Micro-sized anatase TiO_(2) displays inferior capacity as cathode material for magnesium ion batteries because of the higher diffusion energy barrier of Mg^(2+)in anatase TiO_(2) lattice.Herein,we report that nanosize...Micro-sized anatase TiO_(2) displays inferior capacity as cathode material for magnesium ion batteries because of the higher diffusion energy barrier of Mg^(2+)in anatase TiO_(2) lattice.Herein,we report that nanosized anatase TiO_(2) exposed(001)facet doubles the capacity compared to the micro-sized sample ascribed to the interfacial Mg^(2+)ion storage.First-principles calculations reveal that the diffusion energy barrier of Mg^(2+)on the(001)facet is significantly lower than those in the bulk phase and on(100)facet,and the adsorption energy of Mg^(2+)on the(001)facet is also considerably lower than that on(100)facet,which guarantees superior interfacial Mg^(2+)storage of(001)facet.Moreover,anatase TiO_(2) exposed(001)facet displays a significantly higher capacity of 312.9 mAh g^(−1) in Mg-Li dual-salt electrolyte compared to 234.3 mAh g^(−1) in Li salt electrolyte.The adsorption energies of Mg^(2+)on(001)facet are much lower than the adsorption energies of Li+on(001)facet,implying that the Mg^(2+)ion interfacial storage is more favorable.These results highlight that controlling the crystal facet of the nanocrystals effectively enhances the interfacial storage of multivalent ions.This work offers valuable guidance for the rational design of high-capacity storage systems.展开更多
Iron carbodiimide(Fe NCN)anode demonstrates significant potential for rapid sodium-ion storage owing to its high reaction activity and near-metallic conductivity.However,further development of Fe NCN is hindered by in...Iron carbodiimide(Fe NCN)anode demonstrates significant potential for rapid sodium-ion storage owing to its high reaction activity and near-metallic conductivity.However,further development of Fe NCN is hindered by inherent structural instability and ambiguous structure-kinetics correlation.In this study,Fe NCN crystallites with selectively exposed(002)and{010}facets were precisely engineered and synthesized.Notably,the sodium storage kinetics and electrochemical performance of Fe NCN exhibit facet-dependent variations.Polyhedral-Fe NCN(P-Fe NCN)dominated by{010}facets exhibited a pseudocapacitance-driven storage mechanism and delivered exceptional rate capability(372 m Ah/g at5 A/g)and long cyclability(95.8%capacity retention after 300 cycles at 0.5 A/g).In contrast,sheet-like Fe NCN(S-Fe NCN)with predominant(002)facet exposure displayed diffusion-limited kinetics due to sluggish ion diffusion rate.Crucially,time-resolved operando XRD analysis and DFT simulation bridge this performance gap to mechanistic origins:Fe NCN as an intercalation-conversion type anode,the solid-state diffusion is the rate-determining step during charge/discharge process.Active{010}facets possess numerous broad hexagonal tunnels,coupled with a low diffusion barrier of 0.168 e V along{010}directions.This unique architectural configuration enables rapid sodium-ion transport,thereby shifting the diffusioncontrolled kinetics to intercalation-pseudocapacitive behavior.This discovery establishes active facet exposure as a storage kinetic switch,offering a generalized paradigm for optimizing the rate performance and stability of sodium-ion batteries.展开更多
Crystalized CeO_(2)structures were typically considered potential photocatalysts due to their great capacity to alter the active sites’size and ability to absorb light.However,the controllable fabrication of well-def...Crystalized CeO_(2)structures were typically considered potential photocatalysts due to their great capacity to alter the active sites’size and ability to absorb light.However,the controllable fabrication of well-defined hierarchical structures of CeO_(2)with high reactive facets is significant and challenging.Herein,a series of CeO_(2)supports including hierarchical flower-like(F-CeO_(2)),ball-like(B-CeO_(2)),cube-like(C-CeO_(2)),and rod-like CeO_(2)(R-CeO_(2))supports were