Carbon-based materials have gained significant attention in anticancer treatment because of their exceptional biocompatibility,yet critical challenges persist in establishing definitive correlations between their poro...Carbon-based materials have gained significant attention in anticancer treatment because of their exceptional biocompatibility,yet critical challenges persist in establishing definitive correlations between their porous structures and functional performance.We report the use of a silica template to guide pore formation in the design of mesoporous carbon spheres(mC)with tailored pore structures for improved combined photothermal-chemotherapy.The mesopore size of mC has been adjusted by kinetic control of the resin polymerization and silica hydrolysis.Structural characterization showed that 4.4 nm mesopores enabled an exceptional gemcitabine loading of 228 mg g^(−1) and a sustained pH/thermal dual-responsive release with>70%drug release under near-infrared(NIR)irradiation.Finite element analysis demonstrated pore size-dependent heat transfer dynamics,with the improved mC achieving a superior photothermal conversion efficiency of 62%by a combination of N-doping and defect engineering.In vitro evaluations confirmed outstanding biocompatibility with>95%cell viability at 200μg mL^(−1) and potent tumor suppression in pancreatic and biliary cancer models with an~5%cell viability at 25μg mL^(−1) where combined therapy showed a 3.7-fold increased cytotoxicity over monotherapy.The improved structure of mC facilitated cascade therapeutic effects with enhanced tumor permeability derived from NIR-triggered hyperthermia and prolonged therapeutic exposure due to pH-responsive drug release.This pore engineering strategy establishes a structure-function process for next-generation theranostic platforms,addressing the critical limitations of conventional pancreatic and biliary cancer therapies through spatiotemporal control of multimodal treatment.展开更多
Lithium-sulfur(Li-S)batteries boast a theoretical energy density as high as 2600 Wh·kg^(−1),positioning them as a highly attractive option for future advanced energy storage systems.Challenges such as slow transf...Lithium-sulfur(Li-S)batteries boast a theoretical energy density as high as 2600 Wh·kg^(−1),positioning them as a highly attractive option for future advanced energy storage systems.Challenges such as slow transformation kinetics and shuttle effects associated with lithium polysulfides(LiPSs)have seriously hindered their practical applications.In this paper,we present a new method for the synthesis of hollow carbon-sphere-supported Co monatomic catalysts(Co-N-C).This new synthesis method achieves pyrolytic coordination using a precursor rich in imide(-RC=N-)polymers.This synthesis method not only improves the adsorbability and catalytic activity of LiPS but also significantly weakens the shuttle effect and generates Co-N-C with superior conductivity,abundant hollow structures,and a high specific surface area,thus efficiently capturing and restricting the movement of LiPS intermediates.The dispersed Co monoatomic catalysts(Co SACs)were anchored to a highly conductive nitrogen-doped carbon framework and exhibited symmetric N-coordination active sites(Co-N_(4))to ensure fast redox kinetics of LiPS and Li_(2)S_(2)/Li_(2)S solid-state products.The lithium-sulfur battery with Co-N-C as the sulfur carrier showed excellent discharging capacity of 1146.6 mAh·g^(−1) at a discharge rate of 0.5 C and maintained excellent performance at a high discharge rate of 2 C.The capacity decay rate in 500 cycles was only 0.086%per cycle,reflecting excellent long-term cycle stability.This study highlights the key role of the synergistic effect between single-atom cobalt catalysts and hollow carbon spheres in enhancing the efficiency of lithium-sulfur(Li-S)batteries.It also provides valuable insights into the construction and fabrication of highly active monatomic catalysts.The catalytic conversion efficiency of lithium polysulfides is significantly enhanced when embedded in hollow carbon architectures,which serves as a critical strategy for optimizing the electrochemical behavior of next-generation Li-S batteries.展开更多
Exploring efficient and nonprecious metal electrocatalysts of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is crucial for developing rechargeable zinc-air batteries(ZABs).Herein,an alloying-degree c...Exploring efficient and nonprecious metal electrocatalysts of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is crucial for developing rechargeable zinc-air batteries(ZABs).Herein,an alloying-degree control strategy was employed to fabricate nitrogen-doped carbon sphere(NCS)decorated with dual-phase Co/Co_(7)Fe_(3)heterojunctions(CoFe@NCS).The phase composition of materials has been adjusted by controlling the alloying degree.The optimal CoFe_(0.08)@NCS electrocatalyst displays a half-wave potential of 0.80 V for ORR and an overpotential of 283 mV at 10 mA·cm^(-2)for OER in an alkaline electrolyte.The intriguing bifunctional electrocatalytic activity and durability is attributed to the hierarchically porous structure and interfacial electron coupling of highly-active Co_(7)Fe_(3)alloy and metallic Co species.When the CoFe_(0.08)@NCS material is used as air-cathode catalyst of rechargeable liquid-state zinc-air battery(ZAB),the device shows a high peak power-density(157 mW·cm^(-2))and maintains a stable voltage gap over 150 h,outperforming those of the benchmark(Pt/C+RuO_(2))-based device.In particular,the as-fabricated solid-state flexible ZAB delivers a reliable compatibility under different bending conditions.Our work provides a promising strategy to develop metal/alloy-based electrocatalysts for the application in renewable energy conversion technologies.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
Carbon residue is a waste by-product produced during the rapid pyrolysis of biomass into bio-oil,and the fragile nature and poor pore processability making it difficult to dispose.In this study,carbon residues obtaine...Carbon residue is a waste by-product produced during the rapid pyrolysis of biomass into bio-oil,and the fragile nature and poor pore processability making it difficult to dispose.In this study,carbon residues obtained from various biomasses waste are selfassembled into macroscopic porous carbon spheres(CSs),through interactions with cellulose nanofibrils(CNF)and in situ treatment by KOH to remove their high ash content.The micro-and meso-pore structure of CSs can be influenced by the type of raw biomasses,pyrolysis heating rate and structure-directing agent,through KOH removal of multiscale ashes and morphology controlling of CSs.Compared to fast pyrolyzed woody biomass,the resulting CSs derived from silicon-rich biomass residue shows superior mesopore volume ranging from 0.3 cm^(3)/g to 0.5 cm^(3)/g,owing to the ash self-templates(nonmetallic oxides).The optimized CS from fast pyrolyzed bamboo residue demonstrates the best shape factor(0.78),highest carbon oxide(CO_(2))gravimetric adsorption capacity(1.8 mmol/g),and low regeneration energy(32 kJ/mol).The life cycle assessment shows the carbon reduction potential of fast pyrolysis residue derived CSs was most contributed by the global warming potential of produced fixed carbon and bio-oil,which is−557.85 kg CO_(2) eq/t wastes.This study highlights a cost-effective and sustainable strategy for CO_(2) capture by carbon residue.展开更多
