To optimize the CO_(2) adsorption performance of carbon materials,this study proposed a preparation method for biomass-based porous carbon through hydrothermal carbonization coupled with nitrogen source optimization a...To optimize the CO_(2) adsorption performance of carbon materials,this study proposed a preparation method for biomass-based porous carbon through hydrothermal carbonization coupled with nitrogen source optimization and K_(2)CO_(3) activation.The effects of different nitrogen sources(urea,piperazine,melamine,and polyaniline)and activation temperatures on the physicochemical features and CO_(2) adsorption characteristics of the porous carbons were systematically investigated.The results indicated that different nitrogen sources showed varying impacts on the CO_(2) uptake of porous carbons,and not all nitrogen sources enhanced the adsorption performance.The urea and piperazine doped porous carbons exhibited relatively low nitrogen contents and specific surface areas.Whereas the melamine doped carbons showed higher nitrogen contents and specific surface areas,but lacked narrow micropores,limiting their CO_(2) adsorption performance.In contrast,PAC-700,prepared using polyaniline as nitrogen source,featured a well-developed pore structure,abundant narrow micropores and pyrrolic-N groups,endowing it with enhanced CO_(2) adsorption capability.At 0℃/1 bar and 25℃/1 bar,the CO_(2) uptake of PAC-700 reached 6.85 and 4.64 mmol/g,respectively.Additionally,PAC-700 maintained a CO_(2) uptake retention ratio of 99%after 5 adsorption-desorption cycles and exhibited good CO_(2)/N_(2) selectivity of 22.4−51.6.These findings highlighted the advantageous CO_(2) adsorption performance of PAC-700,indicating its substantial application potential in the domain of carbon capture.展开更多
We investigated the influence mechanism of N-doping for dissolved black carbon(DBC)photodegradation of organic pollutants.The degradation performance of N-doped dissolved black carbon(NDBC)for tetracycline(TC)(71%)is ...We investigated the influence mechanism of N-doping for dissolved black carbon(DBC)photodegradation of organic pollutants.The degradation performance of N-doped dissolved black carbon(NDBC)for tetracycline(TC)(71%)is better than that for methylene blue(MB)(28%)under irradiation.These levels are both better than DBC degradation performances for TC(68%)and MB(18%)under irradiation.Reactive species quenching experiments suggest that h and-O,are the main reactive species for NDBC photodegraded TC,while-OH and h*are the main reactive species for NDBC photodegraded MB.-OH is not observed during DBC photodegradation of MB.This is likely because N-doping increases valence-band(VB)energy from 1.55 eV in DBC to 2.04 eV in NDBC;the latter is strong enough to oxidize water to form-OH.Additionally,N-doping increases the DBC band gap of 2.29 to 2.62 eV in NDBC,resulting in a higher separation efficiency of photo-generated electrons-holes in NDBC than in DBC.AIl these factors give NDBC stronger photodegradation performance for TC and MB than DBC.High-performance liquid chromatography-mass spectrometry(HPLC-MS)characterization and toxicity evaluation with the quantitative structure-activity relationship(QSAR)method suggest that TC photodegradation intermediates produced by NDBC have less aromatic structure and are less toxic than those produced by DBC.We adopted a theoretical approach to clarify the relationship between the surface groups of NDBC and the photoactive species produced.Our results add to the understanding of the photochemical behavior of NDBC.展开更多
The electronic structures and the optical properties of N-doped β-Ga2O3 with different N-doping concentrations are studied using the first-principles method.We find that the N substituting O（1） atom is the most sta...The electronic structures and the optical properties of N-doped β-Ga2O3 with different N-doping concentrations are studied using the first-principles method.We find that the N substituting O（1） atom is the most stable structure for the smallest formation energy.After N-doping,the charge density distribution significantly changes,and the acceptor impurity level is introduced above the valence band and intersects with the Fermi level.The impurity absorption edges appear to shift toward longer wavelengths with an increase in N-doping concentration.The complex refractive index shows metallic characteristics in the N-doped β-Ga2O3.展开更多
Graphite materials are widely used as electrode materials for electrochemical energy storage.N-doping is an effective method for enhancing the electrochemical properties of graphite.A novel one-step N-doping method fo...Graphite materials are widely used as electrode materials for electrochemical energy storage.N-doping is an effective method for enhancing the electrochemical properties of graphite.A novel one-step N-doping method for complete and compact carbon paper was proposed for molten salt electrolysis in the Li Cl-KCl-Li3 N system.The results show that the degree of graphitization of carbon paper can be improved by the electrolysis of molten salts,especially at 2.0 V.Nitrogen gas was produced at the anode and nitrogen atoms can substitute carbon atoms of carbon paper at different sites to create nitrogen doping during the electrolysis process.The doping content of N in carbon paper is up to 13.0 wt%.There were three groups of nitrogen atoms,i.e.quaternary N(N-Q),pyrrolic N(N-5),and pyridinic N(N-6)in N-doping carbon paper.N-doping carbon paper as an Al-ion battery cathode shows strong charge-recharge properties.展开更多
N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to...N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to characterize.Limited understanding of doping-derived EDL structure hinders insight into the structure-performance relations and the rational design of high-performance materials.Thus,we analyzed the mass and chemical composition variation of EDL within electrochemical operation by electrochemical quartz crystal microbalance,in-situ X-ray photoelectron spectroscopy,and time-offlight secondary ion mass spectrometry.We found that N-doping triggers specifically adsorbed propylene carbonate solvent in the inner Helmholtz plane(IHP),which prevents ion rearrangement and enhances the migration of cations.However,this specific adsorption accelerated solvent decomposition,rendering rapid performance degradation in practical devices.This work reveals that the surface chemistry of electrodes can cause specific adsorption of solvents and change the EDL structure,which complements the classical EDL theory and provide guidance for practical applications.展开更多
Li metal is the most ideal anode material for next-generation high energy lithium-ion batteries.The uncontrollable growth of Li dendrites,however,hinders its practical application.Herein,we propose the adoption of Zn ...Li metal is the most ideal anode material for next-generation high energy lithium-ion batteries.The uncontrollable growth of Li dendrites,however,hinders its practical application.Herein,we propose the adoption of Zn nanoparticles uniformly embedded in N-doped carbon polyhedra homogeneously built on carbon cloth(Zn@NC@CC)to prevent the formation of Li dendrites.Based on theoretical calculation and experimental observation,lithiophilic Zn nanoparticles and N-doping inside of the assynthesized Zn@NC play a synergistic role in enhancing the adsorption capacity with Li,thus resulting in uniform Li deposition and complete suppression of Li dendrites.Moreover,the porous N-doped carbon polyhedras uniformly distributed on carbon cloth effectively relieves the volume change of Li upon repeated Li stripping/plating process,which contributes to preserving the structural integrity of the whole electrode and hence enhancing its long-term cycling stability.Benefiting from these synergistic effects,the Li-Zn@NC@CC electrode delivers a prolonged lifespan of over 1200 h at 1 mA cm^(-2) with an areal capacity of 1 mA h cm^(-2) in symmetric cells and high Coulombic efficiencies of 95.4%under an ultrahigh capacity of 12 mA h cm^(-2).Remarkably,Li-Zn@NC@CC//LiFePO_(4) full cells deliver a high reversible capacity of 110.2 mA h g^(-1) at 1 C over 200 cycles.展开更多
