Carbon Doping Research Articles

Role of carbon on the enhanced strength-ductility synergy in a high-entropy alloy by multiple synergistic strategies

A new Fe47Mn31Co10Cr10C2 high-entropy alloy (HEA) was developed to investigate the role of carbon in enhancing the strength-ductility synergy by utilizing multiple synergistic strengthening strategies with mitigating the adverse effect of carbon. Compared with the Fe40Mn40Co10Cr10 twinning-induced plasticity (TWIP) HEA, the carbon-doped Fe47Mn31Co10Cr10C2 HEA after annealing at 1173 K for 10 min exhibited a higher strain-hardening rate, and significantly improved yield strength (YS) and ultimate tensile strength (UTS), with maintaining high elongation. The remarkable improvements in YS were mainly attributed to the multiple synergistic strengthening mechanisms, including enhanced grain boundary strengthening, hetero-deformation-induced (HDI) strengthening, and Cr23C6 precipitation strengthening. The higher strain-hardening rate could be ascribed to the enhanced TWIP effect and HDI strain-hardening. The effective stacking fault energy (SFE) of the Fe40Mn40Co10Cr10 and Fe47Mn31Co10Cr10C2 HEAs were calculated by thermodynamics to be 23.4 mJ/m2 and 22.1 mJ/m2, respectively. This revealed that reducing the Mn content effectively counteracted the increasing effect of carbon on the SFE for the carbon-doped HEA. The promotion of deformation twinning in the Fe47Mn31Co10Cr10C2 HEA could be ascribed to the comprehensive effect of the SFE and the stress levels of the alloys. On one hand, compared with the Fe40Mn40Co10Cr10 TWIP HEA, the lower SFE in the Fe47Mn31Co10Cr10C2 HEA led to a drop in the critical stress for deformation twinning. On the other hand, due to the strong multiple synergistic strengthening with carbon doping, the stress levels of the alloys were significantly enhanced, thus making the activation stress of twinning much easier to achieve. This study contributes to the alloy design guidance of properly utilizing carbon to achieve high strength-ductility synergy in alloys by multiple synergistic strategies.

High-performance electrocatalyst for PEMFC cathode: Combination of ultra-small platinum nanoparticles and N-doped carbon support

To accelerate the implementation of zero-emission power installations based on proton-exchange membrane fuel cells, it is necessary to maximize the power characteristics of these devices. For this purpose, we have obtained and tested a new N-doped carbon support and a synthesized Pt/C catalyst based on it with a platinum loading of about 37.3 %. A comparison of the degradation resistance of the initial support and the N-doped one has shown greater stability of the latter. At the same time, Raman spectroscopy has confirmed the presence of the C–N bond, which indicates the successful doping of carbon with nitrogen. The resulting Pt/C catalyst based on an N-doped support is characterized by a substantially narrow size dispersion and an ultra-small nanoparticle size of about 2.6 nm. The high-angle annular dark-field scanning transmission electron microscopy images of the synthesized catalyst have confirmed the presence of individual platinum atoms/clusters uniformly distributed over the surface of the support, and their presence is due to nitrogen embedded into the carbon structure. This material is characterized by a 50 m2 gPt-1 larger electrochemically active surface area and a 227 A gPt-1 greater mass activity compared to the commercial JM40 analog (40 % platinum loading). Meanwhile, the electrochemical parameters remaining after the accelerated stress testing are almost 2 times higher than those of JM40. And the power characteristics in the membrane electrode assembly for the catalyst synthesized by the facile one-pot synthesis method are 13 % (575 mW cm-2) higher than those of the commercial analog (500 mW cm-2). The Pt/C catalyst obtained during the research is deemed promising for commercial use in proton-exchange membrane fuel cells.