prepared by hydrothermal method(BCeO_(2),R-CeO_(2)and C-CeO_(2))or ice-bath method(F-CeO_(2))respectively.V atoms were selected as the active atoms and loaded on these supports.Their structure-activity relationship in photo-assisted thermal propane dehydrogenation(PTPDH)was investigated systematically.The samples were characterized by Xray diffraction,scanning electron microscopy,transmission electron microscopy,N2 adsorption-desorption isotherms,and Fourier transform infrared spectrum.Results show that R-CeO_(2)support exhibits the biggest surface area thus achieving the best dispersion of VOx species.UV-vis spectrum and photoluminescence spectrum indicate that V/F-CeO_(2)has the best light adsorption property and V/R-CeO_(2)has the best carrier migration capacity.The activity tests demonstrate that the V/R-CeO_(2)has the largest net growth rate and the V/F-CeO_(2)has the biggest relative growth ratio.Furthermore,the non-thermal effect was confirmed by the kinetic method,which lowers the propane reaction orders,selectively promoting the first C-H bond activation.The light radiation TPSR experiment confirmed this point.DFT calculations show a good linear relationship between the energy barrier and the exchanged electron number.It inspires the design of high-reactive facets for boosting the intrinsic activity of the C-H bond in photoassisted thermal chemical processes.展开更多
Crack initiation mechanism of dwell fatigue has always been a key problem in rationalizing the dwell effect,and it is not completely understood yet.This study conducted stress-controlled low-cycle fatigue and dwell fa...Crack initiation mechanism of dwell fatigue has always been a key problem in rationalizing the dwell effect,and it is not completely understood yet.This study conducted stress-controlled low-cycle fatigue and dwell fatigue tests on Ti-6Al-3Nb-2Zr-1Mo alloy with bimodal microstructure to reveal its microstructural characteristics and crack initiation mechanisms.The study demonstrated that the faceted primaryα nodules located near the specimen surface acted as crack initiation sites during both fatigue and dwell fatigue tests.Slip trace analysis revealed that faceted cracking occurred at(0001)basal plane with the maximum Schmid factor value through a special cracking mode referred to as(0001)twist boundary cracking.Innovative criteria of parameters C1 and C2 were proposed based on experimental observation and molecular dynamics simulations,which well identify candidates for(0001)twist boundary crack nucleation.It demonstrated that grain pairs combining a moderately high Schmid factor for basal slip and a well-orientated Burgers vector in the out-of-surface plane was the preferable location for surface(0001)twist-boundary crack initiation,and grain pairs combining a high Schmid factor for basal slip and a high normal stress on basal plane are perfect candidates for subsurface cracking.Based on this,phenomeno-logical models are proposed to explain the surface(0001)twist-boundary cracking mechanism from the perspective of surface extrusion-intrusion-induced micro-notches.展开更多
F-B co-doped TiO_(2)nanosheets with exposed anatase(001)facets were synthesized via a one-pot solvothermal method,and their photocatalytic hydrogen evolution performance was investigated.Characterization results confi...F-B co-doped TiO_(2)nanosheets with exposed anatase(001)facets were synthesized via a one-pot solvothermal method,and their photocatalytic hydrogen evolution performance was investigated.Characterization results confirm that this method effectively promotes the growth of the highly active anatase(001)facets and enhances visible and infrared light absorption while inducing oxygen vacancies.Under optimal conditions,the hydrogen evolution reaches 20.57μmol after 10 h of ultraviolet-visible(UV-Vis)light irradiation,exceeding the commercial TiO_(2)nanoparticles Degussa P25 by more than 10 times.These findings highlight the potential of F-B co-doped TiO_(2)nanosheets for efficient photocatalysis.展开更多
