Fascinating with high specific capacity and moderate lithiation potential,SnO_(x)-based materials have been intensively investigated as one of the most promising anodes for lithium-ion batteries.However,due to poor cy...Fascinating with high specific capacity and moderate lithiation potential,SnO_(x)-based materials have been intensively investigated as one of the most promising anodes for lithium-ion batteries.However,due to poor cycling stability,sluggish reaction kinetics,and limited electrochemical reaction reversibility,the development of SnO_(x)-based anodes has been hindered.And the current preparation and modification routes for SnO_(x)-based anodes lack direct and specific illustration.Herein,modification routes for SnO_(x)-based anodes have been emphasized.Firstly,to provide more direct instructions,the tuning routes of morphological structure for SnO_(x)-based electrodes(including slurry-based and self-supported)have been thoroughly discussed from the preparation perspective.Secondly,according to the properties of SnO_(x)-based anodes,the phase structure design ideas have also been properly classified and organized for addressing chemical reaction kinetics or thermodynamic issues.Finally,for future-oriented studies,new insights into the development and commercialization prospects of SnO_(x)-based anodes are also provided.This review,with comprehensive information on SnO_(x)-based anodes,aims to bring more specific guidance and valuable inspiration for peer researchers who are promoting the application of SnO_(x)-based materials for energy conversion and storage devices.展开更多
By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the d...By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.展开更多
Coordination tuning electronic structure of host materials is a quite effective strategy for activating and improving the intrinsic properties.Herein,halogen anion(X-)-incorporated β-FeOOH(β-FeOOH(X),X=F-,Cl-,and Br...Coordination tuning electronic structure of host materials is a quite effective strategy for activating and improving the intrinsic properties.Herein,halogen anion(X-)-incorporated β-FeOOH(β-FeOOH(X),X=F-,Cl-,and Br-) was investigated with a spontaneous adsorption process,which realized a great improvement of supercapacitor performances by adjusting the coordination geometry.Experiments coupled with theoretical calculations demonstrated that the change of Fe-O bond length and structural distortion of β-FeOOH,which is rooted in halogen ions embedment,led to the relatively narrow band gap.Because of the strong electronegativity of X-,the Fe element in β-FeOOH(X)s presented the unexpected high valence state(3+δ),which is facilitating to adsorb S032-species.Consequently,the designed β-FeOOH(X)s exhibited the good electric conductivity and enhanced the contact between electrode and electrolyte.When used as a negative electrode,the β-FeOOH(F) showed the excellent specific capacity of 391.9 F g-1 at 1 A g-1 current density,almost tenfold improvement compared with initial β-FeOOH,with the superior rate capacity and cyclic stability.This combinational design principle of electronic structure and electrochemical performances provides a promising way to develop advanced electrode materials for supercapacitor.展开更多
Triboelectric nanogenerators(TENG),renowned for their remarkable capability to harness weak mechanical energy from the environment,have gained considerable attention owing to their cost-effectiveness,high output,and a...Triboelectric nanogenerators(TENG),renowned for their remarkable capability to harness weak mechanical energy from the environment,have gained considerable attention owing to their cost-effectiveness,high output,and adaptability.This review provides a unique perspective by conducting a comprehensive and in-depth analysis of magnetically assisted TENGs that encompass structures,materials,and self-powered sensing systems.We systematically summarize the diverse functions of the magnetic assistance for TENGs,including system stiffness,components of the hybrid electromagnetic-triboelectric generator,transmission,and interaction forces.In the material domain,we review the incorporation of magnetic nano-composites materials,along with ferrofluid-based TENG and microstructure verification,which have also been summarized based on existing research.Furthermore,we delve into the research progress on physical quantity sensing and human-machine interface in magnetic-assisted TENGs.Our analysis highlights that magnetic assistance extends beyond the repulsive and suction forces under a magnetic field,thereby playing multifaceted roles in improving the output performance and environmental adaptability of the TENGs.Finally,we present the prevailing challenges and offer insights into the future trajectory of the magnetic-assisted TENGs development.展开更多