Designing the highly catalytic activity and durable bifunctional catalysts toward oxygen reduction/evolution reaction(ORR/OER) is paramount for metal–air batteries. Metal–organic frameworks(MOFs)-based materials hav...Designing the highly catalytic activity and durable bifunctional catalysts toward oxygen reduction/evolution reaction(ORR/OER) is paramount for metal–air batteries. Metal–organic frameworks(MOFs)-based materials have attracted a great deal of attention as the potential candidate for effectively catalyzing ORR/OER due to their adjustable composition and porous structure. Herein, we first introduce the Mn species into zeolitic-imidazole frameworks(ZIFs) and then further pyrolyze the Mn-containing bimetallic ZIFs to synthesize core-shell-structured Co@Co4N nanoparticles embedded into MnO-modified porous N-doped carbon nanocubes(Co@Co4N/MnO–NC). Co@Co4N/MnO–NC exhibits the outstanding catalytic activity toward ORR and OER which is attributed to its abundant pyridinic/graphitic N and Co4N,the optimized content of MnO species, highly dispersed catalytic sites and porous carbon matrix. As a result, the Co@Co4N/MnO–NC-based Zn–air battery exhibits enhanced performances, including the high discharge capacity(762 mA h gZn-1), large power density(200.5 mW cm-2), stable potential profile over 72 h, low overpotential(<1.0 V) and superior cycling life(2800 cycles). Moreover, the belt-shaped Co@Co4N/MnO–NC cathode-based Zn–air batteries are also designed which exhibit the superb electrochemical properties at different bending/twisting conditions.展开更多
An efficient method that utilizes simple techniques,easy operation,and low-cost production to create flexible graphene-based materials is a worthy practical challenge.A rapid strategy for preparing flexible,functional...An efficient method that utilizes simple techniques,easy operation,and low-cost production to create flexible graphene-based materials is a worthy practical challenge.A rapid strategy for preparing flexible,functional graphene oxide(GO)is introduced using GO-ethanol dispersion filtration.The filtration process is highly efficient and drying time is significantly reduced by employing ethanol as solvent,due to the fact that ethanol is a volatile liquid.Freestanding GO papers can be harvested with ultralarge size(700 cm2),color variety,and writable characteristics.After reduction,N-doped graphene(NDG)papers still maintain good foldability with improved electric conductivity and porous structure.When used as an electrode for a supercapacitor,the flexible NDG paper device demonstrates good electrochemical performance even with size expansion and extreme double folding.Moreover,this NDG paper capacitor device shows a good electrosorption performance for capacitive deionization of sulfate and chromate in groundwater system.These flexible GO and NDG papers promise potential to facilitate the production of graphene-based materials for practical applications in energy and environmental related fields.展开更多
Introducing moderate iodide vacancies in halide perovskites has been frequently observed to form n-type doping effect and optimize the power conversion efficiency(PCE)of perovskite solar cells(PSCs).However,it has bee...Introducing moderate iodide vacancies in halide perovskites has been frequently observed to form n-type doping effect and optimize the power conversion efficiency(PCE)of perovskite solar cells(PSCs).However,it has been widely recognized that iodide vacancies are mobile and photochemically detrimental.Herein,tris(2-aminoethyl)amine(TAEA),a branched molecule containing three primary amino groups and one tertiary amino group,is reported to passivate the undercoordinated Pb^(2+)ions and meanwhile n-dope the perovskite surface with its multiple amino groups.After TAEA post-treatment,the PSCs show robustly improved fill factor(FF)from 76.2%to 82.9%,improved open-circuit voltage(VOC)from 1.08 to 1.16 V,and enhanced PCE from 19.4%to 23.4%.Moreover,the oxygen stability of the TAEA treated perovskite film has been substantially improved simultaneously,which is essentially different from the decreased oxygen stability in the case of using iodide vacancy as the n-dopant.Benefited from the iodide vacancies filling effect by TAEA,the activation energy(Ea)of ions migration in perovskites also increased from 0.43 to 0.67 eV.展开更多
The development of efficient catalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is of great significance for the practical application of water splitting in alkaline electrolytes.Transitio...The development of efficient catalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is of great significance for the practical application of water splitting in alkaline electrolytes.Transition metal sulfide electrocatalysts have been widely recognized as efficient catalysts for water splitting in alkaline media.In this work,an original and efficient synthesis strategy is proposed for the fabrication of asymmetric anode(N-(Co-Cu)S_(x))and cathode(N-CoS/Cu_(2)S).Impressively,these electrodes exhibit superior performance,benefiting from the construction of three-dimensional(3D)structures and the electronic structure adjustment caused by N-doping with increased active sites,improved mass/charge transport and enhanced evolution and release of gas bubbles.Hence,N-(Co-Cu)S_(x)anode exhibits excellent OER performance with only 217 mV overpotential at 10 mA·cm^(-2),while N-CoS/Cu_(2)S cathode possesses excellent HER performance with only 67 mV overpotential at 10 mA·cm^(-2).N-(Co-Cu)S_(x)||N-CoS/Cu_(2)S electrolyzer presents a low cell voltage of 1.53 V at 10 mA·cm^(-2)toward overall water splitting,which is superior to most recently reported transition metal sulfide-based catalysts.展开更多
Freshwater scarcity has emerged as a critical global environmental challenge.Flow-electrode capacitive deionization(FCDI)represents a promising technology for achieving efficient and low-energy seawater desalination.T...Freshwater scarcity has emerged as a critical global environmental challenge.Flow-electrode capacitive deionization(FCDI)represents a promising technology for achieving efficient and low-energy seawater desalination.This study presents a novel flow-electrode material,nitrogen-doped porous carbon(NPC),which is derived from biomass and demonstrates both cost-effectiveness and high performance.The NPC material is synthesized from bean shells through high-temperature pre-carbonization followed by activation with KHCO_(3),resulting in a rich porous structure,increased specific surface area,and high graphitization degree,which collectively confer superior capacitance performance compared to activated carbon(AC).Desalination experiments indicate that the FCDI performance of the NPC flow-electrode surpasses that of the AC flow-electrode.Specifically,at a voltage of 2.5 V in a 6 g·L^(-1)NaCl solution,the NPC system achieves an average salt removal rate(ASRR)of 104.9 μg·cm^(-2)·min^(-1),with a charge efficiency(CE)of 94.0%and an energy consumption(EC)of only 4.4 kJ·g^(-1).Furthermore,the NPC-based FCDI system exhibits commendable desalination cycling stability,maintaining relatively stable energy consumption and efficiency after prolonged continuous desalination cycles.This research holds significant implications for the advancement of environmentally friendly,low-cost,high-performance FCDI systems for large-scale applications.展开更多
