The development of high-performance and stable electrocatalysts for oxygen evolution reaction(OER)is essential to improve the overall efficiency of water splitting.Here,S-vacancies and iron-doped nickel sulfide nanosh...The development of high-performance and stable electrocatalysts for oxygen evolution reaction(OER)is essential to improve the overall efficiency of water splitting.Here,S-vacancies and iron-doped nickel sulfide nanosheets(Vs-Ni_(2)Fe_(1)S_(2)/NF)were successfully prepared on the surface of nickel foam via solvothermal reaction of nickel-iron layered double hydroxide with sublimed sulfur added with sodium borohydride.Under the synergistic regulation of iron-doped and S-vacancies,Vs-Ni_(2)Fe_(1)S_(2)/NF shows excellent electrocatalytic performance and long-term durability.To reach current densities of 10 and500 mA cm^(-2),Vs-Ni_(2)Fe_(1)S_(2)/NF requires only 185(±5)and 248(±5)mV overpotential,respectively,and can maintain long stability for 350 h at 500 mA cm^(-2).The change of the mechanical pathway from adsorbate evolution mechanism to lattice oxygen oxidation mechanism is due to the increased acidity of the Ni site in Vs-Ni_(2)Fe_(1)S_(2)/NF,which facilitates the decouped proton and electron transfer process.Density functional calculation results show that the introduction of Fe atoms and S vacancies in Ni3S_(2)can enhance the conductivity of the intermediates by regulating the electronic structure of the intermediates,optimize the adsorption or desorption energy,and thus significantly improve the OER activity.For Vs-Ni_(2)Fe_(1)S_(2)/NF(+,-)cell,a voltage of 1.56 V is required to achieve 10 mA cm^(-2).In addition,Vs-Ni_(2)Fe_(1)S_(2)/NF catalyst also showed low overpotential(270 mV at 100 mA cm^(-2))and high alkaline tolerance(100 h at 100 mA cm^(-2))at 30 wt%KOH of 70℃.This shows that it has potential industrial application.展开更多
Vacancy engineering in metal sulfides has garnered enormous attention from researchers because of their outstanding ability to modulate the optical and physiochemical properties of photocatalysts.Typically,in the case...Vacancy engineering in metal sulfides has garnered enormous attention from researchers because of their outstanding ability to modulate the optical and physiochemical properties of photocatalysts.Typically,in the case of sulfides,the catalytic activity is drastically hindered by the quick reassembly of excitons and the photocorrosion effect.Hence designing and generating S-vacancies in metal sulfides has emerged as a potential strategy for attaining adequate water splitting to generate H_(2) and O_(2) because of the simulta-neous improvement in the optoelectronic features.However,developing efficient catalysts that manifest optimal photo(electro)catalytic performance for large-scale applicability remains challenging.Therefore,it is of utmost interest to explore the insightful features of creating S-vacancy and study their impact on catalytic performance.This review article aims to comprehensively highlight the roles of S-vacancy in sulfides for amended overall water-splitting activity.The photocatalytic features of S-vacancies modulated metal sulfides are deliberated,followed by various advanced synthetic and characterization techniques for effectual generation and identification of vacancy defects.The specific aspects of S-vacancies in refin-ing the optical absorption range charge carrier dynamics,and photoinduced surface chemical reactions are critically examined for overall water splitting applications.Finally,the vouchsafing outlooks and op-portunities confronting the defect-engineered(S-vacancy)metal sulfides-based photocatalysts have been summarized.展开更多
The low-dimensional light source shows promise in photonic integrated circuits.Stable layered van der Waals material that exhibits luminescence in the near-infrared optical communication waveband is an essential compo...The low-dimensional light source shows promise in photonic integrated circuits.Stable layered van der Waals material that exhibits luminescence in the near-infrared optical communication waveband is an essential component in on-chip light sources.Herein,the tunable near-infrared photoluminescence(PL)of the air-stable layered titanium trisulfide(TiS3)is reported.Compared with iodine particles as a transport agent,TiS3 grown by chemical vapor transport using sulfur powder as a transport agent has fewer sulfur vacancies,which increases the luminescence intensity by an order of magnitude.The PL emission wavelength can be regulated in the near-infrared regime by thickness control.In addition,we observed an interesting anisotropic strain response of PL in layered TiS3 nanoribbon:a blue shift of PL was achieved when the uniaxial tensile strain was applied along the b-axis,while a negligible shift was observed when the strain was applied along the a-axis.Our work reveals the tunable nearinfrared luminescent properties of TiS3 nanoribbons,suggesting their potential applications as near-infrared light sources in photonic integrated circuits.展开更多