Hexagonal boron nitride(h-BN),with unique structural and properties,has shown enormous potentitoward variety of possible applications.By virtue of partially-ionic character of BN chemical bonds anusually large specifi...Hexagonal boron nitride(h-BN),with unique structural and properties,has shown enormous potentitoward variety of possible applications.By virtue of partially-ionic character of BN chemical bonds anusually large specific surface area,h-BN-related nanostructures exhibit appealing adsorption propertiewhich can be widely applied for separation and purification towards energy and environment treatmenIn this review,recent progress in designing h-BN micro,nano-structure,controlled synthesis,performancoptimizing as well as energy and environment-related adsorption applications are summarized.Strategieto tailor the h-BN can be classified as morphology control,element doping,defect control and surfacmodification,focusing on how to optimize the adsorption performance.In order to insight the intrinsimechanism of tuning strategies for property optimization,the significant adsorption applications of h-Btowards hydrogen storage,CO2 capture,pollutants removal from water and adsorption desulfurization arpresented.展开更多
Three types of β-NaYF_4nanoparticles, uncoated core（NaYF_4：Yb/Ho/Ce）, single-layer coated core@shell（NaYF_4：Yb/Ho/Ce@NaYF_4：Yb） and double-layer coated core@shell@shell（NaYF_4：Yb/Ho@NaYF_4：Yb@NaYF_4：Yb） w...Three types of β-NaYF_4nanoparticles, uncoated core（NaYF_4：Yb/Ho/Ce）, single-layer coated core@shell（NaYF_4：Yb/Ho/Ce@NaYF_4：Yb） and double-layer coated core@shell@shell（NaYF_4：Yb/Ho@NaYF_4：Yb@NaYF_4：Yb） with Ce^（3＋） doped in core, first and second shell, respectively, were synthesized through solvothermal method to investigate the cross-relaxation between Ho^（3＋） and Ce^（3＋） for the tunable upconversion luminescence. By doping Ce^（3＋） into different layers with different doping concentrations, a systematical investigation on the tunable upconversion luminescence from green to red was conducted. The results showed that a remarkable color tuning could be achieved from green to red when increasing the doping concentration of Ce^（3＋） in the same layer of Ho^（3＋）. And if Ce^（3＋） and Ho^（3＋） were separated in different layers, the color tuning would be depressed significantly due to the reduced cross-relaxation between Ho^（3＋） and Ce^（3＋）. Moreover, the UC emission intensity of core@shell and core@shell@shell was enhanced significantly compared with that of unmodified core nanoparticles.展开更多
It is reported that simple beam structure used for FBG tuning can cause FBG chirping. A novel tuning method utilizing the clamped beam structure under pure bending is introduced. In this paper, we experimentally and t...It is reported that simple beam structure used for FBG tuning can cause FBG chirping. A novel tuning method utilizing the clamped beam structure under pure bending is introduced. In this paper, we experimentally and theoretically demonstrate that new method can tune the Bragg wavelength without chirp. Further integration of this package can be used for FBG athermal/MEMS packaging.展开更多
Squaric acid(C_(4)H_(4)O_(4))is an organodioic acid characterized by a conjugated structure that features two carbonyl groups,two hydroxyl groups and a four-membered ring.Compared with other ligands,squaric acid has a...Squaric acid(C_(4)H_(4)O_(4))is an organodioic acid characterized by a conjugated structure that features two carbonyl groups,two hydroxyl groups and a four-membered ring.Compared with other ligands,squaric acid has a shorter molecular length and a more rigid conformation.Its strong coordination ability and distinctive coordination mode endow it with unique functionalities,making squaric acid-based metal‒organic frameworks(SA-MOFs)the focus of considerable interest.In recent decades,the diverse structural properties of both 2D and 3D squaric acid-based MOFs have demonstrated their potential for precise structural design.Furthermore,SA-MOFs show significant promise for high-performance applications in various fields,such as materials science and gas adsorption.This paper provides a systematic review of 2D and 3D SA-MOFs,focusing on their structures and properties from the perspective of synthesis methods.Additionally,it offers insights into SA-MOF materials from foundational principles while discussing future prospects and challenges associated with these innovative frameworks.展开更多
A 3＋1/2cell DC-SC photo-injector for PKU-FEL facility is under development, which is an upgrade design of the successful 1-4-1/2cell DC-SC photo-injector. The Lorentz detuning and tuning structure for the 3＋1/2cell ...A 3＋1/2cell DC-SC photo-injector for PKU-FEL facility is under development, which is an upgrade design of the successful 1-4-1/2cell DC-SC photo-injector. The Lorentz detuning and tuning structure for the 3＋1/2cell superconducting cavity is presented in this paper. The Lorentz force detuning coefficient is 1.2 Hz/（MV/m）^2 with double stiffening rings for the half cell and single stiffening rings between the adjacent TESLA cells. With the special stiffening structure, the 3＋1/2cell whole cavity needs only one tuner. The influences of the tuning on frequency shift, field flatness and average gradient are discussed in this paper. The simulation results show that the stiffening rings＇ design is successful.展开更多