Microalgae are one of the promising feedstocks for biorefinery,contributing significantly to net-zero emissions through carbon capture and utilization.However,the disposal of microalgal byproducts from the manufacturi...Microalgae are one of the promising feedstocks for biorefinery,contributing significantly to net-zero emissions through carbon capture and utilization.However,the disposal of microalgal byproducts from the manufacturing process causes additional environmental pollution,thus,a new application strategy is required.In this study,the Tetraselmis suecica byproduct from the carotenoid extraction process was carbonized and converted into biochar.The converted biochar was proved to be nitrogen-doped biochar(NDB),up to 4.69%,with a specific surface area of 206.59m^(2)/g andwas used as an electrode for a supercapacitor.The NDB electrode(NDB-E)in half-cell showed a maximum specific capacitance of 191 F/g.In a full-cell test,the NDB-E exhibited a high energy density of 7.396 Wh/kg and a high-power density of 18,100 W/kg,and maintained specific capacity of 95.5%after charge and discharge of 10,000 cycles.In conclusion,our study demonstrated that the carotenoid-extracted microalgal byproducts are a useful resource for the supercapacitor production.This approach is the first to convert T.suecica into active materials for supercapacitors.展开更多
As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-...As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-charging performance is hindered by significant volume expansion(>218%)and a low rate of phase diffusion.To overcome these two problems,an N-doped carbon nanoflower coating layer was elaborately in-situ reconstructed on a multiple-wall Bi microsphere by hydrothermal methods and subsequent calcination in this study.The carbon nanoflowers greatly increase specific surface area(40.0 m^(2)·g^(-1))and alleviate the volume expansion(130%).In addition,the incorporation of N-doped carbon nanoflowers leads to a gradual enhancement in the Li adsorption energy of Bi during the process of lithium insertion and improves the electrical conductivity.Therefore,the contribution rate of pseudo-capacitance reached 87.5%at the scan rate of 0.8 mV·s^(-1),and the Li-ion diffusion coefficient(D_(Li^(+)))was calculated in the range of 10^(-10)to 10^(-12)cm^(2)·s^(-1).The Bi@CNFs anode provided a high specific volumetric capacity of 2117.0 mAh·cm^(-3)at 5C and a high capacity retention ratio of 93.2%after 800 cycles.The Bi@CNFs//LiFePO_(4)full cell also displayed a stable capacity of 113.9 mAh·g^(-1)and energy density of 296.1 Wh·kg^(-1)after 100 cycles with a Coulombic efficiency of 97.6%.The mechanism of fast-charging lithium storage was verified by distribution of relaxation time analysis and density functional theory calculation.This paper provides a new strategy to increase the pseudo-capacitance and reduce the volume expansion for the preparation of alloy-type fast-charging electrodes.展开更多
Electrochemical synthesis of ammonia represents a green and environmental-ly friendly method distinct from tradi-tional Harper-Bosch processes,which demand stringent conditions.However,identifying a catalyst with high...Electrochemical synthesis of ammonia represents a green and environmental-ly friendly method distinct from tradi-tional Harper-Bosch processes,which demand stringent conditions.However,identifying a catalyst with high selec-tivity and catalytic activity to cleave the robust triple bond of N_(2)remains a formidable challenge.Herein,we present a systematic study on the geo-metrical and electronic structure,intensity of N_(2)adsorption,reaction intermediates,change in Gibbs free energy,and desorption of by-product hydrazine for the nitrogen reduction reac-tion employing a MnNx-graphene(x=3,4)catalyst from a theoretical perspective.The com-putational results reveal that MnN3-graphene exhibits superior catalytic performance pre-dominantly via the distal mechanism,with a low potential of 0.49 V.Moreover,the detach-ment of the produced NH3 is facilitated with a free energy of only 0.27 eV,significantly lower than those of previous catalysts,ensuring the exceptional durability of MnN_(3)-graphene.This study offers theoretical insights guiding the exploration of single Mn atom catalysts in ammo-nia synthesis.展开更多
CO_(2) conversion to CO via the reverse water-gas shift(RWGS)reaction is limited by a low CO_(2) conversion rate and CO selectivity.Herein,an efficient RWGS catalyst is constructed through Enteromorpha prolifera–deri...CO_(2) conversion to CO via the reverse water-gas shift(RWGS)reaction is limited by a low CO_(2) conversion rate and CO selectivity.Herein,an efficient RWGS catalyst is constructed through Enteromorpha prolifera–derived N-rich mesoporous biochar(EPBC)supported atomic-level Cu-Mo_(2)C clusters(Cu-Mo_(2)C/EPBC).Unlike traditional acti-vated carbon(AC)supported Cu-Mo_(2)C particles(Cu-Mo_(2)C/AC),the Cu-Mo_(2)C/EPBC not only presents the better graphitization degree and larger specific surface area,but also uniformly andfirmly anchors atomic-level Cu-Mo_(2)C clusters due to the existence of pyridine nitrogen.Furthermore,the pyridine N of Cu-Mo_(2)C/EPBC strengthens an unblocked electron transfer between Mo_(2)C and Cu clusters,as verified by X-ray absorption spectroscopy.As a result,the synergistic effect between pyridinic N anchoring and the clusters interaction in Cu-Mo_(2)C/EPBC facilitates an improved CO selectivity of 99.95%at 500℃ compared with traditional Cu-Mo_(2)C/AC(99.60%),as well as about 3-fold CO_(2) conversion rate.Density functional theory calculations confirm that pyr-idine N-modified carbon activates the local electronic redistribution at Cu-Mo_(2)C clusters,which contributes to the decreased energy barrier of the transition state of CO^(*)+O^(*)+2H^(*),thereby triggering the transformation of rate-limited step during the redox pathway.This biomass-derived strategy opens perspective on producing sustain-able fuels and building blocks through the RWGS reaction.展开更多
The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts...The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts,while its symmetric charge distribution nature is not favorable for electron transfer and then hindering the efficient CO_(2)RR.Herein,we constructed a Ni SA/CNs single-atom catalyst.Notably,it features unique Ni-N_(4)-O active sites,featuring one axial O atom and four planar N atoms,constituting a broken symmetrical electronic structure of Ni-N_(4) sites.Furthermore,hierarchical pore structures were obtained with the assistance of NaNO_(3) pore-forming agent during thermal treatment process,which promote electronic and mass transfer.And the resulting high specific surface area can host more Ni-N_(4)-O active sites.These specialized active sites promote the key intermediate(∗CO)adsorption/desorption and suppresses hydrogen evolution.Consequently,the Ni SA/CNs catalyst exhibits a high turnover frequency(TOF)value,reaching 34,081 h^(-1) at-0.98 V vs.RHE.Additionally,it achieves an excellent CO Faradaic efficiency,exceeding 90%,over a wide potential range from-0.4 V to-1.0 V vs.RHE.This work not only offers a new method for the rational synthesize single-atom catalysts with unique Ni-N_(4)-O active sites,but also provides in-depth insight into the origin of catalytic activity of porous carbon-base catalysts.展开更多
Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yard...Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yardlong bean-like Fe_(9)Ni_(9)S_(16)/FeS heterostructures with sulfur vacancies encapsulated in N-doped carbon nanotubes(3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs)are controllably synthesized through Fe/Ni-catalyzed pyrolysis of dicyandiamide followed by sulfidation strategies.1D nanotubes with robust outer walls and internal cavity structures shorten the diffusion paths of ions/electrons and buffer volume expansion and aggregation of active materials.The Fe_(9)Ni_(9)S_(16)/FeS heterostructure provides a powerful driving force for charge transfer by forming built-in electric fields,optimizing ion adsorption,while the Fe_(9)Ni_(9)S_(16)features a wider interlayer spacing that allows for frequent Na+/Li+insertion and extraction,thereby enhancing the reaction kinetics within the electrode.Driven by these synergistic factors,the 3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs demonstrates remarkable electrochemical performance,achieving a substantial reversible capacity of up to 682.1mA h g^(−1)for SIBs at 0.1 A g^(−1)and 782.7 mA h g^(−1)for LIBs at 0.5 A g−1,alongside exceptional cycling stability in SIBs,maintaining 78.7%of its capacity after 1500 cycles at 1 A g^(−1)coupling with the ether-based electrolyte.Employing various electrochemical analyses in conjunction with ex-situ characterization techniques and Density Functional Theory(DFT)calculations,the storage mechanisms and phase transition processes are investigated,elucidating the structure-composition-performance relationships.This work paves the way for a new strategy in designing advanced materials with engineered heterostructures and controllable defects for energy conversion and storage devices.展开更多
Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization(CDI) community. Understanding the causes of performance decay in traditional carbons is cruci...Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization(CDI) community. Understanding the causes of performance decay in traditional carbons is crucial to design a high-performance material. Based on this, here, nitrogen-doped activated carbon(NAC) was prepared by pyrolyzing the blend of activated carbon powder(ACP) and melamine for the positive electrode of asymmetric CDI. By comparing the indicators changes such as conductivity, salt adsorption capacity, pH, and charge efficiency of the symmetrical ACP-ACP device to the asymmetric ACP-NAC device under different CDI cycles, as well as the changes of the electrochemical properties of anode and cathode materials after long-term operation, the reasons for the decline of the stability of the CDI performance were revealed. It was found that the carboxyl functional groups generated by the electro-oxidation of anode carbon materials make the anode zero-charge potential(E_(pzc)) shift positively,which results in the uneven distribution of potential windows of CDI units and affects the adsorption capacity. Furthermore, by understanding the electron density on C atoms surrounding the N atoms, we attribute the increased cyclic stability to the enhanced negativity of the charge of carbon atoms adjacent to quaternary-N and pyridinic-oxide-N.展开更多
Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite ano...Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very lacking.Herein,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an example.An interface model was developed,incorporating the electrode potential and atom electronegativities.As a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following electrochemical reactions at the atomic level.Specifically,the negatively charged N atoms repel the anions and adsorb Li~+at high and low potentials,respectively.Such preferential adsorption suggests that Ndoped graphite can promote Li~+desolvation and regulate the location of Li~+deposition.This CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.展开更多
With the advantage of fast charge transfer,heterojunction engineering is identified as a viable method to reinforce the anodes'sodium storage performance.Also,vacancies can effectively strengthen the Na+adsorption...With the advantage of fast charge transfer,heterojunction engineering is identified as a viable method to reinforce the anodes'sodium storage performance.Also,vacancies can effectively strengthen the Na+adsorption ability and provide extra active sites for Na+adsorption.However,their synchronous engineering is rarely reported.Herein,a hybrid of Co_(0.85)Se/WSe_(2) heterostructure with Se vacancies and N-doped carbon polyhedron(CoWSe/NCP)has been fabricated for the first time via a hydrothermal and subsequent selenization strategy.Spherical aberration-corrected transmission electron microscopy confirms the phase interface of the Co_(0.85)Se/WSe_(2) heterostructure and the existence of Se vacancies.Density functional theory simulations reveal the accelerated charge transfer and enhanced Na+adsorption ability,which are contributed by the Co_(0.85)Se/WSe_(2) heterostructure and Se vacancies,respectively.As expected,the CoWSe/NCP anode in sodium-ion battery achieves outstanding rate capability(339.6 mAh g^(−1) at 20 A g^(−1)),outperforming almost all Co/W-based selenides.展开更多
基金supported by the National Key R&D Program(2022YFC3902403)Fundamental Research Funds for the Central Universities(2024JC001,2019JG002)Technology Innovation Special Fund of Jiangsu Province for Carbon Dioxide Emission Peaking and Carbon Neutrality(BE2022307)。
文摘To optimize the CO_(2) adsorption performance of carbon materials,this study proposed a preparation method for biomass-based porous carbon through hydrothermal carbonization coupled with nitrogen source optimization and K_(2)CO_(3) activation.The effects of different nitrogen sources(urea,piperazine,melamine,and polyaniline)and activation temperatures on the physicochemical features and CO_(2) adsorption characteristics of the porous carbons were systematically investigated.The results indicated that different nitrogen sources showed varying impacts on the CO_(2) uptake of porous carbons,and not all nitrogen sources enhanced the adsorption performance.The urea and piperazine doped porous carbons exhibited relatively low nitrogen contents and specific surface areas.Whereas the melamine doped carbons showed higher nitrogen contents and specific surface areas,but lacked narrow micropores,limiting their CO_(2) adsorption performance.In contrast,PAC-700,prepared using polyaniline as nitrogen source,featured a well-developed pore structure,abundant narrow micropores and pyrrolic-N groups,endowing it with enhanced CO_(2) adsorption capability.At 0℃/1 bar and 25℃/1 bar,the CO_(2) uptake of PAC-700 reached 6.85 and 4.64 mmol/g,respectively.Additionally,PAC-700 maintained a CO_(2) uptake retention ratio of 99%after 5 adsorption-desorption cycles and exhibited good CO_(2)/N_(2) selectivity of 22.4−51.6.These findings highlighted the advantageous CO_(2) adsorption performance of PAC-700,indicating its substantial application potential in the domain of carbon capture.
