Carbon Nanomaterials Research Articles

Electrochemical properties of novel redox active electrode coatings based on heterocyclic polyazines and its nanocomposites with carbon nanomaterials

This work aims to study electrode materials based on unsubstituted polyazines and composites which will allow further advancing both in the molecular design of redox polymers, composites and materials and evaluating their potential applicability. The polymers were prepared by two-phase chemical oxidative polymerization. Polymer-carbon nanocomposites (NC) based on unsubstituted polyphenoxazine were prepared for the first time. The physicochemical and electrochemical properties were compared for NCs based on polyphenothiazine (PPTA), polyphenoxazine (PPOA) and carbon nanomaterials (CNM). The used CNMs comprise reduced graphene oxide (RGO), single-walled and multi-walled carbon nanotubes (SWCNT and MWCNT). The NC structure and morphology were studied by means of FT IR spectroscopy, XRD, FE-SEM and TEM. The limited solubility of some monomers prevents their electrochemical deposition on electrodes. Therefore, to study the electrochemical, spectroelectrochemical behavior and electrochemical impedance of novel redox active electrode coatings, suspensions of synthesized polymers or their NCs were applied onto electrodes and dried. The effect of NC composition on the conductivity and redox activity thereof was discovered. In general, composites have a higher conductivity than individual polymers. Despite differences in electrical conductivity, all samples exhibited electrocatalytic behavior demonstrated for example of Fe(II)/Fe(III) cyanide redox transition on a planar electrode in a K3[Fe(CN)6] solution in 1 M H2SO4. The electronic absorption spectra were recorded in-situ in an electrochemical cell by varying the working electrode potential and showed an electrochromic effect for PPTA and CNM/PPTA. The proposed common equivalent electric circuit allowed explaining the different electrochemical properties of polymers and CNM composites thereof.

Investigation of column purified dye derived carbon nanomaterials for security printing and supercapacitor applications

Literature evidence reveals versatile applications of carbon dots (CDs), but generally mixtures of various types of carbon nanomaterials, molecular intermediates as well as side products are obtained upon hydrothermal treatment of the precursor material. This demands isolation of pure components and their complete characterization before these nano carbonaceous materials are chosen for suitable applications. In the present study, perylenetetracarboxylic dianhydride (PTCDA) is subjected to hydrothermal treatment and the mother liquor obtained is separated using column chromatography technique using dichloromethane-methanol solvent system to isolate fractions of various fluorescent carbonaceous nanostructures. The TEM imaging of nano carbonaceous particles of all five fractions indicated that the first and third fractions were composed of nanoribbons, while the latter two fractions largely contained quasi-spherical nanoparticles of both lesser (carbon quantum dots) and greater (carbon nanodots) than 10 nm dimensions. The XPS results of all the fractions suggested separation based on polarity difference. The ID/IG ratios obtained from Raman spectra implied the presence of several defects on the CDs. The time resolved fluorescence spectra of third, fourth and fifth fractions revealed mono-exponential decay of fluorophores with excitation independent average lifetime values. The fifth fraction exhibited good biocompatibility and the highest absolute fluorescence quantum yield of 58.47 % among all the isolated samples. As these CDs displayed a remarkable rise in the quantum yield to 88.60 % when dispersed in water, a water-based flexo-ink was formulated. The photostable pale yellow flexo print proofs obtained on UV dull paper exhibited a green fluorescence under 365 nm illumination, whereas a yellow glow when shined with blue light, which can serve as an authentication feature for security documents and currency notes. Moreover, as the third fraction constitutes mainly of carbon nanoribbons (CNRs), an optimized polymer electrolyte was prepared along with sodium alginate (SA), and MgCl2 to understand their potential use in energy storage application. A supercapacitor was fabricated and tested for its electrochemical performance such as cyclic voltammtery (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCD). An enhanced current window was observed in the CV of SA/CNRs compared to pure SA and SA/CNRs/Mg films, which indicated a structural interaction of CNRs with SA. The conductivity of SA/CNRs/Mg was lesser than SA/CNRs in EIS studies due to the presence of Mg ions, while pure SA showed lesser conductivity. The dual ionic interaction of Na and Mg along with enhanced structural stability due to doped CNRs favors its convenient supercapacitor application. The fabricated eco-friendly supercapacitor showed a specific capacitance of 84 F/g. The GCD of the device displayed pseudocapacitance behaviour and was quite stable for 2000 cycles with coulombic efficiency of 96 %.