Potassium-ion batteries(PIBs)have attracted tremendous attention during the past several years due to their abundant reserves,wide distribution,fast ionic conductivity,and high operating voltage.The primary obstacle i...Potassium-ion batteries(PIBs)have attracted tremendous attention during the past several years due to their abundant reserves,wide distribution,fast ionic conductivity,and high operating voltage.The primary obstacle impeding the com-mercialization of rechargeable PIBs is the lack of suitable high-performance anode materials.Carbon materials,known for their environmental friendliness,abundant availability,and outstanding comprehensive performance,have received extensive attention because they can be utilized directly as anodes or serve as a constrained matrix for conversion-/alloying-type anodes to enhance the electrochemical performance.Structural tuning and morphological modulation are two common strategies for modifying carbon materials.In this review,the recent progress in carbon materials aimed at enhancing the performance of PIBs through the utilization of these two strategies is systematically summarized.First,the effects of structural tuning and morphological modulation on the electrochemical properties of carbon materials and the corresponding storage mechanisms are reviewed.Second,the performance improvement mechanisms of conversion-/alloying-type anodes utilizing carbon scaf-folds based on these two strategies are systematically discussed.Third,the application of carbon materials based on various modification strategies in various advancedK+storage devices is reviewed.Finally,the challenges and perspectives for the further development of carbon-based materials for PIBs are highlighted.展开更多
Phase engineering can overcome the weaknesses of catalysts by tuning the electronic structures and catalytic functions.In this study,we investigate the role of phase-engineered NiSx,specifically hexagonal,trigonal and...Phase engineering can overcome the weaknesses of catalysts by tuning the electronic structures and catalytic functions.In this study,we investigate the role of phase-engineered NiSx,specifically hexagonal,trigonal and cubic phases,as a cocatalyst decorated onto the semiconductor surface.We demonstrate that NiSx with different phases(i.e.h-NiS,t-NiS and c-NiS_(2))can greatly improve the photocatalytic hydrogen evolution rate of various classical semiconductors including TiO_(2),CdS and carbon nitride(CN).In particular,it is observed that c-NiS_(2) can promote the H2 evolution performance with the highest improvement factor compared with h-NiS and t-NiS regardless of the type of hosting semiconductor.The highly efficient sacrificial hydrogen evolution performance rates are achieved on c-NiS_(2)/CN(4078μmol h^(−1) g^(−1)),c-NiS_(2)/TiO_(2)(345μmol h^(−1) g^(−1))and c-NiS_(2)/CdS(14604μmol h^(−1) g^(−1))under light irradiation(λ>320 nm).As revealed by detailed characterizations and theoretical computations,the significant higher performance of c-NiS_(2) is because c-NiS_(2) possesses more appropriate hydrogen adsorption Gibbs free energy and better ability in facilitating charge migration compared to h-NiS and t-NiS.Our findings highlight the great potential of phase engineering as a general strategy for improving the catalytic performance of different catalysts.展开更多
The development of inexpensive and bifunctional electrocatalysts based on earth-abundant elements for electrocatalytic water splitting,including the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),i...The development of inexpensive and bifunctional electrocatalysts based on earth-abundant elements for electrocatalytic water splitting,including the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),is of great significance.Herein,a new type of CoMo-LDH ultrathin nanosheet was synthesized as a bifunctional electrocatalyst with both OER and HER activity for full water splitting.Benefiting from the ultrathin structure and the tuned electronic structure by the doping of Mo^(6+).展开更多
CO_(2) hydrogenation into valuable chemical products has attracted intensive research interest in recent years,with product selectivity control remaining an important topic that requires fine tuning of the catalytic s...CO_(2) hydrogenation into valuable chemical products has attracted intensive research interest in recent years,with product selectivity control remaining an important topic that requires fine tuning of the catalytic structure and mechanistic understanding.Herein we report our study of anionic phosphorus-regulated indium oxide In_(2)O_(3)(P-In_(2)O_(3))nanocatalyst materials for CO_(2) hydrogenation and achieve nearly fullrange selectivity control between methanol and CO products by means of tuning the P content.In situ DRIFTS experiments and XPS characterization reveal the importance of P anion regulation in controlling the CO_(2) hydrogenation pathways,with an increase in the P content resulting in a decrease in the reducibility of In_(2)O_(3) that alters CO_(2) adsorption configuration by blocking and weakening oxygen vacancy(OV)sites for methanol generation and in the meantime creates new sites predominantly active for CO generation.This study demonstrates excellent control of the product selectivity property by regulating the catalyst composition with P anions and provides mechanistic discussions,which offers a new,effective strategy in CO_(2) hydrogenation catalyst research.展开更多
