Heteroatom-doped Carbon Research Articles

Electrochemiluminescence Reveals the Structure-Catalytic Activity Relationship of Heteroatom-Doped Carbon-Based Materials.

Heteroatom doping can change the chemical environment of carbon-based nanomaterials and improve their catalytic performance. Exploring the structure-catalytic activity relationship of heteroatom-doped carbon-based materials is of great significance for studying catalytic mechanisms and designing highly efficient catalysts, but remains a significant challenge. Recently, reactive oxygen species (ROS)-triggered electrochemiluminescence (ECL) has shown great potential for unveiling the mechanism by which heteroatom-doped carbon-based materials catalyze the oxygen reduction reaction (ORR), owing to the high sensitivity of these materials to the properties of the electrode surface. Herein, two kinds of heteroatom-doped porous carbon (denoted as NP-C and N-C) are synthesized and analyzed by monitoring the cathodic ECL of luminol-H2O2 in the low negative-potential region. P, N-doped NP-C exhibitsbetter catalytic ability for activating H2O2 to generate large amounts of •OH and O2 •-, compared with N-C. A sensitive antioxidant-mediated ECL platform is successfully developed for detecting the antioxidant levels in cells, exhibiting considerable potential for evaluating the antioxidant capacity. The relationship between the structure and catalytic mechanism of heteroatom-doped carbon-based materials is successfully explored using ECL, where this method can be universally applied to carbon-based materials.

Air‐Pyrolysis Precision Synthesis of Functional Porous Carbon Materials

AbstractCarbon materials play a pivo tal role across various advanced applications, yet their synthesis traditionally necessitates inert atmospheres to avert oxidation at high temperatures, thus inflating production costs and resource utilization. Achieving precision synthesis of functional porous carbon materials via air‐pyrolysis remains a formidable challenge. Herein, a streamlined, one‐step lava‐like carbonization approach is introduced enabling the fabrication of porous carbons boasting tailored morphologies (0‐3D), elevated specific surface areas (540.7–1047.6 m2g⁻¹), heteroatom doping, and commendable carbon yields (20‐39.1%) through direct pyrolysis within an air environment. Leveraging recyclable boric acid as a reaction medium, a lava‐like flowing protective barrier above 170 °C is engendered that spontaneously creates an oxygen‐free‐like milieu devoid of high pressure or intricate procedures. This boron‐containing lava serves dually as a template and chemical activator, facilitating pore formation and catalyzing porous carbon production. Notably, the method accommodates a spectrum of carbon sources, encompassing sugars, proteins, graphene oxide, and their metal mixtures. The resultant morphologically customizable carbons exhibit excellent performance in areas as diverse as microwave absorption and electrocatalysis. This work pioneers a novel pathway for large‐scale precision synthesis of high‐quality carbon materials via air‐pyrolysis under mild conditions.

Polymerizable Ionic Liquid-Derived N, S co-Doped sp3/sp2 Carbon as Electrocatalyst for H2O2 Generation.

The H2O2 generation via the green electrochemical process is of high interest. For the H2O2 electrochemical generation, the oxygen reduction reaction (ORR) is important. Unfortunately, the ORR is kinetically sluggish and catalysts are needed. However, noble metal ORR catalysts are pricy and scarcely applicable in applications. Therefore, non-precious metal catalysts are desired. Heteroatom-doped carbons show promise as metal-free ORR catalysts. The ORR catalytic activity will be enhanced by the carbon's sp2 and/or sp3 engineering. For N, S co-Cdoped and sp2/sp3 modulated carbon, a polymerizable ionic liquid of hydrolyzed vinyl imidazolium was studied. The carbon is studied as a metal-free catalyst for the ORR via the 2e- process. It is possible to get an onset potential of 0.88 V vs. RHE with approximately 50 % selectivity for the H2O2. The current study offers a simple technique for synthesizing heteroatom-doped sp2/sp3 designed carbon as catalysts for the electroreduction of O2 to produce H2O2, and a new way of tunning the sp3/sp2 carbon catalytic activity by modulating the ionic liquid.

