The development of appropriate cathode materials with stable structures and fast diffusion kinetics of zinc ions is crucial for aqueous zinc-ion batteries(AZIBs)but remains significantly challenging.Herein,the design ...The development of appropriate cathode materials with stable structures and fast diffusion kinetics of zinc ions is crucial for aqueous zinc-ion batteries(AZIBs)but remains significantly challenging.Herein,the design and synthesis of defect-rich and prismatic-shaped nanohybrids composed of vanadium oxynitride nanoparticles confined in the porous nitrogen-doped carbon framework(VN_(x)O_(y)@NC)are reported.Its unique structural advantages,including enriched defect sites that effectively enhance electrical conductivity,accelerate charge transfer kinetics,and improve structural stability.Additionally,the introduction of structural defects in VN_(x)O_(y)@NC increases the adsorption energy and reduces the hopping barrier of Zn ion,as evidenced by density functional theory(DFT)calculations.The H^(+)and Zn^(2+)co-insertion/extraction mechanism was systematically validated by ex-situ X-ray diffraction and ex-situ X-ray photoelectron spectroscopy tests.Consequently,the VN_(x)O_(y)@NC//Zn batteries exhibit an exceptional capacity of 570.9 mAh g^(-1)at 0.2 A g^(-1),a superior rate capability of 446.7 mAh g^(-1)at 20 A g^(-1),and long cycling life.Furthermore,the corresponding quasisolid-state battery delivers an ultra-high energy density of 271.9 Wh kg^(-1),demonstrating potential for practical applications.This work presents an effective structural and defect engineering strategy for designing advanced electrode materials with promising applications in AZIBs.展开更多
Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the...Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the full potential of vanadium oxides.Here,vanadium oxide nanobelts with sodium-poor and oxygen defect-rich were constructed by regulating the content of pre-embedded sodium ions to strike a balance between pre-embedded ions and structural stability.The introduction of trace sodium ions not only increases the spacing of vanadium oxide layers but also occupies as few active sites as possible,which provides the possibility of massive storage,rapid diffusion and stabilization of the host structure for zinc ions.Moreover,the abundant oxygen defects transform the ion transport pathway from two-dimensional to three-dimensional,which greatly improves the ion transport rate in the host phase.Due to these advantages,the synthesized vanadium oxide nanobelts exhibit remarkable electrochemical properties,and this work provides a new idea for the design of structurally stable layered vanadium oxides with excellent properties.展开更多
Lithium–sulfur batteries exhibit unparalleled merits in theoretical energy density(2600 W h kg^(-1))among next-generation storage systems.However,the sluggish electrochemical kinetics of sulfur reduction reactions,su...Lithium–sulfur batteries exhibit unparalleled merits in theoretical energy density(2600 W h kg^(-1))among next-generation storage systems.However,the sluggish electrochemical kinetics of sulfur reduction reactions,sulfide oxidation reactions in the sulfur cathode,and the lithium dendrite growth resulted from uncontrollable lithium behaviors in lithium anode have inhibited high-rate conversions and uniform deposition to achieve high performances.Thanks to the“adsorption-catalysis”synergetic effects,the reaction kinetics of sulfur reduction reactions/sulfide oxidation reactions composed of the delithiation of Li_(2)S and the interconversions of sulfur species are propelled by lowering the delithiation/diffusion energy barriers,inhibiting polysulfide shuttling.Meanwhile,the anodic plating kinetic behaviors modulated by the catalysts tend to uniformize without dendrite growth.In this review,the various active catalysts in modulating lithium behaviors are summarized,especially for the defect-rich catalysts and single atomic catalysts.The working mechanisms of these highly active catalysts revealed from theoretical simulation to in situ/operando characterizations are also highlighted.Furthermore,the opportunities of future higher performance enhancement to realize practical applications of lithium–sulfur batteries are prospected,shedding light on the future practical development.展开更多
Due to the limited electromagnetic wave(EMW)loss capacity and agglomeration,carbon black(CB)gradually fails to meet the increasingly harsh demanding conditions.Herein,defect-rich bamboo-like carbon nanotubes(CNTs)were...Due to the limited electromagnetic wave(EMW)loss capacity and agglomeration,carbon black(CB)gradually fails to meet the increasingly harsh demanding conditions.Herein,defect-rich bamboo-like carbon nanotubes(CNTs)were grown on CB by the process of chemical vapor deposition.CNTs prepared in situ on CB can assist it to build a developed multilevel conductive network and introduce plentiful CB/CNTs nano-interfaces.What’s more,the defects that accompany the growth of CNTs endow CNTs with a moderate conductivity and good impedance matching,thereby causing an effective microwave absorption(MA).Meanwhile,the high-density defects on CNTs can induce dipole polarization to further strengthen the EMW loss ability.The influence of CNTs with different growth time on MA performance has been explored.Profiting from the structural merits,the synthesized CB-CNT with CNTs growth time of 40 min exhibits the optimal absorbing property,which has the minimum reflection loss of-53.6 d B and maximum effective absorption bandwidth of 4.1 GHz with the thickness of 2.7 mm,covering almost the entire X band.The introduction of defect-rich CNTs significantly enhances the EMW loss ability of CB,which provides a rational strategy for the design of high-efficient microwave absorption materials.展开更多