Incorporation of polydopamine functionalized as double‐sided adhesive to connect phosphotungstic acid in Friedel‐Crafts cross‐linked SPEEK sulfonated poly(ether eether ketone) as proton exchange membranes

AbstractUsing highly sulfonated poly(ether ether ketone) (SPEEK) as the base material, the structure and properties of poly(ether ether ketone) (PEEK) membranes are optimized by precisely controlling the doping of phosphotungstic acid (HPW), dopamine (DA), and various amounts of carbon nanomaterials. Compared with conventional PEEK membranes, this optimized membrane exhibits higher proton conductivity, lower water absorption swelling rate, and excellent thermal stability. Highly SPEEK is soluble in water, thus fails to be used in fuel cell applications. Herein, we conduct Friedel‐Crafts method to obtain cross‐linked highly sulfonated membrane with controlled water uptake and swelling while still maintaining high proton conductivity. The polymer is then doped with phosphotungstic acid (HPW) to acquire enhanced performance. To control HPW leakage, polydopamine (PDA) acting as double‐sided adhesive is incorporated within the membrane. By distributing 1 wt.% PDA, the HPW leakage is reduced almost three times. The composite C‐SPEEK/HPWx/PDAy membranes have exhibited excellent overall performance. Specifically, the best proton conductivity result of C‐SPEEK/HPW50 has reached 0.271 S/cm. Moreover, it has presented superb performance in H2/O2 single cell test recorded as power density of 886.13 mW/cm2 while current density is 1614.20 mA/cm2 at 60°C.

Novel synthesis method of carbon nanofibers (CNFs) by using Proteus mirabilis bacteria

Carbon nanofiber (CNF) is a cylindrical carbon nanomaterial, with diameter around 100 nm and its length sometimes extends up to a few micrometers. Different types of CNFs are synthesized based on the production method, which differs dramatically in terms of structure, composition, and characteristics. Today, using green chemistry methods and microorganisms has resulted in biocompatible nanoparticles materials. In this work Proteus mirabilis bacteria were used as nanometer template for synthesis of carbon nanofibers. For this propose, two carbon electrodes were put into the solution containing Proteus mirabilis bacteria, sodium chloride, nickel chloride, molybdenum powder. To find optimized conditions for the synthesis of CNFs, the parameters of time, kind of electrodes and amount current were studied. The optimized conditions were found as follows: synthesis time 60 s, the carbon–carbon electrode and the electric current (90 A) with voltage of 24 V. The optimized synthesized carbon nanofibers were characterized with the techniques of FTIR spectroscopy, Raman spectroscopy, X-Ray diffraction, scanning electron microscopy coupled with energy dispersive (SEM-EDX) and BET method.

Honeycomb polypore biomass-derived activated porous carbon nanosheets/graphite/nafion composite: Green and sensitive electrocatalyst for nanomolar detection of Hg2+ ions and water-splitting reactions

The electrochemical strategies with green electrocatalysts propose a selective, steady, and sensitive direction for the trace analytes sensing, hydrogen evolution reaction (HER), and oxygen evolution reaction (OER) applications. Herein, Honeycomb Polypore biomass waste-derived NaOH-activated porous nanocarbon material was synthesized, which performs as a multifunctional electrocatalyst for Hg2+ sensing and water-splitting reactions with the support of graphite and Nafion composite. The optimized nanocomposite shows high electrochemical activity for the redox reaction of Hg2+ in 0.1 M phosphate-buffered saline of 5.0 pH with a lower limit of detection value of 2.309 nM, good stability, reproducibility, and anti-interference activity. For water-splitting reactions, the optimized nanocomposite shows better overpotential values of 0.447 V (HER in 0.5 M H2SO4) and 0.305 V (OER in 0.5 M KOH) at 10.0 mA/cm2 of current density. Also, the lower Tafel slope values of 0.089 V/decade and 0.075 V/decade of the optimum electrocatalyst signify superior proficiency towards the HER and OER activities, respectively. These outcomes validate the materials’ excellent multifunctional activity for Hg2+ detection in different water samples and water-splitting reactions, boosting their potential for environmental safety and energy production.

