Zinc telluride(ZnTe)with high density and low cost is considered as promising anode for sodium-ion batteries.However,ZnTe suffers from continuous capacity degradation owing to the low electronic conductivity,large vol...Zinc telluride(ZnTe)with high density and low cost is considered as promising anode for sodium-ion batteries.However,ZnTe suffers from continuous capacity degradation owing to the low electronic conductivity,large volume expansion,and high ion-diffusion energy barriers.Herein,the nitrogen-doped carbon confined ZnTe polyhedron heterostructure(ZnTe/NC)is proposed,exploiting its orbital rehybridization and the realignment of energy level to improve storage performance.Systematic ex situ/in situ characterizations and simulations demonstrated that the elaborate ZnTe/NC offers abundant electron/ion transport pathways,accelerates Na^(+)diffusion kinetics,and alleviates huge volume expansion.Notably,the nitrogen-doped carbon-support interaction induced via electron transfer between ZnTe sites and support elevates the energy level of Zn 3d orbital,greatly enhancing ion adsorption capability and reducing the ion diffusion barrier.As a result,the ZnTe/NC anode delivers a high discharge capacity of 470.5 mAh g^(−1)and long cycling durability over 1000 cycles.This work uncovers that optimizing sodium ion adsorption and diffusion via d-orbital energy level modulation enabled by nitrogen-doped support interaction is an effective method for developing high-performance transition metal telluride anodes for alkali ion storage.展开更多
Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(...Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.展开更多
Traditionally reduced graphene oxide(RGO)-based electromagnetic wave(EMW)absorbing materials have poor absorption effectiveness due to impedance mismatch caused by skin effect.The introduction of structural defects an...Traditionally reduced graphene oxide(RGO)-based electromagnetic wave(EMW)absorbing materials have poor absorption effectiveness due to impedance mismatch caused by skin effect.The introduction of structural defects and the design of heterogeneous interfaces play a crucial role in enhancing the polarization effect of EMW absorbers.In this study,nitrogen-doped reduced graphene oxide/zinc ferrite@nitrogen-doped carbon(NRGO/ZnFe_(2)O_(4)@NC)ternary composite with rich heterogeneous interfaces is constructed by combining solvothermal reaction,in-situ polymerization,annealing treatment with subsequent hydrothermal reaction.The research results have shown that the obtained NRGO/ZnFe_(2)O_(4)@NC ternary composite exhibits a unique core-shell structure and excellent EMW absorption performance.At a thickness of 2.61 mm,the maximum effective absorption bandwidth can reach 7.2 GHz,spanning the entire Ku-band and a portion of the X-band,and the minimum reflection loss is-61.1 dB,which is superior to most reported RGO-based EMW absorbers.The excellent EMW absorbing ability is mainly ascribed to the optimized impedance matching and the enhanced polarization loss caused by the abundant heterogeneous interfaces and structural defects derived from heteroatomic nitrogen doping.Furthermore,the radar cross section in the far field is simulated by a computer simulation technique.This study provides a novel way to prepare core-shell magnetic carbon composites as highly efficient and broadband EMW absorbers.展开更多
Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NH...Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NHMC/Ni/NiO)nanocomposite for developing high-capacity LIBs anode materials through carbonization and selective etching strategies.The synthesized NMHC/Ni/NiO-0.33 composite exhibited a highly regular microstructure with well-dispersed Ni/NiO particles.The composite had a surface area of 408 m^(2)·g^(−1),a mesopore ratio of 75.0%,and a pyridine–nitrogen ratio of 58.9%.The introduction of nitrogen atoms reduced the disordered structure of lignin mesoporous carbon and enhanced its electrical conductivity,thus improving the lithium storage capabilities of the composite.Following 100 cycles at a current density of 0.2 A·g^(−1),the composite demonstrated enhanced Coulomb efficiency and rate performance,achieving a specific discharge capacity of 1230.9 mAh·g^(−1).At a high-current density of 1 A·g^(−1),the composite exhibited an excellent specific discharge capacity of 714.6 mAh·g^(−1).This study presents an innovative method for synthesizing high-performance anode materials of LIBs.展开更多
Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compa...Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compatibility with industrial processes.Graphene is chemically inert and has a zero-bandgap which poses a problem for its use as a functional layer,and nitrogen doping has become an important way to overcome this.Post-plasma treatment has been explored for the synthesis of nitrogen-doped graphene,but the procedures are intricate and not suitable for large-scale production.We report the direct synthesis of nitrogen-doped graphene on a 4-inch sapphire wafer by ethanol-assisted CVD employing pyridine as the carbon feedstock,where the nitrogen comes from the pyridine and the hydroxyl group in ethanol improves the quality of the graphene produced.Additionally,the types of nitrogen dopant produced and their effects on III-nitride epitaxy were also investigated,resulting in the successful illumination of LED devices.This work presents an effective synthesis strategy for the preparation of nitrogen-doped graphene,and provides a foundation for designing graphene functional layers in optoelectronic devices.展开更多
Development of efficient and stable metal catalysts for the selective aqueous phase hydrodeoxygenation(HDO)of biomass-derived oxygenates to value-added biofuels is highly desired.An innovative surface microenvironment...Development of efficient and stable metal catalysts for the selective aqueous phase hydrodeoxygenation(HDO)of biomass-derived oxygenates to value-added biofuels is highly desired.An innovative surface microenvironment modulation strategy was used to construct the nitrogen-doped hollow carbon sphere encapsulated with Pd(Pd@NHCS-X,X:600–800)nanoreactors for catalytic HDO of biomass-derived vanillin in water.The specific surface microenvironments of Pd@NHCS catalysts including the electronic property of active Pd centers and the surface wettability and porous structure of NHCS supports could be well-controlled by the calcination temperature of catalysts.Intrinsic kinetic evaluations demonstrated that the Pd@NHCS-600 catalyst presented a high turnover frequency of 337.77 h^(–1)and a low apparent activation energy of 18.63 kJ/mol.The excellent catalytic HDO performance was attributed to the unique surface microenvironment of Pd@NHCS catalyst based on structure-performance relationship analysis and DFT calculations.It revealed that pyridinic N species dominated the electronic property regulation of Pd sites through electronic metal-support interaction(EMSI)and produced numerous electron-rich active Pd centers,which not only intensified the dissociation and activation of H2 molecules,but also substantially improved the activation capability of vanillin via the enhanced adsorption of–C=O group.The fine hydrophilicity and abundant porous structure promoted the uniform dispersion of catalyst and ensured the effective access of reactants to catalytic active centers in water.Additionally,the Pd@NHCS-600 catalyst exhibited excellent catalytic stability and broad substrate applicability for the selective aqueous phase HDO of various biomass-derived carbonyl compounds.The proposed surface microenvironment modulation strategy will provide a new consideration for the rational design of high-performance nitrogen-doped carbon-supported metal catalysts for catalytic biomass transformation.展开更多