Energy density,the Achilles’heel of aqueous supercapacitors,is simultaneously determined by the voltage window and specific capacitance of the carbon materials,but the strategy of synchronously boosting them has rare...Energy density,the Achilles’heel of aqueous supercapacitors,is simultaneously determined by the voltage window and specific capacitance of the carbon materials,but the strategy of synchronously boosting them has rarely been reported.Herein,we demonstrate that the rational utilization of the interaction between redox mediators(RMs)and carbon electrode materials,especially those with rich intrinsic defects,contributes to extended potential windows and more stored charges concurrently.Using 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxyl(4OH-TEMPO)and intrinsic defect-rich carbons as the RMs and electrode materials,respectively,the potential window and capacitance are increased by 67%and sixfold in a neutral electrolyte.Moreover,this strategy could also be applied to alkaline and acid electrolytes.The first-principle calculation and experimental results demonstrate that the strong interaction between 4OH-TEMPO and defectrich carbons plays a key role as preferential adsorbed RMs may largely prohibit the contact of free water molecules with the electrode materials to terminate the water splitting at elevated potentials.For the RMs offering weaker interaction with the electrode materials,the water splitting still proceeds with a thus sole increase of the stored charges.The results discovered in this work could provide an alternative solution to address the low energy density of aqueous supercapacitors.展开更多
Electrochemical semihydrogenation of acetylene(C_(2)H_(2))using renewable electricity offers a sustainable route for ethylene(C_(2)H_(4))production.However,the development of this technique has been hindered by many c...Electrochemical semihydrogenation of acetylene(C_(2)H_(2))using renewable electricity offers a sustainable route for ethylene(C_(2)H_(4))production.However,the development of this technique has been hindered by many challenges,such as competitive hydrogen evolution reactions(HERs)and overhydrogenation at high current densities,which will reduce the faradaic efficiency(FE)of C_(2)H_(4) and negatively impact downstream processing.Herein,we develop defectrich copper nanocubes(v-Cu NCs)as efficient electrocatalysts that facilitateC_(2)H_(4) adsorption while suppressing HER and overhydrogenation.The superior semihydrogenation performances are verified by the high C_(2)H_(4) FE of 98.3%at an ultrahigh current density of 0.7 A cm^(−2).Remarkably,in a 25 cm^(2) electrolyzer,v-Cu NCs deliver a record-high single-pass conversion of 97.5%forC_(2)H_(4) and C_(2)H_(4) selectivity of 97.4%at a cathode current of 1.6 A with a flow rate of 10 mL min−1,operating stably for 50 h.In-situ Raman spectroscopy and theoretical calculations reveal that uniformly oriented Cu(100)planes and nitrogen vacancies generate strongC_(2)H_(4) adsorption at copper sites,which facilitates hydrogenation kinetics and increases the energy barrier for overhydrogenation.This work offers valuable insights into the implementation ofC_(2)H_(4)-to-C_(2)H_(4) production and the development of efficient electrocatalysts forC_(2)H_(4) semihydrogenation.展开更多
The development of high-efficiency electrocatalysts for oxygen evolution reactions(OERs)plays an important role in the water-splitting process.Herein,we report a facile way to obtain two-dimensional(2D)single-unit-cel...The development of high-efficiency electrocatalysts for oxygen evolution reactions(OERs)plays an important role in the water-splitting process.Herein,we report a facile way to obtain two-dimensional(2D)single-unit-cell-thick layered double hydroxide(LDH)nanosheets(NSs,-1.3 nm)within only 5 min.These nanosheets presented significantly enhanced OER performance compared to bulk LDH systems fabricated using the conventional co-precipitation method.The current strategy further allowed control over the chemical compositions and electrochemical activities of the LDH NSs.For example,CoFe-LDH NSs presented the lowest overpotential of 0.28 V at 10 mA/cm2,and the NiFe-LDHs NSs showed Tafel slopes of 33.4 mV/decade and nearly 100%faradaic efficiency,thus outperforming state-of-the-art IrO2 water electrolysis catalysts.Moreover,positron annihilation lifetime spectroscopy and high-resolution transmission electron microscopy observations confirmed that rich defects and distorted lattices occurred within the 2D LDH NSs,which could supply abundant electrochemically active OER sites.Periodic calculations based on density functional theory(DFT)further showed that the CoFe-and NiFe-LDHs presented very low energy gaps and obvious spin-polarization behavior,which facilitated high electron mobility during the OER process.Therefore,this work presents a combined experimental and theoretical study on 2D single-unit-cell-thick LDH NSs with high OER activities,which have potential application in water splitting for renewable energy.展开更多
Developing low-cost and high-efficiency photocatalysts for hydrogen production from solar water splitting is intriguing but challenging. In this study, unique one-dimensional （1D） multi-node MoS2/CdS hetero-nanowir...Developing low-cost and high-efficiency photocatalysts for hydrogen production from solar water splitting is intriguing but challenging. In this study, unique one-dimensional （1D） multi-node MoS2/CdS hetero-nanowires （NWs） for efficient visible-light photocatalytic H2 evolution are synthesized via a facile hydrothermal method. Flower-like sheaths are assembled from numerous_ defect-rich O-incorporated {0001} MoS2 facet surrounded CdS NW stems are ultrathin nanosheets （NSs）, and {1120}- grown preferentially along the c-axis. Interestingly, the defects in the MoS2 NSs provide additional active S atoms on the exposed edge sites, and the incorporation of O reduces the energy barrier for H2 evolution and increases the electric conductivity of the MoS2 NSs. Moreover, the recombination of photoinduced charge carriers is significantly inhibited by the heterojunction formed between the MoS2 NSs and CdS NWs. Therefore, in the absence of noble metals as co-catalysts, the 1D MoS2 NS/CdS NW hybrids exhibit an excellent H2-generation rate of 10.85 mmol·g^-1·h^-1 and a quantum yield of 22.0% at ,λ = 475 nm, which is far better than those of Pt/CdS NWs, pure MoS2 NSs, and CdS NWs as well as their physical mixtures. Our results contribute to the rational construction of highly reactive nanostructures for various catalytic applications.展开更多