In this work,Dy_(2)O_(3)rods and layered Dy_(2)WO_(6)heterostructure were effectively interconnected by carbon spheres named Dy_(2)O_(3)/Dy_(2)WO_(6)/C-sph nanocomposite with a confined interface and it was fabricated...In this work,Dy_(2)O_(3)rods and layered Dy_(2)WO_(6)heterostructure were effectively interconnected by carbon spheres named Dy_(2)O_(3)/Dy_(2)WO_(6)/C-sph nanocomposite with a confined interface and it was fabricated using a simple solvothermal approach.These ternary nanocomposites were investigated by X-ray diffraction(XRD),UV-visible diffuse-reflectance spectroscopy(UV-DRS),Fourier transform-infrared spectroscopy(FT-IR),Raman,field emission scanning electron microscopy(FESEM)with energy disperse spectroscopy(EDS),high-resolution transmission electron microscopy(HRTEM),and X-ray photoelectron spectroscopy(XPS)analyses systematically.The XRD data expose that the synthesized materials are formed with a virtuous crystalline state.The charge storage properties and electrochemical performances of the as-synthesized nanocomposites and pure components were assessed with the help of cyclic voltammogram(CV),galvanostatic charge-discharge studies(GCD),and electrochemical impedance studies(EIS),respectively.The rare-earth-based novel Dy_(2)O_(3)/Dy_(2)WO_(6)/C-sph nanocomposite as wo rking electrodes established commendable electrochemical perfo rmances with a maximum specific capacitance value of 123 F/g at a current density of 0.4 A/g in 2.0 mol/L aqueous KOH solution.According to the stability measurements,it was observed that the initial capacitance was maintained at~93%even after 2500 cycles,indicating that good electrochemical stability with the lowest internal resistance values was obtained from EIS analysis.The electrochemical measurements suggest that the Dy_(2)O_(3)/Dy_(2)WO_(6)/C-sph nanocomposite enables great competence and can be used as alternative electrode material in supercapacitor devices to avail high energy efficiency in a sustainable approach.展开更多
Currently,electromagnetic radiation and interference have a significant effect on the operation of electronic devices and human health systems.Thus,developing excellent microwave absorbers have a huge significance in ...Currently,electromagnetic radiation and interference have a significant effect on the operation of electronic devices and human health systems.Thus,developing excellent microwave absorbers have a huge significance in the material research field.Herein,a kind of ultrafine zinc oxide(ZnO)nanoparticles(NPs)supported on three-dimensional(3D)ordered mesoporous carbon spheres(ZnO/OMCS)is prepared from silica inverse opal by using phenolic resol precursor as carbon source.The prepared lightweight ZnO/OMCS nanocomposites exhibit 3D ordered carbon sphere array and highly dispersed ultrafine ZnO NPs on the mesoporous cell walls of carbon spheres.ZnO/OMCS-30 shows microwave absorbing ability with a strong absorption(−39.3 dB at 10.4 GHz with a small thickness of 2 mm)and a broad effective absorption bandwidth(9.1 GHz).The outstanding microwave absorbing ability benefits to the well-dispersed ultrafine ZnO NPs and the 3D ordered mesoporous carbon spheres structure.This work opened up a unique way for developing lightweight and high-efficient carbon-based microwave absorbing materials.展开更多
Limited lithium resources have promoted the exploration of new battery technologies.Among them,potassium-ion batteries are considered as promising alternatives.At present,commercial graphite and other carbon-based mat...Limited lithium resources have promoted the exploration of new battery technologies.Among them,potassium-ion batteries are considered as promising alternatives.At present,commercial graphite and other carbon-based materials have shown good prospects as anodes for potassium-ion batteries.However,the volume expansion and structural collapse caused by periodic K+insertion/extraction have severely restricted further development and application of potassium-ion batteries.A hollow biomass carbon ball(NOP-PB)ternarily doped with N,O,and P was synthesized and used as the negative electrode of a potassium-ion battery.X-ray photoelectron spectroscopy,Fourier‐transform infrared spectroscopy,and transmission electron microscopy confirmed that the hollow biomass carbon spheres were successfully doped with N,O,and P.Further analysis proved that N,O,and P ternary doping expands the interlayer distance of the graphite surface and introduces more defect sites.DFT calculations simultaneously proved that the K adsorption energy of the doped structure is greatly improved.The solid hollow hierarchical porous structure buffers the volume expansion of the potassium insertion process,maintains the original structure after a long cycle and promotes the transfer of potassium ions and electrons.Therefore,the NOP‐PB negative electrode shows extremely enhanced electrochemical performance,including high specific capacity,excellent long‐term stability,and good rate stability.展开更多
Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The h...Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The high-cost PGM catalyst in fuel cells can be replaced by earth-abundant transition-metalbased catalysts,that is,an Fe-N-C catalyst,which is considered one of the most promising alternatives.However,the performance of the Fe-N-C catalyst is hindered by the low catalytic activity and poor stability,which is caused by insufficient active sites and the lack of optimization of the triple-phase interface for mass transportation.Herein,a novel Fe–N–C catalyst consisting of mono-dispersed hierarchically mesoporous carbon sphere cores and single Fe atom-dispersed functional shells are presented.The synergistic effect between highly dispersed Fe-active sites and well-organized porous structures yields the combination of high ORR activity and high mass transfer performance.The half-wave potential of the catalyst in 0.1M H_(2)SO_(4) is 0.82 V versus reversible hydrogen electrode,and the peak power density is 812 mW·cm^(−2) in H_(2)–O_(2) fuel cells.Furthermore,it shows superior methanol tolerance,which is almost immune to methanol poisoning and generates up to 162 mW·cm^(−2) power density in direct methanol fuel cells.展开更多
Frequent offshore oil spill accidents, industrial oily sewage, and the indiscriminate disposal of urban oily sewage have caused seri- ous impacts on the human living environment and health. The traditional oil-water s...Frequent offshore oil spill accidents, industrial oily sewage, and the indiscriminate disposal of urban oily sewage have caused seri- ous impacts on the human living environment and health. The traditional oil-water separation methods not only cause easily environmental secondary pollution but also a waste of limited resources. Therefore, in this work, three-dimensional (3D) graphitic carbon sphere (GCS) foams (collectively referred hereafter as 3D foams) with a 3D porous structure, pore size distribution of 25-200 μm, and high porosity of 62vol% were prepared for oil adsorption via gel casting using GCS as the starting materials. The results indicate that the water contact angle (WCA) of the as-prepared 3D foams is 130°. The contents of GCS greatly influenced the hydrophobicity, WCA, and microstructure of the as-prepared samples. The adsorption capacities of the as-prepared 3D foams for paraffin oil, vegetable oil, and vacuum pump oil were approximately 12-15 g/g, which were 10 times that of GCS powder. The as-prepared foams are desirable characteristics of a good sorbent and could be widely used in oil spill accidents.展开更多