We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanopartic...We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanoparticles(NPs)predominantly exposing{200}facets,termed Pd/CN11-2.This facet-specific configuration significantly boosted hydrogen adsorption,leading to notable improvements in catalytic activity.Compared to Pd/XC-72-2 and Pd/g-C_(3)N_(4)-2,Pd/CN11-2 exhibited a remarkable two-fold and nineteen-fold increase in catalytic yield for hydrazo compound hydrogenation,respectively.Pd/CN11-2 also demonstrated robust performance across a range of reaction conditions,maintaining excellent yield.This study emphasizes the critical role of tailored support structures in controlling Pd NPs facets,thereby enhancing hydrogenation efficiency.It provides valuable insights for advancing the industrial application of Pd-based catalysts,underscoring the importance of strategic support modulation for optimizing catalytic performance.展开更多
Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost...Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost-effective electrocatalysts for oxygen redox reactions(OER and ORR).Herein,we report Co/Fe carbon-supported composites as efficient bifunctional catalyst encapsulated in oxidative ammonolysis modified lignin-derived N-doped biochar(Co Fe-Co_(x)N@NOALC).It exhibited exceptional electrochemical performance in aqueous ZAB owing to their uniform dispersed and small particle size,with a peak power density of 154 mW/cm^(2)and a specific capacity of 770 mAh/g.Most notably,it exhibited a long cycle stability,surpassing 1500 h at a current density of 10 mA/cm^(2),with a mere 11.4%decrease in the chargedischarge efficiency of the battery.This study proposes a viable strategy for enhancing the performance and reducing the cost of Zn-air batteries through the utilization of biomass-derived materials.展开更多
Solar-induced water oxidation reaction(WOR)for oxygen evolution is a critical step in the transformation of Earth's atmosphere from a reducing to an oxidation one during its primordial stages.WOR is also associate...Solar-induced water oxidation reaction(WOR)for oxygen evolution is a critical step in the transformation of Earth's atmosphere from a reducing to an oxidation one during its primordial stages.WOR is also associated with important reduction reactions,such as oxygen reduction reaction(ORR),which leads to the production of hydrogen peroxide(H_(2)O_(2)).These transitions are instrumental in the emergence and evolution of life.In this study,transition metals were loaded onto nitrogen-doped carbon(NDC)prepared under the primitive Earth's atmospheric conditions.These metal-loaded NDC samples were found to catalyze both WOR and ORR under light illumination.The chemical pathways initiated by the pristine and metal-loaded NDC were investigated.This study provides valuable insights into potential mechanisms relevant to the early evolution of our planet.展开更多
Utilizing nitrate(NO_(3)^(-))as the nitrogen source to produce ammonia can effectively remove NO_(3)^(-)pollutant while obtaining valuable ammonia,and the understanding of the mechanisms is essential for the design of...Utilizing nitrate(NO_(3)^(-))as the nitrogen source to produce ammonia can effectively remove NO_(3)^(-)pollutant while obtaining valuable ammonia,and the understanding of the mechanisms is essential for the design of new catalysts.In this work,by using density functional theory calculations,the electroreduction mechanisms of nitrate reduction reaction(NO_(3)RR)on transition metal single atom supported on 3N-coordinated N-doped graphene(TM/N_(3)-G)are systematically investigated.It is found that the protonation of ^(*)OH acts as the potential determing steps except for the traditionally considered ^(*)NO_(3)/^(*)NO/^(*)NO_(2) protonation step and the desorption of water may play an important role for NO_(3)RR on some TM/N_(3)-G.By considering the stability of single-atom catalyst(SAC),the preferential adsorption of NO_(3)^(-)larger than H and H_(2)O,the limiting potential of whole NO_(3)RR,the selectivity toward NH3,V(Mn,Os)/pyrrolic-N_(3)-G and Mn(Ru,Ir)/pyridinic-N_(3)-G are screened out as potential SACs for NO_(3)RR.This work provides an understanding of the NO_(3)RR mechanism and highlights several promising NO_(3)RR catalysts based on the TM/N_(3)-G system.展开更多
The recycling of plastics is a significant global concern.Due to the thermosetting properties of melamineformaldehyde(MF)resin plastics,which make heating and melting difficult,their recycling and reuse pose substanti...The recycling of plastics is a significant global concern.Due to the thermosetting properties of melamineformaldehyde(MF)resin plastics,which make heating and melting difficult,their recycling and reuse pose substantial challenges.In this study,we developed nitrogen-doped(N-doped)carbon materials through scalable carbonization of MF resin plastic waste.This metal-free N-doped carbon catalyst achieved a hydrogen peroxide(H_(2)O_(2))production rate of 971.6 mmol gcatalyst^(-1)h^(-1)with a Faradaic efficiency for H_(2)O_(2)(FEH_(2)O_(2))exceeding 90%under acidic conditions.Additionally,a flow cell utilizing this carbon catalyst demonstrated a production rate of 11.3 mol cm^(-2)h^(-1)(22.5 mol g_(catalyst)^(-1)h^(-1))and maintained a record-high current density of approximately 530 mA cm^(-2)over 300 h.In-situ electrochemical surface-enhanced Raman spectroscopy and density functional theory calculations revealed the presence of porphyrin-like carbon defects,which serve as active sites for the continuous and stable generation of^(*)OOH species.The nitrogen-doped carbon materials obtained from large-scale carbonization of MF plastic waste exhibit abundant active sites,making them highly promising electrocatalysts for the two-electron oxygen reduction reaction(2e^(-)ORR).展开更多