Facile design of economic-effective hydrogen evolution reaction(HER)catalysts with non-noble materials are promising for the production of renewable chemical fuels.Two-dimensional(2D)ultrathin transition metal dichalc...Facile design of economic-effective hydrogen evolution reaction(HER)catalysts with non-noble materials are promising for the production of renewable chemical fuels.Two-dimensional(2D)ultrathin transition metal dichalcogenides(TMDs)materials with large specific surface area and abundant catalytic active sites can significantly enhance their catalytic activities.Herein,we design and synthesize an atomically thin Ni-Se-S based hybrid nanosheet(NiSe1.2S0.8)via a simple solvothermal method,the thickness of NiSe1.2S0.8 nanosheets is only about 1.1 nm.Benefiting from the ultrathin nanostructure and rich defects,the optimal NiSe1.2S0.8 exhibits good electrocatalytic activity with the overpotential of 144 mV at−10 mA·cm−2,a small Tafel slope of 59 mV·dec−1,and outstanding catalytic stability in acid electrolyte for HER.The theoretical results show that hybrid electrocatalyst by S incorporation possesses the optimal adsorption free energy of hydrogen(ΔGH*).This study provides a simple method to synthesize a highperformance multicomponent electrocatalysts with the ultrathin nanostructures and abundant defects.展开更多
Spinel zinc ferrite(ZnFe_(2)O_(4),ZFO)is a potential photoanode material for photoelectrochemical(PEC)water splitting because of its ideal bandgap(1.9–2.1 eV)and superior chemical stability in aqueous solutions.Howev...Spinel zinc ferrite(ZnFe_(2)O_(4),ZFO)is a potential photoanode material for photoelectrochemical(PEC)water splitting because of its ideal bandgap(1.9–2.1 eV)and superior chemical stability in aqueous solutions.However,the low charge collection efficiency significantly hinders the improvement in PEC activity.Herein,we report an ultrafast and effective flame activation route to enhance the charge collection properties of ZFO.First,high-temperature flame(>1300℃)facilitated surface and grain boundary diffusions,increasing the grain size and connectivity of the ZFO nanoparticles.Second,the reducing atmosphere of the flame enabled the formation of surface defects(oxygen vacancy and Fe^(2+)),thereby increasing the charge carrier density and surface adsorption sites.Significantly,these two factors promoted charge transport and transfer kinetics,resulting in a 10-fold increase in the photocurrent density over the unactivated ZFO.Furthermore,we deposited a thin Al_(2)O_(3)overlayer to passivate the ZFO surface and then the NiFeOx oxygen evolution catalyst(OEC)to expedite hole injection into the electrolyte.This surface passivation and OEC deposition led to a remarkable photocurrent density of~1 mA/cm^(2)at 1.23 V versus the reversible hydrogen electrode,which is the highest value among all reported ZFO photoanodes.Notably,the NiFeOx/Al_(2)O_(3)/F-ZFO photoanode achieved excellent photocurrent stability over 55 h(96%retention)and superior faradaic efficiency(FE>94%).Our flame activation method is also effective in improving the photocurrent densities of other spinel ferrites:CuFe_(2)O_(4)(93 times),MgFe_(2)O_(4)(16 times),and NiFe_(2)O_(4)(12 times).展开更多
Pulse microwave excite thermoacoustic(TA)shockwave to destroy tumor cells in situ.This has promising applications for precise tumor therapy in deep tissue.Nanoparticle(NP)with high microwave-acoustic conversion is the...Pulse microwave excite thermoacoustic(TA)shockwave to destroy tumor cells in situ.This has promising applications for precise tumor therapy in deep tissue.Nanoparticle(NP)with high microwave-acoustic conversion is the key to enhance the efficiency of therapy.In this study,we firstly developed defect-rich titanium nitride nanoparticles(TiN NPs)for pulse microwave excited thermoacoustic(MTA)therapy.Due to a large number of local structural defects and charge carriers,TiN NPs exhibit excellent electromagnetic absorption through the dual mechanisms of dielectric loss and resistive loss.With pulsed microwave irradiation,it efficiently converts the microwave energy into shockwave via thermocavitation effect,achieving localized mechanical damage of mitochondria in the tumor cell and yielding a precise antitumor effect.In addition to the therapeutic function,the NP-mediated TA process also generates images that provide valuable information,including tumor size,shape,and location for treatment planning and monitoring.The experimental results showed that the TiN NPs could be efficiently accumulated in the tumor via intravenous infusion.With the deep tissue penetration characteristics of microwave,the proposed TiN-mediated MTA therapy effectively and precisely cures tumors in deep tissue without any detectable side effects.The results indicated that defect-rich TiN NPs are promising candidates for tumor therapy.展开更多