Theoretical study on the carbon nanomaterial-supported Pt complex electrocatalysts for efficient and selective chlorine evolution reaction.

Chlorine is an important chemical which has long been produced in chlor-alkali process using dimensionally stable anodes (DSA). However, some serious drawbacks of DSA inspire the development of alternative anodes for chlorine evolution reaction (CER). In this study, we focused on the graphene- and carbon nanotube-supported platinum tetra-phenyl porphyrins as electrocatalysts for CER, which have been theoretically investigated based on density functional theory. Our results reveal that the supported substrates possess potential CER electrocatalytic activity with very low thermodynamic overpotentials (0.012-0.028 V) via Cl* pathway instead of ClO*. The electronic structures analyses showed that electron transfer from the support to the adsorbed chlorine via the Pt center leads to strong Pt-Cl interactions. Furthermore, the supported electrocatalysts exhibited excellent selectivity toward CER because of high overpotentials and reaction barriers of oxygen evolution process. Therefore, our results may pave the way for designing CER electrocatalyst utilizing emerging carbon nanomaterials.

Hierarchical Magnetic Carbon Nanoflowers for Ultra-Efficient Electromagnetic Wave Absorption.

Porous carbon nanomaterials are widely applied in the electromagnetic wave absorption (EMWA) field. Among them, an emerging flower-like carbon nanomaterial, termed carbon nanoflowers (CNFs), has attracted tremendous research attention due to their unique hierarchical flower-like structure. However, the design of flower-like carbon nanomaterials with different magnetic cores for EMWA has rarely been reported. Herein, a general template method is proposed to achieve a set of high-quality magnetic CNFs, namely Co@Void@CNFs, CoNi@CNFs, and Ni@CNFs. The prepared magnetic CNFs have highly accessible surface area and internal space, rich heteroatom content, multi-scale pore system, and uniform and highly dispersed magnetic nanoparticles, as a result, deliver superior EMWA performance. Specifically, when the thickness is 2.6mm, the Co@Void@CNFs exhibit a maximum refection loss (RLmax) of -56.6dB and an effective absorption bandwidth (EAB) from 8.0 to 12.1GHz covering the whole X band. The CoNi@CNFs have an RLmax of up to -57.6dB and a wide EAB of 5.6GHz at just 1.9mm. For the Ni@CNFs, possess an ultra-broad EAB of 6.1GHz, covering the entire Ku band at 2.0mm. Overall, the hierarchical magnetic carbon nanoflowers proposed here offer new insights toward realizing multifunctional integrated carbon nanomaterials for EMWA.

Efficient eco-friendly synthesis of carbon nanotubes over graphite nanosheets from yellow corn: a one-step green approach