Porous carbon spheres are prepared by direct carbonization of potassium salt of resorcinol-formaldehyde resin spheres, and are investigated as COadsorbents. It is found that the prepared carbon materials still maintai...Porous carbon spheres are prepared by direct carbonization of potassium salt of resorcinol-formaldehyde resin spheres, and are investigated as COadsorbents. It is found that the prepared carbon materials still maintain the typical spherical shapes after the activation, and have highly developed ultra-microporosity with uniform pore size, indicating that almost the activation takes place in the interior of the polymer spheres. The narrow-distributed ultra-micropores are attributed to the "in-situ homogeneous activation"effect produced by the mono-dispersed potassium ions as a form of -OK groups in the bulk of polymer spheres. The CS-1 sample prepared under a KOH/resins weight ratio of 1 shows a very high COcapture capacity of 4.83 mmol/g and good CO/Nselectivity of7-45. We believe that the presence of a welldeveloped ultra-microporosity is responsible for excellent COsorption performance at room temperature and ambient pressure.展开更多
A new design route was presented to fabricate cobalt aluminum-layered double hydroxide(CoAl-LDH)thin layers whichgrow on carbon spheres(CSs)through a growth method.The CoAl-LDH thin layers consist of nanoflakes with a...A new design route was presented to fabricate cobalt aluminum-layered double hydroxide(CoAl-LDH)thin layers whichgrow on carbon spheres(CSs)through a growth method.The CoAl-LDH thin layers consist of nanoflakes with a thickness of20nm.The galvanostatic charge-discharge test of the CoAl-LDH/CSs composite shows a great specific capacitance of1198F/g at1A/g(based on the mass of the CoAl-LDH/CSs composite)in6mol/L KOH solution,and the composite displays an impressive specificcapacitance of920F/g even at a high current density of10A/g.Moreover,the composite remains a specific capacitance of928F/gafter1000cycles at2A/g,and the specific capacitance retention is84%,indicating that the composite has high specific capacitance,excellent rate capability and good cycling stability in comparison to pristine CoAl-LDH.展开更多
Synthesis of spherical carbon beads with effective CO_2 capture capability is highly desirable for large scale application of CO2 sorption, but remains challenging. Herein, a facile and efficient strategy to prepare n...Synthesis of spherical carbon beads with effective CO_2 capture capability is highly desirable for large scale application of CO2 sorption, but remains challenging. Herein, a facile and efficient strategy to prepare nitrogen-doped hierarchically porous carbon spheres was developed via co-pyrolyzation of poly(vinylidene chloride) and melamine in alginate gel beads. In this approach, melamine not only serves as the nitrogen precursor, but also acts as a template for the macropores structures. The nitrogen contents in the hierarchically porous carbon spheres reach a high level, ranging from 11.8 wt% to 14.7 wt%, as the melamine amount increases. Owing to the enriched nitrogen functionalities and the special hierarchical porous structure, the carbon spheres exhibit an outstanding CO_2 capture performance, with the dynamic capacity of as much as about 7 wt% and a separation factor about 49 at 25 °C in a gas mixture of CO_2/N_2(0.5:99.5, v/v).展开更多
Porous carbon spheres（PCS） derived from lignin have been prepared through a facile method and fabricated as electrodes for electric double-layer capacitors. Spherical shaped mixtures of lignosulfonate and crystalize...Porous carbon spheres（PCS） derived from lignin have been prepared through a facile method and fabricated as electrodes for electric double-layer capacitors. Spherical shaped mixtures of lignosulfonate and crystalized KOH are formed by spray drying of a solution of lignosulfonate and KOH. Activation by KOH is performed at high temperatures along with lignosulfonate carbonization. With an appropriate pore structure, the obtained PCS have a specific surface area of 1372.87 m^2 g^-1 and show a capacitance of 340 F g^-1 in 3 M KOH at a current density of 0.5 A g^-1. Moreover, a symmetric supercapacitor fabricated using the PCS as electrodes show a maximum capacitance of 68.5 F g^-1, and an energy density of 9.7 W h kg^-1 at a power density of 250 W kg^-1. The capacity retention is more than 94.5% after 5000 galvanostatic chargedischarge cycles. The excellent characteristics seem to be ascribed to the pore structures of PCS that have a large specific surface area and a low electrical resistance.展开更多
In this study, we have established a facile method to synthesize functional hollow carbon spheres with large hollow interior, which can act as active colloidal catalysts. The method includes the following steps： firs...In this study, we have established a facile method to synthesize functional hollow carbon spheres with large hollow interior, which can act as active colloidal catalysts. The method includes the following steps： first, hollow polymer spheres with large hollow interior were prepared using sodium oleate as the hollow core generator, and 2,4-dihydroxybenzoic acid and hexamethylene tetramine （HMT） as the polymer precursors under hydrothermal conditions; Fe3＋ or Ag＋ cations were then introduced into the as-prepared hollow polymer spheres through the carboxyl groups; finally, the hollow polymer spheres can be pseudomorphically converted to hollow carbon spheres during pyrolysis process, meanwhile iron or silver nanoparticles can also be formed in the carbon shell simultaneously. The structures of the obtained functional hollow carbon spheres were characterized by TEM, XRD, and TG. As an example, Ag-doped hollow carbon spheres were used as colloid catalysts which showed high catalytic activity in 4-nitrophenol reduction reaction.展开更多
Porous carbon spheres represent an ideal family of electrode materials forsupercapacitors because of the high surface area,ideal conductivity,negligible aggregation,and ability to achieve space efficient packing.Howev...Porous carbon spheres represent an ideal family of electrode materials forsupercapacitors because of the high surface area,ideal conductivity,negligible aggregation,and ability to achieve space efficient packing.However,the development of new synthetic methods towards porous carbon spheres still remains a great challenge.Herein,N-doped hollow carbon spheres with an ultrahigh surface area of2044 m^(2)/g have been designed based on the phenylenediamine-formaldehyde chemistry.When applied in symmetric supercapacitors with ionic electrolyte(EMIBF_4),the obtained N-doped hollow carbon spheres demonstrate a high capacitance of 234 F/g,affording an ultrahigh energy density of 114.8 Wh/kg.Excellent cycling stability has also been achieved.The impressive capacitive performances make the phenylenediamine-formaldehyde resin derived N-doped carbon a promising candidate electrode material for supercapacitors.展开更多