Zn-air batteries with high energy density and safety have acquired enormous attention,while the practical application is hindered by the sluggish kinetics of the oxygen evolution reaction(OER)and the oxygen reduction ...Zn-air batteries with high energy density and safety have acquired enormous attention,while the practical application is hindered by the sluggish kinetics of the oxygen evolution reaction(OER)and the oxygen reduction reaction(ORR).In this work,a threedimensional(3D)defect-rich bifunctional electrocatalyst(CoFe/N CNFs)comprising irregular hollow CoFe nanospheres in Ndoped carbon nanofibers is presented,which is fabricated from CoFe ZIFs-derived(ZIF:zeolitic-imidazolate framework)polymer nanofibers precursor.The CoFe ZIFs with tunable particle size and composition are constructed using a confined synthesis strategy.Moreover,the Kirkendall diffusion process is available for forming the irregular hollow CoFe nanospheres,and the decomposition of polyvinylpyrrolidone(PVP)results in forming the defective carbon nanofibers,which provide more efficient active sites and enhance the electrocatalytic properties toward both OER and ORR.The optimized CoFe/N CNFs exhibit superior bifunctional activities,outperforming that of the benchmark Pt/C+RuO_(2) catalyst.As a result,the CoFe/N CNFs as an air-cathode endow the rechargeable Zn-air battery with an excellent power density of 149 mW·cm^(−2),energy density of 875 Wh·kg^(−1),and cycling stability.This work provides a new strategy to develop bifunctional electrocatalysts with desired nanostructure and regulated performance toward energy applications.展开更多
Photocatalytic water splitting for hydrogen(H_(2))production is a green sustainable technology,in which highly-efficient steady photocatalysts are fundamentally required.In this work,unique CdS/Cd_(0.5)Zn_(0.5)S-M0_(1...Photocatalytic water splitting for hydrogen(H_(2))production is a green sustainable technology,in which highly-efficient steady photocatalysts are fundamentally required.In this work,unique CdS/Cd_(0.5)Zn_(0.5)S-M0_(1-x)W_(x)S_(2) photocatalyst constructed by CdS hollow nano-spheres with successively surface-modified Cd_(0.5)Zn_(0.5)S shell and defect-rich MO_(1-x)W_(x)S_(2) ultrathin nanosheets was reported for the first time.Interestingly,the Cd_(0.5)Zn_(0.5)S shell could greatly enhance the photo-stability and reduce the carrier recombination of CdS.Meanwhile,enriching active sites and accelerating charge transfer could be achieved via anchoring defect-rich Mo_(1-x)W_(x)S_(2) onto CdS/Cd_(0.5)Zn_(0.5)S hollow heterostructures.Specifically,the optimized CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)Sa(6 h Cd_(0.5)Zn_(0.5)S-coating,7 wt.%Mo_(1-x)W_(x)S_(2),x=0.5)hybrid delivered an exceptional H_(2) generation rate of 215.99 mmol·g^(-1)·h^(-1),which is approximately 502,134,and 23 times that of pure CdS,CdS/Cd_(0.5)Zn_(0.5)S,and 3 wt.%Pt-loaded CdS/Cd_(0.5)Zn_(0.5)S,respectively.Remarkably,a high H_(2) evolution reaction(HER)apparent quantum yield(AQY)of 64.81%was obtained under 420-nm irradiation.In addition,the CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)S_(2) was also durable for H2 production under long-term irradiation.This work provides valuable inspirations to rational design and synthesis of efficient and stable hybrid photocatalysts for solar energy conversion.展开更多
Water electrolysis for hydrogen production offers a promising solution to future energy crises and environmental challenges.Although platinum is an efficient catalyst for hydrogen evolution reactions(HERs),its high co...Water electrolysis for hydrogen production offers a promising solution to future energy crises and environmental challenges.Although platinum is an efficient catalyst for hydrogen evolution reactions(HERs),its high cost and stability challenges limit its widespread use.A novel platinum-based catalyst,comprising platinum nanoparticles on nitrogen-doped porous graphite(Pt-N-porous graphite),addresses these limitations.This catalyst prevents nanoparticle aggregation,provides a high specific surface area of 1308 m^(2)g^(-1),and enhances mass transfer and active site exposure.Additionally,it exhibits superior electrical conductivity compared to commercial Pt-C,enhancing charge transfer efficiency.The Pt-N-porous graphite catalyst achieves an overpotential of 99 mV at 100 mA cm^(-2)and maintains stable performance after 10,000 cycles.Applied as a catalyst-coated membrane(CCM)in a proton exchange membrane(PEM)electrolyzer,it demonstrates excellent performance.Thus,the industrially synthesizable Pt-N-porous graphite catalyst holds great potential for large-scale energy applications.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22225902,U22A20436,and 22209185)the National key Research&Development Program of China(Nos.2022YFE0115900 and 2021YFA1501500)+1 种基金the Postdoctoral Fellowship Program of CPSF,China(No.GZB20230758)Fujian Key Laboratory of Green Extraction and High-value Utilization of New Energy Metals(No.2023-KFKT-2)
文摘The development of appropriate cathode materials with stable structures and fast diffusion kinetics of zinc ions is crucial for aqueous zinc-ion batteries(AZIBs)but remains significantly challenging.Herein,the design and synthesis of defect-rich and prismatic-shaped nanohybrids composed of vanadium oxynitride nanoparticles confined in the porous nitrogen-doped carbon framework(VN_(x)O_(y)@NC)are reported.Its unique structural advantages,including enriched defect sites that effectively enhance electrical conductivity,accelerate charge transfer kinetics,and improve structural stability.Additionally,the introduction of structural defects in VN_(x)O_(y)@NC increases the adsorption energy and reduces the hopping barrier of Zn ion,as evidenced by density functional theory(DFT)calculations.The H^(+)and Zn^(2+)co-insertion/extraction mechanism was systematically validated by ex-situ X-ray diffraction and ex-situ X-ray photoelectron spectroscopy tests.Consequently,the VN_(x)O_(y)@NC//Zn batteries exhibit an exceptional capacity of 570.9 mAh g^(-1)at 0.2 A g^(-1),a superior rate capability of 446.7 mAh g^(-1)at 20 A g^(-1),and long cycling life.Furthermore,the corresponding quasisolid-state battery delivers an ultra-high energy density of 271.9 Wh kg^(-1),demonstrating potential for practical applications.This work presents an effective structural and defect engineering strategy for designing advanced electrode materials with promising applications in AZIBs.