Hierarchical nitrogen-doped carbon nanocages （hNCNC） with large specific surface areas were used as a catalyst support to immobilize Pt nanoparticles by a microwave-assisted polyol method. The Pt/hNCNC catalyst with...Hierarchical nitrogen-doped carbon nanocages （hNCNC） with large specific surface areas were used as a catalyst support to immobilize Pt nanoparticles by a microwave-assisted polyol method. The Pt/hNCNC catalyst with 20 wt% loading has a homogeneous dispersion of Pt nanoparticles with the average size of 3.3 nm, which is smaller than 4.3 and 4.9 nm for the control catalysts with the same loading supported on hierarchical carbon nanocages （hCNC） and commercial Vulcan XC-72, respec- tively. Accordingly, Pt/hNCNC has a larger electrochemical surface area than Pt/hCNC and Pt/XC-72. The Pt/hNCNC catalyst exhibited excellent electrocatalytic activity and stability for methanol oxidation, which was better than the control catalysts. This was attributed to the en- hanced interaction between Pt and hNCNC due to nitrogen participation in the anchoring function. By making use of the unique advantages of the hNCNC support, a heavy Pt loading up to 60 wt% was prepared without serious agglomeration, which gave a high peak-current density per unit mass of catalyst of 95.6 mA/mg for achieving a high power density. These results showed the potential of the Pt/hNCNC catalyst for methanol oxidation and of the new hNCNC support for wide applications.展开更多
The oxygen reduction reaction （ORR） is traditionally performed using noble‐metals catalysts, e.g. Pt. However, these metal‐based catalysts have the drawbacks of high costs, low selectivity, poor stabili‐ties, and...The oxygen reduction reaction （ORR） is traditionally performed using noble‐metals catalysts, e.g. Pt. However, these metal‐based catalysts have the drawbacks of high costs, low selectivity, poor stabili‐ties, and detrimental environmental effects. Here, we describe metal‐free nitrogen‐doped carbon nanoblocks （NCNBs） with high nitrogen contents （4.11%）, which have good electrocatalytic proper‐ties for ORRs. This material was fabricated using a scalable, one‐step process involving the pyrolysis of tris（hydroxymethyl）aminomethane （Tris） at 800℃. Rotating ring disk electrode measurements show that the NCNBs give a high electrocatalytic performance and have good stability in ORRs. The onset potential of the catalyst for the ORR is-0.05 V （vs Ag/AgCl）, the ORR reduction peak potential is-0.20 V （vs Ag/AgCl）, and the electron transfer number is 3.4. The NCNBs showed pronounced electrocatalytic activity, improved long‐term stability, and better tolerance of the methanol crosso‐ver effect compared with a commercial 20 wt%Pt/C catalyst. The composition and structure of, and nitrogen species in, the NCNBs were investigated using Fourier‐transform infrared spectroscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, and X‐ray diffraction. The pyroly‐sis of Tris at high temperature increases the number of active nitrogen sites, especially pyridinic nitrogen, which creates a net positive charge on adjacent carbon atoms, and the high positive charge promotes oxygen adsorption and reduction. The results show that NCNBs prepared by pyrolysis of Tris as nitrogen and carbon sources are a promising ORR catalyst for fuel cells.展开更多
Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air...Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.展开更多
Phosphate residue is regarded as a hazardous waste, which could potentially create significant environmental and health problems if it is not properly treated and disposed of. In this study, nitrogen-doped carbon nano...Phosphate residue is regarded as a hazardous waste, which could potentially create significant environmental and health problems if it is not properly treated and disposed of. In this study, nitrogen-doped carbon nanotubes-FePO_4(NCNTs-FePO_4) composite was successfully synthesized from phosphate residue, and its application as an effective catalyst was explored. Firstly, an effective method was developed to recover FePO_4 from phosphate residue, achieving an impressive FePO_4 mass recovery rate of 98.14%. Then, the NCNTsFePO_4 catalyst was synthesized from the recovered FePO_4 by two main reactions, including surface modification and chemical vapor deposition. Finally, the synthesized NCNTs-FePO_4 was applied to photo-degrade 15 mg/L Rhodamine B(RhB) in a Fenton-like system. The results showed that 98.9% of RhB could be degraded in 60 min, closely following the pseudofirst-order kinetics model. It was found that even after six consecutive cycles, NCNTs-FePO_4 still retained a high catalytic capacity(>50%). Moreover, ·OH radicals participating in the RhB degradation process were evidenced using quenching experiments and electron paramagnetic resonance analysis, and a rational mechanism was proposed. It was demonstrated that the materials synthesized from hazardous phosphate residue can be used as an effective catalyst for dye removal.展开更多
Porous nitrogen-doped carbon is an especially promising material energy storage due to its excellentconductivity, stable physicochemical properties, easy processability, controllable porosity and low price.Herein, we ...Porous nitrogen-doped carbon is an especially promising material energy storage due to its excellentconductivity, stable physicochemical properties, easy processability, controllable porosity and low price.Herein, we reported a novel well-designed hierarchically porous nitrogen-doped carbon （HPNC） via acombination of salt template （ZnC12） and hard template （SiO2） as sulfur host for lithium-sulfur batter-ies. The low-melting ZnC12 is boiled off and leaves behind micropores and small size mesopores duringpyrolysis process, while the silica spheres are removed by acid leaching to generate interconnected 3Dnetwork of macropores. The HPNC-S electrode exhibits an initial specific capacity of 1355 mAh g^-l at 0.IC （IC= 1675 mAh g^-1 ）, a high-rate capability of 623 mAh g-l at 2 C, and a small decay of 0.13% per cycleover 300 cycles at 0.2 C. This excellent rate capability and remarkable long-term cyclability of the HPNC-Selectrode are attributed to its hierarchical porous structures for confining the soluble lithium polysulfideas well as the nitrogen doping for high absorbability of lithium polysulfide.展开更多
High-value reclamation of metal-polluted plants involved in phytoremediation is a big challenge.In this study,nitrogen-doped nanoporous carbon with large specific area of 2359.1 m^(2)g^(-1) is facilely fabricated from...High-value reclamation of metal-polluted plants involved in phytoremediation is a big challenge.In this study,nitrogen-doped nanoporous carbon with large specific area of 2359.1 m^(2)g^(-1) is facilely fabricated from metal-polluted miscanthus waste for efficient energy storage.The synergistic effect of KOH,urea and ammonia solution greatly improve the nitrogen quantity and surface area of the synthesized carbon.Electrodes fabricated with this carbon exhibit the excellent capacitance performance of 340.2 F g^(-1) at 0.5 A g^(-1) and a low combined resistance of 0.116Ω,which are competitive with most of previously reported carbon-based electrodes.In addition,the as-obtained carbon electrode shows a high specific capacitance retention of over 99.6%even after 5000 cycles.Furthermore,the symmetric supercapacitor fabricated using the synthesized carbon achieves a superior energy density of 25.3 Wh kg^(-1)(at 400 W kg^(-1))in 1 mol L^(-1) Na_(2)SO_(4)aqueous solution.This work provides an efficient route to upcycle metal-polluted plant waste for supercapacitor applications.展开更多