Lithium-sulfur(Li-S)batteries are promising for high-energy-density storage,but their performance is limited by sluggish lithium polysulfide(LiPS)conversion kinetics.Here,we tackle this issue by synthesizing ultrafine...Lithium-sulfur(Li-S)batteries are promising for high-energy-density storage,but their performance is limited by sluggish lithium polysulfide(LiPS)conversion kinetics.Here,we tackle this issue by synthesizing ultrafine truncated octahedral TiO_(2) nanocrystals(P-O_(v)-TiO_(2)),featuring specific{101}facets and dual defects—phosphorus doping and oxygen vacancies.Acting as an efficient electrocatalyst in the separator,P-O_(v)-TiO_(2) exhibits superior catalytic properties,where oxygen vacancies modulate the electronic structure,enhancing electron enrichment and charge transfer;phosphorus doping tailors the d-band center of the catalyst,strengthening Ti-S interactions between the{101}facets and LiPSs.As a result,Li-S coin cells modified with P-O_(v)-TiO_(2) achieve a high specific capacity of 895 mAh g^(−1) at 5 C and exhibit a minimal decay rate of 0.14%per cycle over 200 cycles.Furthermore,Li-S pouch cells deliver a high capacity of 1004 mAh g^(−1) at 0.1 C under lean electrolyte conditions.This study elucidates the mechanisms of charge states on specific crystal planes and deepens our understanding of dual-defect engineering in Li-S electrochemistry,offering a promising approach for developing efficient and cost-effective catalysts for Li-S battery applications.展开更多
The facets effect on the catalytic properties of inorganic compounds and metal-organic frameworks(MOFs)has been widely demonstrated,but the intrinsic facets effect free of interference of capping agents has not been d...The facets effect on the catalytic properties of inorganic compounds and metal-organic frameworks(MOFs)has been widely demonstrated,but the intrinsic facets effect free of interference of capping agents has not been discussed.Here we give a proof-of-concept illustration on the intrinsic facets effect by employing the popularly investigated NH2-MIL-125(Ti)MOFs with{001},{111}and{100}facets controllably exposed as model photocatalysts,which were synthesized via a simple supersaturation strategy free of any capping agents.Compared to conventional synthetic routes with capping agents employed,the NH2-MIL-125(Ti)MOFs obtained in this work exhibit remarkably different physical and chemical properties such as surface wettability,charge separation as well as trend of facets effect on photocatalytic water splitting performance.The main reason has been unraveled to originate from unavoidable residue/influence of capping agents during the conventional facets-controlled synthetic routes leading to changed local surface structural environment as well as distinct charge separation property.Our results demonstrate the importance and feasibility of facets-controllable synthesis free of capping agents in getting insight into the intrinsic facets effect of MOFs-related materials.展开更多
ASEAN’s major power balancing strategy refers to the balancing strategy adopted by ASEAN and its member states to seek national and regional security and development by maintaining multi-faceted friendship and impart...ASEAN’s major power balancing strategy refers to the balancing strategy adopted by ASEAN and its member states to seek national and regional security and development by maintaining multi-faceted friendship and impartiality with surrounding major powers.The evolution of this strategy is a process of dynamic adjustment,with ASEAN and its members being the implementing subjects,major powers the objects.展开更多