The electrochemical performance of hard carbon in sodium storage is still limited by its poor cycling stability and rate capability because of the sluggish kinetics process.In this study,we use a simple and effective ...The electrochemical performance of hard carbon in sodium storage is still limited by its poor cycling stability and rate capability because of the sluggish kinetics process.In this study,we use a simple and effective method to accelerate the kinetics process by engineering the structure of the electrode to promote its surface and near-surface reactions.This goal is realized by the use of slightly aggregated ultra-small carbon spheres.The large specific surface area formed by the small spheres can provide abundant active sites for electrochemical reactions.The abundant mesopores and macropores derived from the secondary particle piled structure of the carbon spheres could facilitate the transport of electrolytes,shorten the diffusion distance of Na^(+)and accommodate the volume expansion during cycling.Benefiting from these unique structure features,PG700-3(carbon spheres with the diameters of 40-60 nm carbonized at 700℃)exhibits high performance for sodium storage.A high reversible capacity of 163 mAh g^(-1) could be delivered at a current density of 1.0 A g^(-1) after 100 cycles.Interestingly,at a current density of 10.0 A g^(-1),the specific capacity of PG700-3 gradually increases to 140 mAh g^(-1) after 10000 cycles,corresponding to a capacity retention of 112%.Given the enhanced kinetics of SIBs reactions,PG700-3 exhibits an excellent rate capability,i.e.,230 and 138 mAh g^(-1) at 0.1 and 5.0 A g^(-1),respectively.This study provides a facile method to attain high performance anode materials for SIBs.The design strategy and improvement mechanism could be extended to other materials for high rate applications.展开更多
The strong metal-support interaction inducing combined effect plays a crucial role in the catalysis reaction. Herein, we revealed that the combined advantages of MoSe_(2), Ru, and hollow carbon spheres in the form of ...The strong metal-support interaction inducing combined effect plays a crucial role in the catalysis reaction. Herein, we revealed that the combined advantages of MoSe_(2), Ru, and hollow carbon spheres in the form of Ru nanoparticles(NPs) anchored on a two-dimensionally ordered MoSe_(2) nanosheet-embedded mesoporous hollow carbon spheres surface(Ru/MoSe_(2)@MHCS) for the largely boosted hydrogen evolution reaction(HER) performance. The combined advantages from the conductive support, oxyphilic MoSe_(2), and Ru active sites imparted a strong synergistic effect and charge redistribution in the Ru periphery which induced high catalytic activity, stability, and kinetics for HER. Specifically, the obtained Ru/MoSe_(2)@MHCS required a small overpotential of 25.5 and 38.4 mV to drive the kinetic current density of 10 mA cm^(-2)both in acid and alkaline media, respectively, which was comparable to that of the Pt/C catalyst. Experimental and theoretical results demonstrated that the charge transfer from MoSe_(2) to Ru NPs enriched the electronic density of Ru sites and thus facilitated hydrogen adsorption and water dissociation. The current work showed the significant interfacial engineering in Ru-based catalysts development and catalysis promotion effect understanding via the metal-support interaction.展开更多
Rationally designed hierarchical structures and heteroatomic doping of carbon are effective strategies to enhance the stability and electrical conductivity of materials.Herein,SnSe_(2)flakes were generated in the doub...Rationally designed hierarchical structures and heteroatomic doping of carbon are effective strategies to enhance the stability and electrical conductivity of materials.Herein,SnSe_(2)flakes were generated in the double-walled hollow carbon spheres(DWHCSs),in which N and Se atoms were doped in the carbon walls,to construct SnSe_(2)@N,Se-DWHCSs by confined growth and in-situ derivatization.The N and Sedoped DWHCSs can effectively limit the size increase of SnSe_(2),promote ion diffusion kinetics,and buffer volume expansion,which can be proved by electron microscope observation and density functional theory calculation.Consequently,the SnSe_(2)@N,Se-DWHCSs as an anode material for sodium ion batteries(SIBs)demonstrated a distinguished reversible capacity of 322.8 mAh g^(-1)at 5 A g^(-1)after 1000 cycles and a superior rate ability of 235.3 m Ah g^(-1)at an ultrahigh rate of 15 A g^(-1).Furthermore,the structure evolution and electrochemical reaction processes of SnSe2@N,Se-DWHCSs in SIBs were analyzed by exsitu methods,which confirmed the consecutive hybrid mechanism and the phase transition process.展开更多
Energy conversion technologies like fuel cells and metal-air batteries require oxygen reduction reaction(ORR)electrocatalysts with low cost and high catalytic activity.Herein,N-doped carbon spheres(N-CS)with rich micr...Energy conversion technologies like fuel cells and metal-air batteries require oxygen reduction reaction(ORR)electrocatalysts with low cost and high catalytic activity.Herein,N-doped carbon spheres(N-CS)with rich micropore structure have been synthesized by a facile two-step method,which includes the polymerization of pyrrole and formaldehyde and followed by a facile pyrolysis process.During the preparation,zinc chloride(ZnCl2)was utilized as a catalyst to promote polymerization and provide a hypersaline environment.In addition,the morphology,defect content and activity area of the resultant N-CS catalysts could be regulated by controlling the content of ZnCl2.The optimum N-CS-1 catalyst demonstrated much better catalytic activity and durability towards ORR in alkaline conditions than commercial 20 wt%Pt/C catalysts,of which the half-wave potential reached 0.844 V vs.RHE.When applied in the Zn-air batteries as cathode catalysts,N-CS-1 showed a maximum power density of 175 mW cm^(-2) and long-term discharging stability of over 150 h at 10 mA cm^(-2),which outperformed 20 wt%Pt/C.The excellent performance could be due to its ultrahigh specific surface area of 1757 m2 g1 and rich micropore channels structure.Meanwhile,this work provides an efficient method to synthesize an ultrahigh surface porous carbon material,especially for catalyst application.展开更多
文摘Carbon-based materials have gained significant attention in anticancer treatment because of their exceptional biocompatibility,yet critical challenges persist in establishing definitive correlations between their porous structures and functional performance.We report the use of a silica template to guide pore formation in the design of mesoporous carbon spheres(mC)with tailored pore structures for improved combined photothermal-chemotherapy.The mesopore size of mC has been adjusted by kinetic control of the resin polymerization and silica hydrolysis.Structural characterization showed that 4.4 nm mesopores enabled an exceptional gemcitabine loading of 228 mg g^(−1) and a sustained pH/thermal dual-responsive release with>70%drug release under near-infrared(NIR)irradiation.Finite element analysis demonstrated pore size-dependent heat transfer dynamics,with the improved mC achieving a superior photothermal conversion efficiency of 62%by a combination of N-doping and defect engineering.In vitro evaluations confirmed outstanding biocompatibility with>95%cell viability at 200μg mL^(−1) and potent tumor suppression in pancreatic and biliary cancer models with an~5%cell viability at 25μg mL^(−1) where combined therapy showed a 3.7-fold increased cytotoxicity over monotherapy.The improved structure of mC facilitated cascade therapeutic effects with enhanced tumor permeability derived from NIR-triggered hyperthermia and prolonged therapeutic exposure due to pH-responsive drug release.This pore engineering strategy establishes a structure-function process for next-generation theranostic platforms,addressing the critical limitations of conventional pancreatic and biliary cancer therapies through spatiotemporal control of multimodal treatment.
