N-Graphene Nanowalls via Plasma Nitrogen Incorporation and Substitution: The Experimental Evidence

Nitrogen-Doped 3D-Graphene Advances Near-Infrared Photodetector for Logic Circuits and Image Sensors Overcoming 2D Limitations

The limitations of two-dimensional (2D) graphene in broadband photodetector are overcome by integrating nitrogen (N) doping into three-dimensional (3D) structures within silicon (Si) via plasma-assisted chemical vapor deposition (PACVD) technology. This contributes to the construction of vertical Schottky heterojunction broad-spectrum photodetectors and applications in logic devices and image sensors. The natural nanoscale resonant cavity structure of 3D-graphene enhances photon capture efficiency, thereby increasing photocarrier generation. N-doping can fine-tune the electronic structure, advancing the Schottky barrier height and reducing dark current. The as-fabricated photodetector exhibits exceptional self-driven photoresponse, especially at 1550 nm, with an excellent photoresponsivity (79.6 A/W), specific detectivity (1013 Jones), and rapid response of 130 μs. Moreover, it enables logic circuits, high-resolution pattern image recognition, and broadband spectra recording across the visible to near-infrared range (400-1550 nm). This research will provide new views and technical support for the development and widespread application of high-performance semiconductor-based graphene broadband detectors.

Modulation of Electrokinetic Potentials Using Graphene-Based Surfaces and Variable Substrate Charge Density

Enhanced electrokinetic phenomena, manifested through the observation of a large streaming potential (Vs), were obtained in microchannels with single-layer graphene (SLG)-coated and few-layer graphene (FLG)-coated surfaces. In comparison to silicon microchannels, the Vs obtained for a given pressure difference along the channel (ΔP) was higher by 75% for the graphene-based channels, with larger values in the SLG case. Computational modeling was used to correlate the surface charge density, tuned through plasma processing, and related zeta potential to measured Vs. The implications related to deploying lower dimensional material surfaces for modulating electrokinetic flows were investigated.

Stone-Wales Defect in Graphene

2D graphene the most investigated structures from nanocarbon family studied in the last three decades. It is projected as an excellent material useful for quantum computing, artificial intelligence, and next generation advanced technologies. Graphene exists in several forms and its extraordinary thermal, mechanical, and electronic properties, principally depend on the kind of perfection of the hexagonal atomic lattice. Defects are always considered as undesired components but certain defects in graphene could be an asset for electrochemistry and quantum electronics due to the engineered electronclouds and quantum tunnelling. The authors carefully discuss the Stone-Wales imperfections in graphene and its derivatives comprehensively. A specific emphasis is focused on the experimental and theoretical aspects of the Stone-Wales defects in graphene with respect to structure-property relationships. The corroboration of extrinsic defects like external atomic doping, functionalization, edge distortion in the graphene consisting of Stone-Wales imperfections, which are very significant in designing graphene-based electronic devices, are summarized.

Synergistic effect of electrotrophic perchlorate reducing microorganisms and chemically modified electrodes for enhancing bioelectrochemical perchlorate removal

Perchlorate has been described as an emerging pollutant that compromises water sources and human health. In this study, a new electrotrophic perchlorate reducing microorganism (EPRM) isolated from the Atacama Desert, Dechloromonas sp. CS-1, was evaluated for perchlorate removal in water in a bioelectrochemical reactor (BER) with a chemically modified electrode. BERs were operated for 17 days under batch mode conditions with an applied potential of -500 mV vs. Ag/AgCl. Surface analysis (i.e., SEM, XPS, FT-IR, RAMAN spectroscopy) on the modified electrode demonstrated heterogeneous transformation of the carbon fibers with the incorporation of nitrogen functional groups and the oxidation of the carbonaceous material. The BERs with the modified electrode and the presence of the EAM reached high cathodic efficiency (90.79 ± 9.157%) and removal rate (0.34 ± 0.007 mol m-3-day) compared with both control conditions. The observed catalytic enhancement of CS-1 was confirmed by a reduction in the charge transfer resistance obtained by electrochemical impedance spectroscopy (EIS). Finally, an electrochemical kinetic study revealed an eight-electron perchlorate bioreduction reaction at -638.33 ± 24.132 mV vs. Ag/AgCl. Therefore, our results show the synergistic effect of EPRM and chemically modified electrodes on perchlorate removal in a BER.