Covalent Organic Framework Derived Oxygen/Sulfur-Doped Porous Carbon for Robust High-Capacitance Symmetric Supercapacitors.

Heteroatom-doped porous carbons (HPCs) have been considered promising electrode materials for supercapacitors due to their improvement of energy density by providing extra pseudocapacity. Covalent organic frameworks (COFs) are obtaining great importance in energy storage because of their designable structure and versatile functionality. Herein, we designed and fabricated oxygen and sulfur dual-doped covalent organic framework (COF) derived HPCs with very high heteroatoms content (up to 25.76 atom%) via a facile coupling reaction. The optimized HPCs exhibit a porous structure with high specific surface area (up to 2835 m2 g-1) along with a high specific capacitance (430 F g-1 at 0.5 A g-1), excellent capacitance retention (96.9%), and high coulombic efficiency (98.5%) after 10000 cycles at 5 A g-1. As electrodes for aqueous symmetric supercapacitors, the HPCs exhibits a high energy density of 60 Wh kg-1 at a 250 W kg-1 power density, excellent cycling stability of capacity retention (82.2%) and a high coulombic efficiency (92.3%) after 10000 cycles at 10 A g-1, indicating attractive application potential in chemical energy storage. This work establishes a promising strategy for preparation of high heteroatom content HPCs using COFs and demonstrates great potential for energy storage/conversion devices.

Nitrogen and Sulfur Doped Porous Carbon Sheet with Trace Amount of Iron as Efficient Polysulfide Conversion Catalyst for High Loading Lithium-Sulfur Batteries.

The major challenges in enhancing the cycle life of lithium-sulfur (Li-S) batteries are the polysulfide (PS) shuttling and sluggish reaction kinetics (S to Li2S, Li2S to S). To alleviate the above issues use of hetero atom doped carbon as cathode host matrix is a low-cost and efficient approach as it works as a dual-functional framework for PS anchoring as well as electrocatalyst for faster redox kinetics. Here, the dual role of the Fe-containing heteroatom-doped carbon sheets (CS) in chemisorption of Li2S6 and catalyzing its faster conversion to Li2S is established through UV-Vis, XPS and CV studies. To substantiate the catalytic effect composite cathodes were prepared by encapsulating sulfur in CS which is further blended with carbon nanotubes (CNTs) to form free-standing cathode. The electrochemical performance of the three cathodes viz., S@Fe-N-CS-CNT, S@Fe-S-CS-CNT and S@Fe-NS-CS-CNT were evaluated by constructing Li-S cells. Among all, the S@Fe-NS-CS-CNT delivers a high initial discharge capacity of 1017 mAh g-1 at 0.5 C rate and sustains 751 mAh g-1 capacity after 260 cycles with a capacity retention of 73.8 %. Even at high S-loading (12 mg cm-2), it delivers an initial discharge capacity of 892 mAh g-1 and it retained 575 mAh g-1 after 200 cycles.

Enhanced carbon host with N-reinforced S-sites to catalyze rapid iodine conversion kinetics for Zn-I2 battery

Aqueous zinc-iodine (Zn-I2) battery is a promising energy storage system in the establishment of a low-carbon, clean society, but they are limited by unsatisfied reversible capacity and poor cycle life. Ultimately, this is due to the poor iodine conversion kinetics and the shuttle effect of the intermediate polyiodide. Herein, a N-reinforced S-site carbon host (labeled as NS-YP80F) is designed to resolve these issues. DFT calculation shows that the electrochemical activity of the NS-YP80F with abundant S-site can be further enhanced by introducing N-atom at the original S-site. The synergistic effect of N-reinforced S-site carbon host cannot only enhance the adsorption of polyiodide to avoid the shuttle effect, but also induce the smooth conversion of iodine through enhanced catalytic mechanism. Consequently, the Zn-I2 battery with NS-YP80F@I2 cathode shows high reversible capacity (127 mAh g−1 at 1C) and stable cycling lifespan (15,000 cycles) with a high current density of 50 C. This strategy achieved a breakthrough in the electrochemical activity of the heteroatom doping carbon hosts, and provided a simple and effective solution for optimizing the performance of Zn-I2 battery.

