Sulfur Co-doped Porous Carbon Research Articles

In-situ doped and activated N, S co-doped porous carbon derived from organic salt for application in high-performance potassium-ion batteries

Owing to its abundance in nature and low cost, potassium has attracted considerable attention as a substitute for lithium in the manufacture of secondary-ion batteries. However, developing amorphous carbon materials that show fast K+ ion kinetics for application in high-performance potassium-ion battery (PIB) anodes remains challenging. In this study, we designed and synthesized a 3-D hierarchical nitrogen and sulfur co-doped porous carbon electrode via in-situ doping and activation using acesulfame potassium. Owing to its prominent structural advantages, the as-prepared N, S co-doped electrode showed a high reversible capacity (459.8 mAh g−1 at 0.05 A g−1) and long-term cycle stability (205 mAh g−1 after 1000 cycles at 0.5 A g−1). Further, the results of ex-situ Raman spectroscopy and X-ray photoelectron spectroscopy verified the advantages of N and S co-doping with respect to K+ ion intercalation and adsorption/desorption properties within the carbon matrix. Therefore, our findings enhance understanding regarding the advantages of the dual-doped system with respect to K+ ion storage and highlight an efficient strategy for developing high-performance and durable carbon anode materials for PIBs.

Nitrogen and Sulfur Co-doped Biomass-Derived Porous Carbon Electrodes for Ultra-High-Performance All-Aqueous Thermally Regenerative Flow Batteries.

Developing high-performance electrodes for the all-aqueous thermally regenerative ammonia battery (ATRB) system, serving as superior substitutes for commercial carbon cloth electrodes, is anticipated to enhance performance, yet it lacks effective guidance and research. In this work, theoretical analysis is initially used to evaluate the effective conversion and adsorption capacity of nitrogen and sulfur co-doped carbon with respect to copper ion by density functional theory calculation. On the basis of this concept, the nitrogen and sulfur co-doped biomass-derived porous carbon electrode (DGC) is prepared using natural porous carbon materials and thiourea. Compared with commercial carbon cloth electrodes, ATRB with DGC achieves a significant improvement in maximum power density of 49.2%. Via optimization of the doping conditions, the active sites can be effectively regulated to boost charge transfer at the reaction interface. Furthermore, the rapid charge transfer can match the excellent mass transfer performance, generating an impressive net power density of 847.5 W/m2.

Synthesis of nitrogen and sulfur bi-doped carbon obtained from spent sapelli wood sawdust and polyhydric alcohol with improved catalytic activity for hydrogen evolution reaction

Developing an efficient water electrolysis system is an important solution for on the development of highly active, cost-effective, and stable electrocatalysts. Carbon-based metal-free catalysts are one of the promising candidates for this purpose. Herein, we present a facile strategy to synthesize and characterize nitrogen and sulfur co-doped porous carbon (NS-PC) from spent sapelli wood sawdust and polyhydric alcohol (xylitol) for efficient hydrogen evolution reaction (HER) in alkaline electrolyte. The resultant NS-PC metal-free catalyst exhibits porous structure, high surface areas and enhanced HER performance with lowest Tafel slope of 68.1 mV dec−1. The enhanced performance is due to the high porosity of carbonaceous material and co-existence of active species (N in the forms of graphitic-N, pyridinic-N, pyrrolic-N, and S in the forms of C–S–C) induced by the maximum carbon-carbon bond polarization, charge re-distribution in the carbon matrices with a synergistically HER activity. In addition, this work provides a versatile and effective strategy for synthetizing excellent carbon-based metal free catalysts from the low cost biowaste for large-scale production of hydrogen through HER.