Potassium-ion batteries(KIBs)have great potential for applications in large-scale energy storage devices.However,the larger radius of K+leads to sluggish kinetics and inferior cycling performance,severely restricting ...Potassium-ion batteries(KIBs)have great potential for applications in large-scale energy storage devices.However,the larger radius of K+leads to sluggish kinetics and inferior cycling performance,severely restricting its practical applicability.Herein,we propose a rational strategy involving a Prussian blue analogue-derived graphitized carbon anode with fast and durable potassium storage capability,which is constructed by encapsulating cobalt nanoparticles in nitrogen-doped graphitized carbon(Co-NC).Both experimental and theoretical results show that N-doping effectively promotes the uniform dispersion of cobalt nanoparticles in the carbon matrix through Co-N bonds.Moreover,the cobalt nanoparticles and strong Co-N bonds synergistically form a threedimensional conductive network,increase the number of adsorption sites,and reduce the diffusion energy barrier,thereby facilitating the adsorption and the diffusion kinetics.These multiple effects lead to enhanced reversible capacities of 305 and 208.6 mAh g^−1 after 100 and 300 cycles at 0.05 and 0.1 A g^−1,respectively,demonstrating the applicability of the Co-NC anode for KIBs.展开更多
Direct electrochemical formation of hydrogen peroxide（H2O2） from pure O2 and H2on cheap metal-free earth abundant catalysts has emerged as the highest atom-efficient and environmentally friendly reaction pathway and...Direct electrochemical formation of hydrogen peroxide（H2O2） from pure O2 and H2on cheap metal-free earth abundant catalysts has emerged as the highest atom-efficient and environmentally friendly reaction pathway and is therefore of great interest from an academic and industrial point of view. Very recently,novel metal-free mesoporous nitrogen-doped carbon catalysts have attracted large attention due to the unique reactivity and selectivity for the electrochemical hydrogen peroxide formation [1–3]. In this work,we provide deeper insights into the electrocatalytic activity, selectivity and durability of novel metal-free mesoporous nitrogen-doped carbon catalyst for the peroxide formation with a particular emphasis on the influence of experimental reaction parameters such as p H value and electrode potential for three different electrolytes. We used two independent approaches for the investigation of electrochemical hydrogen peroxide formation, namely rotating ring-disk electrode（RRDE） technique and photometric UV–VIS technique. Our electrochemical and photometric results clearly revealed a considerable peroxide formation activity as well as high catalyst durability for the metal-free nitrogen-doped carbon catalyst material in both acidic as well as neutral medium at the same electrode potential under ambient temperature and pressure. In addition, the obtained electrochemical reactivity and selectivity indicate that the mechanisms for the electrochemical formation and decomposition of peroxide are strongly dependent on the p H value and electrode potential.展开更多
Aniline,pyrrole and phenanthroline,which have different nitrogen compositions,are used as carbon precursors to synthesize nitrogen-doped ordered mesoporous carbons（NOMCs） by the nanocasting method.The effect of the ...Aniline,pyrrole and phenanthroline,which have different nitrogen compositions,are used as carbon precursors to synthesize nitrogen-doped ordered mesoporous carbons（NOMCs） by the nanocasting method.The effect of the precursor on the resultant NOMC is extensively investigated by nitrogen adsorption-desorption measurements,scanning electron microscopy,X-ray photoelectron spectroscopy（XPS）,cyclic voltammetry and rotating ring-disk electrode measurements.Salient findings are as follows.First,the precursor has a significant influence on the specific surface area and textural properties.The NOMC materials derived from pyrrole（C-PY-900：765 m^2/） and phenanthroline（C-Phen-900：746 m^2/） exhibit higher specific surface areas than the aniline analog（C-PA-900：569 m^2/）.Second,the XPS results indicate that the total nitrogen content（ca.3.1–3.3 at%） is similar for the three carbon sources,except for a slight difference in the nitrogen configuration.Furthermore,the content of the nitrogen-activated carbon atoms is found to closely depend on the precursor,which is the highest for the phenanthroline-derived carbon.Third,the electrochemical results reveal that the electrocatalytic activity follows in the order C-PA-900 C-PY-900 C-Phen-900,confirming that the nitrogen-activated carbon atoms are the active sites for the oxygen reduction reaction（ORR）.In summary,the precursor has considerable influence on the composition and textural properties of the NOMC materials,of which the ORR electrocatalytic activity can be enhanced through optimization of the NOMCs.展开更多
基金supported by the National Natural Science Foundation of China(52402298,52172224,52302240)Science and Technology Correspondent Project of Tianjin(24YDTPJC00240)+1 种基金the Macao Young Scholars Program(AM2023011)the Yuanguang Scholars Program,Hebei University of Technology(282022554).
文摘Zinc telluride(ZnTe)with high density and low cost is considered as promising anode for sodium-ion batteries.However,ZnTe suffers from continuous capacity degradation owing to the low electronic conductivity,large volume expansion,and high ion-diffusion energy barriers.Herein,the nitrogen-doped carbon confined ZnTe polyhedron heterostructure(ZnTe/NC)is proposed,exploiting its orbital rehybridization and the realignment of energy level to improve storage performance.Systematic ex situ/in situ characterizations and simulations demonstrated that the elaborate ZnTe/NC offers abundant electron/ion transport pathways,accelerates Na^(+)diffusion kinetics,and alleviates huge volume expansion.Notably,the nitrogen-doped carbon-support interaction induced via electron transfer between ZnTe sites and support elevates the energy level of Zn 3d orbital,greatly enhancing ion adsorption capability and reducing the ion diffusion barrier.As a result,the ZnTe/NC anode delivers a high discharge capacity of 470.5 mAh g^(−1)and long cycling durability over 1000 cycles.This work uncovers that optimizing sodium ion adsorption and diffusion via d-orbital energy level modulation enabled by nitrogen-doped support interaction is an effective method for developing high-performance transition metal telluride anodes for alkali ion storage.