Effects of heteroatom-doped hierarchical porous carbon on hydrogen storage properties of MgH2

In this paper, the nitrogen doped (N-HPC), nitrogen and phosphorus co-doped hierarchical porous carbon (NP-HPC) are prepared by cross-linking phytic acid and poly pyrrole/aniline precursor, respectively. They are mixed with MgH2 by high-energy ball milling, and then their effects and mechanisms on the hydrogen absorption and desorption properties of MgH2 are investigated. Meanwhile, the hydrogen storage properties of MgH2 added with graphite (G) are also compared. The results show that the additions of NP-HPC, N-HPC, and G all exhibit the catalytic effect on the hydrogen absorption and desorption of MgH2. As for the hydrogen desorption, the catalytic effect is enhanced in the order of N-HPC, G and NP-HPC. Compared with pure MgH2, the hydrogen desorption temperature is reduced by 65.3 °C, 79.6 °C and 91.1 °C, respectively. Among them, the MgH2 + NP-HPC system can release 5.17 wt% hydrogen at 300 °C within 30 min. First-principles calculations reveal that the P-doped and vacancy-containing carbon materials significantly reduce the H2 recombination barrier from the surface of MgH2 and distort the atomic structure of near-surface layer of MgH2, which in turn weakens the Mg-H bond strength. This may be the intrinsic reason for the excellent catalytic effect of NP-HPC and vacancy-containing G on the hydrogen desorption performance of MgH2.

Joule heating synthesis for single-atomic Fe sites on porous carbon spheres and armchair-type edge defect engineering dominated oxygen reduction reaction performance

Single-atom catalysts (SACs) embedded in heteroatom-doped carbon are the most promising oxygen reduction reaction (ORR) electrocatalysts. However, the expeditious and facile synthesis of high-performance SACs with Fe-Nx active sites and identifying the role of edge-type defect at the atomic level in carbon support are essential but remain challenging. Herein, Joule heating is applied to anchor Fe single atoms on newly defect rich porous carbon spheres (Fe-N-DCSs) in milliseconds. Fe-N-DCSs achieves exceptional ORR performance, with a half-wave potential (E1/2) of 0.90 V and E1/2 lost of only 20 mV after 30,000 cycles in 0.1 M KOH, and superior Zn-air batteries performances. Density functional theory calculations establish that armchair-type edge defects decorated Fe-N4 active sites boost the desorption of OH* and diminish the ORR overpotential. This work not only provides a speedy route for the fabrication of SACs but also presents new insights into the excellent ORR activity.

Preparation of porous carbon from hydrothermal treatment products of modified antibiotic mycelial residues and its use in CO2 capture

Antibiotic mycorrhizal residues (AMR) are valuable organic wastes but have become a significant environmental and economic challenge due to their potentially hazardous nature and high treatment costs. In this study, an environmentally friendly and low-cost in situ nitrogen-doped porous carbon material was successfully prepared by hydrothermal carbonisation combined with KOH activation for efficient CO2 capture. The obtained material was systematically characterized and tested, and its physical and chemical properties were analyzed. By adjusting the activation temperature from 600 to 800 °C, the prepared porous carbon materials exhibited different specific surface areas (648.41–1712.72 m²/g), pore volumes (0.310–0.879 cm³/g), and the nitrogen was uniformly distributed in the carbon skeleton. The optimal N-doped porous carbon demonstrated the adsorption capacities of 3.99 mmol g−1 at 25 ℃ and 5.35 mmol g−1 at 0 ℃ under 1 bar. In addition, the prepared adsorbents exhibited excellent CO2/N2 selectivity, high isosteric heat, and good cyclic stability. These excellent CO2 adsorption properties were attributed to the highly developed microporous structure of the materials and the uniformly distributed nitrogen functional groups in the carbon skeleton. Overall, the results highlight the great potential of this class of heteroatom-doped novel carbon materials as selective CO2 adsorbents, providing a practical way to seek efficient CO2 abatement solutions.