Tuning humidity sensing properties via grafting fluorine and nitrogen-containing species on single-walled carbon nanotubes

The effect of humidity on the electrical conductivity of single-walled carbon nanotube (SWCNT) films depends on both the conductivity of individual nanotubes and the electrical contacts between them. Here, we study these factors by comparing the sensor response of nanotubes with fluorine- and nitrogen-containing groups attached to the sidewalls. Experiments carried out in a wide range of relative humidity (RH) at room and elevated temperatures showed that the conductivity of non-functionalized SWCNTs and contacts between them decreases upon the adsorption of water molecules. Covalent fluorination reduces the conductivity of SWCNTs and significantly increases the sensitivity of the film to low concentrations of water vapor. The response at high RH decreases due to the large number of water molecules adsorbed on the conductive regions of the nanotubes. As a result of substitutional reactions of fluorinated SWCNTs with dimethylformamide and ethylenediamine, nitrogen-containing groups are added, the amount of which, however, is much less than the amount of fluorine. This modification of the SWCNTs improves intertube contacts in the film and increases the surface area for water adsorption. Our results show that an increase in the number of functional groups on the SWCNT surface enhances the sensitivity of the sensor to low water concentrations and worsens the response at high RH. SWCNTs modified with ethylenediamine have the highest sensitivity over the entire range of RH.

Asymmetric dinitrogen-coordinated nickel single-atomic sites for efficient CO2 electroreduction

Developing highly efficient, selective and low-overpotential electrocatalysts for carbon dioxide (CO₂) reduction is crucial. This study reports an efficient Ni single-atom catalyst coordinated with pyrrolic nitrogen and pyridinic nitrogen for CO₂ reduction to carbon monoxide (CO). In flow cell experiments, the catalyst achieves a CO partial current density of 20.1 mA cm_geo^-2 at -0.15 V vs. reversible hydrogen electrode (V_RHE). It exhibits a high turnover frequency of over 274,000 site^-1 h^-1 at -1.0 V_RHE and maintains high Faradaic efficiency of CO (FE_CO) exceeding 90% within -0.15 to -0.9 V_RHE. Operando synchrotron-based infrared and X-ray absorption spectra, and theoretical calculations reveal that mono CO-adsorbed Ni single sites formed during electrochemical processes contribute to the balance between key intermediates formation and CO desorption, providing insights into the catalyst's origin of catalytic activity. Overall, this work presents a Ni single-atom catalyst with good selectivity and activity for CO₂ reduction while shedding light on its underlying mechanism.

Effects of High-Quality Carbon Nanowalls Ionization-Assisting Substrates on Surface-Assisted Laser Desorption/Ionization Mass Spectrometry Performance

Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) is performed using carbon nanowalls (CNWs) for ionization-assisting substrates. The CNWs (referred to as high-quality CNWs) in the present study were grown using a radical-injection plasma-enhanced chemical vapor deposition (RI-PECVD) system with the addition of oxygen in a mixture of CH₄ and H₂ gases. High-quality CNWs were different with respect to crystallinity and C-OH groups, while showing similar wall-to-wall distances and a wettability comparable to CNWs (referred to as normal CNWs) grown without O₂. The efficiency of SALDI was tested with both parameters of ion intensity and fragmental efficiency (survival yield (SY)) using N-benzylpyridinuim chloride (N-BP-CI). At a laser fluence of 4 mJ/cm², normal CNWs had an SY of 0.97 and an ion intensity of 0.13, while 5-sccm-O₂- high-quality CNWs had an SY of 0.89 and an ion intensity of 2.55. As a result, the sensitivity for the detection of low-molecular-weight analytes was improved with the high-quality CNWs compared to the normal CNWs, while an SY of 0.89 was maintained at a low laser fluence of 4 mJ/cm². SALDI-MS measurements available with the high-quality CNWs ionization-assisting substrate provided high ionization and SY values.

Graphene and Its Derivatives: Synthesis and Application in the Electrochemical Detection of Analytes in Sweat

Wearable sensors and invasive devices have been studied extensively in recent years as the demand for real-time human healthcare applications and seamless human-machine interaction has risen exponentially. An explosion in sensor research throughout the globe has been ignited by the unique features such as thermal, electrical, and mechanical properties of graphene. This includes wearable sensors and implants, which can detect a wide range of data, including body temperature, pulse oxygenation, blood pressure, glucose, and the other analytes present in sweat. Graphene-based sensors for real-time human health monitoring are also being developed. This review is a comprehensive discussion about the properties of graphene, routes to its synthesis, derivatives of graphene, etc. Moreover, the basic features of a biosensor along with the chemistry of sweat are also discussed in detail. The review mainly focusses on the graphene and its derivative-based wearable sensors for the detection of analytes in sweat. Graphene-based sensors for health monitoring will be examined and explained in this study as an overview of the most current innovations in sensor designs, sensing processes, technological advancements, sensor system components, and potential hurdles. The future holds great opportunities for the development of efficient and advanced graphene-based sensors for the detection of analytes in sweat.