The main bottleneck of electrolytic water for hydrogen production in alkaline media is the oxygen evolution reaction(OER)involving four-electron transfer.Designing highly efficient OER catalysts is attractive to accel...The main bottleneck of electrolytic water for hydrogen production in alkaline media is the oxygen evolution reaction(OER)involving four-electron transfer.Designing highly efficient OER catalysts is attractive to accelerate this process.Monoclinic oxides have gained enormous interest as promising candidates for electrocatalysis due to their low cost and abundant storage.The introduction of transition metals into metal oxides to tune the electronic structure of active sites is regarded as one of the promising methods for enhancing OER performance.Herein,we designed a Fe_(2)(MoO_(4))_(3) catalyst by a spray pyrolysis strategy and enhanced the OER performance of Fe_(2)(MoO_(4))_(3) with Co doping,which displayed a low overpotential of 273 mV to drive 10 mA cm^(2).The octahedral Fe site engineering leads to higher reaction kinetics and more active site exposure.Density functional theory(DFT)calculations further revealed that the introduction of Co can reduce the energy barrier for the OER process and weaken the absorption of*-O.This work provides a new insight into the fabrication of monoclinic oxide electrocatalysts for OERs in alkaline media.展开更多
Zeolites,featured by a well-defined microporous structure and tunable acidity,have widely served as core catalysts in the petrochemical and refining industries.In practical applications,dealumination of acidic zeolite...Zeolites,featured by a well-defined microporous structure and tunable acidity,have widely served as core catalysts in the petrochemical and refining industries.In practical applications,dealumination of acidic zeolite framework is often inevitable,and in many cases,strategically employed to tune both zeolite structure and acidity,for enhancing catalytic performance.展开更多
In the past decade,molybdenum ditelluride(MoTe2)has received significant attention from the scientific community due to its structural features and unique properties originate from them.In the current review,the prope...In the past decade,molybdenum ditelluride(MoTe2)has received significant attention from the scientific community due to its structural features and unique properties originate from them.In the current review,the properties,various preparation approaches,and versatile applications of MoTe2 are presented.The review provides a brief update on the state of our fundamental understanding of MoTe2 material and also discusses the issues that need to be resolved.To introduce MoTe2,we briefly summarize its structural,optoelectronic,magnetic,and mechanical properties in the beginning.Then,different preparation meth-ods of MoTe2,such as exfoliation,laser treatment,deposition,hydrothermal,microwave,and molecular beam epitaxy,are included.The excellent electri-cal conductivity,strong optical activity,tunable bandgap,high sensitivity,and impressive stability make it an ideal contender for different applications,includ-ing energy storage,catalysis,sensors,solar cells,photodetectors,and transistors.The performance of MoTe2 in these applications is systematically introduced along with mechanistic insights.At the end of the article,the challenges and possible future directions are highlighted to further modify MoTe2 material for the numerous functionalities.Therefore,the availability of different phases and layer structures implies a potential for MoTe2 to lead an era of two-dimensional materials that began from the exfoliation of graphene.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52071144,51831009 and 51621001)Guangzhou key research and development program(No.202103040001)。
文摘Fascinating with high specific capacity and moderate lithiation potential,SnO_(x)-based materials have been intensively investigated as one of the most promising anodes for lithium-ion batteries.However,due to poor cycling stability,sluggish reaction kinetics,and limited electrochemical reaction reversibility,the development of SnO_(x)-based anodes has been hindered.And the current preparation and modification routes for SnO_(x)-based anodes lack direct and specific illustration.Herein,modification routes for SnO_(x)-based anodes have been emphasized.Firstly,to provide more direct instructions,the tuning routes of morphological structure for SnO_(x)-based electrodes(including slurry-based and self-supported)have been thoroughly discussed from the preparation perspective.Secondly,according to the properties of SnO_(x)-based anodes,the phase structure design ideas have also been properly classified and organized for addressing chemical reaction kinetics or thermodynamic issues.Finally,for future-oriented studies,new insights into the development and commercialization prospects of SnO_(x)-based anodes are also provided.This review,with comprehensive information on SnO_(x)-based anodes,aims to bring more specific guidance and valuable inspiration for peer researchers who are promoting the application of SnO_(x)-based materials for energy conversion and storage devices.