Co–Ni nanoparticle supported on heteroatom-doped carbon derived from garlic powder and eutectic solvent: Its application in Nitroarenes reduction

This paper presents the synthesis of a novel heterogeneous catalyst, PSN-C600-Co2:Ni1, designed for the hydrogenation of nitroaromatic compounds. The catalyst is a porous carbon substrate triply doped with nitrogen, sulfur, and phosphorus, incorporating bimetallic Co and Ni nanoparticles. A natural precursor, garlic biochar, and a biodegradable eutectic solvent were used in the synthesis. Various characterization techniques, including Scanning Electron Microscope (SEM), X-Ray Energy Diffraction Spectroscopy (EDX), Elemental Mapping Measurements (MAP), Thermogravimetric Analysis (TGA), X-Ray Diffraction (XRD), Infrared Spectrometer (FTIR), Transmission Electron Microscope (TEM), Raman Spectroscopy, and Nitrogen Adsorption and Desorption Pattern (N2 adsorption-desorption isotherm), were utilized to examine the features and properties of the synthesized PSN-C600-Co2:Ni1 catalyst.

One-step microwave-assisted synthesis of metal-free heteroatom-doped carbon catalyst for H2O2 electrosynthesis

This study reports on a one-step conversion of polyaniline into a metal-free heteroatom-doped carbon electrocatalyst through microwave heating. A high surface area carbonaceous structure forms after a total synthesis time of only 140 s, with the presence of nitrogen and oxygen functional groups, as confirmed by thorough spectroscopic analysis. This catalyst exhibits high activity (onset potential of 0.73 V vs. RHE), selectivity (82 %), and stability (over a 7.5-hour test period) for the electrochemical oxygen reduction reaction towards hydrogen peroxide in alkaline media. Microwave synthesis reduces heating time by 29-fold and energy consumption by 77-fold, while producing materials with high electrocatalytic efficiency comparable to those conventionally prepared at 700°C. The microwave and the conventionally synthesized heteroatom-doped carbon catalysts show similar electrochemical performances, which can be attributed to the presence of nearly identical nitrogen functional groups and surface area in the two samples. In contrast, the microwave and conventionally synthesized samples exhibit significant variations in their oxygen functional groups. These results suggest that nitrogen functional groups are the main active sites for alkaline hydrogen peroxide formation, while oxygen functional groups play a minor role in the catalytic activity. Our work brings a solid contribution to the debate regarding the active centers for hydrogen peroxide formation.

Ultrasound-assisted fungal self-growth and heteroatom doping for the preparation of high-performance lignocellulose-based supercapacitor electrodes

Biomass materials are widely used as supercapacitor electrode materials due to their cost-effectiveness and eco-friendliness. In this work, ultrasound-assisted impregnation was employed for the thorough mixing of the liquid medium, and fungal treatment was conducted on the three main components of lignocellulose to prepare a fungi-modified heteroatom-doped lignocellulose-based carbon material (LCF-NP). The effects of heteroatom doping, the content of the three main components, and fungal modification on the electrochemical performance of lignocellulose-based carbon materials was investigated. The results revealed the synergistic effect of heteroatom doping and fungal treatment on the electrochemical performance. Compared with its counterpart free of fungal treatment, LCF-NP has a more reasonable pore structure and exhibits excellent electrochemical performance. LCF-NP porous carbon material has the highest specific surface area (792 m2/g), large pore volume (0.523 cm3/g), and ideal specific capacitance (1940 mF/cm2) under the conditions of 1.0 M Na2SO4 electrolyte and current density of 0.5 mA/cm2. After 10,000 cycles, there is almost no loss of capacitance. These results indicate that the joint utilization of heteroatom doping and fungal treatment has a promising application prospect in pore structure regulation and electrochemical performance improvement. This study provides a new strategy for the preparation of lignocellulose-based carbon electrode materials.