A review of the advances in catalyst modification using nonthermal plasma: Process, Mechanism and Applications

With the continuous development of catalytic processes in chemistry, biology, organic synthesis, energy generation and many other fields, the design of catalysts with novel properties has become a new paradigm in both science and industry. Nonthermal plasma has aroused extensive interest in the synthesis and modification of catalysts. An increasing number of researchers are using plasma for the modification of target catalysts, such as modifying the dispersion of active sites, regulating electronic properties, enhancing metal-support interactions, and changing the morphology. Plasma provides an alternative choice for catalysts in the modification process of oxidation, reduction, etching, coating, and doping and is especially helpful for unfavourable thermodynamic processes or heat-sensitive reactions. This review focuses on the following points: (i) the fundamentals behind the nonthermal plasma modification of catalysts; (ii) the latest research progress on the application of plasma modified catalysts; and (iii) main challenges in the field and a vision for future development.

Nitrogen Plasma-Assisted Functionalization of Silicon/Graphite Anodes to Enable Fast Kinetics

The practical use of silicon anodes is interfered by the following key factors: volume expansion, slow kinetics, and low electrical and ionic conductivities. Many studies have focused on surface engineering from the particle to electrode level to achieve stability and energy density. Herein, simple nitrogen gas plasma is introduced as a surface treatment method for silicon-based electrodes to avoid the problems of material synthesis-based functionalizations (e.g., high cost, time consuming, and low quality). The introduction of activated nitrogen gas on electrode surfaces changes the binding energy and resistance of silicon, increasing the reversibility of the charge/discharge reaction of silicon-based anodes. In addition, such doping and dehydrogenation of the electrode surface improve reaction kinetics to 876 mA h g^-1 specific capacity at 8.5 A g^-1 in silicon/graphite anodes even with a high silicon content of 40%. The proposed strategy, through nitrogen plasma, offers advantages for direct functionalization on electrode surfaces by a simple method.

Label-Free Mycotoxin Raman Identification by High-Performing Plasmonic Vertical Carbon Nanostructures

Mycotoxins are widespread chemical entities in the agriculture and food industries that can induce cancer growth and immune deficiency, posing a serious health threat for humankind. These hazardous compounds are produced naturally by various molds (fungi) that contaminate different food products and can be detected in cereals, nuts, spices, and other food products. However, their detection, especially at minimally harmful concentrations, remains a serious analytical challenge. This research shows that high-performing plasmonic substrates (analytical enhancement factor = 5 × 10⁷ ) based on plasma-grown vertical hollow carbon nanotubes can be applied for immediate detection of the most toxic mycotoxins. Due to excellent sensitivity allowing operation at ppb concentrations, it is possible to collect vibrational fingerprints of aflatoxin B₁ , zearalenone, alternariol, and fumonisin B₁ , highlighting the key spectral differences between them using principal component analysis. Regarding time-consuming conventional methods, including thin-layer chromatography, gas chromatography, high-performance liquid chromatography, and enzyme-linked immunosorbent assay, the designed surface-enhanced Raman spectroscopy substrates provide a clear roadmap to reducing the detection time-scale of mycotoxins down to seconds.

Lithium titanate nanoplates embedded with graphene quantum dots as electrode materials for high-rate lithium-ion batteries

Anode materials based on lithium titanate (LTO)/graphene composites are considered as ideal candidates for high-rate lithium-ion batteries (LIBs). Considering the blocking effects of graphene nanosheets in electrodes during ion-transfer processes, construction of LTO/graphene composite structures with enhanced electrical and ionic conductivity via facile and scalable techniques is still challenging for high-rate LIB. In this work, structures of anode materials based on LTO nanoplates embedded with graphene quantum dots (GQDs) are demonstrated for high-rate LIB. The hybrids can be facilely prepared viain situintroduction of GQDs during the process LTO preparation, which enables a uniform dispersion of GQDs within LTO. This method is convenient, rapid, and can be easily scaled-up. The introduction of 0.05 wt.% GQDs can greatly enhance the electrochemical performance of the electrodes. The electrodes with 0.05 wt.% GQDs deliver a specific discharge capacity of 185, 181 and 179 mAh g^-1at 5, 10, and 20 C, respectively. The performance enhancement is suggested to be due to the synergistic interactions between LTO and GQDs. The strategy as well as as-designed structures of LTO/GQDs show potentials for application as high-rate anode materials in LIBs application.