基金supported by the National Natural Science Foundation of China(No.52064035)the Key Research and Development Program of Gansu Province,China(No.25YFGA024)the Natural Science Foundation of Zhejiang Province,China(No.LGG22E020003).
文摘Lithium-sulfur(Li-S)batteries boast a theoretical energy density as high as 2600 Wh·kg^(−1),positioning them as a highly attractive option for future advanced energy storage systems.Challenges such as slow transformation kinetics and shuttle effects associated with lithium polysulfides(LiPSs)have seriously hindered their practical applications.In this paper,we present a new method for the synthesis of hollow carbon-sphere-supported Co monatomic catalysts(Co-N-C).This new synthesis method achieves pyrolytic coordination using a precursor rich in imide(-RC=N-)polymers.This synthesis method not only improves the adsorbability and catalytic activity of LiPS but also significantly weakens the shuttle effect and generates Co-N-C with superior conductivity,abundant hollow structures,and a high specific surface area,thus efficiently capturing and restricting the movement of LiPS intermediates.The dispersed Co monoatomic catalysts(Co SACs)were anchored to a highly conductive nitrogen-doped carbon framework and exhibited symmetric N-coordination active sites(Co-N_(4))to ensure fast redox kinetics of LiPS and Li_(2)S_(2)/Li_(2)S solid-state products.The lithium-sulfur battery with Co-N-C as the sulfur carrier showed excellent discharging capacity of 1146.6 mAh·g^(−1) at a discharge rate of 0.5 C and maintained excellent performance at a high discharge rate of 2 C.The capacity decay rate in 500 cycles was only 0.086%per cycle,reflecting excellent long-term cycle stability.This study highlights the key role of the synergistic effect between single-atom cobalt catalysts and hollow carbon spheres in enhancing the efficiency of lithium-sulfur(Li-S)batteries.It also provides valuable insights into the construction and fabrication of highly active monatomic catalysts.The catalytic conversion efficiency of lithium polysulfides is significantly enhanced when embedded in hollow carbon architectures,which serves as a critical strategy for optimizing the electrochemical behavior of next-generation Li-S batteries.
基金financially supported by the National Natural Science Foundation of China(No.22279047)the Instrumental Analysis Center of Jiangsu University of Science and Technology。
文摘Exploring efficient and nonprecious metal electrocatalysts of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is crucial for developing rechargeable zinc-air batteries(ZABs).Herein,an alloying-degree control strategy was employed to fabricate nitrogen-doped carbon sphere(NCS)decorated with dual-phase Co/Co_(7)Fe_(3)heterojunctions(CoFe@NCS).The phase composition of materials has been adjusted by controlling the alloying degree.The optimal CoFe_(0.08)@NCS electrocatalyst displays a half-wave potential of 0.80 V for ORR and an overpotential of 283 mV at 10 mA·cm^(-2)for OER in an alkaline electrolyte.The intriguing bifunctional electrocatalytic activity and durability is attributed to the hierarchically porous structure and interfacial electron coupling of highly-active Co_(7)Fe_(3)alloy and metallic Co species.When the CoFe_(0.08)@NCS material is used as air-cathode catalyst of rechargeable liquid-state zinc-air battery(ZAB),the device shows a high peak power-density(157 mW·cm^(-2))and maintains a stable voltage gap over 150 h,outperforming those of the benchmark(Pt/C+RuO_(2))-based device.In particular,the as-fabricated solid-state flexible ZAB delivers a reliable compatibility under different bending conditions.Our work provides a promising strategy to develop metal/alloy-based electrocatalysts for the application in renewable energy conversion technologies.
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(Youth Fund,52200168).
文摘Carbon residue is a waste by-product produced during the rapid pyrolysis of biomass into bio-oil,and the fragile nature and poor pore processability making it difficult to dispose.In this study,carbon residues obtained from various biomasses waste are selfassembled into macroscopic porous carbon spheres(CSs),through interactions with cellulose nanofibrils(CNF)and in situ treatment by KOH to remove their high ash content.The micro-and meso-pore structure of CSs can be influenced by the type of raw biomasses,pyrolysis heating rate and structure-directing agent,through KOH removal of multiscale ashes and morphology controlling of CSs.Compared to fast pyrolyzed woody biomass,the resulting CSs derived from silicon-rich biomass residue shows superior mesopore volume ranging from 0.3 cm^(3)/g to 0.5 cm^(3)/g,owing to the ash self-templates(nonmetallic oxides).The optimized CS from fast pyrolyzed bamboo residue demonstrates the best shape factor(0.78),highest carbon oxide(CO_(2))gravimetric adsorption capacity(1.8 mmol/g),and low regeneration energy(32 kJ/mol).The life cycle assessment shows the carbon reduction potential of fast pyrolysis residue derived CSs was most contributed by the global warming potential of produced fixed carbon and bio-oil,which is−557.85 kg CO_(2) eq/t wastes.This study highlights a cost-effective and sustainable strategy for CO_(2) capture by carbon residue.