基金supported by the Project of the State Key Laboratory of Pollution Control and Resource Reuse Foundation,Nanjing University(No.PCRRF21012)。
文摘We investigated the influence mechanism of N-doping for dissolved black carbon(DBC)photodegradation of organic pollutants.The degradation performance of N-doped dissolved black carbon(NDBC)for tetracycline(TC)(71%)is better than that for methylene blue(MB)(28%)under irradiation.These levels are both better than DBC degradation performances for TC(68%)and MB(18%)under irradiation.Reactive species quenching experiments suggest that h and-O,are the main reactive species for NDBC photodegraded TC,while-OH and h*are the main reactive species for NDBC photodegraded MB.-OH is not observed during DBC photodegradation of MB.This is likely because N-doping increases valence-band(VB)energy from 1.55 eV in DBC to 2.04 eV in NDBC;the latter is strong enough to oxidize water to form-OH.Additionally,N-doping increases the DBC band gap of 2.29 to 2.62 eV in NDBC,resulting in a higher separation efficiency of photo-generated electrons-holes in NDBC than in DBC.AIl these factors give NDBC stronger photodegradation performance for TC and MB than DBC.High-performance liquid chromatography-mass spectrometry(HPLC-MS)characterization and toxicity evaluation with the quantitative structure-activity relationship(QSAR)method suggest that TC photodegradation intermediates produced by NDBC have less aromatic structure and are less toxic than those produced by DBC.We adopted a theoretical approach to clarify the relationship between the surface groups of NDBC and the photoactive species produced.Our results add to the understanding of the photochemical behavior of NDBC.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10974077)the Natural Science Foundation of Shandong Province,China (Grant No. 2009ZRB01702)the Shandong Provincial Higher Educational Science and Technology Program,China (Grant No. J10LA08)
文摘The electronic structures and the optical properties of N-doped β-Ga2O3 with different N-doping concentrations are studied using the first-principles method.We find that the N substituting O（1） atom is the most stable structure for the smallest formation energy.After N-doping,the charge density distribution significantly changes,and the acceptor impurity level is introduced above the valence band and intersects with the Fermi level.The impurity absorption edges appear to shift toward longer wavelengths with an increase in N-doping concentration.The complex refractive index shows metallic characteristics in the N-doped β-Ga2O3.
基金the National Natural Science Foundation of China(No.51725401)the Fundamental Research Funds for the Central Universities(No.FRT-TP-18-003C2)。
文摘Graphite materials are widely used as electrode materials for electrochemical energy storage.N-doping is an effective method for enhancing the electrochemical properties of graphite.A novel one-step N-doping method for complete and compact carbon paper was proposed for molten salt electrolysis in the Li Cl-KCl-Li3 N system.The results show that the degree of graphitization of carbon paper can be improved by the electrolysis of molten salts,especially at 2.0 V.Nitrogen gas was produced at the anode and nitrogen atoms can substitute carbon atoms of carbon paper at different sites to create nitrogen doping during the electrolysis process.The doping content of N in carbon paper is up to 13.0 wt%.There were three groups of nitrogen atoms,i.e.quaternary N(N-Q),pyrrolic N(N-5),and pyridinic N(N-6)in N-doping carbon paper.N-doping carbon paper as an Al-ion battery cathode shows strong charge-recharge properties.
基金the National Science Foundation for Excellent Young Scholars of China(21922815)the National Natural Science Foundation of China(22179139)+2 种基金the National Key Research and Development Program of China(2020YFB1505800)the Youth Innovation Promotion Association of CAS(2019178)the“Transformational Technologies for Clean Energy and Demonstration”Strategic Priority Research Program of the CAS(XDA21000000)。
文摘N-doped porous carbon has been extensively investigated for broad electrochemical applications.The performance is significantly impacted by the electrochemical double layer(EDL),which is material dependent and hard to characterize.Limited understanding of doping-derived EDL structure hinders insight into the structure-performance relations and the rational design of high-performance materials.Thus,we analyzed the mass and chemical composition variation of EDL within electrochemical operation by electrochemical quartz crystal microbalance,in-situ X-ray photoelectron spectroscopy,and time-offlight secondary ion mass spectrometry.We found that N-doping triggers specifically adsorbed propylene carbonate solvent in the inner Helmholtz plane(IHP),which prevents ion rearrangement and enhances the migration of cations.However,this specific adsorption accelerated solvent decomposition,rendering rapid performance degradation in practical devices.This work reveals that the surface chemistry of electrodes can cause specific adsorption of solvents and change the EDL structure,which complements the classical EDL theory and provide guidance for practical applications.
基金partially supported by the National Science Fund for Distinguished Young Scholars(51625102)the National Natural Science Foundation of China(51971065,51901045)+3 种基金the National Natural Science Foundation of China(NSFCàU1903217)the National Natural Science Foundation of China(No.21978073)the Innovation Program of Shanghai Municipal Education Commission(2019-01-07-00-07-E00028)the Programs for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning。
文摘Li metal is the most ideal anode material for next-generation high energy lithium-ion batteries.The uncontrollable growth of Li dendrites,however,hinders its practical application.Herein,we propose the adoption of Zn nanoparticles uniformly embedded in N-doped carbon polyhedra homogeneously built on carbon cloth(Zn@NC@CC)to prevent the formation of Li dendrites.Based on theoretical calculation and experimental observation,lithiophilic Zn nanoparticles and N-doping inside of the assynthesized Zn@NC play a synergistic role in enhancing the adsorption capacity with Li,thus resulting in uniform Li deposition and complete suppression of Li dendrites.Moreover,the porous N-doped carbon polyhedras uniformly distributed on carbon cloth effectively relieves the volume change of Li upon repeated Li stripping/plating process,which contributes to preserving the structural integrity of the whole electrode and hence enhancing its long-term cycling stability.Benefiting from these synergistic effects,the Li-Zn@NC@CC electrode delivers a prolonged lifespan of over 1200 h at 1 mA cm^(-2) with an areal capacity of 1 mA h cm^(-2) in symmetric cells and high Coulombic efficiencies of 95.4%under an ultrahigh capacity of 12 mA h cm^(-2).Remarkably,Li-Zn@NC@CC//LiFePO_(4) full cells deliver a high reversible capacity of 110.2 mA h g^(-1) at 1 C over 200 cycles.