A feasible method to prepare yolk@shell nanoreactor with multiple cores and enhanced Fenton-like performance by confinement effect

At present, yolk@shell nanoreactor has drawn much attention in Fenton reaction, since the degradation rate could be accelerated by confinement effect, and metal leaching could be suppressed under the shell protection. To further improve the performance of traditional yolk@shell nanoreactor with single core, in this work, a yolk@shell nanoreactor with multiple CoFe nanoparticles as cores and nitrogen-atom doped carbon (NC) as shell was prepared. In peroxymonosulfate (PMS)-based Fenton-like reaction, 93.8 % of degradation efficiency was realized within 30 min over CoFe@NC, much better than the reference broken CoFe@NC (B-CoFe@NC), confirming the positive function of integrated yolk@shell structure. Based on the radical trapping experiment, 1O2 was the most important reactive oxygen species in CoFe@NC, while SO4•- played a dominated role in B-CoFe@NC, reflecting the different catalytic mechanism in these two catalysts. To reveal the confinement effect, electron paramagnetic resonance analysis was carried out to trace the 1O2 source. And they were originated from SO4•- and •OH with high concentrations inside the yolk@shell CoFe@NC nanoreactor. This study provided a novel method to construct yolk@shell nanoreactor with multiple cores and gave a novel insight on enhanced Fenton-like performance via confinement effect.

Self-assembling gelatin based delivery of multienzyme activity nanozyme and photosensitizer for ROS storm based cancer therapy

Nanozymes with multienzyme activity for reactive oxygen species (ROS) generation and intracellular redox imbalance are attractive strategy for cancer therapy. However, it is severely limited by low biocompatibility and catalytic efficiency, hypoxic and high levels of GSH in the tumor microenvironment. To address these issues, a copper doping carbon nanozyme (CC) with multienzyme activity was designed and integrated with photosensitizer Ce6 and gelatin to fabricate ROS amplifier (CCC). Gelatin endowed CCC with good biocompatibility, low hemolysis, and enzyme responsive degradation. CCC with high CAT-like, POD-like, OXD-like, and GSHox-like activities can induce the intracellular ROS storm formation to eliminate the cancer cells. The OXD-like activity and PDT performance mediated 1O2 generation was markedly potentiated by the CAT-like activity of CCC via catalyzing high expression of H2O2 to generate O2. At the same time, a large amount of ·OH were produced through POD-like activity of CCC and GSH was depleted by the GSHox-like activities of CCC, resulting in a destructive ROS storm formation and cellular redox homeostasis disruption. Both in vivo and in vitro experiments showed that CCC displayed satisfactory anti-tumor activity and biocompatibility. Our work provides a novel strategy for the development of nanozyne enhanced photodynamic therapy of cancer.

Nitrogen and sulfur co-doped carbonized lignin nanotubes for supercapacitor applications

Carbon electrode material is crucial for the development of electric double-layered supercapacitor in clean energy storage and rechargeable aspects. Although lignin consists the promising biomass based carbon resource for containing higher carbon atom ratio than 60 %, it is still the difficult challenge to precisely tailoring the porous structure characteristics and surface property to facilitate the electrolyte penetration and rapid ion transportation. Herein, the lignin nanotubes (LNT) were successfully synthesized in a convenient molecular self-assembly way, which were subsequently carbonized and activated, with introduction of melamine as nitrogen doping agent, into hetero-atom doped lignin carbon nanotubes (LCNT) as electrode material for supercapacitor. The resultant LCNT exhibit excellent pore structure, and high degree of graphitization. At a current density of 0.5 A/g, the as high specific capacitance as 391.4 F/g was achieved. Furthermore, under symmetric double-layered capacitor electrode systems, the as prepared N, S co-doped LCNT electrode demonstrated a specific capacitance of 28.6 F/g at a high current density of 20 A/g, which presented a practically applicable energy storage efficiency. It has convincingly demonstrate the substantial potential of LCNT as biomass derived carbon materials for electrochemical energy storage devices, positioning them as a promising and competitive candidate for electrode materials.

