach for the design of multifunctional interfaces for Zn anode.

Functionalized Metal-Free Carbon Nanosphere Catalyst for the Selective C-N Bond Formation under Open-Air Conditions

A versatile shape-controlled carbon nanomaterial that can efficiently catalyze the selective C-N coupling reactions under metal-free and open-air conditions was developed by applying N-doping and KOH activation strategies in candle soot (ANCS). The TEM and elemental mapping results showed the formation of sphere-shaped carbon particles as well as the uniform distribution of nitrogen species in the carbon framework. KOH activation enhanced the specific surface area of carbon, whereas N-doping enriched the electron-deficient nature by introducing functional N-based pyrrolic/graphitic structures in the carbon framework. The synergistic effect of N-doping and KOH activation significantly improved the catalytic efficiency of the carbon catalyst (ANCS), giving a 96% conversion of o-phenylenediamine (OPD) with a good selectivity to 2-phenylbenzimidazole (97%). In contrast, the pristine carbon exhibited very low activity (48% conversion of the OPD and 36% selectivity to 2-phenylbenzimidazole). Besides, the ANCS nanomaterial provided a facile catalytic approach for the homo- and cross-C-N condensation of various aromatic amines and diamines to produce diverse functional imines and benzimidazoles at mild conditions. This work provided promising insights into developing advanced, metal-free carbon-based catalysts for selective C-N coupling reactions to produce valuable drug motifs.

Enhanced Performance of Laser-Induced Graphene Supercapacitors via Integration with Candle-Soot Nanoparticles

Laser-induced graphene (LIG) has been emerging as a promising electrode material for supercapacitors due to its cost-effective and straightforward fabrication approach. However, LIG-based supercapacitors still face challenges with limited capacitance and stability. To overcome these limitations, in this work, we present a novel, cost-effective, and facile fabrication approach by integrating LIG materials with candle-soot nanoparticles. The composite electrode is fabricated by laser irradiation on a Kapton sheet to generate LIG material, followed by spray-coating with candle-soot nanoparticles and annealing. Materials characterization reveals that the annealing process enables a robust connection between the nanoparticles and the LIG materials and enhances nanoparticle graphitization. The prepared supercapacitor yields a maximum specific capacitance of 15.1 mF/cm2 at 0.1 mA/cm2, with a maximum energy density of 2.1 μWh/cm2 and a power density of 50 μW/cm2. Notably, the synergistic activity of candle soot and LIG surpasses the performances of previously reported LIG-based supercapacitors. Furthermore, the cyclic stability of the device demonstrates excellent capacitance retention of 80% and Coulombic efficiency of 100% over 10000 cycles.

Biomass Porous Carbons Derived from Banana Peel Waste as Sustainable Anodes for Lithium-Ion Batteries

Disordered carbons derived from banana peel waste (BPW) were successfully obtained by employing a simple one-step activation/carbonization method. Different instrumental techniques were used to characterize the structural, morphological, and textural properties of the materials, including X-ray diffraction, thermogravimetric analysis, porosimetry and scanning electron microscopy with energy-dispersive X-ray spectroscopy. The chemical activation with different porogens (zinc chloride, potassium hydroxide and phosphoric acid) could be used to develop functional carbonaceous structures with high specific surface areas and significant quantities of pores. The BPW@H3PO4 carbon exhibited a high specific surface area (815 m2 g-1), chemical stability and good conductivity for use as an anode in lithium-ion batteries. After 200 cycles, this carbon delivered a reversible capacity of 272 mAh g-1 at 0.2 C, showing a notable retention capacity and good cycling performance even at high current densities, demonstrating its effectiveness and sustainability as an anode material for high-energy applications in Li-ion batteries.

Synthesis of Fe0/Fe3O4@porous carbon through a facile heat treatment of iron-containing candle soots for peroxymonosulfate activation and efficient degradation of sulfamethoxazole