基金the National Natural Science Foundation of China(21905151 and 51772162)Outstanding Youth Foundation of Shandong Province,China(ZR2019JQ14)+4 种基金the Natural Science Foundation of Shandong Province(ZR2018BB034)Taishan Scholar Young Talent ProgramMajor Scientific and Technological Innovation Project(2019JZZY020405)China Postdoctoral Science Foundation(2019M652499)the State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University(2019-23)。
文摘Designing the highly catalytic activity and durable bifunctional catalysts toward oxygen reduction/evolution reaction(ORR/OER) is paramount for metal–air batteries. Metal–organic frameworks(MOFs)-based materials have attracted a great deal of attention as the potential candidate for effectively catalyzing ORR/OER due to their adjustable composition and porous structure. Herein, we first introduce the Mn species into zeolitic-imidazole frameworks(ZIFs) and then further pyrolyze the Mn-containing bimetallic ZIFs to synthesize core-shell-structured Co@Co4N nanoparticles embedded into MnO-modified porous N-doped carbon nanocubes(Co@Co4N/MnO–NC). Co@Co4N/MnO–NC exhibits the outstanding catalytic activity toward ORR and OER which is attributed to its abundant pyridinic/graphitic N and Co4N,the optimized content of MnO species, highly dispersed catalytic sites and porous carbon matrix. As a result, the Co@Co4N/MnO–NC-based Zn–air battery exhibits enhanced performances, including the high discharge capacity(762 mA h gZn-1), large power density(200.5 mW cm-2), stable potential profile over 72 h, low overpotential(<1.0 V) and superior cycling life(2800 cycles). Moreover, the belt-shaped Co@Co4N/MnO–NC cathode-based Zn–air batteries are also designed which exhibit the superb electrochemical properties at different bending/twisting conditions.
基金This study was supported by the National Key R&D Program of China(2016YFE0102000)the National Natural Science Foundation of China(41672236,41807184)Fang Zhang also acknowledges the support of Young Elite Scientist Sponsorship Program by CAST(2015QNRC001).
文摘An efficient method that utilizes simple techniques,easy operation,and low-cost production to create flexible graphene-based materials is a worthy practical challenge.A rapid strategy for preparing flexible,functional graphene oxide(GO)is introduced using GO-ethanol dispersion filtration.The filtration process is highly efficient and drying time is significantly reduced by employing ethanol as solvent,due to the fact that ethanol is a volatile liquid.Freestanding GO papers can be harvested with ultralarge size(700 cm2),color variety,and writable characteristics.After reduction,N-doped graphene(NDG)papers still maintain good foldability with improved electric conductivity and porous structure.When used as an electrode for a supercapacitor,the flexible NDG paper device demonstrates good electrochemical performance even with size expansion and extreme double folding.Moreover,this NDG paper capacitor device shows a good electrosorption performance for capacitive deionization of sulfate and chromate in groundwater system.These flexible GO and NDG papers promise potential to facilitate the production of graphene-based materials for practical applications in energy and environmental related fields.
基金support from National Natural Science Foundation of China(Nos.52273202 and 62104261)Y.B.Y.and Y.L.acknowledge the program of the Natural Science Foundation of Hunan Province(Nos.2025JJ30026 and 2023JJ40695)+2 种基金L.M.D.and Y.B.Y.acknowledge financial support from the National Key Research and Development Program of China(Nos.2022YFB3803300 and 2023YFE0116800)Y.B.Y.and Y.Z.acknowledge the Key Project of the Natural Science Program of Xinjiang Uygur Autonomous Region(No.2023D01D03)L.M.D.acknowledges the financial support from the Beijing Natural Science Foundation(No.IS23037).
文摘Introducing moderate iodide vacancies in halide perovskites has been frequently observed to form n-type doping effect and optimize the power conversion efficiency(PCE)of perovskite solar cells(PSCs).However,it has been widely recognized that iodide vacancies are mobile and photochemically detrimental.Herein,tris(2-aminoethyl)amine(TAEA),a branched molecule containing three primary amino groups and one tertiary amino group,is reported to passivate the undercoordinated Pb^(2+)ions and meanwhile n-dope the perovskite surface with its multiple amino groups.After TAEA post-treatment,the PSCs show robustly improved fill factor(FF)from 76.2%to 82.9%,improved open-circuit voltage(VOC)from 1.08 to 1.16 V,and enhanced PCE from 19.4%to 23.4%.Moreover,the oxygen stability of the TAEA treated perovskite film has been substantially improved simultaneously,which is essentially different from the decreased oxygen stability in the case of using iodide vacancy as the n-dopant.Benefited from the iodide vacancies filling effect by TAEA,the activation energy(Ea)of ions migration in perovskites also increased from 0.43 to 0.67 eV.
基金supported by the Science and Technology Project of Southwest Petroleum University(No.2021JBGS03)the Local Science and Technology Development Fund Projects Guided by the Central Government of China(No.2021ZYD0060)+2 种基金the National Natural Science Foundation of China(Nos.22209143 and 52371241)Guangdong High-level Innovation Institute Project(Nos.2021B0909050001 and 2021CX02L365)Guangdong Basic and Applied Basic Research Foundation(No.2023B1515120095).
文摘The development of efficient catalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is of great significance for the practical application of water splitting in alkaline electrolytes.Transition metal sulfide electrocatalysts have been widely recognized as efficient catalysts for water splitting in alkaline media.In this work,an original and efficient synthesis strategy is proposed for the fabrication of asymmetric anode(N-(Co-Cu)S_(x))and cathode(N-CoS/Cu_(2)S).Impressively,these electrodes exhibit superior performance,benefiting from the construction of three-dimensional(3D)structures and the electronic structure adjustment caused by N-doping with increased active sites,improved mass/charge transport and enhanced evolution and release of gas bubbles.Hence,N-(Co-Cu)S_(x)anode exhibits excellent OER performance with only 217 mV overpotential at 10 mA·cm^(-2),while N-CoS/Cu_(2)S cathode possesses excellent HER performance with only 67 mV overpotential at 10 mA·cm^(-2).N-(Co-Cu)S_(x)||N-CoS/Cu_(2)S electrolyzer presents a low cell voltage of 1.53 V at 10 mA·cm^(-2)toward overall water splitting,which is superior to most recently reported transition metal sulfide-based catalysts.
基金supported by the National Natural Science Foundation of China(52202093)the National College Student Innovation and Entrepreneurship Training Program of Jiangsu University of Science and Technology(202410289005Z).
文摘Freshwater scarcity has emerged as a critical global environmental challenge.Flow-electrode capacitive deionization(FCDI)represents a promising technology for achieving efficient and low-energy seawater desalination.This study presents a novel flow-electrode material,nitrogen-doped porous carbon(NPC),which is derived from biomass and demonstrates both cost-effectiveness and high performance.The NPC material is synthesized from bean shells through high-temperature pre-carbonization followed by activation with KHCO_(3),resulting in a rich porous structure,increased specific surface area,and high graphitization degree,which collectively confer superior capacitance performance compared to activated carbon(AC).Desalination experiments indicate that the FCDI performance of the NPC flow-electrode surpasses that of the AC flow-electrode.Specifically,at a voltage of 2.5 V in a 6 g·L^(-1)NaCl solution,the NPC system achieves an average salt removal rate(ASRR)of 104.9 μg·cm^(-2)·min^(-1),with a charge efficiency(CE)of 94.0%and an energy consumption(EC)of only 4.4 kJ·g^(-1).Furthermore,the NPC-based FCDI system exhibits commendable desalination cycling stability,maintaining relatively stable energy consumption and efficiency after prolonged continuous desalination cycles.This research holds significant implications for the advancement of environmentally friendly,low-cost,high-performance FCDI systems for large-scale applications.