基金supported by the National Natural Science Foundation of China(No.22179109).
文摘Although the enhancement of the zinc storage performance of layered vanadium oxides can be realized by the ionic pre-intercalation strategy,it also occupies a large number of active sites and thus fails to release the full potential of vanadium oxides.Here,vanadium oxide nanobelts with sodium-poor and oxygen defect-rich were constructed by regulating the content of pre-embedded sodium ions to strike a balance between pre-embedded ions and structural stability.The introduction of trace sodium ions not only increases the spacing of vanadium oxide layers but also occupies as few active sites as possible,which provides the possibility of massive storage,rapid diffusion and stabilization of the host structure for zinc ions.Moreover,the abundant oxygen defects transform the ion transport pathway from two-dimensional to three-dimensional,which greatly improves the ion transport rate in the host phase.Due to these advantages,the synthesized vanadium oxide nanobelts exhibit remarkable electrochemical properties,and this work provides a new idea for the design of structurally stable layered vanadium oxides with excellent properties.
基金fellowship funding supported by the Alexander von Humboldt Foundationfinancial funding support from the Natural Science Foundation of Jiangsu Province(BK.20210636)Natural Science Foundation of China(21773294 and 21972164)。
文摘Lithium–sulfur batteries exhibit unparalleled merits in theoretical energy density(2600 W h kg^(-1))among next-generation storage systems.However,the sluggish electrochemical kinetics of sulfur reduction reactions,sulfide oxidation reactions in the sulfur cathode,and the lithium dendrite growth resulted from uncontrollable lithium behaviors in lithium anode have inhibited high-rate conversions and uniform deposition to achieve high performances.Thanks to the“adsorption-catalysis”synergetic effects,the reaction kinetics of sulfur reduction reactions/sulfide oxidation reactions composed of the delithiation of Li_(2)S and the interconversions of sulfur species are propelled by lowering the delithiation/diffusion energy barriers,inhibiting polysulfide shuttling.Meanwhile,the anodic plating kinetic behaviors modulated by the catalysts tend to uniformize without dendrite growth.In this review,the various active catalysts in modulating lithium behaviors are summarized,especially for the defect-rich catalysts and single atomic catalysts.The working mechanisms of these highly active catalysts revealed from theoretical simulation to in situ/operando characterizations are also highlighted.Furthermore,the opportunities of future higher performance enhancement to realize practical applications of lithium–sulfur batteries are prospected,shedding light on the future practical development.
基金financially supported by National Natural Science Foundation of China(52072304,52172103)Natural Science Basic Research Plan in Shaanxi(2022JC-25)+1 种基金the Key R&D Program of Shaanxi Provence(2019ZDLGY04-02)China Postdoctoral Science Foundation(2021M702659)。
文摘Due to the limited electromagnetic wave(EMW)loss capacity and agglomeration,carbon black(CB)gradually fails to meet the increasingly harsh demanding conditions.Herein,defect-rich bamboo-like carbon nanotubes(CNTs)were grown on CB by the process of chemical vapor deposition.CNTs prepared in situ on CB can assist it to build a developed multilevel conductive network and introduce plentiful CB/CNTs nano-interfaces.What’s more,the defects that accompany the growth of CNTs endow CNTs with a moderate conductivity and good impedance matching,thereby causing an effective microwave absorption(MA).Meanwhile,the high-density defects on CNTs can induce dipole polarization to further strengthen the EMW loss ability.The influence of CNTs with different growth time on MA performance has been explored.Profiting from the structural merits,the synthesized CB-CNT with CNTs growth time of 40 min exhibits the optimal absorbing property,which has the minimum reflection loss of-53.6 d B and maximum effective absorption bandwidth of 4.1 GHz with the thickness of 2.7 mm,covering almost the entire X band.The introduction of defect-rich CNTs significantly enhances the EMW loss ability of CB,which provides a rational strategy for the design of high-efficient microwave absorption materials.