Photocatalysis is a promising technology for purification of indoor air by oxidation of volatile organic compounds.This study provides a comprehensive analysis of the adsorption and photo-oxidation of surface-adsorbed...Photocatalysis is a promising technology for purification of indoor air by oxidation of volatile organic compounds.This study provides a comprehensive analysis of the adsorption and photo-oxidation of surface-adsorbed acetone on three SrTiO_(3)morphologies:cubes(for which exclusively{100}facets are exposed),{110}-truncated cubes,and{100}-truncated rhombic dodecahedrons,respectively,all prepared by hydrothermal synthesis.In situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy shows that cubic crystals contain a high quantity of surface-OH groups,enabling significant quantities of adsorbed acetone in the form ofη^(1)-enolate when exposed to gas phase acetone.Contrary,{110}facets exhibit fewer surface-OH groups,resulting in relatively small quantities of adsorbedη^(1)-acetone,without observable quantities of enolate.Interestingly,acetate and formate signatures appear in the spectra of cubic,surfaceη^(1)-enolate containing,SrTiO_(3)upon illumination,while besides acetate and formate,the formation of(surface)formaldehyde was observed on truncated cubes,and dodecahedrons,by conversion of adsorbedη^(1)-acetone.Time-Resolved Photoluminescence studies demonstrate that the lifetimes of photogenerated charge carriers vary with crystal morphology.The shortest carrier lifetime(τ_(1)=33±0.1 ps)was observed in{110}-truncated cube SrTiO_(3),likely due to a relatively strong built-in electric field promoting electron transport to{100}facets and hole transport to{110}facets.The second lifetime(τ_(2)=259±1 ps)was also the shortest for this morphology,possibly due to a higher amount of surface trap states.Our results demonstrate that SrTiO_(3)crystal morphology can be tuned to optimize performance in photocatalytic oxidation.展开更多
Nanostructured ceria has attracted much attention in the field of redox catalysts due to the numerous active sites with excellent redox ability.Based on the acidic medium etching strategy,we constructed the strong bin...Nanostructured ceria has attracted much attention in the field of redox catalysts due to the numerous active sites with excellent redox ability.Based on the acidic medium etching strategy,we constructed the strong binding centers(hydroxyl sites and strong acid sites)on the surfaces of nanostructured ceria,which regulate the adsorption process of KA-Oil(the mixture of cyclohexanol and cyclohexanone)and to promote high KA-Oil selectivity in cyclohexane oxidation.The three CeO_(2)(nanocube,nanorod and nanopolyhedron)with different exposed crystal planes were treated by acid etching to change the surface sites and catalytic properties.The transition behavior of surface sites during etching was revealed,abundant strong binding centers were proved to be constructed successfully.And especially for the nanorod treated by acid(Acid@CeO_(2)-NR)with the strongest response for sulfuric acid etching,the strong adsorption of cyclohexanone by strong binding centers was confirmed based on the in-situ DRIFTs.The sulfuric acid etching strategy to enhance the selective oxidation of cyclohexane based on the construction of strong binding centers was proved to be feasible and effective,Acid@CeO_(2)-NR with strongest etching response achieved the dramatic promotion of KA-Oil selectivity from 64.1%to 92.3%.展开更多
Rational tuning of crystallographic surface and metal doping were effective to enhance the catalytic performance of metal organic frameworks,but limited work has been explored for achieving modulation of crystal facet...Rational tuning of crystallographic surface and metal doping were effective to enhance the catalytic performance of metal organic frameworks,but limited work has been explored for achieving modulation of crystal facets and metal doping in a single system.MIL-68(In)was promising for photocatalytic applications due to its low toxicity and excellent photoresponsivity.However,its catalytic activity was constrained by severe carrier recombination and a lack of active sites.Herein,increased(001)facet ratio and active sites exposure were simultaneously realized by cobalt doping in MIL-68(In)through a one-pot solvothermal strategy.Optimized MIL-68(In/Co)-2.5 exhibited remarkable catalytic performance in comparison with pristine MIL-68(In)and other MIL-68(In/Co).The reaction kinetic constant and degradation efficiency of MIL-68(In/Co)were approximately twice and 17%higher than the pristine MIL-68(In)in 36 min reaction,respectively.Density functional theory calculations revealed that Co dopant could modulate the orientation of MIL-68(In)facets,facilitate the exchange of electrons and reduce the adsorption energy of peroxymonosulfate(PMS).This work provides a novel pathway for improvement of In-based MOFs in PMS/vis system,it also promotes the profound comprehension of the correlation between crystal facet regulation and catalytic activation in the PMS/vis system.展开更多