Endowing bilayer transition-metal dichalcogenides(TMDs)with tunable magnetism is significant to investigate the coupling of multiple electron degrees of freedom(DOFs).However,effectively inducing and tuning the magnet...Endowing bilayer transition-metal dichalcogenides(TMDs)with tunable magnetism is significant to investigate the coupling of multiple electron degrees of freedom(DOFs).However,effectively inducing and tuning the magnetic interaction of bilayer TMDs are still challenges.Herein,we report a strategy to tune the interlayer exchange interaction of centimeter-scale MoS2 bilayer with substitutional doping of Co ion,by introducing sulfur vacancy(V_(s))to modulate the interlayer electronic coupling.This strategy could transform the interlayer exchange interaction from antiferromagnetism(AFM)to ferromagnetism(FM),as revealed by the magnetic measurements.Experimental characterizations and theoretical calculations indicate that the enhanced magnetization is mainly because the hybridization of Co 3d band and Vs-induced impurity band alters the forms of interlayer orbital hybridizations between the partial Co atoms in upper and lower layers,and also enhances the intralayer FM.Our work paves the way for tuning the interlayer exchange interaction with defects and could be extended to other two-dimensional(2D)magnetic materials.展开更多
Electronic modulation on the inert basal plane of transition-metal dichalcogenides(TMDs)through vacancy defect excitation,although extremely challenging,is urgent for understanding the factors that impact the hydrogen...Electronic modulation on the inert basal plane of transition-metal dichalcogenides(TMDs)through vacancy defect excitation,although extremely challenging,is urgent for understanding the factors that impact the hydrogen evolution reaction(HER)catalytic activity.Here,ultrathin WS2 nanosheets with precise quantitative single atomic S-vacancy on the inert basal plane were flexible prepared through hydrogen peroxide etching strategy.The as-synthesized single atomic S-vacancy defect WS2(SVD-WS2)nanoflake with the activated basal plane exhibited an impressive overpotential of 137 mV at a current density of 10 mA·cm^(-2) and a Tafel slope of 53.9 mV dec^(-1).Furthermore,anchoring on the defect graphene matrix,the assembled two-dimensional(2D)stacking heterojunction exhibits further enhanced HER catalytic activity(an overpotential of 108 mV vs.10 mA·cm^(-2) and a Tafel slope of 48.3 mV·dec^(-1))and stability(〜10%decline after 9,000 cycles),which attributed to the electronic structure modulation from the synergetic interactions between SVD-WS_(2) and defect graphene.Our finding provides a smart defects introduce strategy to trigger high-efficiency hydrogen evolution over WS_(2) nanosheets and a general 2D heterojunctions fabricated inspiration based on strong interaction interface.展开更多
基金supported by the National Natural Science Foundation of China(22308206 and 22278255)the Graduate Innovation Fund of Shaanxi University of Science and Technology,China。
文摘The development of high-performance and stable electrocatalysts for oxygen evolution reaction(OER)is essential to improve the overall efficiency of water splitting.Here,S-vacancies and iron-doped nickel sulfide nanosheets(Vs-Ni_(2)Fe_(1)S_(2)/NF)were successfully prepared on the surface of nickel foam via solvothermal reaction of nickel-iron layered double hydroxide with sublimed sulfur added with sodium borohydride.Under the synergistic regulation of iron-doped and S-vacancies,Vs-Ni_(2)Fe_(1)S_(2)/NF shows excellent electrocatalytic performance and long-term durability.To reach current densities of 10 and500 mA cm^(-2),Vs-Ni_(2)Fe_(1)S_(2)/NF requires only 185(±5)and 248(±5)mV overpotential,respectively,and can maintain long stability for 350 h at 500 mA cm^(-2).The change of the mechanical pathway from adsorbate evolution mechanism to lattice oxygen oxidation mechanism is due to the increased acidity of the Ni site in Vs-Ni_(2)Fe_(1)S_(2)/NF,which facilitates the decouped proton and electron transfer process.Density functional calculation results show that the introduction of Fe atoms and S vacancies in Ni3S_(2)can enhance the conductivity of the intermediates by regulating the electronic structure of the intermediates,optimize the adsorption or desorption energy,and thus significantly improve the OER activity.For Vs-Ni_(2)Fe_(1)S_(2)/NF(+,-)cell,a voltage of 1.56 V is required to achieve 10 mA cm^(-2).In addition,Vs-Ni_(2)Fe_(1)S_(2)/NF catalyst also showed low overpotential(270 mV at 100 mA cm^(-2))and high alkaline tolerance(100 h at 100 mA cm^(-2))at 30 wt%KOH of 70℃.This shows that it has potential industrial application.
基金This research was supported by Brain Pool Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(No.2020H1D3A1A04081409。
文摘Vacancy engineering in metal sulfides has garnered enormous attention from researchers because of their outstanding ability to modulate the optical and physiochemical properties of photocatalysts.Typically,in the case of sulfides,the catalytic activity is drastically hindered by the quick reassembly of excitons and the photocorrosion effect.Hence designing and generating S-vacancies in metal sulfides has emerged as a potential strategy for attaining adequate water splitting to generate H_(2) and O_(2) because of the simulta-neous improvement in the optoelectronic features.However,developing efficient catalysts that manifest optimal photo(electro)catalytic performance for large-scale applicability remains challenging.Therefore,it is of utmost interest to explore the insightful features of creating S-vacancy and study their impact on catalytic performance.This review article aims to comprehensively highlight the roles of S-vacancy in sulfides for amended overall water-splitting activity.The photocatalytic features of S-vacancies modulated metal sulfides are deliberated,followed by various advanced synthetic and characterization techniques for effectual generation and identification of vacancy defects.The specific aspects of S-vacancies in refin-ing the optical absorption range charge carrier dynamics,and photoinduced surface chemical reactions are critically examined for overall water splitting applications.Finally,the vouchsafing outlooks and op-portunities confronting the defect-engineered(S-vacancy)metal sulfides-based photocatalysts have been summarized.