Developing highly efficient, reusable, non-toxic and low-cost catalysts is of great importance for persulfate-based advanced oxidation processes (AOPs). In this work, ferrocene was mixed into paraffin to prepare a candle, and the iron-containing candle soots were collected and heated at 500 °C~900 °C under N₂ atmosphere for 1 h to prepare magnetically recyclable Fe⁰/Fe₃O₄@porous carbon (Fe⁰/Fe₃O₄@PC) catalysts. The Fe⁰/Fe₃O₄@PC-700 obtained after pyrolysis at 700 °C exhibited the best catalytic activity for sulfamethoxazole (SMX) degradation. 10 mg/L SMX could be completely degraded within 10 min by 0.2 g/L of Fe⁰/Fe₃O₄@PC-700 and 0.5 mM PMS at pH 5.0. The carbon shell effectively inhibited the Fe leaching of Fe⁰/Fe₃O₄@PC-700, and 99.73% of Fe was retained after five consecutive cycles. In the Fe⁰/Fe₃O₄@PC-700/PMS system, SMX was degraded through the sulfate radical (SO₄·^¯), hydroxyl radical (·OH), superoxide radical (O₂·^¯) dominated radical pathway, and the singlet oxygen (¹O₂) dominated non-radical pathway. The coexisting inorganic ions and natural organic matters (NOM) in actual water inhibited the degradation of SMX. Finally, four possible degradation pathways were proposed based on the degradation intermediates of SMX. This work provides a facile heat treatment of iron-containing candle soots strategy to prepare the metal@carbon catalysts for PMS-based AOP.

Application of candle soot CNPs-TiO2-PVP composite in the detection of volatile organic compounds with aldehyde, amine and ketone functional groups by resistance and impedance responses

We have fabricated a solid-state gas sensor using a composite sensor layer made up of three different sensing materials namely; candle soot Carbon nanoparticles, Titanium dioxide and Poly (vinyl) pyrrolidone (PVP). The study was carried out to study the sensor’s response towards butyraldehyde, diethylamine and isobutyrophenone vapour at room temperature. The sensor was prepared by mixing candle soot CNPs, TiO2 and PVP in dimethylformamide using the ratio (2:1:3) respectively. The sensing materials were characterised using Brunauer–Emmett–Teller (BET), x-ray diffraction (XRD), Transmission and Scanning Electron Microscopy (TEM, SEM). The sensor’s response was measured by injecting a volume of 1 to 5 μl of each liquid analyte in a round-bottomed glass and an LCR metre was used to measure the ∆R and ∆Z responses. In both parameters, the sensor responded well to the different analytes, the response of the sensor linearly increases as the analyte vapour concentration increases. The sensors were discovered to exhibit more sensitivity of 0.07 Ω ppm−1 towards diethylamine in ∆R response and it was more sensitive towards isobutyrophenone in ∆Z response giving a sensitivity of 0.14 Ω ppm−1 while Butyraldehyde had the fastest response time of 145 s and Diethylamine had the fasted recovery time 130 s.

Multifunctional superhydrophobic adsorbents by mixed-dimensional particles assembly for polymorphic and highly efficient oil-water separation

Supra-wetting materials, especially superhydrophobic absorption materials, as an emerging advanced oil-water separation material have attracted extensive concern in the treatment of oil spillage and industrial oily wastewater. However, it is still a challenge to fabricate robust and multifunctional superhydrophobic materials for the multitasking oil-water separation and fast clean-up of the viscous crude oil by an environment-friendly and scalable method. Herein, a solid-solid phase ball-milling strategy without chemical reagent-free modification was proposed to construct heterogeneous superhydrophobic composites by using waste soot as the solid-phase superhydrophobic modifier. A series of covalent bond restricted soot-graphene (S-GN) or soot-Fe₃O₄ (S-Fe₃O₄) composite materials with a peculiar micro-nano structure are prepared. Through "glue+superhydrophobic particles" method, the prepared soot-based composite particles are facilely loaded on the porous skeleton of the sponge to obtain multifunctional superhydrophobic adsorbents. The reported superhydrophobic adsorbents exhibited robust chemical and mechanical stability, convenient magnetic collection, the high oil absorption capacity of 60-142 g g^-1, durable recyclability (>250 cycles), efficient separation efficiency (>99.5%) and outstanding self-heated performance, which enable them to be competent for oil-water separation in multitasking and complex environment (floating oils, continuous oil collection, oil-in-water emulsion, and viscous oil-spills).