The present work reports the synthesis of multi-wall carbon nanotubes (MWCNTs) over graphite nanosheets by an easy and simple approach without using any external catalyst. Simply, yellow corn seeds were thermally annealed in a hydrogen atmosphere at 1050 °C for 3 h without any pretreatments. Notably, the growth of MWCNTs was observed to preferentially occur on the outer surface of the corn shell. This uncomplicated approach not only emphasizes the feasibility of synthesizing carbon nanomaterials using agricultural by-products but also underscores the potential applications of these synthesized materials in various fields. Samples were examined through a comprehensive analysis employing various techniques, including scanning electron microscopy (SEM), Raman spectroscopy, FTIR, X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The findings unveiled the formation of rolled graphene accompanied by the presence of vertical multi-wall carbon nanotubes (MWCNTs) positioned over stacked graphene sheets. This detailed characterization provides insights into the structural features and arrangement of the synthesized materials, paving the way for a deeper understanding of their potential applications. The pyrolysis temperature is a crucial factor in the morphological characteristics of the synthesized carbon nanostructures. While graphene cage-like structures were obtained at 800 °C, small carbon nanotubes were grafted to larger ones and formed three-dimensional hierarchical morphologies when the annealing temperature increased to 900 °C. The growth mechanism of the carbon nanotubes was explained based on the jet self-extrusion of the generated gases through the inherent pores of the corn seeds. The current technique employed in manufacturing MWCNTs shows significant promise as a green synthesis method for producing catalyst-free MWCNTs suitable for industrial applications including sensors and energy storage materials.

Enhancing Trace Pb2⁺ Detection via Novel Functional Materials for Improved Electrocatalytic Redox Processes on Electrochemical Sensors: A Short Review

The efficient detection of lead ions (Pb2⁺) is significant for environmental protection and public health. Electrochemical detection has emerged as one of the most promising technologies due to its low detection limits, high sensitivity, and cost-effectiveness. However, significant challenges remain, including issues related to sensitivity, selectivity, interference, and the stability of electrode materials. This review explores recent advancements in the field, focusing on integrating novel catalytic materials and innovative sensor construction methods. Particular emphasis is placed on enhancing the electrocatalytic redox processes on sensor surfaces using advanced nanomaterials such as MXenes, ferrite-based nanomaterials, carbon nanomaterials, and metal–organic frameworks (MOFs). Additionally, the role of biomaterials and enzymes in improving electrochemical sensors’ selectivity and anti-interference capabilities is discussed. Despite the impressive low detection limits achieved, real-world applications present additional challenges due to the complex composition of environmental samples. The review concludes with future perspectives on overcoming these challenges by leveraging the unique properties of catalytic materials to develop more effective and reliable electrochemical sensors for trace Pb2⁺ detection.

Nitrogen-doped carbon quantum dots as antimicrobial agents against gram-positive Bacillus subtilis and Staphylococcus aureus under visible white light-emitting diode

Carbon nanomaterials, such as carbon quantum dots (CQDs), are excellent candidates for antibacterial agent development as they are cost-effective. Nitrogen-doped CQDs (N-doped CQDs) exhibit antibacterial activity against gram-positive bacteria. However, investigation of N-CQDs and their efficacy against the selected bacterial strains under visible light irradiation has not been carried out. Here, we aimed to evaluate N-CQDs for their efficacy as a photosensitizer for antimicrobial photodynamic therapy (aPDT). N-CQDs were synthesized using the hydrothermal method with 1,3,6-trinitropyrene (TNP) as the nitrogen and carbon source. Antimicrobial tests of N-CQDs were conducted against gram-positive (Bacillus subtilis NCIB 3610, Staphylococcus aureus Newman, and S. aureus USA300) and gram-negative (Escherichia coli K12) bacteria at different concentrations (0–100 mg/L). The N-CQDs exerted a moderate growth-inhibitory effect on gram-positive bacteria in the dark. However, in the presence of white light generated using 20-W light-emitting diode, N-CQDs could completely kill the bacteria at a low concentration of 20 mg/L. The minimal inhibitory concentration of N-CQDs for the two S. aureus strains (Newman and USA300) was 20 mg/L under light conditions, whereas that for B. subtilis was 100 mg/L. The results demonstrate that N-CQDs may be used as a photosensitizer in aPDT and as an antibacterial agent.