基金Supported by the National Basic Research Program of China(973 Program)under Grant Nos 2011CBA00106 and2012CB927400the National Natural Science Foundation of China under Grant Nos 11274332 and 11227902Helmholtz Association through the Virtual Institute for Topological Insulators(VITI).M.Y.Li and D.W.Shen are also supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB04040300
文摘By means of oxide molecular beam epitaxy with shutter-growth mode, we fabricate a series of electron-doped （Sr1-xLax）2IrO4 （001） （x=0, 0.05, 0.1 and 0.15） single crystalline thin films and then investigate the doping dependence of the electronic structure utilizing in-situ angle-resolved photoemission spectroscopy. It is found that with the increasing doping content, the Fermi levels of samples progressively shift upward. Prominently, an extra electron pocket crossing the Fermi level around the M point is evidently observed in the 15% nominal doping sample. Moreover, bulk-sensitive transport measurements confirm that the doping effectively suppresses the insulating state with respect to the as-grown Sr2IrO4, though the doped samples still remain insulating at low temperatures due to the localization effect possibly stemming from disorders including oxygen deficiencies. Our work provides another feasible doping method to tune electronic structure of Sr2 IrO4.
基金supported by the National Natural Science Foundation of China(Nos.2177060378,21627813,and 21521005)the Program for Changjiang Scholars,Innovative Research Teams in Universities(No.IRT1205)the Fundamental Research Funds for the Central Universities(Nos.12060093063 and XK1803-05).
文摘Coordination tuning electronic structure of host materials is a quite effective strategy for activating and improving the intrinsic properties.Herein,halogen anion(X-)-incorporated β-FeOOH(β-FeOOH(X),X=F-,Cl-,and Br-) was investigated with a spontaneous adsorption process,which realized a great improvement of supercapacitor performances by adjusting the coordination geometry.Experiments coupled with theoretical calculations demonstrated that the change of Fe-O bond length and structural distortion of β-FeOOH,which is rooted in halogen ions embedment,led to the relatively narrow band gap.Because of the strong electronegativity of X-,the Fe element in β-FeOOH(X)s presented the unexpected high valence state(3+δ),which is facilitating to adsorb S032-species.Consequently,the designed β-FeOOH(X)s exhibited the good electric conductivity and enhanced the contact between electrode and electrolyte.When used as a negative electrode,the β-FeOOH(F) showed the excellent specific capacity of 391.9 F g-1 at 1 A g-1 current density,almost tenfold improvement compared with initial β-FeOOH,with the superior rate capacity and cyclic stability.This combinational design principle of electronic structure and electrochemical performances provides a promising way to develop advanced electrode materials for supercapacitor.
基金supported by the General Program of the National Natural Science Foundation of China(NSFC,No.52075061)the Key Program of the National Natural Science Foundation of China(NSFC,No.U22B2089)the Science Fund for Distinguished Young Scholars of Chongqing(No.CSTB2022 NSCQ-JQX0006).
文摘Triboelectric nanogenerators(TENG),renowned for their remarkable capability to harness weak mechanical energy from the environment,have gained considerable attention owing to their cost-effectiveness,high output,and adaptability.This review provides a unique perspective by conducting a comprehensive and in-depth analysis of magnetically assisted TENGs that encompass structures,materials,and self-powered sensing systems.We systematically summarize the diverse functions of the magnetic assistance for TENGs,including system stiffness,components of the hybrid electromagnetic-triboelectric generator,transmission,and interaction forces.In the material domain,we review the incorporation of magnetic nano-composites materials,along with ferrofluid-based TENG and microstructure verification,which have also been summarized based on existing research.Furthermore,we delve into the research progress on physical quantity sensing and human-machine interface in magnetic-assisted TENGs.Our analysis highlights that magnetic assistance extends beyond the repulsive and suction forces under a magnetic field,thereby playing multifaceted roles in improving the output performance and environmental adaptability of the TENGs.Finally,we present the prevailing challenges and offer insights into the future trajectory of the magnetic-assisted TENGs development.