Nitrogen Functionalization of CVD Grown Three-Dimensional Graphene Foam for Hydrogen Evolution Reactions in Alkaline Media

Three-dimensional graphene foam (3D-GrFoam) is a highly porous structure and sustained lattice formed by graphene layers with sp2 and sp3 hybridized carbon. In this work, chemical vapor deposition (CVD)-grown 3D-GrFoam was nitrogen-doped and platinum functionalized using hydrothermal treatment with different reducing agents (i.e., urea, hydrazine, ammonia, and dihydrogen hexachloroplatinate (IV) hydrate, respectively). X-ray photoelectron spectroscopy (XPS) survey showed that the most electrochemically active nitrogen-doped sample (GrFoam3N) contained 1.8 at % of N, and it exhibited a 172 mV dec-1 Tafel plot associated with the Volmer-Heyrovsky hydrogen evolution (HER) mechanism in 0.1 M KOH. By the hydrothermal process, 0.2 at % of platinum was anchored to the graphene foam surface, and the resultant sample of GrFoamPt yielded a value of 80 mV dec-1 Tafel associated with the Volmer-Tafel HER mechanism. Furthermore, Raman and infrared spectroscopy analysis, as well as scanning electron microscopy (SEM) were carried out to understand the structure of the samples.

Applications of 2D-Layered Palladium Diselenide and Its van der Waals Heterostructures in Electronics and Optoelectronics

The rapid development of two-dimensional (2D) transition-metal dichalcogenides has been possible owing to their special structures and remarkable properties. In particular, palladium diselenide (PdSe₂) with a novel pentagonal structure and unique physical characteristics have recently attracted extensive research interest. Consequently, tremendous research progress has been achieved regarding the physics, chemistry, and electronics of PdSe₂. Accordingly, in this review, we recapitulate and summarize the most recent research on PdSe₂, including its structure, properties, synthesis, and applications. First, a mechanical exfoliation method to obtain PdSe₂ nanosheets is introduced, and large-area synthesis strategies are explained with respect to chemical vapor deposition and metal selenization. Next, the electronic and optoelectronic properties of PdSe₂ and related heterostructures, such as field-effect transistors, photodetectors, sensors, and thermoelectric devices, are discussed. Subsequently, the integration of systems into infrared image sensors on the basis of PdSe₂ van der Waals heterostructures is explored. Finally, future opportunities are highlighted to serve as a general guide for physicists, chemists, materials scientists, and engineers. Therefore, this comprehensive review may shed light on the research conducted by the 2D material community.

Advanced Carbon-Nickel Sulfide Hybrid Nanostructures: Extending the Limits of Battery-Type Electrodes for Redox-Based Supercapacitor Applications

Transition-metal sulfides combined with conductive carbon nanostructures are considered promising electrode materials for redox-based supercapacitors due to their high specific capacity. However, the low rate capability of these electrodes, still considered "battery-type" electrodes, presents an obstacle for general use. In this work, we demonstrate a successful and fast fabrication process of metal sulfide-carbon nanostructures ideal for charge-storage electrodes with ultra-high capacity and outstanding rate capability. The novel hybrid binder-free electrode material consists of a vertically aligned carbon nanotube (VCN), terminated by a nanosized single-crystal metallic Ni grain; Ni is covered by a nickel nitride (Ni₃N) interlayer and topped by trinickel disulfide (Ni₃S₂, heazlewoodite). Thus, the electrode is formed by a Ni₃S₂/Ni₃N/Ni@NVCN architecture with a unique broccoli-like morphology. Electrochemical measurements show that these hybrid binder-free electrodes exhibit one of the best electrochemical performances compared to the other reported Ni₃S₂-based electrodes, evidencing an ultra-high specific capacity (856.3 C g^-1 at 3 A g^-1), outstanding rate capability (77.2% retention at 13 A g^-1), and excellent cycling stability (83% retention after 4000 cycles at 13 A g^-1). The remarkable electrochemical performance of the binder-free Ni₃S₂/Ni₃N/Ni@NVCN electrodes is a significant step forward, improving rate capability and capacity for redox-based supercapacitor applications.