Thermally treated candle soot as a novel catalyst for hydrogen peroxide in-situ production enhancement in the bio-electro-Fenton system

Thermally treated candle soot (TCS) was used as a two-electron (2e¯) oxygen reduction reaction (ORR) catalyst to in situ produce H₂O₂ in a bio-electro-Fenton (BEF) system. Compared with the pristine candle soot (CS), TCS showed larger Brunauer-Emmett-Teller (BET) surface area (102.54 m² g^-1 vs. 61.79 m² g^-1), higher mesoporous ratio (50.39% vs. 34.98%), and improved hydrophilicity. X-ray photoelectron spectra (XPS) results revealed that the C-O-C was the dominant oxygen-containing group of the CS, and its percentage reached at 80.55%. However, the C-O-C ratio of the TCS decreased to 48.93%, whilst it's CO and OC-O ratios significantly increased to 27.92% and 23.15%. The TCS showed a high H₂O₂ selectivity (87.5%∼97.0%) at the neutral pH condition, which was much higher than that of the commonly used carbon black (CB) catalyst. Finally, the H₂O₂ concentration maxima (C_max-_H2O2) of the bio-electro-Fenton system running with the TCS air-cathode (BEF-TCS) achieved at 32.02 mg/L, which was 6.29 times higher than that of the BEF-CB (5.09 mg/L). The removal and mineralization ratios of the SMX in the BEF-TCS reached at 83.0% and 79.0%, respectively. This paper reported a novel 2e¯ ORR electro-catalyst which was low-cost, easily available and highly efficiency.

Self-Concentrated Surface-Enhanced Raman Scattering-Active Droplet Sensor with Three-Dimensional Hot Spots for Highly Sensitive Molecular Detection in Complex Liquid Environments

In this work, a surface-enhanced Raman scattering (SERS)-active droplet with three-dimensional (3D) hot spots prepared from a superhydrophobic SERS substrate, which is inspired by the nut wizard strategy, was developed for ultrasensitive detection in complex liquid environments. The SERS substrate was composed of silver-capped parylene C-coated carbon nanoparticles (Ag-PC@CNPs). Such a SERS substrate was prepared by candle-soot deposition to provide a porous carbon nanoparticle layer followed by deposition of a parylene C film to protect the CNPs and then sputtering of silver nanoparticles. Similar to a nut wizard, a droplet rolling on the Ag-PC@CNP-coated substrate picked up the Ag-PC@CNPs. In this way, a self-concentrated and extremely sensitive SERS-active droplet sensor with 3D hot spots was formed. The sensor did not require precise laser focusing and showed relatively high repeatability and much higher sensitivity than those of a corresponding SERS substrate with two-dimensional hot spots. The sensor also achieved high sensitivity and specificity in complex liquid environments; in addition, bovine serum albumin with a concentration as low as 1 pM can be achieved. Consequently, an extremely simple, flexible, and highly sensitive SERS detection technique applicable to liquid biopsy analysis is anticipated.

Behind the Candelabra: A Facile Flame Vapor Deposition Method for Interfacial Engineering of Garnet Electrolyte To Enable Ultralong Cycling Solid-State Li-FeF3 Conversion Batteries

The frustrating interfacial issue between Li metal anode and solid electrolyte is the main obstacle that restricts the commercial promotion of solid-state batteries. The garnet-type ceramic electrolyte with high stability against metallic Li has drawn much attention, but it also suffers from huge interfacial resistance and Li dendrite penetration due to the unavoidable formation of the carbonate passivation layer and limited interface contact. Herein, we propose a facile and effective method of flame vapor deposition to spray candle soot (CS) coating on the garnet surface. It enables the reduction of the carbonate layer and the conversion to a highly lithiophilic interlayer especially when in contact with molten Li. The lithiophilicity is rooted in the enrichment of graphitic polycrystalline domains in CS, which can be chemically or electrochemically lithiated to form the ionic/electronic dual-conductive network containing LiC₆ moieties. The CS interlayer binds the Li metal with the garnet electrolyte tightly with gradual transition of Li-ion conductivity, leading to a significant reduction of the area-specific resistance to 50 Ω cm² at 60 °C with high cycling and current endurance. Garnet-based symmetric cells and solid-state full cells conducting this strategy exhibit impressive electrochemical reversibility and durability under the preservation of the compact interface and smooth Li plating/stripping. The modified Li/garnet/FeF₃ batteries exhibit a discharge capacity as high as 500 mA h g^-1 and long-term cyclability for at least 1500 cycles (with capacity preserved at 281.7 and 201 mA h g^-1 at 100 and 200 μA cm^-2, respectively). This candle combustion strategy can be extended to more ceramic electrolytes compatible with high-temperature pretreatment.