基金supported by Selective Excellence Research Initiative-2023,SRM Institute of Science and Technology(SRMIST/R/AR(A)/SERI2023/174/26-3944)。
文摘In this work,Dy_(2)O_(3)rods and layered Dy_(2)WO_(6)heterostructure were effectively interconnected by carbon spheres named Dy_(2)O_(3)/Dy_(2)WO_(6)/C-sph nanocomposite with a confined interface and it was fabricated using a simple solvothermal approach.These ternary nanocomposites were investigated by X-ray diffraction(XRD),UV-visible diffuse-reflectance spectroscopy(UV-DRS),Fourier transform-infrared spectroscopy(FT-IR),Raman,field emission scanning electron microscopy(FESEM)with energy disperse spectroscopy(EDS),high-resolution transmission electron microscopy(HRTEM),and X-ray photoelectron spectroscopy(XPS)analyses systematically.The XRD data expose that the synthesized materials are formed with a virtuous crystalline state.The charge storage properties and electrochemical performances of the as-synthesized nanocomposites and pure components were assessed with the help of cyclic voltammogram(CV),galvanostatic charge-discharge studies(GCD),and electrochemical impedance studies(EIS),respectively.The rare-earth-based novel Dy_(2)O_(3)/Dy_(2)WO_(6)/C-sph nanocomposite as wo rking electrodes established commendable electrochemical perfo rmances with a maximum specific capacitance value of 123 F/g at a current density of 0.4 A/g in 2.0 mol/L aqueous KOH solution.According to the stability measurements,it was observed that the initial capacitance was maintained at~93%even after 2500 cycles,indicating that good electrochemical stability with the lowest internal resistance values was obtained from EIS analysis.The electrochemical measurements suggest that the Dy_(2)O_(3)/Dy_(2)WO_(6)/C-sph nanocomposite enables great competence and can be used as alternative electrode material in supercapacitor devices to avail high energy efficiency in a sustainable approach.
基金The authors are grateful of the financial support by the National Natural Science Foundation of China(51902083 and 21606068)the Foundation Strengthening Program(2019-JCJQ-142-00)the Higher Education Science and Technology Research Project of Hebei Province(ZD2019087).
文摘Currently,electromagnetic radiation and interference have a significant effect on the operation of electronic devices and human health systems.Thus,developing excellent microwave absorbers have a huge significance in the material research field.Herein,a kind of ultrafine zinc oxide(ZnO)nanoparticles(NPs)supported on three-dimensional(3D)ordered mesoporous carbon spheres(ZnO/OMCS)is prepared from silica inverse opal by using phenolic resol precursor as carbon source.The prepared lightweight ZnO/OMCS nanocomposites exhibit 3D ordered carbon sphere array and highly dispersed ultrafine ZnO NPs on the mesoporous cell walls of carbon spheres.ZnO/OMCS-30 shows microwave absorbing ability with a strong absorption(−39.3 dB at 10.4 GHz with a small thickness of 2 mm)and a broad effective absorption bandwidth(9.1 GHz).The outstanding microwave absorbing ability benefits to the well-dispersed ultrafine ZnO NPs and the 3D ordered mesoporous carbon spheres structure.This work opened up a unique way for developing lightweight and high-efficient carbon-based microwave absorbing materials.
基金The authors are grateful for support from the National Natural Science Foundation of China(No.21671160).
文摘Limited lithium resources have promoted the exploration of new battery technologies.Among them,potassium-ion batteries are considered as promising alternatives.At present,commercial graphite and other carbon-based materials have shown good prospects as anodes for potassium-ion batteries.However,the volume expansion and structural collapse caused by periodic K+insertion/extraction have severely restricted further development and application of potassium-ion batteries.A hollow biomass carbon ball(NOP-PB)ternarily doped with N,O,and P was synthesized and used as the negative electrode of a potassium-ion battery.X-ray photoelectron spectroscopy,Fourier‐transform infrared spectroscopy,and transmission electron microscopy confirmed that the hollow biomass carbon spheres were successfully doped with N,O,and P.Further analysis proved that N,O,and P ternary doping expands the interlayer distance of the graphite surface and introduces more defect sites.DFT calculations simultaneously proved that the K adsorption energy of the doped structure is greatly improved.The solid hollow hierarchical porous structure buffers the volume expansion of the potassium insertion process,maintains the original structure after a long cycle and promotes the transfer of potassium ions and electrons.Therefore,the NOP‐PB negative electrode shows extremely enhanced electrochemical performance,including high specific capacity,excellent long‐term stability,and good rate stability.
基金We gratefully acknowledge support from the National Natural Science Foundation of China(Grant Nos.21905220,51772240,21503158,51425301,U1601214,21703184)the China Postdoctoral Science Foundation(2020M673408)+5 种基金the Key Research and Development Plan of Shaanxi Province,China(Grant No.2018ZDXM-GY-135)the Fundamental Research Funds for“Young Talent Support Plan”of Xi'an Jiaotong University(HG6J003)the“1000‐Plan program”of Shaanxi Province,the Promotion Program for Young and Middle-Aged Teacher in Science and Technology Research of Huaqiao University(ZQN-PY506)the Scientific Research Funds of Huaqiao University(17BS405)the State Key Laboratory for Mechanical Behavior of Materials(20192101)the Natural Science Foundation Committee of Jiangsu Province(BK20201190).
文摘Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The high-cost PGM catalyst in fuel cells can be replaced by earth-abundant transition-metalbased catalysts,that is,an Fe-N-C catalyst,which is considered one of the most promising alternatives.However,the performance of the Fe-N-C catalyst is hindered by the low catalytic activity and poor stability,which is caused by insufficient active sites and the lack of optimization of the triple-phase interface for mass transportation.Herein,a novel Fe–N–C catalyst consisting of mono-dispersed hierarchically mesoporous carbon sphere cores and single Fe atom-dispersed functional shells are presented.The synergistic effect between highly dispersed Fe-active sites and well-organized porous structures yields the combination of high ORR activity and high mass transfer performance.The half-wave potential of the catalyst in 0.1M H_(2)SO_(4) is 0.82 V versus reversible hydrogen electrode,and the peak power density is 812 mW·cm^(−2) in H_(2)–O_(2) fuel cells.Furthermore,it shows superior methanol tolerance,which is almost immune to methanol poisoning and generates up to 162 mW·cm^(−2) power density in direct methanol fuel cells.
基金the National Nat-ural Science Foundation of China(Nos.51872210 and 51672194)the Program for Innovative Teams of Outstand-ing Young and Middle-aged Researchers in the Higher Edu-cation Institutions of Hubei Province,China(No.T201602)the Key Program of Natural Science Foundation of Hubei Province,China(No.2017CFA004).