基金financially supported by the National Natural Science Foundation of China(22179145,22138013,and 21975287)Shandong Provincial Natural Science Foundation(ZR2020ZD08)+1 种基金Taishan Scholar Project(no.ts201712020)the startup support grant from China University of Petroleum(East China)
文摘Energy density,the Achilles’heel of aqueous supercapacitors,is simultaneously determined by the voltage window and specific capacitance of the carbon materials,but the strategy of synchronously boosting them has rarely been reported.Herein,we demonstrate that the rational utilization of the interaction between redox mediators(RMs)and carbon electrode materials,especially those with rich intrinsic defects,contributes to extended potential windows and more stored charges concurrently.Using 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxyl(4OH-TEMPO)and intrinsic defect-rich carbons as the RMs and electrode materials,respectively,the potential window and capacitance are increased by 67%and sixfold in a neutral electrolyte.Moreover,this strategy could also be applied to alkaline and acid electrolytes.The first-principle calculation and experimental results demonstrate that the strong interaction between 4OH-TEMPO and defectrich carbons plays a key role as preferential adsorbed RMs may largely prohibit the contact of free water molecules with the electrode materials to terminate the water splitting at elevated potentials.For the RMs offering weaker interaction with the electrode materials,the water splitting still proceeds with a thus sole increase of the stored charges.The results discovered in this work could provide an alternative solution to address the low energy density of aqueous supercapacitors.
基金supported by the National Natural Science Foundation of China(grant nos.22322807,22168023,22268029,and 22108243)the Natural Science Foundation of Jiangxi Province(grant no.20224ACB204003)+1 种基金the China Scholarship Council(grant no.202206820025)the Australian Research Council(ARC)through the ARC Discovery project(grant no.DP230101579).
文摘Electrochemical semihydrogenation of acetylene(C_(2)H_(2))using renewable electricity offers a sustainable route for ethylene(C_(2)H_(4))production.However,the development of this technique has been hindered by many challenges,such as competitive hydrogen evolution reactions(HERs)and overhydrogenation at high current densities,which will reduce the faradaic efficiency(FE)of C_(2)H_(4) and negatively impact downstream processing.Herein,we develop defectrich copper nanocubes(v-Cu NCs)as efficient electrocatalysts that facilitateC_(2)H_(4) adsorption while suppressing HER and overhydrogenation.The superior semihydrogenation performances are verified by the high C_(2)H_(4) FE of 98.3%at an ultrahigh current density of 0.7 A cm^(−2).Remarkably,in a 25 cm^(2) electrolyzer,v-Cu NCs deliver a record-high single-pass conversion of 97.5%forC_(2)H_(4) and C_(2)H_(4) selectivity of 97.4%at a cathode current of 1.6 A with a flow rate of 10 mL min−1,operating stably for 50 h.In-situ Raman spectroscopy and theoretical calculations reveal that uniformly oriented Cu(100)planes and nitrogen vacancies generate strongC_(2)H_(4) adsorption at copper sites,which facilitates hydrogenation kinetics and increases the energy barrier for overhydrogenation.This work offers valuable insights into the implementation ofC_(2)H_(4)-to-C_(2)H_(4) production and the development of efficient electrocatalysts forC_(2)H_(4) semihydrogenation.
基金This work was supported by the National Basic Research Program of China(No.2014CB932103),the National Natural Science Foundation of China(Nos.21301016 and 21473013),and the Beijing Municipal Natural Science Foundation(No.2152016).
文摘The development of high-efficiency electrocatalysts for oxygen evolution reactions(OERs)plays an important role in the water-splitting process.Herein,we report a facile way to obtain two-dimensional(2D)single-unit-cell-thick layered double hydroxide(LDH)nanosheets(NSs,-1.3 nm)within only 5 min.These nanosheets presented significantly enhanced OER performance compared to bulk LDH systems fabricated using the conventional co-precipitation method.The current strategy further allowed control over the chemical compositions and electrochemical activities of the LDH NSs.For example,CoFe-LDH NSs presented the lowest overpotential of 0.28 V at 10 mA/cm2,and the NiFe-LDHs NSs showed Tafel slopes of 33.4 mV/decade and nearly 100%faradaic efficiency,thus outperforming state-of-the-art IrO2 water electrolysis catalysts.Moreover,positron annihilation lifetime spectroscopy and high-resolution transmission electron microscopy observations confirmed that rich defects and distorted lattices occurred within the 2D LDH NSs,which could supply abundant electrochemically active OER sites.Periodic calculations based on density functional theory(DFT)further showed that the CoFe-and NiFe-LDHs presented very low energy gaps and obvious spin-polarization behavior,which facilitated high electron mobility during the OER process.Therefore,this work presents a combined experimental and theoretical study on 2D single-unit-cell-thick LDH NSs with high OER activities,which have potential application in water splitting for renewable energy.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Nos. 21431003 and 21521091） and China Ministry of Science and Technology （No. 2016YFA0202801）. We also thank Dr. Lina Zhang and Ms. Xiaohua Gu for their kind help with the TEM measurements.
文摘Developing low-cost and high-efficiency photocatalysts for hydrogen production from solar water splitting is intriguing but challenging. In this study, unique one-dimensional （1D） multi-node MoS2/CdS hetero-nanowires （NWs） for efficient visible-light photocatalytic H2 evolution are synthesized via a facile hydrothermal method. Flower-like sheaths are assembled from numerous_ defect-rich O-incorporated {0001} MoS2 facet surrounded CdS NW stems are ultrathin nanosheets （NSs）, and {1120}- grown preferentially along the c-axis. Interestingly, the defects in the MoS2 NSs provide additional active S atoms on the exposed edge sites, and the incorporation of O reduces the energy barrier for H2 evolution and increases the electric conductivity of the MoS2 NSs. Moreover, the recombination of photoinduced charge carriers is significantly inhibited by the heterojunction formed between the MoS2 NSs and CdS NWs. Therefore, in the absence of noble metals as co-catalysts, the 1D MoS2 NS/CdS NW hybrids exhibit an excellent H2-generation rate of 10.85 mmol·g^-1·h^-1 and a quantum yield of 22.0% at ,λ = 475 nm, which is far better than those of Pt/CdS NWs, pure MoS2 NSs, and CdS NWs as well as their physical mixtures. Our results contribute to the rational construction of highly reactive nanostructures for various catalytic applications.