The Tetrapyrollic Motif in Nitrogen Doped Carbons and M‐N‐C Electrocatalysts as Active Site in the Outer‐Sphere Mechanism of the Alkaline Oxygen Reduction Reaction

The Tetrapyrollic Motif in Nitrogen Doped Carbons and M‐N‐C Electrocatalysts as Active Site in the Outer‐Sphere Mechanism of the Alkaline Oxygen Reduction Reaction

Enhanced nitrogen electroreduction to ammonia activities on Sb2S3 electrocatalyst by sulfur defects coupled with carbon doping

Exploiting effective, robust while cheap catalysts for the nitrogen reduction reaction (NRR) is of great significance in the scalability and renewability of electrochemical NH3 synthesis. Herein, a synergetic strategy of C dopants and S vacancies was employed into Sb2S3 (marked as C-Sb2S3-x) to boost the electrochemical NRR performance. The induced effects of C dopants and S vacancies of Sb2S3 on the physical and electrochemical behaviors were throughly investigated. Experiments verify that, the content of low oxidation state in Sb species are remarkably enhanced after introducing C dopants and S vacancies, this facilitate the enhanced electric conductivity and NRR activities of C-Sb2S3-x, together with the encouraged reaction kinetics. The prepared C-Sb2S3-x delivered an optimized NH3 yield rate of 47.2 μg h−1 mg−1cat. at −0.6 V along with a high Faradaic efficiency value of 6.4 % at −0.5 V in acid, outperforming than those of Sb2S3 and most disclosed sulfid NRR electrocatalysts. Density functional theory calculations validate that, cooperation of C doping and S vacancy could achieve the elevated NH3 yield rate, Faradaic efficiency as well as competitive stability. This approach puts forward an effective strategy for transition metal compounds to be more suitable for efficient electrocatalysis.

Carbon doping and bridging oxygen benefit for g-C3N4 to photocatalytic H2 production from methanol/water splitting: Experiments and theoretical calculations

Water-based homogeneous pre-assembly and thermal polycondensation were used to prepare carbon-doped oxygen-bridged layer-twisted graphite carbon nitride (g-C3N4) heterojunction for highly efficient photocatalytic hydrogen evolution (PHE). Despite the narrow band gap of around 0.91 eV, g-C3N4 heterojunction exhibited an excellent hydrogen evolution rate (563.87 μmolg−1h−1) in 30 % methanol/water solution without precious metal assisting catalysts, 36.85 times higher than g-C3N4. C doping in heptazine ring and bridging O caused the adjacent layer of g-C3N4 to twist by 11° in three-dimensional space. Noticeably, carbon doping in triazine ring was favorable to the establishment of build-in electric field between adjacent layers owing to the delocalized large π bonds. Bridging oxygen acted as a conversion switch for electron storage and transport of photogenerated charge from innerlayer (unmodified layer) with high Fermi level to outlayer (modified layer) with low Fermi level. This work provided an insightful guidance to novel layer-twisted g–C3N4–based photocatalysts for efficient H2 production.

Atomically dispersed Co/Mn immobilized on O, N dual doped hollow carbon spheres as sulfur host for lithium sulfur batteries

The regulation of the chemical coordination environment in the electrocatalyst can effectively suppress the shuttle effect of sulfur species in lithium-sulfur batteries. However, the mechanism of the atomically dispersed dual metal atom with the coordination of various heteroatoms used as the sulfur cathode catalyst and trapper remains unknown. This study introduces, for the first time, atomically dispersed Co and Mn in-situ immobilized on O, N dual-doped hollow carbon spheres (SACoMn/C-(N, O)) as sulfur host. Experiments combined with density functional theory calculations reveal that the synergy between Co-(N, O) and Mn-(N, O) sites enhances the nucleation/deposition and decomposition capabilities of Li2S. This enhancement is attributed to the anchoring-coupling-conversion behavior of sulfur species on the SACoMn/C-(N, O) surface, which effectively restrains the shuttle effect and facilitates the conversion kinetics. Moreover, the cooperation of dual metal atoms with O, N non-metal atoms embedded in the carbon network structure accelerates electric transport and ion diffusion kinetics. The cathode demonstrates a high initial specific capacity of 890 mAh·g−1 at 1 C and show exceptional long-term cycling durability, with a low capacity degradation of 0.037 % per cycle after 1700 cycles. This research may offer novel insights into the design of dual metal atom-decorated, functionalized carbon materials to improve the conversion reaction in sulfur cathodes.