Hierarchical design of carbon nanofibers wrapped antimony selenide nanorods with heteroatom-doped carbon quantum dots as efficient anode material of high-performance sodium-ion batteries

Researchers have focused on sodium-ion batteries (SIBs) due to low precursor costs and abundant reserves. However, low efficiency of anode materials hinders SIB commercialization, mainly due to large ionic radius and slow kinetics of Na+. Metal selenides such as Sb2Se3 have regarded as promising anode materials of SIBs due to high theoretical capacities. Despite this, the practical application has been limited by the poor rate capability, conductivity, and stability. In this study, one-dimensional Sb2Se3 nanorods and nitrogen-doped carbon quantum dots (N-CQDs) combined with carbon nanofibers (CNFs) have been developed as an effective anode material of SIBs. The uniform distribution of N-CQDs in the Sb2Se3 coated CNFs (Sb2Se3/CNFs) anode results in the highest reversible capacity of 647.9 mAhg−1 at 0.05 Ag-1. Moreover, the Sb2Se3 and N-CQDs coated CNFs (Sb2Se3@N-CQDs/CNFs) anode presents a good rate performance and retains a high reversible capacity of 444.7 mAhg−1 at a high current density of 0.4 Ag-1. Additionally, the Sb2Se3@N-CQDs/CNFs anode demonstrates excellent stability, retaining 78.8% of the initial capacity after 100 cycles. The improved electrochemical performance is attributed to low volume expansion and good conductivity due to carbon coating and addition of N-CQDs. Galvanostatic intermittent titration technique is also used to examine Na+ diffusion coefficients.

Uranium extraction from wastewater by heteroatom-doped carbon microspheres derived from polyphosphazene loading with zinc oxide

The effective management of uranium-contaminated wastewater is crucial for environmental protection and public health safety. In this context, a novel composite was synthesized involving the intergration of zinc oxide into heteroatom-doped polyphosphazene carbon microspheres (TAC/ZnO) by hydrothermal method. The incorporation of ZnO into TAC significantly enhanced the porosity, offering more adsorption sites and improving the uranium adsorption performance. The optimal adsorption experiment achieved a remarkable adsorption capacity of 513.9 mg.g−1 for U(VI) at a pH of 5.5 within just 80 min. Additionally, the adsorption process was found to be endothermic and spontaneous, following both the Langmuir isothermal adsorption model and the pseudo-second-order kinetic model. Moreover, the TAC/ZnO presented higher selectivity for U(VI) in the presence of other cations. Even after 8 cycles, TAC/ZnO maintained a good removal rate for U(VI), decreasing from 97.54 % to 81.95 %. Furthermore, the findings from X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations indicated that the adsorption mechanism of U(VI) on TAC/ZnO may involve the coordinated interaction between oxygen atoms in Zn-O and nitrogen atoms in pyridinie-N-oxide with uranyl ions. Overall, this study presents an easily prepared, cost-effective, and highly efficient adsorbent that offers potential for large-scale production and practical application in purifying radioactive wastewater.

In-situ N, P co-doped porous carbon derived from biomass waste for supercapacitors

The development of heteroatom-doped porous carbon derived from biomass waste with high-performance electrodes for supercapacitors has been drawn extensive research. Herein, N, P co-doped porous carbon (NPC) was successfully synthesized using Chinese fir sawdust as a carbon source, NaOH as an activator, urea as a nitrogen source, and melamine phosphate as the phosphorus and nitrogen source by pretreatment with low-temperature NaOH/urea system. The low-temperature pretreatment and melamine phosphate greatly promoted the porous structure and uniform distributions of heteroatom about the NPC. The optimized NPC exhibits high specific surface area (1849 m2/g), hierarchical porous structure with high mesoporosity (87.3 %), appropriate heteroatom content (3.32 at% N, 0.36 at% P), and excellent wettability. This unique facilitates improved electrolyte diffusion efficiency and ion transfer rate. In the three-electrode system, the specific capacitance of the NPC electrode is as high as 260 F/g at 0.5 A/g and remains at 235 F/g at 10 A/g, and the charge transfer resistance is very low (0.08 Ω). In addition, the assembled symmetric supercapacitors deliver an energy density of 15.9 Wh/kg at a power density of 246 W/kg, a long cycling life with 90 % capacitance retention after 5000 cycles. The environment-friendly NPC has a broad development prospect for carbon-based high-performance electrodes for supercapacitors.