基金This work was supported by the National Key R&D Program of China(No.2021YFA1200804)the National Natural Science Foundation of China(Grant Nos.62274175,T2325025,and 61927813)+1 种基金Jiangsu Province Key R&D Program(Nos.BE2023009-5 and BE2021007-3)the open Foundation of Key Laboratory of Nanodevices of Jiangsu Province(No.ZS2301).
文摘The low-dimensional light source shows promise in photonic integrated circuits.Stable layered van der Waals material that exhibits luminescence in the near-infrared optical communication waveband is an essential component in on-chip light sources.Herein,the tunable near-infrared photoluminescence(PL)of the air-stable layered titanium trisulfide(TiS3)is reported.Compared with iodine particles as a transport agent,TiS3 grown by chemical vapor transport using sulfur powder as a transport agent has fewer sulfur vacancies,which increases the luminescence intensity by an order of magnitude.The PL emission wavelength can be regulated in the near-infrared regime by thickness control.In addition,we observed an interesting anisotropic strain response of PL in layered TiS3 nanoribbon:a blue shift of PL was achieved when the uniaxial tensile strain was applied along the b-axis,while a negligible shift was observed when the strain was applied along the a-axis.Our work reveals the tunable nearinfrared luminescent properties of TiS3 nanoribbons,suggesting their potential applications as near-infrared light sources in photonic integrated circuits.
基金supported by the National Natural Science Foundation of China(Nos.11975234,11775225,12075243,12005227,51790491,U2032150 and U1732148)the Users with Excellence Program of Hefei Science Center CAS(Nos.2019HSC-UE002,2020HSC-UE002,2020HSC-CIP013 and 2021HSC-UE002)+1 种基金the Postdoctoral Science Foundation of China(Nos.2020M682041,2020TQ0316 and 2019M662202)the National Key Research and Development Program of China(No.2019YFA0307900)。
文摘Endowing bilayer transition-metal dichalcogenides(TMDs)with tunable magnetism is significant to investigate the coupling of multiple electron degrees of freedom(DOFs).However,effectively inducing and tuning the magnetic interaction of bilayer TMDs are still challenges.Herein,we report a strategy to tune the interlayer exchange interaction of centimeter-scale MoS2 bilayer with substitutional doping of Co ion,by introducing sulfur vacancy(V_(s))to modulate the interlayer electronic coupling.This strategy could transform the interlayer exchange interaction from antiferromagnetism(AFM)to ferromagnetism(FM),as revealed by the magnetic measurements.Experimental characterizations and theoretical calculations indicate that the enhanced magnetization is mainly because the hybridization of Co 3d band and Vs-induced impurity band alters the forms of interlayer orbital hybridizations between the partial Co atoms in upper and lower layers,and also enhances the intralayer FM.Our work paves the way for tuning the interlayer exchange interaction with defects and could be extended to other two-dimensional(2D)magnetic materials.
基金the National Natural Science Foundation of China(Nos.52072182,U1732126,and 51872145)the China Postdoctoral Science Foundation(Nos.2019M650120 and 2020M671554)the National Synergetic Innovation Center for Advanced Materials(SICAM).
文摘Electronic modulation on the inert basal plane of transition-metal dichalcogenides(TMDs)through vacancy defect excitation,although extremely challenging,is urgent for understanding the factors that impact the hydrogen evolution reaction(HER)catalytic activity.Here,ultrathin WS2 nanosheets with precise quantitative single atomic S-vacancy on the inert basal plane were flexible prepared through hydrogen peroxide etching strategy.The as-synthesized single atomic S-vacancy defect WS2(SVD-WS2)nanoflake with the activated basal plane exhibited an impressive overpotential of 137 mV at a current density of 10 mA·cm^(-2) and a Tafel slope of 53.9 mV dec^(-1).Furthermore,anchoring on the defect graphene matrix,the assembled two-dimensional(2D)stacking heterojunction exhibits further enhanced HER catalytic activity(an overpotential of 108 mV vs.10 mA·cm^(-2) and a Tafel slope of 48.3 mV·dec^(-1))and stability(〜10%decline after 9,000 cycles),which attributed to the electronic structure modulation from the synergetic interactions between SVD-WS_(2) and defect graphene.Our finding provides a smart defects introduce strategy to trigger high-efficiency hydrogen evolution over WS_(2) nanosheets and a general 2D heterojunctions fabricated inspiration based on strong interaction interface.