Carbon-doped ZnO thin films: A transparent conductive oxide for application in solar-blind photodetectors

Transparent conductive oxide (TCO) films are crucial in optoelectronic devices, such as photodetectors, due to their unique blend of transparency and electrical conductivity. ZnO is a top choice for TCOs owing to its excellent properties, non-toxicity, and cost-effectiveness. In this work, we explore the potential of carbon doping to enhance the electrical properties of ZnO films for transparent conductive applications. Our findings reveal that C-doped ZnO (ZnO:C) films retain the pristine high quality and surface morphology despite an increase in defects with higher C doping. Notably, C doping does not compromise the visible light transmittance of ZnO films, while inducing a gradual increase in optical bandgap, indicative of the typical Burstein–Moss effect. As carbon doping increases, the ZnO:C films exhibit improved carrier concentration, lower resistivity, and sustained high mobility, achieving optimal performance with an electron concentration of 3.73 × 1019 cm−3, resistivity of 3.69 × 10−3 Ω cm, and mobility of 46.08 cm2 V−1 s−1. Finally, we utilized ZnO:C films as a transparent electrode material in ε-Ga2O3-based photodetector, achieving the development of transparent device and attaining high-performance solar-blind detection capabilities. This work provides a strategy for developing a transparent conductive oxide, with ZnO:C emerging as a promising rival to IIIA-doped ZnO for optoelectronic applications.

A new fabricated hetero-atom doped carbon quantum dots as a fluorescent probe for metronidazole determination using garlic and red lentils with microwave assistance.

Biocompatible and highly fluorescent phosphorus, nitrogen and sulfur carbon quantum dots (P,N,S-CQDs) were synthesized using a quick and ecologically friendly process inspired from plant sources. Garlic and red lentils were utilized as natural and inexpensive sources for efficient synthesis of the carbon-based quantum dots using green microwave-irradiation, which provides an ultrafast route for carbonization of the organic biomass and subsequent fabrication of P,N,S-CQDs within only 3 min. The formed P,N,S-CQDs showed excellent blue fluorescence at λem= 412 nm when excited at 325 nm with a quantum yield up to 26.4%. These fluorescent dots were used as a nano-sensor for the determination of the commonly used antibacterial and antiprotozoal drug, metronidazole (MTR). As MTR lacked native fluorescence and prior published techniques had several limitations, the proposed methodology became increasingly relevant. This approach affords sensitive detection with a wide linear range of 0.5-100.0μM and LOD and LOQ values of 0.14 μM and 0.42 μM, respectively. As well as, it is cost-effective and ecologically benign. The MTT test was used to evaluate the in-vitro cytotoxicity of the fabricated P,N,S-CQDs. The findings supported a minimally cytotoxic impact and good biocompatibility, which provide a future perspective for the applicability of these CQDs in biomedical applications.

MOF-Derived Nanoparticles with Enhanced Acoustical Performance for Efficient Mechano-Sonodynamic Therapy.

Ultrasound (US) generates toxic reactive oxygen species (ROS) by acting on sonosensitizers for cancer treatment, and the mechanical damage induced by cavitation effects under US is equally significant. Therefore, designing a novel sonosensitizer that simultaneously possesses efficient ROS generation and enhanced mechanical effects is promising. In this study, carbon-doped zinc oxide nanoparticles (C-ZnO) are constructed for mechano-sonodynamic cancer therapy. The presence of carbon (C) doping optimizes the electronic structure, thereby enhancing the ROS generation triggered by US, efficiently inducing tumor cell death. On the other hand, the high specific surface area and porous structure brought about by C doping enable C-ZnO to enhance the mechanical stress induced by cavitation bubbles under US irradiation, causing severe mechanical damage to tumor cells. Under the dual effects of sonodynamic therapy (SDT) and mechanical therapy mediated by C-ZnO, excellent anti-tumor efficacy is demonstrated both in vitro and in vivo, along with a high level of biological safety. This is the first instance of utilizing an inorganic nanomaterial to achieve simultaneous enhancement of ROS production and US-induced mechanical effects for cancer therapy. This holds significant importance for the future development of novel sonosensitizers and advancing the applications of US in cancer treatment.