Developing high-performance narrow-bandgap (NBG) perovskite solar cells based on tin-lead (Sn-Pb) perovskite is critical for the advancement of all-perovskite tandem solar cells. However, the limitations of the device...Developing high-performance narrow-bandgap (NBG) perovskite solar cells based on tin-lead (Sn-Pb) perovskite is critical for the advancement of all-perovskite tandem solar cells. However, the limitations of the device current density and efficiency are magnified by the issues concerning poor carrier transport caused by a substantial number of defects in thick NBG films. This problem is further exacerbated by the quality of film crystallization, which is associated with the rapid and uncontrolled crystallization of Sn-rich perovskite chemistry using the antisolvent approach. We regulate the crystallization of Sn-contained perovskite with a mild gas-quench approach to fabricate a highly crystal-oriented and well-arranged NBG perovskite absorber. This strategy effectively boosts electron transport and light absorption of the NBG perovskite. Consequently, the average power conversion efficiency (PCE) of the NBG perovskite solar cells increases from 19.50% to 21.18%, with the best device achieving an excellent PCE of 21.84%. Furthermore, when combined with a wide-bandgap perovskite subcell to form an all-perovskite tandem solar cell, a PCE of 25.23% is achieved. After being stored in the glovebox for 1000 h, the unencapsulated device maintains over 90% of its initial PCE, demonstrating long-term stability and durability. This work presents a promising approach for developing high-efficiency NBG perovskite solar cells.展开更多
The facet effect of metal-organic frameworks(MOF)on regulating the property of loaded co-catalysts is an important but unexplored issue in the field of photocatalysis.In this work,a series of MIL-125-NH_(2)polyhedrons...The facet effect of metal-organic frameworks(MOF)on regulating the property of loaded co-catalysts is an important but unexplored issue in the field of photocatalysis.In this work,a series of MIL-125-NH_(2)polyhedrons(MIL=Materials Institute Lavoisier)with facet exposure of{001},{001}/{111}and{111}are synthesized and used to load Pd-based co-catalysts for photocatalytic oxygen reduction reaction(ORR)toward H_(2)O_(2)production.The different facets with distinct chemical environments(Ti-O clusters on{111}facets and carboxyl ligands on{001}facets)result in the selective loading of Pd0and PdO dominated cocatalysts on{001}and{111}facets,respectively.The{001}/{111}co-exposed MIL-125-NH_(2)thus enables the spatially separated loading of Pd0and Pd O dual cocatalysts respectively.Pd0efficiently traps the photoexcited electrons and PdO trends to capture the holes,collaboratively promoting the directional separation of photogenerated electron-hole pairs.As a result,the photocatalytic ORR activity is significantly enhanced with a H_(2)O_(2)production rate of 128.6 mmol L^(-1)g^(-1)h^(-1),superior than pristine and single cocatalyst modified MIL-125-NH_(2)samples.Our findings provide new insight into the design of high-performance photocatalysts.展开更多