基金This work was supported by the National Natural Science Foundation of China(Nos.21771191 and 21875285)Taishan Scholar Foundation(No.ts201511019)+1 种基金the Shandong Natural Science Fund(No.ZR2017QB012)the Fundamental Research Funds for the Central Universities(No.19CX05001A).
文摘Facile design of economic-effective hydrogen evolution reaction(HER)catalysts with non-noble materials are promising for the production of renewable chemical fuels.Two-dimensional(2D)ultrathin transition metal dichalcogenides(TMDs)materials with large specific surface area and abundant catalytic active sites can significantly enhance their catalytic activities.Herein,we design and synthesize an atomically thin Ni-Se-S based hybrid nanosheet(NiSe1.2S0.8)via a simple solvothermal method,the thickness of NiSe1.2S0.8 nanosheets is only about 1.1 nm.Benefiting from the ultrathin nanostructure and rich defects,the optimal NiSe1.2S0.8 exhibits good electrocatalytic activity with the overpotential of 144 mV at−10 mA·cm−2,a small Tafel slope of 59 mV·dec−1,and outstanding catalytic stability in acid electrolyte for HER.The theoretical results show that hybrid electrocatalyst by S incorporation possesses the optimal adsorption free energy of hydrogen(ΔGH*).This study provides a simple method to synthesize a highperformance multicomponent electrocatalysts with the ultrathin nanostructures and abundant defects.
基金supported by the Basic Science Research Program of the National Research Foundation of Korea,funded by the Ministry of Science,ICT,and Future Planning(Grant Nos.NRF-2019R1A2C2002024 and 2021R1A4A1031357).
文摘Spinel zinc ferrite(ZnFe_(2)O_(4),ZFO)is a potential photoanode material for photoelectrochemical(PEC)water splitting because of its ideal bandgap(1.9–2.1 eV)and superior chemical stability in aqueous solutions.However,the low charge collection efficiency significantly hinders the improvement in PEC activity.Herein,we report an ultrafast and effective flame activation route to enhance the charge collection properties of ZFO.First,high-temperature flame(>1300℃)facilitated surface and grain boundary diffusions,increasing the grain size and connectivity of the ZFO nanoparticles.Second,the reducing atmosphere of the flame enabled the formation of surface defects(oxygen vacancy and Fe^(2+)),thereby increasing the charge carrier density and surface adsorption sites.Significantly,these two factors promoted charge transport and transfer kinetics,resulting in a 10-fold increase in the photocurrent density over the unactivated ZFO.Furthermore,we deposited a thin Al_(2)O_(3)overlayer to passivate the ZFO surface and then the NiFeOx oxygen evolution catalyst(OEC)to expedite hole injection into the electrolyte.This surface passivation and OEC deposition led to a remarkable photocurrent density of~1 mA/cm^(2)at 1.23 V versus the reversible hydrogen electrode,which is the highest value among all reported ZFO photoanodes.Notably,the NiFeOx/Al_(2)O_(3)/F-ZFO photoanode achieved excellent photocurrent stability over 55 h(96%retention)and superior faradaic efficiency(FE>94%).Our flame activation method is also effective in improving the photocurrent densities of other spinel ferrites:CuFe_(2)O_(4)(93 times),MgFe_(2)O_(4)(16 times),and NiFe_(2)O_(4)(12 times).
基金supported by the National Natural Science Foundation of China(No.62075066)the Science and Technology Planning Project of Guangdong Province,China(Nos.2019A1515012054)+1 种基金the Scientific and Technological Planning Project of Guangzhou City(No.201805010002)the Science and Technology Program of Guangzhou(No.2019050001).
文摘Pulse microwave excite thermoacoustic(TA)shockwave to destroy tumor cells in situ.This has promising applications for precise tumor therapy in deep tissue.Nanoparticle(NP)with high microwave-acoustic conversion is the key to enhance the efficiency of therapy.In this study,we firstly developed defect-rich titanium nitride nanoparticles(TiN NPs)for pulse microwave excited thermoacoustic(MTA)therapy.Due to a large number of local structural defects and charge carriers,TiN NPs exhibit excellent electromagnetic absorption through the dual mechanisms of dielectric loss and resistive loss.With pulsed microwave irradiation,it efficiently converts the microwave energy into shockwave via thermocavitation effect,achieving localized mechanical damage of mitochondria in the tumor cell and yielding a precise antitumor effect.In addition to the therapeutic function,the NP-mediated TA process also generates images that provide valuable information,including tumor size,shape,and location for treatment planning and monitoring.The experimental results showed that the TiN NPs could be efficiently accumulated in the tumor via intravenous infusion.With the deep tissue penetration characteristics of microwave,the proposed TiN-mediated MTA therapy effectively and precisely cures tumors in deep tissue without any detectable side effects.The results indicated that defect-rich TiN NPs are promising candidates for tumor therapy.
