Carbon Doping Research Articles

Enhancing Ozone Decomposition in Humid Environments through Carbon Doping to Disrupt the Hydrogen Bond Network in Mullite YMn2O5.

The strong adsorption of water molecules at the active site of the catalyst presents significant challenges in ozone decomposition, particularly at room temperature and in humid environments. To address this issue, we doped carbon atoms into the Mn-mullite YMn2O5 catalyst to replace oxygen, resulting in efficient and stable ozone decomposition under highly humid conditions. Utilizing DFT calculations, our study demonstrated that carbon doping disrupts hydrogen bond networks on the catalyst surface, thereby reducing water adsorption. Furthermore, carbon doping regulated the electronic structure of active sites, fundamentally reversing the adsorption strength of water and ozone molecules, which avoids the decline in catalytic activity caused by competitive water adsorption. Experimentally, under room temperature and relative humidity (RH) 50%, the carbon-doped YMn2O5 catalyst maintained 100% conversion in decomposing 100 ppm of ozone for at least 24 h, surpassing the most reported catalysts against water poisoning. Furthermore, the utilization of a carbon-doped mullite-loaded air cleaner demonstrated promising application in degrading ozone. The approach of enhancing catalyst water resistance through carbon doping, which disrupts hydrogen bonds, provided valuable insights into the design of stable and efficient room-temperature ozonolysis catalysts.

Interference mechanism of electrolyte cations on vanadium-oxygen binary doped carbon nitride for hydrogen evolution from artificial seawater splitting: Coupling experiments, DFT calculations and machine learning

Photocatalytic H2 production from seawater splitting is a promising method for sustainable energy conversion technology. The vanadium-oxygen binary doped carbon nitride (VOX-CN) is successfully prepared for H2 production. Benefiting from the electronic structure alteration, the maximum H2 yield on VOX-CN in artificial seawater reaches 4475.74 μmol h−1g−1, 10 times higher than that of CN in deionized water. The impact of ions on the photocatalytic activity of VO2-CN is followed by Na+ > Mg2+ > K+ > Ca2+. The adsorption of electrolyte ions promotes the formation of delocalized electron clouds on the surface of VO2-CN, facilitating more electrons to participate in H+ reduction. Screening based on six machine models, the decision tree regression algorithm is used to reveal the interaction between cation type, their concentration and H2 yield. Pearson heatmap indicates that Na+, Mg2+, and K+ ions are positively correlated with H2 yield, whereas Ca2+ shows a negative correlation. The interactions among Na+, Mg2+ and K+ atoms facilitate H2 production in multi-ion system, whereas Ca2+ ions do the opposite, especially for high concentration. This work proposes new insights into the interference on H2 yield between the structure alteration of CN framework and the change of ion type and concentration.

In-Situ Constructing N,S-Codoped Carbon Heterointerface for High-Rate Cathode of Sodium-Ion Batteries.

Na3V2(PO4)3 (NVP) is considered one of the promising choices for cathodes of sodium-ion batteries, but the poor conductivity resulted inferior rate performance limited the practical development of NVP cathodes. In this study, we successfully synthesized N/S dual-atom doped carbon coatings in situ through a simple one-step solid-state sintering method. The uniformly coated carbon layer can inhibit the agglomeration and growth of active materials during the sintering process, shorten the Na+ migration path, and increase the contact area with the electrolyte, thus facilitating rapid Na+ migration. Notably, the doping of N elements can alter the electron distribution of carbon coating, enhancing electron conductivity. Furthermore, the introduction of S elements in the carbon layer can induce the formation of stable C-S-C bonds in the molecular layer, expanding the interlayer spacing, which is beneficial for Na+ transport and storage. Therefore, the modified NVP@NSC composite provides a high specific capacity of 90.3 mAh g-1 at a rate of 20 C, with a capacity retention rate of 94.4% after 8000 cycles, demonstrating excellent stability at high current densities. Moreover, the full cell exhibits remarkable electrochemical performance at 5 C. This research contributes to the practical development of NVP cathodes.

Preparation of Fe2O3 nanoparticles with ultrathin carbon covered as lithium storage anodes

This study focuses on the development of ultrathin carbon (UTC) treated with Fe2O3 nanoparticles as anode materials for lithium-ion batteries (LIBs). Here, a simple hydrothermal method has been adopted to prepare Fe2O3@C nanocomposite, followed by annealing. The obtained Fe2O3@C demonstrates Fe2O3 nanoparticles (NPs) with uniform carbon, which effectively mitigates volume expansion and enhances electrochemical performance. Encouraging, the first principal calculations ensure that carbon doping in Fe2O3 can notably reduce the band gap from 2.12 to 1.10 eV and enhance electronic conductivity.