文摘Frequent offshore oil spill accidents, industrial oily sewage, and the indiscriminate disposal of urban oily sewage have caused seri- ous impacts on the human living environment and health. The traditional oil-water separation methods not only cause easily environmental secondary pollution but also a waste of limited resources. Therefore, in this work, three-dimensional (3D) graphitic carbon sphere (GCS) foams (collectively referred hereafter as 3D foams) with a 3D porous structure, pore size distribution of 25-200 μm, and high porosity of 62vol% were prepared for oil adsorption via gel casting using GCS as the starting materials. The results indicate that the water contact angle (WCA) of the as-prepared 3D foams is 130°. The contents of GCS greatly influenced the hydrophobicity, WCA, and microstructure of the as-prepared samples. The adsorption capacities of the as-prepared 3D foams for paraffin oil, vegetable oil, and vacuum pump oil were approximately 12-15 g/g, which were 10 times that of GCS powder. The as-prepared foams are desirable characteristics of a good sorbent and could be widely used in oil spill accidents.
基金the financial supports by the Natural Science Foundation of China (NSFC21576158, 21476132, 21576159 and 21403130)Shandong Provincial Natural Science Foundation, China (No. 2015 ZRB01765)
文摘Porous carbon spheres are prepared by direct carbonization of potassium salt of resorcinol-formaldehyde resin spheres, and are investigated as COadsorbents. It is found that the prepared carbon materials still maintain the typical spherical shapes after the activation, and have highly developed ultra-microporosity with uniform pore size, indicating that almost the activation takes place in the interior of the polymer spheres. The narrow-distributed ultra-micropores are attributed to the "in-situ homogeneous activation"effect produced by the mono-dispersed potassium ions as a form of -OK groups in the bulk of polymer spheres. The CS-1 sample prepared under a KOH/resins weight ratio of 1 shows a very high COcapture capacity of 4.83 mmol/g and good CO/Nselectivity of7-45. We believe that the presence of a welldeveloped ultra-microporosity is responsible for excellent COsorption performance at room temperature and ambient pressure.
基金Project(21471162) supported by the National Natural Science Foundation of ChinaProject(2015H6016) supported by the Science and Technology Project of Fujian Province,China
文摘A new design route was presented to fabricate cobalt aluminum-layered double hydroxide(CoAl-LDH)thin layers whichgrow on carbon spheres(CSs)through a growth method.The CoAl-LDH thin layers consist of nanoflakes with a thickness of20nm.The galvanostatic charge-discharge test of the CoAl-LDH/CSs composite shows a great specific capacitance of1198F/g at1A/g(based on the mass of the CoAl-LDH/CSs composite)in6mol/L KOH solution,and the composite displays an impressive specificcapacitance of920F/g even at a high current density of10A/g.Moreover,the composite remains a specific capacitance of928F/gafter1000cycles at2A/g,and the specific capacitance retention is84%,indicating that the composite has high specific capacitance,excellent rate capability and good cycling stability in comparison to pristine CoAl-LDH.
基金supported by the National Key R&D Program of China (2016YFB0600902)the Dalian National Laboratory for Clean Energy (DNL180401)the National Natural Science Foundation of China (21925803)。
文摘Synthesis of spherical carbon beads with effective CO_2 capture capability is highly desirable for large scale application of CO2 sorption, but remains challenging. Herein, a facile and efficient strategy to prepare nitrogen-doped hierarchically porous carbon spheres was developed via co-pyrolyzation of poly(vinylidene chloride) and melamine in alginate gel beads. In this approach, melamine not only serves as the nitrogen precursor, but also acts as a template for the macropores structures. The nitrogen contents in the hierarchically porous carbon spheres reach a high level, ranging from 11.8 wt% to 14.7 wt%, as the melamine amount increases. Owing to the enriched nitrogen functionalities and the special hierarchical porous structure, the carbon spheres exhibit an outstanding CO_2 capture performance, with the dynamic capacity of as much as about 7 wt% and a separation factor about 49 at 25 °C in a gas mixture of CO_2/N_2(0.5:99.5, v/v).
文摘Porous carbon spheres（PCS） derived from lignin have been prepared through a facile method and fabricated as electrodes for electric double-layer capacitors. Spherical shaped mixtures of lignosulfonate and crystalized KOH are formed by spray drying of a solution of lignosulfonate and KOH. Activation by KOH is performed at high temperatures along with lignosulfonate carbonization. With an appropriate pore structure, the obtained PCS have a specific surface area of 1372.87 m^2 g^-1 and show a capacitance of 340 F g^-1 in 3 M KOH at a current density of 0.5 A g^-1. Moreover, a symmetric supercapacitor fabricated using the PCS as electrodes show a maximum capacitance of 68.5 F g^-1, and an energy density of 9.7 W h kg^-1 at a power density of 250 W kg^-1. The capacity retention is more than 94.5% after 5000 galvanostatic chargedischarge cycles. The excellent characteristics seem to be ascribed to the pore structures of PCS that have a large specific surface area and a low electrical resistance.
基金supported by NSFC (No. 20873014 and 21073026)the Program for New Century Excellent Talents in University of China (NCET-09-0254)
文摘In this study, we have established a facile method to synthesize functional hollow carbon spheres with large hollow interior, which can act as active colloidal catalysts. The method includes the following steps： first, hollow polymer spheres with large hollow interior were prepared using sodium oleate as the hollow core generator, and 2,4-dihydroxybenzoic acid and hexamethylene tetramine （HMT） as the polymer precursors under hydrothermal conditions; Fe3＋ or Ag＋ cations were then introduced into the as-prepared hollow polymer spheres through the carboxyl groups; finally, the hollow polymer spheres can be pseudomorphically converted to hollow carbon spheres during pyrolysis process, meanwhile iron or silver nanoparticles can also be formed in the carbon shell simultaneously. The structures of the obtained functional hollow carbon spheres were characterized by TEM, XRD, and TG. As an example, Ag-doped hollow carbon spheres were used as colloid catalysts which showed high catalytic activity in 4-nitrophenol reduction reaction.
基金supported by the National Natural Science Foundation of China(Nos.21805219,51521001)the National Key Research and Development Program of China(No.2016YFA0202603)+1 种基金the Program of Introducing Talents of Discipline to Universities(No.B17034)the Yellow Crane Talent(Science&Technology)Program of Wuhan City。
文摘Porous carbon spheres represent an ideal family of electrode materials forsupercapacitors because of the high surface area,ideal conductivity,negligible aggregation,and ability to achieve space efficient packing.However,the development of new synthetic methods towards porous carbon spheres still remains a great challenge.Herein,N-doped hollow carbon spheres with an ultrahigh surface area of2044 m^(2)/g have been designed based on the phenylenediamine-formaldehyde chemistry.When applied in symmetric supercapacitors with ionic electrolyte(EMIBF_4),the obtained N-doped hollow carbon spheres demonstrate a high capacitance of 234 F/g,affording an ultrahigh energy density of 114.8 Wh/kg.Excellent cycling stability has also been achieved.The impressive capacitive performances make the phenylenediamine-formaldehyde resin derived N-doped carbon a promising candidate electrode material for supercapacitors.