Photocatalytic ozonation holds promise for advanced water purification,yet its development has been hindered by a limited understanding of ozone activation mechanisms and its related photogenerated electron transfer d...Photocatalytic ozonation holds promise for advanced water purification,yet its development has been hindered by a limited understanding of ozone activation mechanisms and its related photogenerated electron transfer dynamics.Herein,we employed in-situ DRIFTS and Raman spectroscopy to elucidate the distinct adsorption and activation behaviors of ozone(O_(3))on the{001}and{110}crystal facets of Bi_(2)O_(2)CO_(3)(BOC)nanosheets.BOC-{001}demonstrates superior photocatalytic ozonation performance,with 85%phenol mineralization and excellent durability,significantly outperforming the 53%mineralization rate of BOC-{110}.This enhanced activity is attributed to non-dissociative ozone adsorption and favorable adsorption energy over{001}facet,which facilitate the one-electron O_(3) reduction pathway.Furthermore,crystal facet engineering strengthens the built-in electric field,promoting exciton dissociation and the generation of localized charge carriers.The synergistic effects of optimized electron availability and ozone adsorption significantly boost the production of reactive oxygen species.These findings provide a deeper understanding of the critical roles of O_(3) adsorption and electron transfer in radical generation,which could provide some guidance for the strategic development of highly effective photocatalytic ozonation catalysts.展开更多
The electrochemical CO_(2)reduction(ECR)to hydrocarbon products is an attractive pathway to decrease CO_(2)emission and advance a carbon-neutral process.Among the products of ECR,methane(CH_(4))stands out due to its h...The electrochemical CO_(2)reduction(ECR)to hydrocarbon products is an attractive pathway to decrease CO_(2)emission and advance a carbon-neutral process.Among the products of ECR,methane(CH_(4))stands out due to its high calorific value,serving as the main component of natural gas.However,the development of ECR catalysts capable of producing CH_(4)with both high activity and stability remains critically urgent.This review summarizes and explores the research progress and future application strategies for ECR toward CH_(4)production.Combining experiments,in-situ characterizations,and theoretical calculations,this review examines mechanism of CH_(4)formation in ECR.It then clarifies key factors affecting Cu-based catalysts for CH_(4)production,including facet dependence,size effects,and valence states.Next,this review details emerging strategies such as sub-nanoscale catalysts,Cu/oxides interface engineering,and Cu surface modification.Finally,future directions highlight in-situ characterization,reactor design,and high-throughput screening,guiding industrial CH_(4)production.展开更多
基金supported by the National Key R&D Program of China(No.2023YFB3809500)the Fundamental Research Funds for the Central Universities(No.2024CDJXY003)+1 种基金the Venture&Innovation Support Program for Chongqing Overseas Returnees(cx2023087)The Chongqing Technology Innovation and Application Development Project(No.2024TIAD-KPX0003).
文摘Micro-sized anatase TiO_(2) displays inferior capacity as cathode material for magnesium ion batteries because of the higher diffusion energy barrier of Mg^(2+)in anatase TiO_(2) lattice.Herein,we report that nanosized anatase TiO_(2) exposed(001)facet doubles the capacity compared to the micro-sized sample ascribed to the interfacial Mg^(2+)ion storage.First-principles calculations reveal that the diffusion energy barrier of Mg^(2+)on the(001)facet is significantly lower than those in the bulk phase and on(100)facet,and the adsorption energy of Mg^(2+)on the(001)facet is also considerably lower than that on(100)facet,which guarantees superior interfacial Mg^(2+)storage of(001)facet.Moreover,anatase TiO_(2) exposed(001)facet displays a significantly higher capacity of 312.9 mAh g^(−1) in Mg-Li dual-salt electrolyte compared to 234.3 mAh g^(−1) in Li salt electrolyte.The adsorption energies of Mg^(2+)on(001)facet are much lower than the adsorption energies of Li+on(001)facet,implying that the Mg^(2+)ion interfacial storage is more favorable.These results highlight that controlling the crystal facet of the nanocrystals effectively enhances the interfacial storage of multivalent ions.This work offers valuable guidance for the rational design of high-capacity storage systems.