Effect of glucose addition on the morphology and activity of ZnO supported on mesoporous zeolite SBA-15 for the removal of hydrogen sulfide

Zinc oxide with its high equilibrium constant for sulfidation, can be utilized to purify H2S-containing gases, but its low kinetics at room temperature limits its sulfur loading capacity. This study use glucose as an organic additive and carbon source to prepare carbon doped ZnO adsorbents with different ZnO loadings (5-20wt%) through initial wet impregnation. It was observed that the sulfur capacity of 15wt% Zn/SBA-15-G (10.9mg/g) was approximately 1.65 times higher than that of 15wt% Zn/SBA-15 (6.6mg/g). This improvement was attributed to the use of glucose, which led to better ZnO dispersion, a narrower distribution of ZnO particle size, and the formation of C-O-Zn bonds that increased the number of hydroxyl groups on the ZnO surface. DFT calculations also indicated that carbon doping could lower the activation energy of the reaction between ZnO and H2S and shorten the reaction pathway. Consequently, the prepared ZnO adsorbent demonstrated enhanced desulfurization efficiency at room temperature. Furthermore, regeneration experiments conducted on the desulfurizer after use revealed that achieving complete regeneration is a challenge.

Magnetic injection of α-CP nanoribbons and investigation of spintronic device applications of magnetic α-CP nanoribbons based on first principles calculations

Since the successful synthesis of α-phosphorus carbide (α-CP) using carbon doping technology, α-CP has exhibited excellent carrier mobility and anisotropy at room temperature, underscoring its potential for spintronic applications. The application of CP in spintronic devices is limited due to its lack of magnetism. Effective magnetic injection in non-magnetic semiconductors can typically be achieved by doping with magnetic atoms. In this study, we calculated the electromagnetic properties of transition metal (TM) atoms adsorbed at different positions on α-CP using first principles. Notably, we found that α-CP nanoribbons adsorbed with Fe and Mn atoms of a specific width exhibit stable half-metallicity. We discovered that α-CP nanoribbons adsorbed with Fe and Mn atoms of a specific width exhibit stable half-metal properties and design magnetic tunnel junctions with half-metallic Fe_H12 and Mn_H12 adsorption structures. The results show that Mn_H12 and Fe_H12 devices exhibit a highly efficient spin filtering effect, with a TMR as high as 5521%. These findings provide theoretical guidance for the application of CP-based spintronic devices.

Heterointerfacial engineering of N,P-doped carbon nanosheets supported Co/Co2P nanoparticles for boosting oxygen reduction and oxygen evolution reactions towards rechargeable Zn-air battery

Transition metal phosphides (TMPs) with high electrocatalytic activity for the oxygen evolution reaction (OER) are reckoned as a substitution of precious group metals catalysts in rechargeable Zn-air battery. In this work, Co/Co2P heterojunction nanoparticles supported N,P-doped carbon nanosheets (Co/Co2P@NPCNS) were designed and prepared via a facile one-step molten salt-assisted pyrolysis process. Density function theory calculations reveal that the heterogeneous interactions of Co/Co2P effectively enhance the bifunctional electrocatalytic activity for oxygen reduction reaction (ORR) and OER. The synergistic interaction between the Co/Co2P heterojunction nanoparticles with highly exposed active sites and excellent catalytic activity and the two-dimensional doped carbon nanosheets with high conductivity contributes to Co/Co2P@NPCNS exhibiting preeminent bifunctional ORR/OER activity and stability with a high half-wave potential for ORR (0.87 V), a low overpotential for OER (302 mV at 10 mA cm−2) and a low potential gap (0.66 V). The homemade rechargeable Zn-air battery performs high peak power density (187 mW cm−2) and exceptional endurance. This heterogeneous interface tactic of integrating TMPs with heteroatom-doped carbon materials may shed light on the research and development of non-precious metal electrocatalysts.