基金the support from the National Key Research and Development Program(No.2018YFB1107500)Liao Ning Revitalization Talents Program(XLYC1907144)+1 种基金the National Natural Science Foundation of China(No.51503024)Dalian Youth Science and Technology Star Project Support Program(No.2017RQ104)。
文摘The electrochemical performance of hard carbon in sodium storage is still limited by its poor cycling stability and rate capability because of the sluggish kinetics process.In this study,we use a simple and effective method to accelerate the kinetics process by engineering the structure of the electrode to promote its surface and near-surface reactions.This goal is realized by the use of slightly aggregated ultra-small carbon spheres.The large specific surface area formed by the small spheres can provide abundant active sites for electrochemical reactions.The abundant mesopores and macropores derived from the secondary particle piled structure of the carbon spheres could facilitate the transport of electrolytes,shorten the diffusion distance of Na^(+)and accommodate the volume expansion during cycling.Benefiting from these unique structure features,PG700-3(carbon spheres with the diameters of 40-60 nm carbonized at 700℃)exhibits high performance for sodium storage.A high reversible capacity of 163 mAh g^(-1) could be delivered at a current density of 1.0 A g^(-1) after 100 cycles.Interestingly,at a current density of 10.0 A g^(-1),the specific capacity of PG700-3 gradually increases to 140 mAh g^(-1) after 10000 cycles,corresponding to a capacity retention of 112%.Given the enhanced kinetics of SIBs reactions,PG700-3 exhibits an excellent rate capability,i.e.,230 and 138 mAh g^(-1) at 0.1 and 5.0 A g^(-1),respectively.This study provides a facile method to attain high performance anode materials for SIBs.The design strategy and improvement mechanism could be extended to other materials for high rate applications.
基金supported by the National Natural Science Foundation of China (21972124, 22272148)the Priority Academic Program Development of Jiangsu Higher Education Institution。
文摘The strong metal-support interaction inducing combined effect plays a crucial role in the catalysis reaction. Herein, we revealed that the combined advantages of MoSe_(2), Ru, and hollow carbon spheres in the form of Ru nanoparticles(NPs) anchored on a two-dimensionally ordered MoSe_(2) nanosheet-embedded mesoporous hollow carbon spheres surface(Ru/MoSe_(2)@MHCS) for the largely boosted hydrogen evolution reaction(HER) performance. The combined advantages from the conductive support, oxyphilic MoSe_(2), and Ru active sites imparted a strong synergistic effect and charge redistribution in the Ru periphery which induced high catalytic activity, stability, and kinetics for HER. Specifically, the obtained Ru/MoSe_(2)@MHCS required a small overpotential of 25.5 and 38.4 mV to drive the kinetic current density of 10 mA cm^(-2)both in acid and alkaline media, respectively, which was comparable to that of the Pt/C catalyst. Experimental and theoretical results demonstrated that the charge transfer from MoSe_(2) to Ru NPs enriched the electronic density of Ru sites and thus facilitated hydrogen adsorption and water dissociation. The current work showed the significant interfacial engineering in Ru-based catalysts development and catalysis promotion effect understanding via the metal-support interaction.
基金The funding support from the Natural Science Research Project of Jiangsu Higher Education Institutions(Grant No.21KJA530004)the 2021 Young Scientist Exchange Program between the Republic of Korea and the People’s Republic of Chinaa Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Rationally designed hierarchical structures and heteroatomic doping of carbon are effective strategies to enhance the stability and electrical conductivity of materials.Herein,SnSe_(2)flakes were generated in the double-walled hollow carbon spheres(DWHCSs),in which N and Se atoms were doped in the carbon walls,to construct SnSe_(2)@N,Se-DWHCSs by confined growth and in-situ derivatization.The N and Sedoped DWHCSs can effectively limit the size increase of SnSe_(2),promote ion diffusion kinetics,and buffer volume expansion,which can be proved by electron microscope observation and density functional theory calculation.Consequently,the SnSe_(2)@N,Se-DWHCSs as an anode material for sodium ion batteries(SIBs)demonstrated a distinguished reversible capacity of 322.8 mAh g^(-1)at 5 A g^(-1)after 1000 cycles and a superior rate ability of 235.3 m Ah g^(-1)at an ultrahigh rate of 15 A g^(-1).Furthermore,the structure evolution and electrochemical reaction processes of SnSe2@N,Se-DWHCSs in SIBs were analyzed by exsitu methods,which confirmed the consecutive hybrid mechanism and the phase transition process.
基金financially supported by the National Key R&D Program of China (No. 2018YFB0104000 and No. 2019YFA0210300)National Nature Science Foundation of China (No.21571189 and No.21671200)+3 种基金Natural Science Foundation of Jiangsu Province (BK20200991)Hunan Provincial Science and Technology Plan Project of China (No. 2019GK2033, No. 2017TP1001, CPS2019K06 and No. 2018RS3009)Postdoctoral International Exchange Program Funding of China (No. [2018]115)China Postdoctoral Science Foundation (2019M652802)
文摘Energy conversion technologies like fuel cells and metal-air batteries require oxygen reduction reaction(ORR)electrocatalysts with low cost and high catalytic activity.Herein,N-doped carbon spheres(N-CS)with rich micropore structure have been synthesized by a facile two-step method,which includes the polymerization of pyrrole and formaldehyde and followed by a facile pyrolysis process.During the preparation,zinc chloride(ZnCl2)was utilized as a catalyst to promote polymerization and provide a hypersaline environment.In addition,the morphology,defect content and activity area of the resultant N-CS catalysts could be regulated by controlling the content of ZnCl2.The optimum N-CS-1 catalyst demonstrated much better catalytic activity and durability towards ORR in alkaline conditions than commercial 20 wt%Pt/C catalysts,of which the half-wave potential reached 0.844 V vs.RHE.When applied in the Zn-air batteries as cathode catalysts,N-CS-1 showed a maximum power density of 175 mW cm^(-2) and long-term discharging stability of over 150 h at 10 mA cm^(-2),which outperformed 20 wt%Pt/C.The excellent performance could be due to its ultrahigh specific surface area of 1757 m2 g1 and rich micropore channels structure.Meanwhile,this work provides an efficient method to synthesize an ultrahigh surface porous carbon material,especially for catalyst application.