基金financially supported by National Natural Science Foundation of China(22466010)Guizhou Provincial Basic Research Program(Natural Science)ZK[2023]47 and key program ZD[2025]075+6 种基金Innovation and Entrepreneurship Project for overseas Talents in Guizhou Province[2022]02Specific Natural Science Foundation of Guizhou University(X202207)the national undergraduate innovation and entrepreneurship training program(gzugc2023006gzusc2024012)SRT project of Guizhou university(2023SRT0292023SRT024)supported by Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University。
文摘Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.
基金supported by the Open Research Fund Program of Engineering Technology Research Center of Coal Resources Comprehensive Utilization,Anhui Province,Anhui University of Science and Technology(Grant No.MTYJZX202301)the Anhui Provincial Natural Science Foundation(Grant No.2008085J27).
文摘Traditionally reduced graphene oxide(RGO)-based electromagnetic wave(EMW)absorbing materials have poor absorption effectiveness due to impedance mismatch caused by skin effect.The introduction of structural defects and the design of heterogeneous interfaces play a crucial role in enhancing the polarization effect of EMW absorbers.In this study,nitrogen-doped reduced graphene oxide/zinc ferrite@nitrogen-doped carbon(NRGO/ZnFe_(2)O_(4)@NC)ternary composite with rich heterogeneous interfaces is constructed by combining solvothermal reaction,in-situ polymerization,annealing treatment with subsequent hydrothermal reaction.The research results have shown that the obtained NRGO/ZnFe_(2)O_(4)@NC ternary composite exhibits a unique core-shell structure and excellent EMW absorption performance.At a thickness of 2.61 mm,the maximum effective absorption bandwidth can reach 7.2 GHz,spanning the entire Ku-band and a portion of the X-band,and the minimum reflection loss is-61.1 dB,which is superior to most reported RGO-based EMW absorbers.The excellent EMW absorbing ability is mainly ascribed to the optimized impedance matching and the enhanced polarization loss caused by the abundant heterogeneous interfaces and structural defects derived from heteroatomic nitrogen doping.Furthermore,the radar cross section in the far field is simulated by a computer simulation technique.This study provides a novel way to prepare core-shell magnetic carbon composites as highly efficient and broadband EMW absorbers.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22278092,22078116 and 22222805)Guangdong Provincial Key Research and Development Program(No.2020B1111380002)+2 种基金Science and Technology Research Project of Guangzhou(Nos.2023A03J0034,2023A04J0077 and 202102020467)State Key Laboratory of Pulp and Paper Engineering(No.202313)Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.202255464).
文摘Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NHMC/Ni/NiO)nanocomposite for developing high-capacity LIBs anode materials through carbonization and selective etching strategies.The synthesized NMHC/Ni/NiO-0.33 composite exhibited a highly regular microstructure with well-dispersed Ni/NiO particles.The composite had a surface area of 408 m^(2)·g^(−1),a mesopore ratio of 75.0%,and a pyridine–nitrogen ratio of 58.9%.The introduction of nitrogen atoms reduced the disordered structure of lignin mesoporous carbon and enhanced its electrical conductivity,thus improving the lithium storage capabilities of the composite.Following 100 cycles at a current density of 0.2 A·g^(−1),the composite demonstrated enhanced Coulomb efficiency and rate performance,achieving a specific discharge capacity of 1230.9 mAh·g^(−1).At a high-current density of 1 A·g^(−1),the composite exhibited an excellent specific discharge capacity of 714.6 mAh·g^(−1).This study presents an innovative method for synthesizing high-performance anode materials of LIBs.
基金National Natural Science Foundation of China(T2188101)。
文摘Among the synthesis techniques for graphene,chemical vapor deposition(CVD)enables the direct growth of graphene films on insulating substrates.Its advantages include uniform coverage,high quality,scalability,and compatibility with industrial processes.Graphene is chemically inert and has a zero-bandgap which poses a problem for its use as a functional layer,and nitrogen doping has become an important way to overcome this.Post-plasma treatment has been explored for the synthesis of nitrogen-doped graphene,but the procedures are intricate and not suitable for large-scale production.We report the direct synthesis of nitrogen-doped graphene on a 4-inch sapphire wafer by ethanol-assisted CVD employing pyridine as the carbon feedstock,where the nitrogen comes from the pyridine and the hydroxyl group in ethanol improves the quality of the graphene produced.Additionally,the types of nitrogen dopant produced and their effects on III-nitride epitaxy were also investigated,resulting in the successful illumination of LED devices.This work presents an effective synthesis strategy for the preparation of nitrogen-doped graphene,and provides a foundation for designing graphene functional layers in optoelectronic devices.
文摘Development of efficient and stable metal catalysts for the selective aqueous phase hydrodeoxygenation(HDO)of biomass-derived oxygenates to value-added biofuels is highly desired.An innovative surface microenvironment modulation strategy was used to construct the nitrogen-doped hollow carbon sphere encapsulated with Pd(Pd@NHCS-X,X:600–800)nanoreactors for catalytic HDO of biomass-derived vanillin in water.The specific surface microenvironments of Pd@NHCS catalysts including the electronic property of active Pd centers and the surface wettability and porous structure of NHCS supports could be well-controlled by the calcination temperature of catalysts.Intrinsic kinetic evaluations demonstrated that the Pd@NHCS-600 catalyst presented a high turnover frequency of 337.77 h^(–1)and a low apparent activation energy of 18.63 kJ/mol.The excellent catalytic HDO performance was attributed to the unique surface microenvironment of Pd@NHCS catalyst based on structure-performance relationship analysis and DFT calculations.It revealed that pyridinic N species dominated the electronic property regulation of Pd sites through electronic metal-support interaction(EMSI)and produced numerous electron-rich active Pd centers,which not only intensified the dissociation and activation of H2 molecules,but also substantially improved the activation capability of vanillin via the enhanced adsorption of–C=O group.The fine hydrophilicity and abundant porous structure promoted the uniform dispersion of catalyst and ensured the effective access of reactants to catalytic active centers in water.Additionally,the Pd@NHCS-600 catalyst exhibited excellent catalytic stability and broad substrate applicability for the selective aqueous phase HDO of various biomass-derived carbonyl compounds.The proposed surface microenvironment modulation strategy will provide a new consideration for the rational design of high-performance nitrogen-doped carbon-supported metal catalysts for catalytic biomass transformation.