Boost of Charge Storage Performance of Graphene Nanowall Electrodes by Laser-Induced Crystallization of Metal Oxide Nanostructures

Major research efforts are being carried out for the technological advancement to an energetically sustainable society. However, for the full commercial integration of electrochemical energy storage devices, not only materials with higher performance should be designed and manufactured but also more competitive production techniques need to be developed. The laser processing technology is well extended at the industrial sector for the versatile and high throughput modification of a wide range of materials. In this work, a method based on laser processing is presented for the fabrication of hybrid electrodes composed of graphene nanowalls (GNWs) coated with different transition-metal oxide nanostructures for electrochemical capacitor (EC) applications. GNW/stainless steel electrodes grown by plasma enhanced chemical vapor deposition were decorated with metal oxide nanostructures by means of their laser surface processing while immersed in aqueous organometallic solutions. The pseudocapacitive nature of the laser-induced crystallized oxide materials prompted an increase of the GNW electrodes' capacitance by 3 orders of magnitude, up to ca. 28 F/cm³ at 10 mV/s, at both the positive and negative voltages. Finally, asymmetric aqueous and solid-state ECs revealed excellent stability upon tens of thousands of charge-discharge cycles.

Recent Advances in Electrical Doping of 2D Semiconductor Materials: Methods, Analyses, and Applications

Two-dimensional materials have garnered interest from the perspectives of physics, materials, and applied electronics owing to their outstanding physical and chemical properties. Advances in exfoliation and synthesis technologies have enabled preparation and electrical characterization of various atomically thin films of semiconductor transition metal dichalcogenides (TMDs). Their two-dimensional structures and electromagnetic spectra coupled to bandgaps in the visible region indicate their suitability for digital electronics and optoelectronics. To further expand the potential applications of these two-dimensional semiconductor materials, technologies capable of precisely controlling the electrical properties of the material are essential. Doping has been traditionally used to effectively change the electrical and electronic properties of materials through relatively simple processes. To change the electrical properties, substances that can donate or remove electrons are added. Doping of atomically thin two-dimensional semiconductor materials is similar to that used for silicon but has a slightly different mechanism. Three main methods with different characteristics and slightly different principles are generally used. This review presents an overview of various advanced doping techniques based on the substitutional, chemical, and charge transfer molecular doping strategies of graphene and TMDs, which are the representative 2D semiconductor materials.

Plasma-assisted defect engineering of N-doped NiCo2O4 for efficient oxygen reduction

Defect control is a promising way to enhance the electrocatalysis performance of metal oxides. Oxygen vacancy enriched NiCo₂O₄ was successfully prepared using cold plasma. Oxygen as a plasma-forming gas introduces oxygen vacancies via electron etching. The concentration of oxygen vacancies can be controlled by different plasma-forming gas. CoO, which formed on the plasma samples, is beneficial for quick charge transfer and electrocatalytic performance. A high amount of nitrogen atoms of up to 10.1% was doped on NiCo₂O₄ because of the enriched oxygen vacancies and improved the stability of the oxygen defects and the conductivity of the catalyst. Electrocatalytic studies showed that the plasma-induced N-doped NiCo₂O₄ shows enhanced electrocatalytic performance for the oxygen reduction reaction (ORR). It shows a typical four-electron process that considerably improves the current density and onset potential. The HO₂^- % was as low as 0.59% and current density was 4.9 mA cm^-2 at 0.2 V (Vs. RHE) on the plasma-treated NiCo₂O₄. Calculations based on density functional theory reveal the mechanism for the promotion of the catalytic ORR activity via plasma treatment. This increases the electron density near the Fermi level, reducing the work function, and changing the position of the d-band center.