Defect engineering of porous carbon with high N/S doping for potassium ion storage

The primary research challenge concerning K-ion batteries revolves around ensuring their optimal cycle stability and specific capacity, particularly the inherent sluggish kinetics induced by the relatively large radius of K+. In this study, we report a pore-size controllable synthetic approach employing salt-template precursors. Herein, nitrogen and sulfur co-doped porous carbon materials with rich carbon defect engineering was synthesized through the salt template method, where the doped heteroatoms can both offer a lot of carbon defect content and redox active sites that are helpful for enhancing potassium ion storage kinetics. As a result, the electrode with abundant doping atom content realizes a good capacity and long cycle lifespan (274.8 mA h g−1 after 200 cycles at 0.05 A/g). Inspiringly, PIHCs assembled by N/S co-doped carbon anode exhibit excellent cycling stability (93.4 % capacity retention for 1000 cycles) and a high energy density of 141.2 Wh kg−1 and a power density of 1.6 kW kg−1. Importantly, the density functional theory calculation combining electrochemical kinetic analysis further demonstrates that role of N and S doping plays dominant roles in total storage mechanism. This work gives a deep insight about the roles of external defects in doping carbon materials for potassium storage.

Biomass carbon aerogels by polyatomic synergistic modification and synchronous activation for supercapacitors

The regulation and modification of carbon aerogel are essential for the construction of supercapacitors electrode with high energy density. Heteroatom doping has also been used in the modification of carbon aerogels to further improve the properties of materials. In this work, nitrogen and sulfur co-doped porous biomass carbon aerogels (NSPCs) for high-performance supercapacitors were innovatively synthesized by a straightforward and highly efficient one-step gel and synchronous activation strategy. Such a covalently interconnected hierarchical porous structure with co-doped nitrogen and sulfur greatly improves the pore structure and wettability of the materials and forms functional groups to provide additional pseudocapacitance. Owing to these structural advantages and the component synergy, the NSPCs exhibit high electrolyte ion storage ability, unhindered ion channels, and excellent electrochemical performance, and display a specific capacitance of 344.3 F g−1, and a capacitance retention rate of 91.5 % after 10,000 cycles. Additionally, the NSPCs-based symmetric supercapacitor showed a high energy density of 12.82 Wh kg−1.

Unraveling the Ion Uptake Capacitive Deionization of Sea- and Highly Saline-Water by Sulfur and Nitrogen Co-Doped Porous Carbon Modified with Molybdenum Sulfide.

In parallel to the depletion of potable water reservoirs, novel technologies have been developed for seawater softening, as it is the most abundant source for generating deionized water. Although salt removal at subosmotic pressures and ambient temperatures by applying low-operating potentials with high energy efficiency made capacitive deionization (CDI) an advantageous water-softening process, its practical application is limited by insufficient ion removal capacity and low concentration influent. The performance of a CDI system is in progress with engineering the electrode active materials, also facilitating the advance design in highly saline- and seawater study. Herein, an innovative strategy was developed to provide high-performance CDI systems based on efficient and electrochemical ion-uptake active materials with a simple initial preparation. Nitrogen-doped porous carbons (N-pCs) received benefits from a high specific surface area and good surface wettability. The N-pCs were modified with molybdenum oxide/sulfide intercalative array and developed as CDI electrode active materials for desalination of both low/medium saline- and seawater. The MoS2/S,N-pC electrode materials exhibited perfect optimized salt adsorption capacity (SACs) of 47.9 mg g-1 when compared to N-pC (37.9 mg g-1) and MoO3/N-pC (39.6 mg g-1) counterparts at 1.4 V in a 750 ppm NaCl solution. In addition, the assembled CDI cells exhibited reasonable cycle stability and retained 96.7% of their initial SAC in continuous CDI cycles for 128,000 s. The fabricated CDI cell rendered an excellent salt removal efficiency (SRE, %) of 13.34% from the real seawater sample at 1.2 V. In detail, the SRE % of the NaCl, KCl, MgCl2, and CaCl2 soluble salts with respect to seawater sample exhibited a remarkable SRE % of 30.8%, 36%, 32.6%, and 19.3%, respectively. These SRE % values (>13.34%) provide convincing evidence on the reasonable ion uptake capability of the fabricated CDI cells for removing Na+, K+, Mg2+, and Ca2+ ions compared to other soluble component. The advanced cell design parallel to the promising outcomes provided herein makes these CDI systems immensely propitious for efficient water softening.