Graphene nanoribbon hydrogel scaffold for highly conductive and robust polyimide nanocomposite

Although highly loaded graphitic nanocarbon materials effectively enhance the electrical, mechanical, and thermal properties of polymeric materials, their practical implementation has been hindered by severe aggregation issues. Here, we propose a method to achieve homogeneous nanocarbon-polyimide (PI) composites by integrating graphene oxide nanoribbons (GONRs) with polyamic acid ammonium (PAA) salt, a precursor of PI. Self-assembled scaffold structure of GONRs hydrogel enables the uniform integration and immobilization of PAA within the GONR scaffold, mitigating aggregation concerns. The resulting GONR/PAA hydrogel, formed through physical interactions, can be coated onto substrates via a shear stress-induced bar coating method due to its viscoelastic rheological properties. Subsequent heat treatment at 400 °C triggers the imidization reaction of PAA and the reduction of GONR, facilitating the formation of uniformly integrated GNR/PI nanocomposite coatings. Under optimized conditions, incorporating a high-loading GONR content in PAA (95 wt% of GONR and 5 wt% of PAA) yielded GNR/PI composites with excellent mechanical properties, exhibiting a hardness of 0.75 GPa and an elastic modulus of 8.3 GPa. Additionally, this GNR/PI composite displayed a good electrical conductivity of 3890 S/m, attributed to the electrical pathways formed by GNRs within the PI matrix.

Lignin-based Carbon NanomaterialsforBiochemical Sensing Applications.

Lignin-based carbon nanomaterials offer several advantages, including biodegradability, biocompatibility, high specific surface area, ease of functionalization, low toxicity, and cost-effectiveness. These materials show promise in biochemical sensing applications, particularly in the detection of metal ions, organic compounds, and human biosignals. Various methods can be employed to synthesize carbon nanomaterials with different dimensions ranging from 0D to 3D, resulting in diverse structures and physicochemical properties. This study provides an overview of the preparation techniques and characteristics of multidimensional (0-3D) lignin-based carbon nanomaterials, such as carbon dots (CDs), carbon nanotubes (CNTs), graphene, and carbon aerogels (CAs). Additionally, the sensing capabilities of these materials are compared and summarized, followed by a discussion on the potential challenges and future prospects in sensor development.

The introduction of rich active sites on 0D@2D nanocarbon via light illuminating with high-efficient electrocatalytic H2O2 production

Two-dimensional (2D) carbon-based materials are high-quality electrocatalytic materials with high mass transfer interfaces. However, the intrinsic 2D surfaces often lack of abundant active sites and outstanding electron transport channels. Herein, a 0D@2D nanocarbon material with affluent unsaturated oxygen-containing groups (UOCGSs) active sites and excellent electron channels are constructed via a novel sodium ion-capping and light illuminating strategy. With the aid of the light illuminating, the final 0D@2D product exhibits a superior practical H2O2 production rate of up to 1109 mmol·gcatalyst−1 h−1 with a high level of onset potential 0.78V and 94 % H2O2 selectivity in H-cell. This improved performance arises from the introduction of UOCGSs and excellent charge transfer on the 0D@2D interface. Obviously, this work exhibits a new green stagey for the design of 0D@2D carbon-based structure via light illuminating.

Synthesis and Characterization of Nanocellulose/Polyacrylonitrile‐based Carbon Nanofibers: An Approach toward Low Cost and Sustainable Agro Waste based Carbon Nanomaterials

AbstractThe cost of polymer precursors and high energy need in carbonization for the preparation of carbon materials are two limiting factors in the commercialization of carbon‐based materials. In this study, carbon nanofiber films were prepared by adding a very small concentration of polymer polyacrylonitrile in nanocellulose (extracted from agro waste i.e., rice straws) with an overall aim of producing carbon nanomaterials with cost effective, renewable and sustainable carbon source. Polyacrylonitrile (PAN) added nanocellulose solution was drop‐casted to prepare Nanocellulose/Polyacrylonitrile‐based nanofibers film (NC/PAN). It was further stabilized in air atmosphere at 280 °C followed by carbonized in nitrogen atmosphere at 700 °C. It was found that addition of NC/PAN have 18 % lower activation energies than PAN. Results of tunneling electron microscopy showed that polyacrylonitrile/nanocellulose films carbonized at 700 °C temperature exhibited amorphous carbon nanofibers structure similar to bare polyacrylonitrile based carbon film carbonized at higher temperature of 1000 °C‐1200 °C. Furthermore, polyacrylonitrile/nanocellulose based carbon nanofibers have showed high degree of carbonization ((ID)/(IG)=0.87) as compared to bare polyacrylonitrile based carbon nanofibers film ((ID)/(IG)=1.02). This may be attributed to chiral nature of nanocellulose which served as a template to orientation of graphene planes and showed efficient carbonization.