基金supported by the National Research Foundation of Korea(NRF)grant funded by Ministry of Science,ICT(Nos.2018M3A7B4070990,2020R1A2C2103137,2020R1F1A1076359,and 2022R1C1C2011696)the Education(Nos.2020R1A2C2103137 and 2020R1F1A1076359)Materials,Components&Equipment Research Program funded by the Gyeonggi Province。
文摘Microalgae are one of the promising feedstocks for biorefinery,contributing significantly to net-zero emissions through carbon capture and utilization.However,the disposal of microalgal byproducts from the manufacturing process causes additional environmental pollution,thus,a new application strategy is required.In this study,the Tetraselmis suecica byproduct from the carotenoid extraction process was carbonized and converted into biochar.The converted biochar was proved to be nitrogen-doped biochar(NDB),up to 4.69%,with a specific surface area of 206.59m^(2)/g andwas used as an electrode for a supercapacitor.The NDB electrode(NDB-E)in half-cell showed a maximum specific capacitance of 191 F/g.In a full-cell test,the NDB-E exhibited a high energy density of 7.396 Wh/kg and a high-power density of 18,100 W/kg,and maintained specific capacity of 95.5%after charge and discharge of 10,000 cycles.In conclusion,our study demonstrated that the carotenoid-extracted microalgal byproducts are a useful resource for the supercapacitor production.This approach is the first to convert T.suecica into active materials for supercapacitors.
基金supported by the project of the National Natural Science Foundation of China(NSFC,Nos.5216040127,52164048 and U1802256)Central Guidance for Local Science and Technology Development Funds(No.202107AB110011)the Analysis and Test Funds of Kunming University of Science and Technology(No.2021M0202230188).
文摘As one of the alloy-type lithium-ion electrodes,Bi has outstanding application prospects for large volume capacity(3800 mAh·cm^(-3))and high electronic conductivity(1.4×10^(7)S·m^(-1)).However,the fast-charging performance is hindered by significant volume expansion(>218%)and a low rate of phase diffusion.To overcome these two problems,an N-doped carbon nanoflower coating layer was elaborately in-situ reconstructed on a multiple-wall Bi microsphere by hydrothermal methods and subsequent calcination in this study.The carbon nanoflowers greatly increase specific surface area(40.0 m^(2)·g^(-1))and alleviate the volume expansion(130%).In addition,the incorporation of N-doped carbon nanoflowers leads to a gradual enhancement in the Li adsorption energy of Bi during the process of lithium insertion and improves the electrical conductivity.Therefore,the contribution rate of pseudo-capacitance reached 87.5%at the scan rate of 0.8 mV·s^(-1),and the Li-ion diffusion coefficient(D_(Li^(+)))was calculated in the range of 10^(-10)to 10^(-12)cm^(2)·s^(-1).The Bi@CNFs anode provided a high specific volumetric capacity of 2117.0 mAh·cm^(-3)at 5C and a high capacity retention ratio of 93.2%after 800 cycles.The Bi@CNFs//LiFePO_(4)full cell also displayed a stable capacity of 113.9 mAh·g^(-1)and energy density of 296.1 Wh·kg^(-1)after 100 cycles with a Coulombic efficiency of 97.6%.The mechanism of fast-charging lithium storage was verified by distribution of relaxation time analysis and density functional theory calculation.This paper provides a new strategy to increase the pseudo-capacitance and reduce the volume expansion for the preparation of alloy-type fast-charging electrodes.
基金supported by the Excellent Research and Innovation Team Project of Anhui Province(2022AH010001)。
文摘Electrochemical synthesis of ammonia represents a green and environmental-ly friendly method distinct from tradi-tional Harper-Bosch processes,which demand stringent conditions.However,identifying a catalyst with high selec-tivity and catalytic activity to cleave the robust triple bond of N_(2)remains a formidable challenge.Herein,we present a systematic study on the geo-metrical and electronic structure,intensity of N_(2)adsorption,reaction intermediates,change in Gibbs free energy,and desorption of by-product hydrazine for the nitrogen reduction reac-tion employing a MnNx-graphene(x=3,4)catalyst from a theoretical perspective.The com-putational results reveal that MnN3-graphene exhibits superior catalytic performance pre-dominantly via the distal mechanism,with a low potential of 0.49 V.Moreover,the detach-ment of the produced NH3 is facilitated with a free energy of only 0.27 eV,significantly lower than those of previous catalysts,ensuring the exceptional durability of MnN_(3)-graphene.This study offers theoretical insights guiding the exploration of single Mn atom catalysts in ammo-nia synthesis.
基金support from National Natural Science Foundation of China(32101474 and 42377249)National Key Research and Development Program of China(2023YFD2201605).
文摘CO_(2) conversion to CO via the reverse water-gas shift(RWGS)reaction is limited by a low CO_(2) conversion rate and CO selectivity.Herein,an efficient RWGS catalyst is constructed through Enteromorpha prolifera–derived N-rich mesoporous biochar(EPBC)supported atomic-level Cu-Mo_(2)C clusters(Cu-Mo_(2)C/EPBC).Unlike traditional acti-vated carbon(AC)supported Cu-Mo_(2)C particles(Cu-Mo_(2)C/AC),the Cu-Mo_(2)C/EPBC not only presents the better graphitization degree and larger specific surface area,but also uniformly andfirmly anchors atomic-level Cu-Mo_(2)C clusters due to the existence of pyridine nitrogen.Furthermore,the pyridine N of Cu-Mo_(2)C/EPBC strengthens an unblocked electron transfer between Mo_(2)C and Cu clusters,as verified by X-ray absorption spectroscopy.As a result,the synergistic effect between pyridinic N anchoring and the clusters interaction in Cu-Mo_(2)C/EPBC facilitates an improved CO selectivity of 99.95%at 500℃ compared with traditional Cu-Mo_(2)C/AC(99.60%),as well as about 3-fold CO_(2) conversion rate.Density functional theory calculations confirm that pyr-idine N-modified carbon activates the local electronic redistribution at Cu-Mo_(2)C clusters,which contributes to the decreased energy barrier of the transition state of CO^(*)+O^(*)+2H^(*),thereby triggering the transformation of rate-limited step during the redox pathway.This biomass-derived strategy opens perspective on producing sustain-able fuels and building blocks through the RWGS reaction.