Preparation of Multi-element Doped Carbon Nanospheres with Core-shell Structure Derived from Polystyrene as Lubricating Additives for Improving Tribological Behavior

In this study, the multi-element doped carbon nanospheres with core-shell structure (N,P,S-PCNs) have been successfully synthesized through the carbonization of hyper-cross-linked polystyrene nanospheres (HPSs) encapsulated with poly(cyclotriphosphazene-co-4,4’-sulfonyldiphenol) (PZS). The phosphonitrilic chloride trimer can in-situ assemble on HPSs surface, forming a poly(phosphonitrilic chloride trimer) film via sulfonyldiphenol as cross-linking agent to obtain HPSs@PZS. Subsequently, the HPSs@PZS undergoes high-temperature calcination under N2 atmosphere, and PZS with a well-preserved encapsulation capability efficiently incorporated N, P and S into carbon nanospheres to gain multi-element (N,P,S) co-doped carbon nanospheres (N,P,S-PCNs) with core-shell structure. The prepared N,P,S-PCNs exhibit exceptional dispersibility and stability as lubricant additives, effectively mitigating friction (reduced to 0.106) and wear (decreased by 84.0 %). The lubrication performance of N,P,S-PCNs is exceptional due to the nanospheres' remarkable ability to enter the gaps between friction pairs and form a deposition film on the surfaces. Moreover, the nanospheres can undergo a chemical reaction with the matrix surface, resulting in the formation of a chemical protective film. The composite protective film (deposition film and chemical protective film) significantly enhances the lubricants' ability to reduce friction and resist wear.

Synergistic effects of carbon coating and Bi-bridge in S-scheme C@CuO/Bi/Bi2MoO6 nanocomposites for enhanced photoreduction of Cr(VI)

The S-scheme mechanism in photocatalysis offers a promising approach to significantly enhance photoreductive activity. Here, using Bi dots as electronic media, and by changing the amount of added C@CuO on the surface of flower-shaped Bi2MoO6, a diverse range of CBM-x heterojunctions, were synthesized using a multi-step approach that incorporated solvothermal preparation and calcination methods. CBM-10 exhibited excellent photocatalytic activity: 96.9 % of Cr(VI) removal in 30 min, which was 38.0-fold better than CuO, 4.2-fold higher than pristine Bi2MoO6. Furthermore, even after five cycles of use, CBM-10 showed outstanding stability. Experiments to capture the active species revealed that electrons play a crucial role in the photocatalytic reduction of Cr(VI). In these heterojunctions, carbon doping leads to the formation of coatings on the semiconductor materials to promote the migration and separation of photogenerated carriers. The presence of carbon coating is beneficial to improve the stability of CBM-10. Bi dots grown on Bi2MoO6 nanosheets can act as electron transport channels in C@CuO/Bi/Bi2MoO6, accelerate photoinduced carrier separation. The internal electric field, and the existence of “S-scheme” charge transfer mechanism was verified by the combination of atomic force microscope and synchronous illumination X-ray photoelectron spectroscopy. This process significantly mitigates the recombination of photo-induced carriers, enhancing the overall photoreduction efficacy. This study presents a novel method for developing S-scheme heterojunction to enhance the effectiveness of Cr(VI) decontamination, paves a promising route to heavy metal removal by mild photo-reductive system, and provides new insights into the design of photocatalysts with enhanced redox capabilities.

Vanadium doped ZIF-L derived V-NC peroxidase-like nanozymes for tannic acid sensing

Transition metal-based nitrogen doping carbon nanozyme has attracted great attention owning to their high potential to replace natural enzymes. In this study, we prepared novel vanadium doped ZIF-L derived N-doped carbon nanozyme (V-NC) via facilely pyrolysis strategy. The cross-shaped morphology endows V-NC with unique V-Nx active sites, hierarchical pore character and large specific surface area, leading to its good peroxidase-mimetic activity. The steady-state kinetics trials revealed the low Km values of V-NC for TMB and H2O2, demonstrating its good affinity to TMB and H2O2. Mechanism research revealed that the excellent peroxidase-like activity of V-NC resulted from co-participation of •OH and O2•−, which were confirmed by reactive oxygen species (ROS) scavenging experiments and EPR trials. Under optimized operational conditions, and by virtue of the antioxidant properties of tannic acid (TA), a colorimetric sensing assay based on the peroxidase-like activity of V-NC was developed for sensitive detection of TA in the 0.1–2.5 µM linear range with low detection limit of 19.8 nM and the relative standard deviation (RSD, n = 3) of below 5%. This work renders a new idea for designing and developing high activity N-doped carbon nanozyme, and provides an accurate and feasible assay for the analysis of TA in real samples.