Hydrophilic and Insulative Interface Strategy Against Side Reactions for Dendrite‐Free Zinc Metal Anodes

AbstractThe zinc dendrite growth and the parasitic hydrogen evolution reactions (HER) hinder the commercialization of zinc batteries. To address this, a hydroxyl‐rich Boehmite coating (HR‐BC) strategy is developed that combines excellent electrical insulation and high zinc ion conductivity. The hydrophilic hydroxyl groups facilitate hydrogen bond formation with the hydrated zinc ions, accelerating the de‐solvation process and suppressing the HER. Additionally, the electrically insulative nature of Boehmite prevents the reduction of zinc ions within HR‐BC and results in preferential Zn deposition underneath it, leading to a dendrite‐free “sandwich structure” of HR‐BC//Zn deposition//Zn foil. Symmetric cells using HR‐BC‐Zn electrodes obtain an ultralong and stable cycling lifetime of 1700 h at 5 mA cm−2, along with a high cumulative plating capacity of 4250 mAh cm−2. When paired with a V2O5 cathode, the HR‐BC‐Zn anode demonstrates a high capacitance retention of 90% and an average Coulombic efficiency (CE) of 99.8% after 4000 cycles. Furthermore, when combined with a heteroatoms‐doped carbon (HDC) cathode, the HR–BC–Zn//HDC pouch‐type cell exhibits superior lifetime performance with nearly 100% average CE after 15000 cycles at 3.0 A g−1. This work highlights the effectiveness of hydrophilic and insulative coating strategies in fostering the progression of long‐lasting zinc‐based energy storage systems.

Optimizing sodium storage mechanisms and electrochemical performance of high Nitrogen-Doped hard carbon anode materials Derived from waste plastics for Sodium-Ion batteries

The development of high-performance hard-carbon (HC) anode materials for sodium-ion batteries was constrained by slow charge-transfer kinetics and sodium-storage mechanisms. In this paper, high nitrogen-doped (12.24 %) HC with an efficient interworking structure was synthesized in situ using waste plastics as precursors by utilizing the strong 2-D self-template effect of guanine. Elucidating the mechanism of sodium storage in heteroatom-doped carbon with coexisting heterocyclic and graphitic nitrogen, which synergistically enhances electrochemical activity, utilizing a range of in-situ and ex-situ characterization methods. Based on density functional theory (DFT), it has been discovered that the doping of pyrrole nitrogen (N5) and pyridinium nitrogen (N6) can effectively expand the interlayer spacing during the Na+ sodiated/de-sodiated process, thereby enhancing electrochemical activity. The optimized HC has increased the Na+ diffusion coefficient by 1.5 orders of magnitude (10-8.2 cm2 s−1 vs 10-9.76 cm2 s−1) and exhibits high reversible capacity (452 mAh/g@20 mA g−1), high rate performance (388mAh/g@500 mA g−1), superior cycling stability (87.6 % @500 mA g−1 after 2,000 cycles). The full cell exhibits good cyclic stability (91.87 %@100 mA g−1 after 2,00 cycles), while the designed pouch cell also demonstrates favorable cycle life (90.78 %@200 mA g−1 after 100 cycles).