基金financially supported by National High-Level Talent FundNational Natural Science Foundation of China (Nos. 22372138,22461160253,22121001,and 22072118)+3 种基金thank financial support from State Key Laboratory of Physical Chemistry of Solid Surfaces of Xiamen UniversityShenzhen Science and Technology Program (No. JCYJ20220530143401002)supported by Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM) (No. HRTP-[2022]-3)the Fundamental Research Funds for the Central Universities (No. 20720220008)
文摘The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts,while its symmetric charge distribution nature is not favorable for electron transfer and then hindering the efficient CO_(2)RR.Herein,we constructed a Ni SA/CNs single-atom catalyst.Notably,it features unique Ni-N_(4)-O active sites,featuring one axial O atom and four planar N atoms,constituting a broken symmetrical electronic structure of Ni-N_(4) sites.Furthermore,hierarchical pore structures were obtained with the assistance of NaNO_(3) pore-forming agent during thermal treatment process,which promote electronic and mass transfer.And the resulting high specific surface area can host more Ni-N_(4)-O active sites.These specialized active sites promote the key intermediate(∗CO)adsorption/desorption and suppresses hydrogen evolution.Consequently,the Ni SA/CNs catalyst exhibits a high turnover frequency(TOF)value,reaching 34,081 h^(-1) at-0.98 V vs.RHE.Additionally,it achieves an excellent CO Faradaic efficiency,exceeding 90%,over a wide potential range from-0.4 V to-1.0 V vs.RHE.This work not only offers a new method for the rational synthesize single-atom catalysts with unique Ni-N_(4)-O active sites,but also provides in-depth insight into the origin of catalytic activity of porous carbon-base catalysts.
基金supported by the program of National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and Future planning(grant number 2022R1A4A1034312,2023R1A2C1007413)by the Commercialization Promotion Agency for R&D Outcomes(COMPA)grant funded by the Korean Government(Ministery of Science and ICT)(RS-2023-00304764)。
文摘Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yardlong bean-like Fe_(9)Ni_(9)S_(16)/FeS heterostructures with sulfur vacancies encapsulated in N-doped carbon nanotubes(3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs)are controllably synthesized through Fe/Ni-catalyzed pyrolysis of dicyandiamide followed by sulfidation strategies.1D nanotubes with robust outer walls and internal cavity structures shorten the diffusion paths of ions/electrons and buffer volume expansion and aggregation of active materials.The Fe_(9)Ni_(9)S_(16)/FeS heterostructure provides a powerful driving force for charge transfer by forming built-in electric fields,optimizing ion adsorption,while the Fe_(9)Ni_(9)S_(16)features a wider interlayer spacing that allows for frequent Na+/Li+insertion and extraction,thereby enhancing the reaction kinetics within the electrode.Driven by these synergistic factors,the 3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs demonstrates remarkable electrochemical performance,achieving a substantial reversible capacity of up to 682.1mA h g^(−1)for SIBs at 0.1 A g^(−1)and 782.7 mA h g^(−1)for LIBs at 0.5 A g−1,alongside exceptional cycling stability in SIBs,maintaining 78.7%of its capacity after 1500 cycles at 1 A g^(−1)coupling with the ether-based electrolyte.Employing various electrochemical analyses in conjunction with ex-situ characterization techniques and Density Functional Theory(DFT)calculations,the storage mechanisms and phase transition processes are investigated,elucidating the structure-composition-performance relationships.This work paves the way for a new strategy in designing advanced materials with engineered heterostructures and controllable defects for energy conversion and storage devices.
文摘Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization(CDI) community. Understanding the causes of performance decay in traditional carbons is crucial to design a high-performance material. Based on this, here, nitrogen-doped activated carbon(NAC) was prepared by pyrolyzing the blend of activated carbon powder(ACP) and melamine for the positive electrode of asymmetric CDI. By comparing the indicators changes such as conductivity, salt adsorption capacity, pH, and charge efficiency of the symmetrical ACP-ACP device to the asymmetric ACP-NAC device under different CDI cycles, as well as the changes of the electrochemical properties of anode and cathode materials after long-term operation, the reasons for the decline of the stability of the CDI performance were revealed. It was found that the carboxyl functional groups generated by the electro-oxidation of anode carbon materials make the anode zero-charge potential(E_(pzc)) shift positively,which results in the uneven distribution of potential windows of CDI units and affects the adsorption capacity. Furthermore, by understanding the electron density on C atoms surrounding the N atoms, we attribute the increased cyclic stability to the enhanced negativity of the charge of carbon atoms adjacent to quaternary-N and pyridinic-oxide-N.
基金supported by the National Natural Science Foundation of China(T2322015,22209094,22209093,and 22109086)the National Key Research and Development Program(2021YFB2500300)+2 种基金the Open Research Fund of CNMGE Platform&NSCC-TJOrdos-Tsinghua Innovative&Collaborative Research Program in Carbon Neutralitythe Tsinghua University Initiative Scientific Research Program。
文摘Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very lacking.Herein,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an example.An interface model was developed,incorporating the electrode potential and atom electronegativities.As a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following electrochemical reactions at the atomic level.Specifically,the negatively charged N atoms repel the anions and adsorb Li~+at high and low potentials,respectively.Such preferential adsorption suggests that Ndoped graphite can promote Li~+desolvation and regulate the location of Li~+deposition.This CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.
基金support from the Natural Science Foundation of Jilin Province(Grant No.20200201073JC)the National Natural Science Foundation of China(Grant No.52130101)+1 种基金Interdisciplinary Integration and Innovation Project of JLU(Grant No.JLUXKJC2021ZY01)the Fundamental Research Funds for the Central Universities.
文摘With the advantage of fast charge transfer,heterojunction engineering is identified as a viable method to reinforce the anodes'sodium storage performance.Also,vacancies can effectively strengthen the Na+adsorption ability and provide extra active sites for Na+adsorption.However,their synchronous engineering is rarely reported.Herein,a hybrid of Co_(0.85)Se/WSe_(2) heterostructure with Se vacancies and N-doped carbon polyhedron(CoWSe/NCP)has been fabricated for the first time via a hydrothermal and subsequent selenization strategy.Spherical aberration-corrected transmission electron microscopy confirms the phase interface of the Co_(0.85)Se/WSe_(2) heterostructure and the existence of Se vacancies.Density functional theory simulations reveal the accelerated charge transfer and enhanced Na+adsorption ability,which are contributed by the Co_(0.85)Se/WSe_(2) heterostructure and Se vacancies,respectively.As expected,the CoWSe/NCP anode in sodium-ion battery achieves outstanding rate capability(339.6 mAh g^(−1) at 20 A g^(−1)),outperforming almost all Co/W-based selenides.