基金supported by the National Natural Science Foundation of China(21503264,22179081 and 22076117)Natural Science Foundation of Shanghai(20ZR1422500).
文摘We synthesized CN11,a carbon nitride material rich in sp^(3)hybrid graphitic nitrogen(sp^(3)-N),employing a facile oxalic acid-assisted melamine molecular assembly strategy.CN11 promoted the formation of Pd nanoparticles(NPs)predominantly exposing{200}facets,termed Pd/CN11-2.This facet-specific configuration significantly boosted hydrogen adsorption,leading to notable improvements in catalytic activity.Compared to Pd/XC-72-2 and Pd/g-C_(3)N_(4)-2,Pd/CN11-2 exhibited a remarkable two-fold and nineteen-fold increase in catalytic yield for hydrazo compound hydrogenation,respectively.Pd/CN11-2 also demonstrated robust performance across a range of reaction conditions,maintaining excellent yield.This study emphasizes the critical role of tailored support structures in controlling Pd NPs facets,thereby enhancing hydrogenation efficiency.It provides valuable insights for advancing the industrial application of Pd-based catalysts,underscoring the importance of strategic support modulation for optimizing catalytic performance.
基金sponsored by the National Natural Science Foundation of China(Nos.U23A6005 and 22178069)。
文摘Zn-air battery(ZAB)has garnered significant attention owing to its environmental friendliness and safety attributes.A critical challenge in advancing ZAB technology lies in the development of high-performance and cost-effective electrocatalysts for oxygen redox reactions(OER and ORR).Herein,we report Co/Fe carbon-supported composites as efficient bifunctional catalyst encapsulated in oxidative ammonolysis modified lignin-derived N-doped biochar(Co Fe-Co_(x)N@NOALC).It exhibited exceptional electrochemical performance in aqueous ZAB owing to their uniform dispersed and small particle size,with a peak power density of 154 mW/cm^(2)and a specific capacity of 770 mAh/g.Most notably,it exhibited a long cycle stability,surpassing 1500 h at a current density of 10 mA/cm^(2),with a mere 11.4%decrease in the chargedischarge efficiency of the battery.This study proposes a viable strategy for enhancing the performance and reducing the cost of Zn-air batteries through the utilization of biomass-derived materials.
基金supported by the National Key Technologies R&D Program of China(Nos.2022YFE0114800 and 2021YFA1502100)National Natural Science Foundation of China(Nos.22075047,22032002,U1905214,21961142019)the 111 Project(Nos.D16008)。
文摘Solar-induced water oxidation reaction(WOR)for oxygen evolution is a critical step in the transformation of Earth's atmosphere from a reducing to an oxidation one during its primordial stages.WOR is also associated with important reduction reactions,such as oxygen reduction reaction(ORR),which leads to the production of hydrogen peroxide(H_(2)O_(2)).These transitions are instrumental in the emergence and evolution of life.In this study,transition metals were loaded onto nitrogen-doped carbon(NDC)prepared under the primitive Earth's atmospheric conditions.These metal-loaded NDC samples were found to catalyze both WOR and ORR under light illumination.The chemical pathways initiated by the pristine and metal-loaded NDC were investigated.This study provides valuable insights into potential mechanisms relevant to the early evolution of our planet.
基金partially supported by the National Natural Science Foundation of China(No.22373092,No.22288201)CAS Project for Young Scientists in Basic Research(YSBR-051)supported by USTC Tang Scholarship。
文摘Utilizing nitrate(NO_(3)^(-))as the nitrogen source to produce ammonia can effectively remove NO_(3)^(-)pollutant while obtaining valuable ammonia,and the understanding of the mechanisms is essential for the design of new catalysts.In this work,by using density functional theory calculations,the electroreduction mechanisms of nitrate reduction reaction(NO_(3)RR)on transition metal single atom supported on 3N-coordinated N-doped graphene(TM/N_(3)-G)are systematically investigated.It is found that the protonation of ^(*)OH acts as the potential determing steps except for the traditionally considered ^(*)NO_(3)/^(*)NO/^(*)NO_(2) protonation step and the desorption of water may play an important role for NO_(3)RR on some TM/N_(3)-G.By considering the stability of single-atom catalyst(SAC),the preferential adsorption of NO_(3)^(-)larger than H and H_(2)O,the limiting potential of whole NO_(3)RR,the selectivity toward NH3,V(Mn,Os)/pyrrolic-N_(3)-G and Mn(Ru,Ir)/pyridinic-N_(3)-G are screened out as potential SACs for NO_(3)RR.This work provides an understanding of the NO_(3)RR mechanism and highlights several promising NO_(3)RR catalysts based on the TM/N_(3)-G system.
基金supported by the National Natural Science Foundation of China(Grant No.22276123,22025505)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(SL2022ZD105)State Key Lab of Metal Matrix Composite。
文摘The recycling of plastics is a significant global concern.Due to the thermosetting properties of melamineformaldehyde(MF)resin plastics,which make heating and melting difficult,their recycling and reuse pose substantial challenges.In this study,we developed nitrogen-doped(N-doped)carbon materials through scalable carbonization of MF resin plastic waste.This metal-free N-doped carbon catalyst achieved a hydrogen peroxide(H_(2)O_(2))production rate of 971.6 mmol gcatalyst^(-1)h^(-1)with a Faradaic efficiency for H_(2)O_(2)(FEH_(2)O_(2))exceeding 90%under acidic conditions.Additionally,a flow cell utilizing this carbon catalyst demonstrated a production rate of 11.3 mol cm^(-2)h^(-1)(22.5 mol g_(catalyst)^(-1)h^(-1))and maintained a record-high current density of approximately 530 mA cm^(-2)over 300 h.In-situ electrochemical surface-enhanced Raman spectroscopy and density functional theory calculations revealed the presence of porphyrin-like carbon defects,which serve as active sites for the continuous and stable generation of^(*)OOH species.The nitrogen-doped carbon materials obtained from large-scale carbonization of MF plastic waste exhibit abundant active sites,making them highly promising electrocatalysts for the two-electron oxygen reduction reaction(2e^(-)ORR).