ZnO quantum dots @ nitrogen and sulfur Co-doped porous carbon nanosheets for the detection of lung cancer biomarkers in exhaled breath

The development of non-selective sensors as an e-nose system for breath analysis application generates unique breath prints delineating the fundamental body metabolism aiding early diagnosis of lung cancer. In this work, size dependent ZnO quantum dots (QDs) were controlled by pH and finely dispersed on nitrogen and sulfur co-doped porous carbon nanosheet (CNS) for exploration of their chemi-resistive gas sensing property. Application of these nanocomposites to different lung cancer biomarkers (toluene, isoprene acetone and benzene) depicts unique responses to each at different operating temperatures. Particularly, the composite with lower ZnO QDs size on sulfur rich porous carbon nanosheet (SC-SQD) exhibited 2.5 times of the response to toluene compared to the composite with higher QDs size and sulfur poor porous carbon nanosheet (NC-LQD) in the concentration range between 1 ppm and 5 ppm. It was demonstrated that for 5 ppm of toluene, a response of 31.4 was observed with a response and recovery time of 18 s and 58 s, respectively. The sensor exhibited an estimated lower limit of detection of 800 ppb. Besides, the sensor exhibited a gradual decrease (∼9.55%) in response to 5 ppm toluene at 90% humidity. This superior performance can be explained by the density of defect states, reactive oxygen species (ROS) and oxidation states of functionalization.

N, S co-doped porous graphene-like carbon synthesized by a facile coal tar pitch-blowing strategy for high-performance supercapacitors

Herein, coal tar pitch (CTP) derived nitrogen and sulfur co-doped porous graphene-like carbon (NSPC) is performed by an ammonium sulfate-assisted chemical blowing strategy. Afterward, NSPC was activated by KOH to form a-NSPC features a bubble-like structure with a thin porous shell and a well-balanced porous ratio. Serving as electrode materials for supercapacitors, the capacitance of a-NSPC was 368 F g−1 at 0.5 A g−1. Meanwhile, the prepared materials exhibit excellent cycling stability after 10,000 cycles. This work may not only prepare superior electrode materials but also provide a feasible strategy for large-scale production of high-performance and low-cost electrode materials.

Facile Synthesis of Functionalized Porous Carbon by Direct Pyrolysis of Anacardium occidentale Nut-Skin Waste and Its Utilization towards Supercapacitors.

Preparing electrode materials plays an essential role in the fabrication of high-performance supercapacitors. In general, heteroatom doping in carbon-based electrode materials enhances the electrochemical properties. Herein, nitrogen, oxygen, and sulfur co-doped porous carbon (PC) materials were prepared by direct pyrolysis of Anacardium occidentale (AO) nut-skin waste for high-performance supercapacitor applications. The as-prepared AO-PC material possessed interconnected micropore/mesopore structures and exhibited a high specific surface area of 615 m2 g-1. The Raman spectrum revealed a moderate degree of graphitization of AO-PC materials. These superior properties of the as-prepared AO-PC material help to deliver high specific capacitance. After fabricating the working electrode, the electrochemical performances including cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy measurements were conducted in 1 M H2SO4 aqueous solution using a three-electrode configuration for supercapacitor applications. The AO-PC material delivered a high specific capacitance of 193 F g-1 at a current density of 0.5 A g-1. The AO-PC material demonstrated <97% capacitance retention even after 10,000 cycles of charge-discharge at the current density of 5 A g-1. All the above outcomes confirmed that the as-prepared AO-PC from AO nut-skin waste via simple pyrolysis is an ideal electrode material for fabricating high-performance supercapacitors. Moreover, this work provides a cost-effective and environmentally friendly strategy for adding value to biomass waste by a simple pyrolysis route.