基金financially supported by the National Natural Science Foundation of China (Nos. 21606113, 21676128, and 21722604)the International Postdoctoral Exchange Fellowship by China Postdoctoral Science Foundation (No. 20170055)
文摘Hexagonal boron nitride(h-BN),with unique structural and properties,has shown enormous potentitoward variety of possible applications.By virtue of partially-ionic character of BN chemical bonds anusually large specific surface area,h-BN-related nanostructures exhibit appealing adsorption propertiewhich can be widely applied for separation and purification towards energy and environment treatmenIn this review,recent progress in designing h-BN micro,nano-structure,controlled synthesis,performancoptimizing as well as energy and environment-related adsorption applications are summarized.Strategieto tailor the h-BN can be classified as morphology control,element doping,defect control and surfacmodification,focusing on how to optimize the adsorption performance.In order to insight the intrinsimechanism of tuning strategies for property optimization,the significant adsorption applications of h-Btowards hydrogen storage,CO2 capture,pollutants removal from water and adsorption desulfurization arpresented.
基金Project supported by the National Key Basic Research Program of China(2013CB921800)the National Natural Science Foundation of China(11374291,11204292,11274299,11311120047)the Fundamental Research Funds for the Central Universities(WK2030020021)
文摘Three types of β-NaYF_4nanoparticles, uncoated core（NaYF_4：Yb/Ho/Ce）, single-layer coated core@shell（NaYF_4：Yb/Ho/Ce@NaYF_4：Yb） and double-layer coated core@shell@shell（NaYF_4：Yb/Ho@NaYF_4：Yb@NaYF_4：Yb） with Ce^（3＋） doped in core, first and second shell, respectively, were synthesized through solvothermal method to investigate the cross-relaxation between Ho^（3＋） and Ce^（3＋） for the tunable upconversion luminescence. By doping Ce^（3＋） into different layers with different doping concentrations, a systematical investigation on the tunable upconversion luminescence from green to red was conducted. The results showed that a remarkable color tuning could be achieved from green to red when increasing the doping concentration of Ce^（3＋） in the same layer of Ho^（3＋）. And if Ce^（3＋） and Ho^（3＋） were separated in different layers, the color tuning would be depressed significantly due to the reduced cross-relaxation between Ho^（3＋） and Ce^（3＋）. Moreover, the UC emission intensity of core@shell and core@shell@shell was enhanced significantly compared with that of unmodified core nanoparticles.
文摘It is reported that simple beam structure used for FBG tuning can cause FBG chirping. A novel tuning method utilizing the clamped beam structure under pure bending is introduced. In this paper, we experimentally and theoretically demonstrate that new method can tune the Bragg wavelength without chirp. Further integration of this package can be used for FBG athermal/MEMS packaging.
基金supported by the Fundamental Research Funds for the Central Universities(WK9990000113)the Chinese Academy of Sciences Talent Introduction Program(KJ9990007009).
文摘Squaric acid(C_(4)H_(4)O_(4))is an organodioic acid characterized by a conjugated structure that features two carbonyl groups,two hydroxyl groups and a four-membered ring.Compared with other ligands,squaric acid has a shorter molecular length and a more rigid conformation.Its strong coordination ability and distinctive coordination mode endow it with unique functionalities,making squaric acid-based metal‒organic frameworks(SA-MOFs)the focus of considerable interest.In recent decades,the diverse structural properties of both 2D and 3D squaric acid-based MOFs have demonstrated their potential for precise structural design.Furthermore,SA-MOFs show significant promise for high-performance applications in various fields,such as materials science and gas adsorption.This paper provides a systematic review of 2D and 3D SA-MOFs,focusing on their structures and properties from the perspective of synthesis methods.Additionally,it offers insights into SA-MOF materials from foundational principles while discussing future prospects and challenges associated with these innovative frameworks.