Incorporation-limiting mechanisms during nitrogenation of monolayer graphene films in nitrogen flowing afterglows

Monolayer graphene films are exposed to the flowing afterglow of a low-pressure microwave nitrogen plasma, characterized by the absence of ion irradiation and significant populations of N atoms and N₂(A) metastables. Hyperspectral Raman imaging of graphene domains reveals damage generation with a progressive rise of the D/G and D/2D band ratios following subsequent plasma treatments. Plasma-induced damage is mostly zero-dimensional and the graphene state remains in the pre-amorphous regime. Over the range of experimental conditions investigated, damage formation increases with the fluence of energy provided by heterogenous surface recombination of N atoms and deexcitation of N₂(A) metastable species. In such conditions, X-ray photoelectron spectroscopy reveals that the nitrogen incorporation (either as pyridine, pyrrole, or quaternary moieties) does not simply increase with the fluence of plasma-generated N atoms but is also linked to the damage generation. Based on these findings, a surface reaction model for monolayer graphene nitrogenation is proposed. It is shown that the nitrogen incorporation is first limited by the plasma-induced formation of defect sites at low damage and then by the adsorption of nitrogen atoms at high damage.

A Review of Strategies for the Synthesis of N-Doped Graphene-Like Materials

Methods for synthesizing nitrogen-doped graphene-like materials have attracted significant attention among the scientific community because of the possible applications of such materials in electrochemical devices such as fuel cells, supercapacitors and batteries, as well as nanoelectronics and sensors. The aim of this paper is to review recent advances in this scientific niche. The most common synthesis technique is nitridization of as-deposited graphene or graphene-containing carbon mesh using a non-equilibrium gaseous plasma containing nitrogen or ammonia. A variety of chemical bonds have been observed, however, it is still a challenge how to ensure preferential formation of graphitic nitrogen, which is supposed to be the most favorable. The nitrogen concentration depends on the processing conditions and is typically few at.%; however, values below 1 and up to 20 at.% have been reported. Often, huge amounts of oxygen are found as well, however, its synergistic influence on N-doped graphene is not reported. The typical plasma treatment time is several minutes. The results reported by different authors are discussed, and future needs in this scientific field are summarized. Some aspects of the characterization of graphene samples with X-ray photoelectron spectroscopy and Raman spectroscopy are presented as well.

Low-temperature low-power PECVD synthesis of vertically aligned graphene

The need for 2D vertical graphene nanosheets (VGNs) is driven by its great potential in diverse energy, electronics, and sensor applications, wherein many cases a low-temperature synthesis is preferred due to requirements of the manufacturing process. Unfortunately, most of today's known methods, including plasma, require either relatively high temperatures or high plasma powers. Herein, we report on a controllable synthesis of VGNs at a pushed down low-temperature boundary for synthesis, the low temperatures (450 °C) and low plasma powers (30 W) using capacitively coupled plasma (CCP) driven by radio-frequency power at 13.56 MHz. The strategies implemented also include unrevealing the role of Nickel (Ni) catalyst thin film on the substrates (Si/Al). It was found that the Ni catalyst on Si/Al initiates the nucleation/growth of VGNs at 450 °C in comparison to the substrates without Ni catalyst. With increasing temperature, the graphene nanosheets become bigger in size, well-structured and well separated. The role of Ni catalysts is hence to boost the growth rate, density, and quality of the growing VGNs. Furthermore, this CCP method can be used to synthesize VGNs at the lowest temperatures possible so far on a variety of substrates and provide new opportunities in the practical application of VGNs.

Oriented Carbon Nanostructures from Plasma Reformed Resorcinol-Formaldehyde Polymer Gels for Gas Sensor Applications

Oriented carbon nanostructures (OCNs) with dominant graphitic characteristics have attracted research interest for various applications due to the excellent electrical and optical properties owing to their vertical orientation, interconnected structures, electronic properties, and large surface area. Plasma enhanced chemical vapor deposition (PECVD) is considered as a promising method for the large-scale synthesis of OCNs. Alternatively, structural reformation of natural carbon precursor or phenol-based polymers using plasma-assisted surface treatment is also considered for the fabrication of OCNs. In this work, we have demonstrated a fast technique for the synthesis of OCNs by plasma-assisted structure reformation of resorcinol-formaldehyde (RF) polymer gels using radio-frequency inductively coupled plasma (rf-ICP). A thin layer of RF polymer gel cast on a glass substrate was used as the carbon source and treated with rf plasma under different plasma discharge conditions. Argon and hydrogen gases were used in surface treatment, and the growth of carbon nanostructures at different discharge parameters was systematically examined. This study explored the influence of the gas flow rate, the plasma power, and the treatment time on the structural reformation of polymer gel to produce OCNs. Moreover, the gas-sensing properties of as-prepared OCNs towards ethanol at atmospheric conditions were also investigated.