One-step synthesis of nitrogen and sulfur co-doped hierarchical porous carbon derived from acesulfame potassium as a dual-function agent for supercapacitors and lithium‑sulfur batteries

Acesulfame potassium (AK) is an artificial sweetener that contains N and S functional groups in its organic moiety and is suitable as porous carbon precursor. In this study, AK derived carbon (AKC) was obtained via direct carbonization and in situ doping without additives under the dual conditions of inert gas protection and high temperatures. The obtained AKCs exhibited high porosity structure with a specific surface area of 2043 m2 g−1 and 3.22 wt% N and 8.61 wt% S dual heteroatom doping. When applied to the supercapacitor electrode, the AKC ensured a high capacitance of 264 F g−1 at 0.5 A g−1, which maintained 86.1 % of the initial capacitance after 5000 cycles at 5 A g−1, and an ultra-high energy density of 16.3 Wh kg−1 in a full cell device. By analyzing its application in the lithium‑sulfur battery cathode, the S-loaded AKC exhibited a high capacity of 1075 mAh g−1 at 0.1C, and 490.5 mAh g−1 after 150 cycles with 66.5 % of capacity retention. The excellent performance of AKC can be attributed to its high specific surface area, pore structure, and sulfur and nitrogen co-doping combine effect. Overall, AKCs exhibited excellent electrochemical performances, thereby proposing a new synthetic strategy of preparing dual heteroatom doped porous carbon for high-performance electrode materials through a single precursor and low-cost perspective.

Nitrogen and sulfur co-doped porous carbon derived from polypyrrole-polythiophene for efficient peroxydisulfate activation towards degradation of aniline

To enhance the catalytic activity of carbon materials and streamline their synthesis process, it is necessary to optimize the doping of heteroatoms and reduce the dependence on organic solvents. This can be achieved by utilizing carbonized Polypyrrole-Polythiophene (C(Ppy-Pth)), which is obtained through simultaneous and in-situ co-doping of N and S. This material can serve as an effective activator of peroxydisulfate (PDS) for the degradation of aniline (AN). The results showed that Ppy-Pth could be efficiently synthesized by using cetyltrimethyl ammonium bromide, pyrrole, thiophene, FeCl3, and H2O2 in water. Based on the price, self-decomposition and oxidation efficiency, the performance of PDS activated by C(Ppy-Pth) was superior to that of peroxymonosulfate (PMS) in degrading AN. The optimum conditions for catalyzing PDS and degrading 30 mg/L AN by C(Ppy-Pth) were 0.10 g/L C(Ppy-Pth)-1000-1/1, 2.10 mM PDS, and pH0 = 3.00, which resulted in 86.69% AN removal in 30 min. Carbonation temperature, N/S ratio and pyridine N content are the key factors affecting the catalytic activity of C(Ppy-Pth). Quenching, probe, and electrochemical experiment revealed that in the catalytic PDS system with C(Ppy-Pth)-1000-1/1 (pH0 = 3.00), the oxidation of AN mainly occurred through the generation of hydroxyl radical (·OH), superoxide anion (O2·-), and electron transfer on the C(Ppy-Pth)-1000-1/1 surface. The steady-state concentration of ·OH and O2·- were 2.65 × 10−14 M and 1.97 × 10−13 M, respectively, and the contribution rate of ·OH oxidation was 31.28%. The oxidation of AN by sulfate radical (SO4·-) and singlet oxygen (1O2) could be neglected. This study provides a promising strategy for the construction of PDS catalyst and wastewater treatment.

N, S co-doped porous carbon nanosheet foam as MALDI matrix for efficient and direct profiling of biomolecules and environmental contaminants