Green synthesis of N,S dual heteroatom-doped fluorescent carbon dots (N,S-CDs) and their applications in gentamicin sensing and dual-switch anti-counterfeiting encryption

Herein, we report a facile one-step solvothermal synthesis of nitrogen and sulfur co-doped fluorescent carbon dots (N,S-CDs) using benzoic acid as the carbon source and sulfonamide as the doping agent. The synthesized N,S-CDs exhibit stable photoluminescence with an impressive fluorescence quantum yield of 16.8 %. These N,S-CDs maintain their luminescent properties under various challenging conditions, including high salt concentrations, elevated temperatures, UV radiation exposure, acidic or alkaline environments, long-term storage, and different solvents. Notably, the photoluminescence of N,S-CDs is excitation-wavelength dependent, with emission wavelengths tunable from 470 nm to 585 nm. Furthermore, the N,S-CDs display distinct fluorescent hues in aqueous and ethanolic media, presenting a novel dual-switch anti-counterfeiting ink system. Leveraging the sensitivity of N,S-CDs to gentamicin, we have developed a facile and rapid detection method for this antibiotic, which has been successfully applied to the analysis of authentic milk samples. This research contributes a novel and efficient protocol for the fabrication of high-performance carbon dots, thereby expanding their potential applications in food analysis and anti-counterfeiting technologies.

Aspartic acid/ thiourea − derived N and S − doped porous carbon as a metal-free electrocatalyst for oxygen and hydrogen evolution reactions

The preparation of high-efficiency electrocatalysts for the oxygen and hydrogen evolution process (OER and HER) using an easy, green, and facile preparation method is crucial for the effective and economical use of clean energy sources. Heteroatom-doped carbon nanomaterials are effective metal-free electrocatalysts for HER and OER reactions. Herein, N and S co-doped porous carbon nanocomposite (NS-PC) was constructed as a low-cost metal-free catalyst via pyrolysis of the Thiourea and L-aspartic acid. Doping heteroatoms (N and S) into the carbon structure can induce charge redistribution, expose many active sites, accelerate charge transfer, and thus effectively improve the catalytic activity. The NS-PC electrocatalyst demonstrates proper bifunctional electrocatalytic performance for HER and OER with long-term stability in KOH electrolytes. As a result, the NS-PC requires an overpotential of 139 mV and 315 mV in the current density of 10 mA cm– 2 and the Tafel slope of 59.6 and 69.8 mV dec−1 for HER and OER, respectively. As-papered NS-PC electrocatalyst offers the development of multi-functional electrocatalysts in the water splitting process using biological substances such as amino acids.

Incorporation of nitrogen and oxygen in carbon: A highly tuned electrochemistry with facile synthesis and its influence on optical and electrode performance in supercapacitors

A new approach for synthesizing heteroatom-doped carbon nanostructures has been developed, in which nitrogen and oxygen have been effectively infused into the graphitic core using the required precursors. The heteroatoms incorporated into the carbon matrix and their corresponding structural features are examined. The observed X-ray diffraction pattern reveals the presence of amorphous carbon forms that resemble carbon nitride in their structure. The presence of additional N–O and C–O bonds gives strong evidence of a graphitic structure with oxygen and nitrogen incorporation, as shown by the Fourier transform-infrared peaks. The X-ray photoelectron spectroscopy analysis reveals important information regarding the bond formation in the graphitic core of the sample. The study focused on examining the porous and intricately interconnected network structures, showcasing a variety of particle morphologies, and was carried out using scanning electron and transmission electron microscopy. The lattice defects are investigated using transmission electron microscopy-high angle annular dark field technique to explore the surface morphology. The influence of incorporated O and N in carbon structure drastically reduced the electron density of the graphitic core. As a result, the absorption bands observed were around 300–400 nm, showing the semiconductors' absorption characteristics. Three-electrode electrochemical systems are fabricated with working electrodes based on COx and CNx materials. The COx and CNx-modified electrodes were meticulously tested for their performance in supercapacitor applications. The COx samples exhibit a significant specific capacity value of 439.20 C g−1 under a low current density of 4 A g−1. The CNx samples demonstrate a specific capacity of 420.00 C g−1 under 4 A g−1 current density.