基金supported by the National Natural Science Foundation of China(21473089,51232003,21373108,51571110,21573107)the Nation-al Basic Research Program of China(973 Program,2013CB932902)+2 种基金Suzhou Science and Technology Projects(ZXG2013025)Changzhou Science and Technology Projects(CE20130032)supported by a Project Funded by the Technology Support Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Hierarchical nitrogen-doped carbon nanocages （hNCNC） with large specific surface areas were used as a catalyst support to immobilize Pt nanoparticles by a microwave-assisted polyol method. The Pt/hNCNC catalyst with 20 wt% loading has a homogeneous dispersion of Pt nanoparticles with the average size of 3.3 nm, which is smaller than 4.3 and 4.9 nm for the control catalysts with the same loading supported on hierarchical carbon nanocages （hCNC） and commercial Vulcan XC-72, respec- tively. Accordingly, Pt/hNCNC has a larger electrochemical surface area than Pt/hCNC and Pt/XC-72. The Pt/hNCNC catalyst exhibited excellent electrocatalytic activity and stability for methanol oxidation, which was better than the control catalysts. This was attributed to the en- hanced interaction between Pt and hNCNC due to nitrogen participation in the anchoring function. By making use of the unique advantages of the hNCNC support, a heavy Pt loading up to 60 wt% was prepared without serious agglomeration, which gave a high peak-current density per unit mass of catalyst of 95.6 mA/mg for achieving a high power density. These results showed the potential of the Pt/hNCNC catalyst for methanol oxidation and of the new hNCNC support for wide applications.
基金supported by the National Natural Science Foundation of China (21375088,21575090)Scientific Research Project of Beijing Educational Committee (KM201410028006)+1 种基金Scientific Research Base Development Program of the Beijing Municipal Commission of EducationYouth Talent Project of the Beijing Municipal Commission of Education (CIT & TCD201504072)~~
文摘The oxygen reduction reaction （ORR） is traditionally performed using noble‐metals catalysts, e.g. Pt. However, these metal‐based catalysts have the drawbacks of high costs, low selectivity, poor stabili‐ties, and detrimental environmental effects. Here, we describe metal‐free nitrogen‐doped carbon nanoblocks （NCNBs） with high nitrogen contents （4.11%）, which have good electrocatalytic proper‐ties for ORRs. This material was fabricated using a scalable, one‐step process involving the pyrolysis of tris（hydroxymethyl）aminomethane （Tris） at 800℃. Rotating ring disk electrode measurements show that the NCNBs give a high electrocatalytic performance and have good stability in ORRs. The onset potential of the catalyst for the ORR is-0.05 V （vs Ag/AgCl）, the ORR reduction peak potential is-0.20 V （vs Ag/AgCl）, and the electron transfer number is 3.4. The NCNBs showed pronounced electrocatalytic activity, improved long‐term stability, and better tolerance of the methanol crosso‐ver effect compared with a commercial 20 wt%Pt/C catalyst. The composition and structure of, and nitrogen species in, the NCNBs were investigated using Fourier‐transform infrared spectroscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, and X‐ray diffraction. The pyroly‐sis of Tris at high temperature increases the number of active nitrogen sites, especially pyridinic nitrogen, which creates a net positive charge on adjacent carbon atoms, and the high positive charge promotes oxygen adsorption and reduction. The results show that NCNBs prepared by pyrolysis of Tris as nitrogen and carbon sources are a promising ORR catalyst for fuel cells.
基金financially supported by the National Natural Science Foundation of China (Nos. 21506081, 21705058, 21676126)the Provincial Natural Science Foundation of Jiangsu (Nos. BK20170524, BK20160492)+2 种基金China Postdoctoral Science Foundation (No. 2018T110450)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsThe financial support from an ARC Discovery Project (No. DP180102003)
文摘Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.
基金supported by the Science and Technology Development Foundation of Pudong New Area (No.PKJ2014Z03)Dawn Program of Shanghai (No.09SG54)+1 种基金Material Science and Engineering Key Subject of Shanghai Polytechnic University (No.XXKZD1601)Gaoyuan Discipline of Shanghai-Environmental Science and Engineering (Resource Recycling Science and Engineering)
文摘Phosphate residue is regarded as a hazardous waste, which could potentially create significant environmental and health problems if it is not properly treated and disposed of. In this study, nitrogen-doped carbon nanotubes-FePO_4(NCNTs-FePO_4) composite was successfully synthesized from phosphate residue, and its application as an effective catalyst was explored. Firstly, an effective method was developed to recover FePO_4 from phosphate residue, achieving an impressive FePO_4 mass recovery rate of 98.14%. Then, the NCNTsFePO_4 catalyst was synthesized from the recovered FePO_4 by two main reactions, including surface modification and chemical vapor deposition. Finally, the synthesized NCNTs-FePO_4 was applied to photo-degrade 15 mg/L Rhodamine B(RhB) in a Fenton-like system. The results showed that 98.9% of RhB could be degraded in 60 min, closely following the pseudofirst-order kinetics model. It was found that even after six consecutive cycles, NCNTs-FePO_4 still retained a high catalytic capacity(>50%). Moreover, ·OH radicals participating in the RhB degradation process were evidenced using quenching experiments and electron paramagnetic resonance analysis, and a rational mechanism was proposed. It was demonstrated that the materials synthesized from hazardous phosphate residue can be used as an effective catalyst for dye removal.
基金financially supported by the National Key Research and Development Program of China (2016YFB0101202)the NSFC of China (Grants 91534205,21436003 and 21576031)Graduate Research and Innovation Foundation of Chongqing China (Grant No.CYB17021)
文摘Porous nitrogen-doped carbon is an especially promising material energy storage due to its excellentconductivity, stable physicochemical properties, easy processability, controllable porosity and low price.Herein, we reported a novel well-designed hierarchically porous nitrogen-doped carbon （HPNC） via acombination of salt template （ZnC12） and hard template （SiO2） as sulfur host for lithium-sulfur batter-ies. The low-melting ZnC12 is boiled off and leaves behind micropores and small size mesopores duringpyrolysis process, while the silica spheres are removed by acid leaching to generate interconnected 3Dnetwork of macropores. The HPNC-S electrode exhibits an initial specific capacity of 1355 mAh g^-l at 0.IC （IC= 1675 mAh g^-1 ）, a high-rate capability of 623 mAh g-l at 2 C, and a small decay of 0.13% per cycleover 300 cycles at 0.2 C. This excellent rate capability and remarkable long-term cyclability of the HPNC-Selectrode are attributed to its hierarchical porous structures for confining the soluble lithium polysulfideas well as the nitrogen doping for high absorbability of lithium polysulfide.