基金supported by the National Natural Science Foundation of China(Nos.11902256 and 51573148)the Natural Science Basic Research Program of Shaanxi(No.2019JQ-479)+2 种基金the Key Research and Development Program of Shaanxi Province(No.2020ZDGY01-01)the Fundamental Research Funds for the Central Universities(No.D5000220202)the China Scholarship Council and thanks eceshi(www.eceshi.com)for the Raman analysis.
文摘Zn-air batteries with high energy density and safety have acquired enormous attention,while the practical application is hindered by the sluggish kinetics of the oxygen evolution reaction(OER)and the oxygen reduction reaction(ORR).In this work,a threedimensional(3D)defect-rich bifunctional electrocatalyst(CoFe/N CNFs)comprising irregular hollow CoFe nanospheres in Ndoped carbon nanofibers is presented,which is fabricated from CoFe ZIFs-derived(ZIF:zeolitic-imidazolate framework)polymer nanofibers precursor.The CoFe ZIFs with tunable particle size and composition are constructed using a confined synthesis strategy.Moreover,the Kirkendall diffusion process is available for forming the irregular hollow CoFe nanospheres,and the decomposition of polyvinylpyrrolidone(PVP)results in forming the defective carbon nanofibers,which provide more efficient active sites and enhance the electrocatalytic properties toward both OER and ORR.The optimized CoFe/N CNFs exhibit superior bifunctional activities,outperforming that of the benchmark Pt/C+RuO_(2) catalyst.As a result,the CoFe/N CNFs as an air-cathode endow the rechargeable Zn-air battery with an excellent power density of 149 mW·cm^(−2),energy density of 875 Wh·kg^(−1),and cycling stability.This work provides a new strategy to develop bifunctional electrocatalysts with desired nanostructure and regulated performance toward energy applications.
基金support from the National Natural Science Foundation of China(Nos.51802170,51772162,and 21801150)the Natural Science Foundation of Shandong Province(Nos.ZR2019MB001,ZR2018BEM014,and ZR2019JQ14)+3 种基金the Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(No.2019KJC004)the Taishan Scholar Project of Shandong Province(No.ts201712047)the Special Fund Project to Guide Development of Local Science and Technology by Central Government,the Open Research Fund of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University(No.2019-22)the Taishan Scholar Program of Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology.
文摘Photocatalytic water splitting for hydrogen(H_(2))production is a green sustainable technology,in which highly-efficient steady photocatalysts are fundamentally required.In this work,unique CdS/Cd_(0.5)Zn_(0.5)S-M0_(1-x)W_(x)S_(2) photocatalyst constructed by CdS hollow nano-spheres with successively surface-modified Cd_(0.5)Zn_(0.5)S shell and defect-rich MO_(1-x)W_(x)S_(2) ultrathin nanosheets was reported for the first time.Interestingly,the Cd_(0.5)Zn_(0.5)S shell could greatly enhance the photo-stability and reduce the carrier recombination of CdS.Meanwhile,enriching active sites and accelerating charge transfer could be achieved via anchoring defect-rich Mo_(1-x)W_(x)S_(2) onto CdS/Cd_(0.5)Zn_(0.5)S hollow heterostructures.Specifically,the optimized CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)Sa(6 h Cd_(0.5)Zn_(0.5)S-coating,7 wt.%Mo_(1-x)W_(x)S_(2),x=0.5)hybrid delivered an exceptional H_(2) generation rate of 215.99 mmol·g^(-1)·h^(-1),which is approximately 502,134,and 23 times that of pure CdS,CdS/Cd_(0.5)Zn_(0.5)S,and 3 wt.%Pt-loaded CdS/Cd_(0.5)Zn_(0.5)S,respectively.Remarkably,a high H_(2) evolution reaction(HER)apparent quantum yield(AQY)of 64.81%was obtained under 420-nm irradiation.In addition,the CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)S_(2) was also durable for H2 production under long-term irradiation.This work provides valuable inspirations to rational design and synthesis of efficient and stable hybrid photocatalysts for solar energy conversion.
基金funded by the National Natural Science Foundation of China(No.52202446)the Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001)+2 种基金the Young Elite Scientists Sponsorship Program by BAST(No.BYESS2023050)the Beijing Association for Science and Technology’s Golden-Bridge Seed Funding Program(No.ZZ22042)the Fundamental Research Funds for the Central Universities of China。
文摘Water electrolysis for hydrogen production offers a promising solution to future energy crises and environmental challenges.Although platinum is an efficient catalyst for hydrogen evolution reactions(HERs),its high cost and stability challenges limit its widespread use.A novel platinum-based catalyst,comprising platinum nanoparticles on nitrogen-doped porous graphite(Pt-N-porous graphite),addresses these limitations.This catalyst prevents nanoparticle aggregation,provides a high specific surface area of 1308 m^(2)g^(-1),and enhances mass transfer and active site exposure.Additionally,it exhibits superior electrical conductivity compared to commercial Pt-C,enhancing charge transfer efficiency.The Pt-N-porous graphite catalyst achieves an overpotential of 99 mV at 100 mA cm^(-2)and maintains stable performance after 10,000 cycles.Applied as a catalyst-coated membrane(CCM)in a proton exchange membrane(PEM)electrolyzer,it demonstrates excellent performance.Thus,the industrially synthesizable Pt-N-porous graphite catalyst holds great potential for large-scale energy applications.