基金Supported by Major State Basic Research Development Program of China(2002CB713600)
文摘A 3＋1/2cell DC-SC photo-injector for PKU-FEL facility is under development, which is an upgrade design of the successful 1-4-1/2cell DC-SC photo-injector. The Lorentz detuning and tuning structure for the 3＋1/2cell superconducting cavity is presented in this paper. The Lorentz force detuning coefficient is 1.2 Hz/（MV/m）^2 with double stiffening rings for the half cell and single stiffening rings between the adjacent TESLA cells. With the special stiffening structure, the 3＋1/2cell whole cavity needs only one tuner. The influences of the tuning on frequency shift, field flatness and average gradient are discussed in this paper. The simulation results show that the stiffening rings＇ design is successful.
基金financially supported by the Postdoctoral Innovation Talents Support Program of China(BX2021067)the Pujiang Talent Program of Shanghai(20PJ1401400)+2 种基金the Open Fund of the Guangdong Provincial Key Laboratory of Advance Energy Storage Materials(Grant No.asem202101)Aerospace Innovation Fund of Shanghai(SAST2020098)the China Postdoctoral Science Foundation(No.2022M710711).
文摘Potassium-ion batteries(PIBs)have attracted tremendous attention during the past several years due to their abundant reserves,wide distribution,fast ionic conductivity,and high operating voltage.The primary obstacle impeding the com-mercialization of rechargeable PIBs is the lack of suitable high-performance anode materials.Carbon materials,known for their environmental friendliness,abundant availability,and outstanding comprehensive performance,have received extensive attention because they can be utilized directly as anodes or serve as a constrained matrix for conversion-/alloying-type anodes to enhance the electrochemical performance.Structural tuning and morphological modulation are two common strategies for modifying carbon materials.In this review,the recent progress in carbon materials aimed at enhancing the performance of PIBs through the utilization of these two strategies is systematically summarized.First,the effects of structural tuning and morphological modulation on the electrochemical properties of carbon materials and the corresponding storage mechanisms are reviewed.Second,the performance improvement mechanisms of conversion-/alloying-type anodes utilizing carbon scaf-folds based on these two strategies are systematically discussed.Third,the application of carbon materials based on various modification strategies in various advancedK+storage devices is reviewed.Finally,the challenges and perspectives for the further development of carbon-based materials for PIBs are highlighted.
基金support from Natural Science Foundation of Jiangsu Province(BK20210827)China Postdoctoral Science Foundation(2021M700117)National Natural Science Foundation of China(22178152,U1904215).
文摘Phase engineering can overcome the weaknesses of catalysts by tuning the electronic structures and catalytic functions.In this study,we investigate the role of phase-engineered NiSx,specifically hexagonal,trigonal and cubic phases,as a cocatalyst decorated onto the semiconductor surface.We demonstrate that NiSx with different phases(i.e.h-NiS,t-NiS and c-NiS_(2))can greatly improve the photocatalytic hydrogen evolution rate of various classical semiconductors including TiO_(2),CdS and carbon nitride(CN).In particular,it is observed that c-NiS_(2) can promote the H2 evolution performance with the highest improvement factor compared with h-NiS and t-NiS regardless of the type of hosting semiconductor.The highly efficient sacrificial hydrogen evolution performance rates are achieved on c-NiS_(2)/CN(4078μmol h^(−1) g^(−1)),c-NiS_(2)/TiO_(2)(345μmol h^(−1) g^(−1))and c-NiS_(2)/CdS(14604μmol h^(−1) g^(−1))under light irradiation(λ>320 nm).As revealed by detailed characterizations and theoretical computations,the significant higher performance of c-NiS_(2) is because c-NiS_(2) possesses more appropriate hydrogen adsorption Gibbs free energy and better ability in facilitating charge migration compared to h-NiS and t-NiS.Our findings highlight the great potential of phase engineering as a general strategy for improving the catalytic performance of different catalysts.
基金financially supported by the National Natural Science Foundation of China for Youths(No.21601067,21506081,21501112,51603092)the Natural Science Foundation of the Jiangsu Province for Youths(No.BK20160492)+3 种基金the Natural Science Foundation of Shandong Province(No.ZR2018JL009)the University Natural Science Research of Jiangsu(No.16KJB150008)the Funding for Scientific Research Startup of Jiangsu University(No.15JDG161)a project funded by the Priority Academic Program Development of the Jiangsu Higher Education Institutions.