Ar/NH3 Plasma Etching of Cobalt-Nickel Selenide Microspheres Rich in Selenium Vacancies Wrapped with Nitrogen Doped Carbon Nanotubes as Highly Efficient Air Cathode Catalysts for Zinc-Air Batteries.

This work utilizes defect engineering, heterostructure, pyridine N-doping, and carbon supporting to enhance cobalt-nickel selenide microspheres' performance in the oxygen electrode reaction. Specifically, microspheres mainly composed of CoNiSe2 and Co9Se8 heterojunction rich in selenium vacancies (VSe·) wrapped with nitrogen-doped carbon nanotubes (p-CoNiSe/NCNT@CC) are prepared by Ar/NH3 radio frequency plasma etching technique. The synthesized p-CoNiSe/NCNT@CC shows high oxygen reduction reaction (ORR) performance (half-wave potential (E1/2) = 0.878V and limiting current density (JL) = 21.88mA cm-2). The JL exceeds the 20wt% Pt/C (19.34mA cm-2) and the E1/2 is close to the 20wt% Pt/C (0.881V). It also possesses excellent oxygen evolution reaction (OER) performance (overpotential of 324 mV@10mA cm-2), which even exceeds that of the commercial RuO2 (427 mV@10mA cm-2). The density functional theorycalculation indicates that the enhancement of ORR performance is attributed to the synergistic effect of plasma-induced VSe· and the CoNiSe2-Co9Se8 heterojunction. The p-CoNiSe/NCNT@CC electrode assembled Zinc-air batteries (ZABs) show a peak power density of 138.29mW cm-2, outperforming the 20wt% Pt/C+RuO2 (73.9mW cm-2) and other recently reported catalysts. Furthermore, all-solid-state ZAB delivers a high peak power density of 64.83mW cm-2 and ultra-robust cycling stability even under bending.

Mesoporous carbon-doped boron nitrides for cathodic and anodic hydrogen peroxide electrosynthesis

Mesoporous carbon-doped hexagonal boron nitrides (C-doped BN) with high surface area were prepared by annealing organic resin polymer/silica in NaBH4 and NaNH2 inorganic salts, which were found to be efficient metal-free bifunctional electrocatalyst for both 2e− ORR and 2e− WOR. It could efficiently catalyze 2e− ORR to H2O2 in 2 M KHCO3 (1650 mmol g−1 h−1) with Faraday efficiency of 93–98 % in half reaction, while it was very active for 2e− WOR to generate H2O2 in 2 M KHCO3 with 551 mmol g−1 h−1 H2O2 production rate in half reaction. When pairing them in one H-type cell, H2O2 solution could be totally produced over C-doped BN in both anode and cathode cells. The better electron conductivity from sharper band gap caused by carbon doping and higher surface area of 304 m2 g−1 contributed to its efficient electrocatalytic activity. The C-doped BN served an effective bifunctional electrocatalyst for 2e− ORR and 2e− WOR.