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.

Effective Near-Infrared Light-Driven Photocatalytic Reduction of CO2 by Dual-Site Doped Carbon Nitrides

Effective Near-Infrared Light-Driven Photocatalytic Reduction of CO₂ by Dual-Site Doped Carbon Nitrides

Effective Determination of Diosmin Using Nitrogen Doped Carbon Dots as Probe Based on Internal Filtering Effect.

The establishment of a convenient and efficient testing method is crucial and needed for the monitoring of diosmin. In this study, nitrogen doped carbon dots (N-CDs) with the particle size distribution of 2.5-5.7nm and the average diameter of 4.1nm were successfully synthesized using a simple strategy. N-CDs exhibited excellent and stable fluorescence performance with the quantum yield of 22.33%. Correspondingly, a fluorescence analytical method was developed for diosmin determination using N-CDs as probe. UV-vis absorbance spectroscopy and the evaluation of internal filtering parameters verified that the mechanism causing the quenching of N-CDs was an internal filtering effect (IFE). The concentration of diosmin can be directly evaluated based on the quenched fluorescence intensities. After optimizing experimental conditions, it was found that the fluorescence quenching efficiency ((F0-F)/F0) of N-CDs exhibited a good linear relationship with the concentration of diosmin (CDiosmin) in the range of 3.0-50µg/mL. The limit of detection (LOD) was 0.86µg/mL based on 3σ/slope (n = 13). This method was successfully applied to accurately determine the content of diosmin in diosmin tablets and human plasma samples with good reproducibility. It stands out for its simplicity, speed, and acceptable determination performance.

Phosphorous doped graphitic carbon nitride (P‐g‐C3N4) as an electrochemical platform for the simultaneous detection of xanthine and caffeine

A one step strategy was employed for the preparation of phosphorous doped g‐C3N4 (P‐g‐C3N4) using melamine phosphate. Herein, the precursor upon thermal condensation at 550º C resulted in the formation of P‐g‐C3N4 nanosheets. The as‐synthesised P‐g‐C3N4 nanosheets were characterized by UV‐vis, FT‐IR and Raman spectroscopy. Later, surface morphological analysis were carried out using FESEM and HRTEM. Moreover, the crystalline nature and elemental composition analysis were conducted using XRD and XPS. Following this, P‐g‐C3N4 nanosheets modified glassy carbon (GC) electrode was employed for the simultaneous detection of xanthene and caffeine. The modified electrode was found to be linear in the range of 0.1 to 100 μM (for xanthine) and 0.05 to 100 μM (for caffeine). The limit of detection was found to be 10 nM and 14 nM for xanthine and caffeine respectively. Further, the electrode exhibited a highly selective detection towards each of these analyte when they co‐exists.

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 Ni Loadings on the Structure and Morphology of Carbon Nanotubes Using Nickel Doped Iron Oxide Catalysts

AbstractIron oxide and their different doped iron oxide catalyst have been used for decades and are considered as efficient catalysts in several synthesis schemes including synthesis of carbon nanotubes. The iron oxide of the catalyst is abundant in nature, high catalytic activity at low over potentials, stability in basic media and low cost, making it environmentally and economically attractive. Nickel doped iron oxide catalyst have not been reported in the literature. Doping of nickel over iron oxide catalyst, different percentage 1 %, 5 %, 10 % and 20 % were done by impregnation method. The samples were characterized by X‐Ray powder Diffraction (XRD), Fourier‐Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive X‐ray (EDX) and Thermo Gravimetric Analysis (TGA). Nickel doped iron oxide was used as catalyst for the synthesis of carbon nanotubes (CNTs) and doping changed the morphology of carbon nanotube (CNTs). FTIR results confirmed the doping and presence of different functional groups. Chemical vapor deposition (CVD) was carried out for the synthesis of multiwall carbon nanotubes (MWCNTs) on nickel doped iron oxide catalyst for different percentage (1 %, 5 %, 10 % and 20 %) separately. CVD assembly was carried in tube furnace and the reaction was checked at two different temperature i.e 700 °C and 750 °C and using methane and compressed natural gas (CNG) as precursors. The catalyst was activated in the furnace at 800 °C for an hour. Methane and argon were used in proportion 2 : 1 inside the furnace. SEM showed formation of CNTs at 750 °C with CNG precursor. Formation of CNTs increased with increasing doping with this CNTs was confirmed by SEM.