基金financial supports from KeyArea Research and Development Program of Guangdong Province(2019B110209003)Guangdong Basic and Applied Basic Research Foundation(2019B1515120058,2020A1515011149)+3 种基金National Key R&D Program of China(2018YFD0800700)National Ten Thousand Talent Plan,National Natural Science Foundation of China(21776324)the Fundamental Research Funds for the Central Universities(19lgzd25)Hundred Talent Plan(201602)from Sun Yatsen University。
文摘High-value reclamation of metal-polluted plants involved in phytoremediation is a big challenge.In this study,nitrogen-doped nanoporous carbon with large specific area of 2359.1 m^(2)g^(-1) is facilely fabricated from metal-polluted miscanthus waste for efficient energy storage.The synergistic effect of KOH,urea and ammonia solution greatly improve the nitrogen quantity and surface area of the synthesized carbon.Electrodes fabricated with this carbon exhibit the excellent capacitance performance of 340.2 F g^(-1) at 0.5 A g^(-1) and a low combined resistance of 0.116Ω,which are competitive with most of previously reported carbon-based electrodes.In addition,the as-obtained carbon electrode shows a high specific capacitance retention of over 99.6%even after 5000 cycles.Furthermore,the symmetric supercapacitor fabricated using the synthesized carbon achieves a superior energy density of 25.3 Wh kg^(-1)(at 400 W kg^(-1))in 1 mol L^(-1) Na_(2)SO_(4)aqueous solution.This work provides an efficient route to upcycle metal-polluted plant waste for supercapacitor applications.
基金supported by National Natural Science Foundation of China(Grant No.51932011,51802356)Innovation-Driven Project of Central South University(No.2020CX024)+3 种基金the Research Support Fund of the Collaborative Innovation Center of Manganese-Zinc-Vanadium Industrial Technology in Hunan Province(No.201809)the Program of Youth Talent Support for Hunan Province(2018RS3098)Hunan Provincial Innovation Foundation for Postgraduate(Grant No.CX2017B045)the Fundamental Research Funds for the Central Universities of Central South University(Grant No.2020zzts075).
文摘Potassium-ion batteries(KIBs)have great potential for applications in large-scale energy storage devices.However,the larger radius of K+leads to sluggish kinetics and inferior cycling performance,severely restricting its practical applicability.Herein,we propose a rational strategy involving a Prussian blue analogue-derived graphitized carbon anode with fast and durable potassium storage capability,which is constructed by encapsulating cobalt nanoparticles in nitrogen-doped graphitized carbon(Co-NC).Both experimental and theoretical results show that N-doping effectively promotes the uniform dispersion of cobalt nanoparticles in the carbon matrix through Co-N bonds.Moreover,the cobalt nanoparticles and strong Co-N bonds synergistically form a threedimensional conductive network,increase the number of adsorption sites,and reduce the diffusion energy barrier,thereby facilitating the adsorption and the diffusion kinetics.These multiple effects lead to enhanced reversible capacities of 305 and 208.6 mAh g^−1 after 100 and 300 cycles at 0.05 and 0.1 A g^−1,respectively,demonstrating the applicability of the Co-NC anode for KIBs.
基金supported by the Technische Universitat Berlin,the Max Planck Society and the Cluster of Excellence“Unifying Concepts in Catalysis(Uni Cat)”
文摘Direct electrochemical formation of hydrogen peroxide（H2O2） from pure O2 and H2on cheap metal-free earth abundant catalysts has emerged as the highest atom-efficient and environmentally friendly reaction pathway and is therefore of great interest from an academic and industrial point of view. Very recently,novel metal-free mesoporous nitrogen-doped carbon catalysts have attracted large attention due to the unique reactivity and selectivity for the electrochemical hydrogen peroxide formation [1–3]. In this work,we provide deeper insights into the electrocatalytic activity, selectivity and durability of novel metal-free mesoporous nitrogen-doped carbon catalyst for the peroxide formation with a particular emphasis on the influence of experimental reaction parameters such as p H value and electrode potential for three different electrolytes. We used two independent approaches for the investigation of electrochemical hydrogen peroxide formation, namely rotating ring-disk electrode（RRDE） technique and photometric UV–VIS technique. Our electrochemical and photometric results clearly revealed a considerable peroxide formation activity as well as high catalyst durability for the metal-free nitrogen-doped carbon catalyst material in both acidic as well as neutral medium at the same electrode potential under ambient temperature and pressure. In addition, the obtained electrochemical reactivity and selectivity indicate that the mechanisms for the electrochemical formation and decomposition of peroxide are strongly dependent on the p H value and electrode potential.
基金supported by the National Natural Science Foundation of China(21476087,21576101)the Innovation Project of Guangdong Department of Education(2014KTSCX016)+1 种基金the Science&Technology Research Project of Guangdong Province(2013B010405005,2014A010105041)the Fundamental Research Funds for the Central Universities~~
文摘Aniline,pyrrole and phenanthroline,which have different nitrogen compositions,are used as carbon precursors to synthesize nitrogen-doped ordered mesoporous carbons（NOMCs） by the nanocasting method.The effect of the precursor on the resultant NOMC is extensively investigated by nitrogen adsorption-desorption measurements,scanning electron microscopy,X-ray photoelectron spectroscopy（XPS）,cyclic voltammetry and rotating ring-disk electrode measurements.Salient findings are as follows.First,the precursor has a significant influence on the specific surface area and textural properties.The NOMC materials derived from pyrrole（C-PY-900：765 m^2/） and phenanthroline（C-Phen-900：746 m^2/） exhibit higher specific surface areas than the aniline analog（C-PA-900：569 m^2/）.Second,the XPS results indicate that the total nitrogen content（ca.3.1–3.3 at%） is similar for the three carbon sources,except for a slight difference in the nitrogen configuration.Furthermore,the content of the nitrogen-activated carbon atoms is found to closely depend on the precursor,which is the highest for the phenanthroline-derived carbon.Third,the electrochemical results reveal that the electrocatalytic activity follows in the order C-PA-900 C-PY-900 C-Phen-900,confirming that the nitrogen-activated carbon atoms are the active sites for the oxygen reduction reaction（ORR）.In summary,the precursor has considerable influence on the composition and textural properties of the NOMC materials,of which the ORR electrocatalytic activity can be enhanced through optimization of the NOMCs.