Candle soot derived carbon nanoparticles: An assessment of cellular and progressive toxicity using Drosophila melanogaster model

The biomedical demand of the nanomaterials is continuously increasing due to their wide range of applications in the field. However, before the implementation of these nanomaterials, toxicity assessment is essential for its safe usage. In the present study, the toxicity of carbon nanoparticles (CNPs) was investigated which was derived from candle soot and compared with commercially available multi-walled carbon nanotubes (CNTs) by using Drosophila melanogaster as a model system. First instar Drosophila larvae were exposed to CNPs as well as CNTs, and the toxic effects of these nanomaterials were compared. The result shows that both nanomaterials enhance the level of reactive oxygen species and oxidative stress in the Drosophila, which leads to the upregulation of heat shock proteins that may cause cytotoxicity in exposed Drosophila larvae. In contrast, exposure to CNPs and CNTs did not affect the developmental period of the larvae. Morphology of the internal organs, brain, gut and Malpighian tubules was also not altered in the exposed larvae. Similarly, no change observed in the cytoskeleton (F-actin) of these organs. Reproductive performance was slightly reduced in the case of CNPs compare to control. However, CNTs exposure did not show any significant effect on the reproductive performance of the flies that emerged from exposed larvae in comparison to control. Hence the study concludes that exposure to CNPs and CNTs cause a moderate level of cytotoxicity in Drosophila. The study also indicates that the inexpensive CNPs may use as an alternative to expensive CNTs for biomedical and biological applications.

Surface topographies of biomimetic superamphiphobic materials: design criteria, fabrication and performance

Superamphiphobicity is a wetting phenomenon that not only water but also oils or organic solvents with low surface tension exhibit large contact angles above 150° along with low contact angle hysteresis on solid surface. It is well known that both chemical constituent and surface roughness have impacts on the wettability of solid surface. Herein, several fundamental wetting states and design criteria for re-entrant structures are introduced first. Then, various chemical modification materials endowing solid substrates low surface energy are summarized subsequently. Furthermore, roughening processes conferring hierarchical or re-entrant topographic structures on surfaces are classified based on different types of topographies abstracted from the natural oil-repellent creatures (mushroom-like structures) as well as bio-inspired superamphiphobic surfaces (i.e., randomly distributed nanostructures, regularly patterned microstructures and other complex hierarchical structures). Significantly, the impalement pressure and formulated rules of various re-entrant profiles are recommended in detail. At the same time, fabrication, outstanding performances such as mechanical durability, chemical stability are also mentioned according to different types of morphologies. Beyond that, current fabrication obstacles and future prospects are proposed simultaneously in the end.

Candle Soot Carbon Nanoparticles in Photoacoustics: Advantages and Challenges for Laser Ultrasound Transmitters

This manuscript provides a review of candle-soot nanoparticle (CSNP) composite laser ultrasound transmitters (LUT), and compares and contrasts this technology to other carboncomposite designs. Among many carbon-based composite LUTs, a CSNP composite has shown its advantages of maximum energy conversion and fabrication simplicity for developing highly efficient ultrasound transmitters. This review focuses on the advantages and challenges of the CSNP-composite transmitter in the aspects of nanostructure design, fabrication procedure, and promising applications. Included are a brief description of the basic principles of the laser ultrasound transmitter, a review of general properties of CSNPs, as well as details on the fabrication method, photoacoustic performance, and design factors. A comparison of the CSNP-nanocomposite to other carbon-nanocomposites is provided. Lastly, representative applications of carbon-nanocomposite transmitters and future perspectives on CSNP-composite transmitters are presented.

Water-Dispersible Candle Soot-Derived Carbon Nano-Onion Clusters for Imaging-Guided Photothermal Cancer Therapy

Herein, water-dispersible carbon nano-onion clusters (CNOCs) with an average hydrodynamic size of ≈90 nm are prepared by simply sonicating candle soot in a mixture of oxidizing acid. The obtained CNOCs have high photothermal conversion efficiency (57.5%), excellent aqueous dispersibility (stable in water for more than a year without precipitation), and benign biocompatibility. After polyethylenimine (PEI) and poly(ethylene glycol) (PEG) modification, the resultant CNOCs-PEI-PEG have a high photothermal conversion efficiency (56.5%), and can realize after-wash photothermal cancer cell ablation due to their ultrahigh cellular uptake (21.3 pg/cell), which is highly beneficial for the selective ablation of cancer cells via light-triggered intracellular heat generation. More interestingly, the cellular uptake of CNOCs-PEI-PEG is so high that the internalized nanoagents can be directly observed under a microscope without fluorescent labeling. Besides, in vivo experiments reveal that CNOCs-PEI-PEG can be used for photothermal/photoacoustic dual-modal imaging-guided photothermal therapy after intravenous administration. Furthermore, CNOCs-PEI-PEG can be efficiently cleared from the mouse body within a week, ensuring their excellent long-term biosafety. To the best of the authors' knowledge, the first example of using candle soot as raw material to prepare water-dispersible onion-like carbon nanomaterials for cancer theranostics is represented herein.