Chemiresistive NH3 and H2S sensors based on thin films of vitamin B12 derivatives

Despite the large number of materials, e.g. semiconducting oxides, carbon nanomaterials, conducting polymers and others, that are used as active layers of chemiresistive sensors to ammonia and hydrogen sulfide, the search for new materials remains an urgent task. Special attention is paid to the search for environmentally friendly materials. Corrinoids are naturally occurring coordination complexes consisting of a central cobalt ion and a tetrapyrrole ligand called a corrin ring. Cobalamins and their derivatives are widely used as active layers of optical and electrochemical sensors. At the same time, vitamin B12 derivatives have not been studied as active layers of chemiresistive gas sensors. In this work, films of two vitamin B12 derivatives, viz. dicyanocobyrinic acid heptabutyl ester (DC) and its aquacyano form, aquacyanocobyrinic acid heptabutyl ester (AC), deposited by spin coating and drop casting techniques onto interdigitated electrodes, were tested for the first time as active layers of chemiresistive sensors for the detection of low concentrations of ammonia and hydrogen sulfide (1–50 ppm) in air. It was shown that films of both vitamin B12 derivatives demonstrated reversible sensor response to NH3 and H2S at room temperature. The limit of detection (LOD) of H2S was 0.1 ppm for both vitamin B12 derivatives, while LOD of ammonia was noticeably lower (0.06 ppm) in the case of AC films than in the case of DC films (0.4 ppm). Both sensors demonstrated a fairly low regeneration time, which did not exceed 180 s for 5 ppm of NH3 and 185 s for 5 ppm of H2S.

Dispersion effect of nano-structure pyrolytic carbon on mechanical, electrical, and microstructural characteristics of cement mortar composite

ABSTRACT In material science, converting waste into nanomaterials by green technologies highlights the interest in producing sustainable carbon nanomaterial (SCN). This study first-ever utilized tyre-char as a Nano-Structure Pyrolytic Carbon (NSPC) to develop electrically conductive composites. Unlike other carbon nanomaterials, the efficiency of NSPC particle as an SCN in developing electrically conductive composites was investigated in terms of dispersion, mechanical, water absorption, electrical resistivity, and microstructure. The results of sedimentation and zeta potential (−19 mV) showed the excellent dispersion of NSPC particle in water with the combined effect of superplasticizer and ultrasonication. The compressive (40.37%) and flexural strength (10.76%) than that of plain cement mortar composite (CMC) is achieved with 2 wt.% and 1.5 wt.% of NSPC particle, respectively. The water absorption rate and volume of permeable voids were reduced, exhibiting less agglomerations. The percolation zone of AC and DC resistivity of NSPC composite ranges between 1 and 2 wt.%, and the established percolation threshold is at 2 wt.%. XRD analysis showed C-S-H formation consistently increased with curing age, and HR-SEM with EDAX analysis exhibits the dense microstructure and well-distributed NSPC particle at the nanoscale. These experimental outcomes significantly enhanced the reliability and provided a framework for tailoring NSPC particle as SCN for developing electrically conductive composite.

Influence of carbon quantum dots on foam stability: a molecular dynamics study

Abstract Carbon quantum dots are employed in foam for enhanced oil recovery. This study focuses on the impact of carbon quantum dots on the stability of oil displacement foam. Molecular dynamics simulations are conducted to investigate commonly used models of carbon quantum dots and surfactant foams in oil displacement. The research delves into the interfacial properties of the foam film, the flow characteristics of water molecules, and the interaction between carbon quantum dots and surfactants. Insights gained from these three aspects reveal the influence of carbon quantum dots on surfactant foam films. This work provides theoretical guidance for the utilization of carbon nanomaterials in foam-assisted oil recovery.