A ratiometric fluorescence sensing system for rapid detection of glyphosate in miscellaneous beans

To establish a ratiometric fluorescence sensing system for the detection of glyphosate, nitrogen-sulfur doped carbon quantum dots nano-fluorescent probe was prepared by one-step hydrothermal method. At an excitation wavelength of 360 nm, the emission peak with maximum fluorescence intensity was obtained at 470 nm. The generation of 2.3-diaminophenazine by o-phenylenediamine oxidation produces a new fluorescence emission peak at 570 nm and a decrease in fluorescence at 470 nm. The fluorescence peaks at 470 and 570 nm form a ratio state. In the presence of glyphosate, reduces the oxidation of 2.3-diaminophenazine, this results in enhanced fluorescence at 470 nm and weakened fluorescence at 570 nm. Under the best conditions, the ratiometric fluorescence sensing system has good selectivity, the linear at glyphosate concentrations of 0.005–10 µg/mL, the limit of detection was 2.88 µg/kg, the limit of quantitation was 4.07 µg/kg. In addition, it is worth mentioning that this developed sensing system has shown good detection performance in 10 miscellaneous samples, the simple, efficient, and highly sensitive ratiometric fluorescence detection sensing strategy is provided.

Rapid Electronic Transport Channel of Co‐P with Mo in a Heterostructure Embedded with P, N Dual Doped Porous Carbon for Electrocatalytic Oxygen and Hydrogen Evolution

AbstractWe developed a molybdenum (Mo)‐doped cobalt (Co)‐heterostructure embedded on a phosphorous (P) and nitrogen (N) dual‐doped porous carbon which exhibits an intrinsic electronic transport channel of Co to Mo and P. The P,Mo,O−Co/PNC/NF (NF=Nickel foam) electrode offers 335 mV overpotential at 10 mA cm−2 in OER as compared with PMA‐ZIF67‐NC/NF and ZIF67‐NC/NF electrode with an overpotential of 357 and 373 mV respectively. Linear sweep voltammetry (LSV) of overall water splitting (OWS) supports that the current density gradually increased at a cell potential of 1.6 V with a maximum of 40 mA with a corresponding cell potential of 1.79 V at a current density of 10 mA cm−2. Density functional theory (DFT) calculations for water adsorption on optimized [111] surface of Co, CoMo, and CoMoP2 with adsorbed H2O and corresponding lattice determine the electron density difference of [111] surface with adsorbed H2O for Eads (eV) 4.23 corresponds to adsorption energy for CoMoP2. XANE‐EXAFS spectroscopy of P,Mo,O−Co/PNC at Co K edge and Mo K edge suggests the presence of higher valence of both Cox+ and Mox+ without metallic Co and Mo and Co−P and Mo−P bonds as major structural units due to phosphidation as determined by R‐space FT‐EXAFS spectra.

Targeted enhancement of ultra-micropore in highly oxygen-doped carbon derived from biomass for efficient CO2 capture: Insights from experimental and molecular simulation studies

The preparation of efficient CO2adsorbents is crucial for CO2capture. Compared to polymer-basedcarbons and metal-organic frameworks(MOFs), biomass-basedcarbon exhibits lower adsorption performance. Here, we prepared high oxygen doped ultramicroporous carbon through hydrothermal treatment and mechanical compaction assisted KOH activation. The study found that mechanical compaction treatment can target a 24 % increase in the volume of ultra-micropores, resulting in a CO2capture of the prepared ultramicroporous carbon reaching 5.6 mmol g−1, which is 22 % higher than that of conventionally prepared porous carbon. Molecular simulation calculations roughly estimated that functional groups and pore structures contribute 60 % and 40 %, respectively, to CO2capture at 0.15 bar, and 47 % and 53 % at 1 bar. Meanwhile, we found that the selectivity of CO2/N2is mainly related to the trend of oxygen functional groups, and is not significantly correlated with the micropore volume smaller than 0.7 nm. Theoretical calculations revealed that the introduction of oxygen groups into porous carbon resulted in an increase in selectivity of over 150 %, which is stronger than the effect of pore structure. This work provides valuable theoretical and experimental support for the design, preparation, and application of adsorbents for capturing CO2in flue gas.

Cu,Zn,I-Doped Carbon Dots with Boosted Triple Antioxidant Nanozyme Activity for Treatment of DSS-Induced Colitis.