Candle soot derived carbon nanoparticles: Assessment of physico-chemical properties, cytotoxicity and genotoxicity

In this study, an evaluation of physico-chemical properties, cytotoxicity and genotoxicity of candle soot derived carbon nanoparticles (CNPs) was carried out. Several physico-chemical characterizations including scanning electron microscopy, transmission electron microscope, Brunauer-Emmet-Teller surface area and pore-size distribution, X-ray diffraction, Fourier transform infrared and Raman spectroscopy were implemented to characterize prepared CNPs. Propidium iodide uptake, reactive oxygen species assay and trypan blue exclusion and comet assay tests were executed to determine the toxicity of CNPs. It is found that the CNPs have insignificant cytotoxicity and genotoxicity and could be used in diverse biological and environmental applications as an alternative to expensive less toxic carbon materials.

Cost-Effective Surface Modification of Carbon Cloth Electrodes for Microbial Fuel Cells by Candle Soot Coating

This study explored an economically-feasible and environmentally friendly attempt to provide more electrochemically promising carbon cloth anodes for microbial fuel cells (MFCs) by modifying them with candle soot coating. The sponge-like structure of the deposited candle soot apparently increased the surface areas of the carbon cloths for bacterial adhesion. The superhydrophilicity of the deposited candle soot was more beneficial to bacterial propagation. The maximum power densities of MFCs configured with 20-s (13.6 ± 0.9 mW·m−2), 60-s (19.8 ± 0.2 mW·m−2), and 120-s (17.6 ± 0.8 mW·m−2) candle-soot-modified carbon cloth electrodes were apparently higher than that of an MFC configured with an unmodified electrode (10.2 ± 0.2 mW·m−2). The MFCs configured with the 20- and 120-s candle-soot-modified carbon cloth electrodes exhibited lower power densities than that of the MFC with the 60-s candle-soot-modified carbon cloth electrode. This suggested that the insufficient residence time of candle soot led to an incomplete formation of the hydrophilic surface, whereas protracted candle sooting would lead to a thick deposited soot film with a smaller conductivity. The application of candle soot for anode modification provided a simple, rapid, cost-effective, and environment-friendly approach to enhancing the electron-transfer capabilities of carbon cloth electrodes. However, a postponement in the MFC construction may lead to a deteriorated hydrophilicity of the candle-soot-modified carbon cloth.

Facile Fabrication and Characterization of a PDMS-Derived Candle Soot Coated Stable Biocompatible Superhydrophobic and Superhemophobic Surface

We report a simple, inexpensive, rapid, and one-step method for the fabrication of a stable and biocompatible superhydrophobic and superhemophobic surface. The proposed surface comprises candle soot particles embedded in a mixture of PDMS+n-hexane serving as the base material. The mechanism responsible for the superhydrophobic behavior of the surface is explained, and the surface is characterized based on its morphology and elemental composition, wetting properties, mechanical and chemical stability, and biocompatibility. The effect of %n-hexane in PDMS, the thickness of the PDMS+n-hexane layer (in terms of spin coating speed) and sooting time on the wetting property of the surface is studied. The proposed surface exhibits nanoscale surface asperities (average roughness of 187 nm), chemical compositions of soot particles, very high water and blood repellency along with excellent mechanical and chemical stability and excellent biocompatibility against blood sample and biological cells. The water contact angle and roll-off angle is measured as 160° ± 1° and 2°, respectively, and the blood contact angle is found to be 154° ± 1°, which indicates that the surface is superhydrophobic and superhemophobic. The proposed superhydrophobic and superhemophobic surface offers significantly improved (>40%) cell viability as compared to glass and PDMS surfaces.

A floral variant of mesoporous carbon as an anode material for high performance sodium and lithium ion batteries

Flower-like mesoporous carbon simply prepared by direct pyrolysis of zinc citrate exhibits excellent sodium and lithium storage performances.