文摘The development of inexpensive and bifunctional electrocatalysts based on earth-abundant elements for electrocatalytic water splitting,including the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),is of great significance.Herein,a new type of CoMo-LDH ultrathin nanosheet was synthesized as a bifunctional electrocatalyst with both OER and HER activity for full water splitting.Benefiting from the ultrathin structure and the tuned electronic structure by the doping of Mo^(6+).
基金the Ohio Development Services Agency(R-16-04)for the financial support of this study.
文摘CO_(2) hydrogenation into valuable chemical products has attracted intensive research interest in recent years,with product selectivity control remaining an important topic that requires fine tuning of the catalytic structure and mechanistic understanding.Herein we report our study of anionic phosphorus-regulated indium oxide In_(2)O_(3)(P-In_(2)O_(3))nanocatalyst materials for CO_(2) hydrogenation and achieve nearly fullrange selectivity control between methanol and CO products by means of tuning the P content.In situ DRIFTS experiments and XPS characterization reveal the importance of P anion regulation in controlling the CO_(2) hydrogenation pathways,with an increase in the P content resulting in a decrease in the reducibility of In_(2)O_(3) that alters CO_(2) adsorption configuration by blocking and weakening oxygen vacancy(OV)sites for methanol generation and in the meantime creates new sites predominantly active for CO generation.This study demonstrates excellent control of the product selectivity property by regulating the catalyst composition with P anions and provides mechanistic discussions,which offers a new,effective strategy in CO_(2) hydrogenation catalyst research.
基金This study is supported by the Fundamental Research Funds for the Central Universities(2020XZZX002-07).This study is also supported by Major Scientific Project of Zhejiang Lab(2020MC0AD01).This work is also supported by the Natural Science Foundation of China(No.21776248 and 21676246)and the Zhejiang Provincial Natural Science Foundation of China(No.LR17B060003).
文摘The main bottleneck of electrolytic water for hydrogen production in alkaline media is the oxygen evolution reaction(OER)involving four-electron transfer.Designing highly efficient OER catalysts is attractive to accelerate this process.Monoclinic oxides have gained enormous interest as promising candidates for electrocatalysis due to their low cost and abundant storage.The introduction of transition metals into metal oxides to tune the electronic structure of active sites is regarded as one of the promising methods for enhancing OER performance.Herein,we designed a Fe_(2)(MoO_(4))_(3) catalyst by a spray pyrolysis strategy and enhanced the OER performance of Fe_(2)(MoO_(4))_(3) with Co doping,which displayed a low overpotential of 273 mV to drive 10 mA cm^(2).The octahedral Fe site engineering leads to higher reaction kinetics and more active site exposure.Density functional theory(DFT)calculations further revealed that the introduction of Co can reduce the energy barrier for the OER process and weaken the absorption of*-O.This work provides a new insight into the fabrication of monoclinic oxide electrocatalysts for OERs in alkaline media.
文摘Zeolites,featured by a well-defined microporous structure and tunable acidity,have widely served as core catalysts in the petrochemical and refining industries.In practical applications,dealumination of acidic zeolite framework is often inevitable,and in many cases,strategically employed to tune both zeolite structure and acidity,for enhancing catalytic performance.
文摘In the past decade,molybdenum ditelluride(MoTe2)has received significant attention from the scientific community due to its structural features and unique properties originate from them.In the current review,the properties,various preparation approaches,and versatile applications of MoTe2 are presented.The review provides a brief update on the state of our fundamental understanding of MoTe2 material and also discusses the issues that need to be resolved.To introduce MoTe2,we briefly summarize its structural,optoelectronic,magnetic,and mechanical properties in the beginning.Then,different preparation meth-ods of MoTe2,such as exfoliation,laser treatment,deposition,hydrothermal,microwave,and molecular beam epitaxy,are included.The excellent electri-cal conductivity,strong optical activity,tunable bandgap,high sensitivity,and impressive stability make it an ideal contender for different applications,includ-ing energy storage,catalysis,sensors,solar cells,photodetectors,and transistors.The performance of MoTe2 in these applications is systematically introduced along with mechanistic insights.At the end of the article,the challenges and possible future directions are highlighted to further modify MoTe2 material for the numerous functionalities.Therefore,the availability of different phases and layer structures implies a potential for MoTe2 to lead an era of two-dimensional materials that began from the exfoliation of graphene.