Nanozyme-mediated antioxidative therapy is a promising star for treating a myriad of important diseases through eliminating excessive reactive oxygen species (ROS) such as O2·- and H2O2, a critical mechanism for inflammatory bowel disease (IBD). This work provides a high biocompatibility iodine-copper-zinc covalent doped carbon dots (Cu,Zn,I-CDs) with the catalase (CAT)-, superoxide dismutase (SOD)- and glutathione peroxidase (GPx)-like catalytic activities for treating ulcerative colitis (UC) by scavenging overproduced ROS. We found that I dopant aids in counteracting the positive charge at Cu,Zn dopants brought on by low pH, enabling Cu,Zn,I-CDs to process strong triple antioxidant nanozyme activities rather than Cu,Zn-CDs. Vitro experiments displayed that the Cu,Zn,I-CDs could scavenge the excessive ROS to protect cellular against oxidative stress and reduce the expression of proinflammatory cytokines, such as TNF-α, IL-1β, and IL-6. In sodium dextran sulfate (DSS)-induced colitis mice models, Cu,Zn,I-CDs with excellent biocompatibility could effectively relieve the inflammation of the colon, containing the reduction of the colon length, the damaged epithelium, the infiltration of inflammatory cells, and upregulation of antioxidant genes. Therefore, the therapy of Cu,Zn,I-CD antioxidant nanozymes is an effective approach and provides a novel strategy for UC treatment.

One-step thermal oxidation synthesis of carbon-doped TiO2 with enhanced photocatalytic activity using CO2 as the carbon source

The study proposed a simplified carbon doping synthesis strategy to enhance the photocatalytic activity of titanium dioxide (TiO2). Utilizing CO2 gas as the carbon source, the material was directly synthesized onto a titanium substrate through a one-step thermal oxidation method. Raman and XPS analyses indicated that with the increase in CO2 partial pressure, the influence of the carbon source was amplified, resulting in carbon doping in a graphite-like structure and the induction of oxygen vacancies. Electrochemical impedance spectroscopy and UV–vis spectra demonstrated that the introduced carbon species acted as a photosensitizer, augmenting the transfer of photogenerated carriers. Photoluminescence spectra suggested that oxygen vacancies could enhance the non-radiative scattering of photogenerated carriers. These two effects synergistically improved the photocatalytic activity of TiO2 significantly, although the degree of enhancement was dependent on the optimized ratio of carbon content to oxygen vacancy content. Only with optimal carbon content and oxygen vacancy levels could the undesired radiative recombination of photogenerated carriers be prevented, ensuring that the energy derived from visible light was effectively utilized to drive chemical reactions. Under these optimal conditions, the TC-O5 and TC-O10 samples exhibited excellent photocatalytic degradation performance of methyl orange under visible light, with degradation rates of 86.27% and 82.54%, respectively, and displayed outstanding cycling stability, with the degradation rate remaining above 90% for three cycles. This method proved to be simple, efficient, and easily operable, offering significant advantages for industrial-scale preparation.

Boosting anions storage via union of in-situ N doping and mesoporous hollow hard carbon nanospheres for advanced dual-ion capacitors

High structural strength in-situ N-doped mesoporous hollow hard carbon nanospheres (NMHS) is prepared to overcome the low anions storage capacity (93 mAh g−1) of easy exfoliated graphite for dual-ion capacitors (DICs). The rich mesoporous structure facilitates the anions diffusion, and the hollow cavity provides expansion space in storage and weakens the high diffusion resistance in the nuclear bulge. With the synergistic effect, The NMHS delivers a high reversible capacity of 100 mAh g−1 with a low decay of 8 % over 5000 cycles at 2 A g−1. In-situ Raman reveals the storage mechanism on hard carbon is “adsorption (major)-intercalation (minor)”. DFT calculations decode the effective storage action of graphitic N and pyridinic N. Consequently, the assembled NMHS-DICs exhibit good long-cycle performance and heterotherm stability, providing a high energy/power density of 200 Wh kg−1 and 11858 W kg−1. This work verifies a feasible cathode design strategy with future application potential on DICs.