It is still urgent to develop a powerful method for high-throughput and sensitive analysis of various small biomolecules and environmental contaminants. Herein, a three-dimensional foam consisting of nitrogen and sulfur co-doped porous carbon (N, S-C) nanosheet synthesized was served as an excellent matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) efficiently and directly detecting various small biomolecules and pollutant compounds. This N, S-C nanosheet possessed the advantages of carbon foam for resonant chamber, high-contents of N/S heteroatoms co-doping, large surface area, hierarchical pore and good UV absorption. The use of N, S-C matrix could exhibit higher MS intensities, lower background noise, better salt tolerance and higher sensitivity for probing the various analytes, much superior to the traditional CHCA (α-cyano-4-hydroxycinnamic acid) matrix and control materials (C and N-C). The limit of detection (LOD)s of 1-hydroxy-pyrene, 4-nitrocatechol and nitroguaiacol were calculated to be 0.1 μg/mL, 1 μg/mL and 8 μg/mL at a signal-to-noise ratio (S/N) of 3. Moreover, the rapid and precise detections of 4-nitrocatechol, nitroguaiacol, and 1-hydroxy-pyrene in PM2.5 real sample have also been achieved. Through density functional theory (DFT) simulations, we reveal the sensing mechanism of small molecular deprotonation with the N and S co-doping into carbon matrix. This work may be promising to provide an excellent carbon matrix for the analysis of MALDI-TOF MS method in the biological and environmental field.

Utilization of nitrogen, sulfur co-doped porous carbon micron spheres as bifunctional electrocatalysts for electrochemical detection of cadmium, lead and mercury ions and oxygen evolution reaction

The development of high-performance bifunctional electrocatalysts for oxygen evolution reaction and heavy metal ion (HMI) detection is significant and challenging. Here, a novel nitrogen, sulfur co-doped porous carbon sphere bifunctional catalyst was designed and fabricated by hydrothermal followed by carbonization using starch as carbon source and thiourea as nitrogen, sulfur source for HMI detection and oxygen evolution reactions. Under the synergistic effect of pore structure, active sites and nitrogen, sulfur functional groups, C-S0.75-HT-C800 demonstrated excellent HMI detection performance and oxygen evolution reaction activity. Under optimized conditions, the detection limits (LODs) of C-S0.75-HT-C800 sensor were 3.90, 3.86 and 4.91 nM for Cd2+, Pb2+ and Hg2+ when detected individually; and the sensitivities were 13.12, 19.50 and 21.19 μA/μM. The sensor also obtained high recoveries of Cd2+, Hg2+ and Pb2+ in river water samples. During the oxygen evolution reaction, a Tafel slope of 70.1 mV/dec and a low overpotential of 277 mV were obtained for C-S0.75-HT-C800 electrocatalyst with a current density of 10 mA/cm2 in basic electrolyte. This research offers a neoteric and simple strategy in the design as well as fabrication of bifunctional carbon-based electrocatalysts.

Nitrogen and sulfur-codoped porous carbon derived from zein/poly(ionic liquid) complexes as electrode material for high-performance supercapacitor

Nitrogen and sulfur-codoped porous carbon derived from zein/poly(ionic liquid) complexes as electrode material for high-performance supercapacitor

Biomass-derived nitrogen and sulfur co-doped sheet-like porous carbon for high-performance supercapacitors

Nitrogen and sulfur co-doped porous carbon materials with excellent electrochemical performance were prepared using a one-step carbonization and activation method.

Nitrogen and Sulfur Codoped Porous Carbon Directly Derived from Potassium Citrate and Thiourea for High-Performance Supercapacitors.

By introducing a heteroatom into carbon material, an effective improvement in capacitance can be realized owing to surface oxidation and reduction reactions of pseudocapacitors. Herein, a simple one-pot carbonization activation method was proposed to convert potassium citrate into three-dimensional interconnected porous carbon (PC). Then, an effective double heteroatom doping method by thiourea was used to prepare nitrogen-sulfur-doped PC (N,S-PC). This porous structure facilitates the storage of a large number of ions and reduces their diffusion path. The synthesized N,S-PC nanomaterial has a capacitance of 674 F/g at 1 A/g in a 1 M H2SO4 electrolyte, can retain 94.41% of the initial capacitance after 10 000 cycles at 5 A/g, and has a long cycle life. More importantly, a symmetric supercapacitor assembled with this material can exhibit an energy density of up to 32.6 (W·h)/kg at a high-power density of 750 W/kg. This is due to the high performance of N,S-PC in supercapacitor electrode materials.

Nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons for supercapacitors

To achieve high-performance supercapacitors, nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons (CHC-SK) are successfully prepared by one-step carbonization. In the synthesis, two effective strategies of structure design and heteroatom doping are both used to increase capacitance of carbon materials. To control and design of structure, potassium citrate as a novel pore-former is introduced into chitosan hydrogel systems. It plays three roles in pore formation and thereby can be effective to optimize structure and improve surface area of CHC-SK. In addition, thiourea as binary doping of nitrogen and sulfur can effectively maximize the pseudocapacitance of CHC-SK. Therefore, CHC-SK with large surface area (1596.4 m2 g−1) and high heteroatom content (5.43% for nitrogen, 2.62% for sulfur) show excellent electrochemical performances. The specific capacitance of CHC-SK reaches up to 366.8 F g−1 at 0.5 A g−1. Even at the high current density of 10A g−1, its capacitance retention is 97.1% for 10,000 cycles. This simple strategy for the synthesis of nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons with high specific capacitance has promising applications in the future.

Biomass derived nitrogen and sulfur co-doped porous carbons for efficient CO2 adsorption

• N, S co-doped porous carbons were synthesized from biomass hazelnut shell. • Thiourea acts both N and S agent. • The resultant carbon exhibits high CO 2 uptake, 6.44 mmol/g at 0 °C and 1 bar. • The sorbents also exhibit various other good CO 2 adsorption properties. • Joints effects of narrow microporosity, N and S content decides CO 2 uptake. In this work, novel nitrogen and sulfur co-doped porous carbons were synthesized by thiourea modification of carbonized hazelnut shell, then followed by KOH activation. In current preparation protocol, thiourea acted as both N and S agent, thereby, nitrogen and sulfur were simultaneously doped into the carbon skeleton by a single-step reaction. After KOH activation, the resultant sorbents hold advanced porosity and a certain amount of N and S contents. This series of sorbents possess the highest CO 2 uptake of 4.30 and 6.44 mmol g −1 at 1 bar, 25 °C and 0 °C, respectively. Comprehensive investigations found that the joint effects of narrow microporostiy, N and S content govern the CO 2 uptake of these adsorbents. Moreover, these adsorbents display various exceptional CO 2 adsorption performances such as excellent reversibility, fast CO 2 adsorption kinetics, moderate heat of adsorption, good CO 2 /N 2 selectivity and high dynamic CO 2 capture capacity. Therefore, these hazelnut shell derived N, S co-doped carbons are promising in actual CO 2 capture.

Constructing Sulfur and Nitrogen Codoped Porous Carbon with Optimized Defect-Sites and Electronic Structure Promises High Performance Potassium-Ion Storage

Constructing Sulfur and Nitrogen Codoped Porous Carbon with Optimized Defect-Sites and Electronic Structure Promises High Performance Potassium-Ion Storage

3D nitrogen and sulfur co-doped hierarchical porous carbon derived from mung bean jelly for high performance supercapacitors

Design and preparation of biomass derived heteroatom-doped hierarchical porous carbons with excellent capacitive performances draw extensive research attention for supercapacitors. Herein, 3D nitrogen and sulfur co-doped hierarchical porous carbon (NSHPC) derived from mung bean jelly with mung bean starch as carbon source and thiourea as both nitrogen source and sulfur source is successfully prepared. By virtue of manipulating the preparation method, the obtained NSHPC possesses a high specific surface area of 2420 m2 g−1 and a large total pore volume of 1.64 cm3 g−1. The NSHPC electrode displays a high specific capacitance of 330.2F g−1 at the current density of 0.5 A g−1 and still maintains 66.2% of its original specific at the high current density of 20 A g−1 in three-electrode system. In addition, a symmetric device based on NSHPC electrodes delivers an energy density of 8.3 W h kg−1 at the power density of 101.6 W kg−1, and>70.6% of energy density is kept even under the high power density of 19.3 kW kg−1. This study provides a facile and efficient method of applying biomass as a precursor to obtain heteroatom-doped hierarchical porous carbons for high performance supercapacitors.