Energy‐Saving Hydrogen Production from Methanol Electrocatalysis Catalyzed by Molybdenum Phosphide/Nitrogen‐Doped Carbon Polyhedrons Supported Pt Nanoparticles

Comprehensive SummaryImproving the catalytic efficiency and anti‐poisoning ability of Pt‐based catalysts is very critical in methanol electrolysis technology for high‐purity hydrogen generation. Herein, the nitrogen‐doped carbon polyhedrons‐encapsulated MoP (MoP@NC) supported Pt nanoparticles were demonstrated to be effective for methanol electrolysis resulting from the combined advantages. The nitrogen‐doped carbon polyhedrons not only greatly enhanced the conductivity but also effectively prevented the aggregation of MoP to offer Pt anchoring sites. The electronic structure modification of Pt from their interaction reduced the adsorption energy of CO*, resulting in good CO‐poisoning resistance and accelerated reaction kinetics. Specifically, Pt‐MoP@NC exhibited the highest peak current density of 106.4 mA·cm–2 for methanol oxidation and a lower overpotential of 28 mV at 10 mA·cm–2 for hydrogen evolution. Energy‐saving hydrogen production from methanol electrolysis was demonstrated in the two‐electrode systems assembled by Pt‐MoP@NC which required a low cell voltage of 0.65 V to reach a kinetic current density of 10 mA·cm–2 on the glass carbon system, about 1.02 V less than that of water electrolysis.

Synergistic enhancement of lithium iron phosphate electrochemical performance by organic zinc source doping and crystalline carbon layer capping

In this study, lithium iron phosphate (LFP) is prepared as cathode material by hydrothermal synthesis method and the combined effect of doping and capping is applied to co-modify it. We thoroughly investigate how Zn2+ doping and PA capping layer affect the crystal structure, microscopic morphology, and electrochemical properties of LFP cathode materials. The experimental results show that when co-modified with 5 % Zn2+ doping combined with 7 % PA capping layer, the resulting cathode material exhibits a discharge specific capacity of 165.5 mAh g−1, and the capacity retention rate can still be maintained at a high level of 98.6 % after 200 charge–discharge cycles.

Charge carrier dynamics of chemical vapor deposited carbon-doped titanium dioxide photoanodes

This study explores the synthesis of carbon-doped titanium dioxide TiO2(C) photoanodes through a single-step, low-pressure chemical vapor deposition (LCPVD) method, investigating the influence of carbon doping and oxygen vacancies on photoelectrochemical performance. The research employs morphological, structural, and photoelectrochemical characterization methods, including intensity-modulated photocurrent spectroscopy (IMPS) and distribution of relaxation times (DRT) analysis. We correlate the simultaneous presence of surface carbon and oxygen defects to improved charge separation and collection for TiO2(C) photoanodes. This work provides a comprehensive and detailed explanation of the photoelectrochemical performance of TiO2 electrodes, showing the potential behind combined IMPS-DRT analysis for photoelectrode characterization.

Electrolytic conversion of CO2 to proportionally tunable syngas using nickel-nitrogen doped carbon materials derived from Chlorella sp.

Chlorella sp., a common type of algae found in global surface waters, is prone to causing "blooms" and can accumulate significant amounts of nutrients such as nitrogen, phosphorus, and carbon. While carbon materials derived from Chlorella sp. are widely used in the field of adsorption, there are relatively few reports focused on electrocatalysis. This study utilized Chlorella sp. as a raw material to synthesize functional carbon materials, and prepared nitrogen-doped (CN), nickel-doped (CNi), and nitrogen-nickel co-doped (CNNi) carbon-based catalysts with both metal and non-metal elements. The results showed that the CN, CNi and CNNi catalysts possessed certain electrocatalytic properties, among which the CNNi material had the best electrocatalytic activity towards CO2 reduction (CO2RR). In 1.0 M KHCO3, the CNNi catalyst exhibited an instantaneous current density of 15.4 mA/cm2 under the potential of -0.82V (vs. RHE). In terms of product selectivity, the Faraday efficiency of CO on the CNNi electrode was up to 90% when the electrode potential was -0.62 V (vs. RHE), while the selectivity of the CN and CNi catalysts for CO was only 59% under the optimal conditions. The co-doping of nitrogen and nickel significantly enhanced the electrocatalytic activity and the selectivity towards CO of Chlorella-based carbon materials.