Enhanced synthesis of sponge-type multiwalled carbon nanotubes using SiO2-Fe2O3 catalysts via aerosol-assisted chemical vapor deposition: Electrochemical and absorption capacity studies

Carbon nanotube sponges synthesized at the laboratory scale typically use a Fe-based organometallic catalyst, but low-cost alternatives with a higher yield ratio are needed for large-scale production. This work introduces a catalyst made from a mixture of silicon dioxide (SiO2) and hematite (Fe2O3) as an innovative alternative for the high-yield production of spongy-type multi-walled carbon nanotubes (ST-MWCNTs). We used a ball-milled mixture of SiO2 and Fe2O3 powders as the catalyst and toluene and N, N-dimethylformamide as carbon and nitrogen sources in an aerosol-assisted catalytic chemical vapor deposition system. Incorporating SiO2 into the Fe-based catalyst increased production yield to 184 % of the catalyst weight. The synthesized ST-MWCNTs exhibited a high crystallinity ratio (ID/IG = 0.34) with a unique entangled bundle-type nanotube configuration. At the same time, the presence of Si atoms and oxygen-type functionalities, demonstrated by X-ray photoelectron spectroscopy, modified their electrochemical behavior, making them suitable for supercapacitor or sensor applications. Additionally, the spongy structure demonstrated a reversible absorption capacity of over 15 times its weight with organic solvents like gasoline or ethylene glycol. This new catalyst configuration opens alternatives for generating higher amounts of 3D carbon nanomaterials with potential energy storage, water filtration, and environmental remediation applications.

On the Use of Nanoparticles in Dental Implants.

Results obtained in physics, chemistry and materials science on nanoparticles have drawn significant interest in the use of nanostructures on dental implants. The main focus concerns nanoscale surface modifications of titanium-based dental implants in order to increase the surface roughness and provide a better bone-implant interfacial area. Surface coatings via the sol-gel process ensure the deposition of a homogeneous layer of nanoparticles or mixtures of nanoparticles on the titanium substrate. Nanotubular structures created on the titanium surface by anodic oxidation yield an interesting nanotopography for drug release. Carbon-based nanomaterials hold great promise in the field of dentistry on account of their outstanding mechanical properties and their structural characteristics. Carbon nanomaterials that include carbon nanotubes, graphene and its derivatives (graphene oxide and graphene quantum dots) can be used as coatings of the implant surface. Their antibacterial properties as well as their ability to be functionalized with adequate chemical groups make them particularly useful for improving biocompatibility and promoting osseointegration. Nevertheless, an evaluation of their possible toxicity is required before being exploited in clinical trials.

Cost Optimization of Graphene Oxide-Modified Ultra-High-Performance Concrete Based on Machine Learning Methods

The use of carbon nanomaterials in ultra-high-performance concrete (UHPC) to improve its mechanical properties and durability is growing. Graphene oxide (GO) has emerged as one of the most promising nanomaterials in recent years for enhancing the properties of UHPC. The majority of research so far has been on the properties of UHPC enhanced with GO, but its high cost has limited its application in engineering. This work suggests a machine learning (ML)-based approach to optimize the mix ratio in order to lower the cost of graphene oxide-modified UHPC. To do this, an artificial neural network (ANN) is used to create the prediction model for the 28-day compressive strength and slump flow of UHPC. The performance of this model is then compared using nine different ML techniques. Subsequently, considering the restrictions of the UHPC component content, component proportion, and absolute volume, a genetic algorithm (GA) is adopted to lower the UHPC cost. The sensitivity analysis is carried out in the end. This study’s findings indicate that there is a decent degree of prediction accuracy since the difference between the ANN model’s predictions and the experimental outcomes is just 10%. The cost of UHPC optimized by GA is reduced to 776 $/m3, significantly lower than the average cost of UHPC.