基金supported by the National Natural Science Foundation of China(No.52002305)Natural Science Basic Research Program in Shanxi Province of China(Nos.202403021221184,202403021222281)+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2025JC-YBMS-478,23JK0424)College Students’Innovation Program of Taiyuan Normal University(No.CXCY2443)。
文摘Iron carbodiimide(Fe NCN)anode demonstrates significant potential for rapid sodium-ion storage owing to its high reaction activity and near-metallic conductivity.However,further development of Fe NCN is hindered by inherent structural instability and ambiguous structure-kinetics correlation.In this study,Fe NCN crystallites with selectively exposed(002)and{010}facets were precisely engineered and synthesized.Notably,the sodium storage kinetics and electrochemical performance of Fe NCN exhibit facet-dependent variations.Polyhedral-Fe NCN(P-Fe NCN)dominated by{010}facets exhibited a pseudocapacitance-driven storage mechanism and delivered exceptional rate capability(372 m Ah/g at5 A/g)and long cyclability(95.8%capacity retention after 300 cycles at 0.5 A/g).In contrast,sheet-like Fe NCN(S-Fe NCN)with predominant(002)facet exposure displayed diffusion-limited kinetics due to sluggish ion diffusion rate.Crucially,time-resolved operando XRD analysis and DFT simulation bridge this performance gap to mechanistic origins:Fe NCN as an intercalation-conversion type anode,the solid-state diffusion is the rate-determining step during charge/discharge process.Active{010}facets possess numerous broad hexagonal tunnels,coupled with a low diffusion barrier of 0.168 e V along{010}directions.This unique architectural configuration enables rapid sodium-ion transport,thereby shifting the diffusioncontrolled kinetics to intercalation-pseudocapacitive behavior.This discovery establishes active facet exposure as a storage kinetic switch,offering a generalized paradigm for optimizing the rate performance and stability of sodium-ion batteries.
基金the National Key R&D Program of China(Nos.2021YFA1501301,2021YFC2901100)the National Natural Science Foundation of China(Nos.22178381,22035009).
文摘Crystalized CeO_(2)structures were typically considered potential photocatalysts due to their great capacity to alter the active sites’size and ability to absorb light.However,the controllable fabrication of well-defined hierarchical structures of CeO_(2)with high reactive facets is significant and challenging.Herein,a series of CeO_(2)supports including hierarchical flower-like(F-CeO_(2)),ball-like(B-CeO_(2)),cube-like(C-CeO_(2)),and rod-like CeO_(2)(R-CeO_(2))supports were prepared by hydrothermal method(BCeO_(2),R-CeO_(2)and C-CeO_(2))or ice-bath method(F-CeO_(2))respectively.V atoms were selected as the active atoms and loaded on these supports.Their structure-activity relationship in photo-assisted thermal propane dehydrogenation(PTPDH)was investigated systematically.The samples were characterized by Xray diffraction,scanning electron microscopy,transmission electron microscopy,N2 adsorption-desorption isotherms,and Fourier transform infrared spectrum.Results show that R-CeO_(2)support exhibits the biggest surface area thus achieving the best dispersion of VOx species.UV-vis spectrum and photoluminescence spectrum indicate that V/F-CeO_(2)has the best light adsorption property and V/R-CeO_(2)has the best carrier migration capacity.The activity tests demonstrate that the V/R-CeO_(2)has the largest net growth rate and the V/F-CeO_(2)has the biggest relative growth ratio.Furthermore,the non-thermal effect was confirmed by the kinetic method,which lowers the propane reaction orders,selectively promoting the first C-H bond activation.The light radiation TPSR experiment confirmed this point.DFT calculations show a good linear relationship between the energy barrier and the exchanged electron number.It inspires the design of high-reactive facets for boosting the intrinsic activity of the C-H bond in photoassisted thermal chemical processes.
基金supported by the National Natural Science Foundation of China(Nos.52074231,52274396 and 52001258)the Chongqing Natural Science Foundation(No.cstc2020jcyj-msxmX1056).
文摘Crack initiation mechanism of dwell fatigue has always been a key problem in rationalizing the dwell effect,and it is not completely understood yet.This study conducted stress-controlled low-cycle fatigue and dwell fatigue tests on Ti-6Al-3Nb-2Zr-1Mo alloy with bimodal microstructure to reveal its microstructural characteristics and crack initiation mechanisms.The study demonstrated that the faceted primaryα nodules located near the specimen surface acted as crack initiation sites during both fatigue and dwell fatigue tests.Slip trace analysis revealed that faceted cracking occurred at(0001)basal plane with the maximum Schmid factor value through a special cracking mode referred to as(0001)twist boundary cracking.Innovative criteria of parameters C1 and C2 were proposed based on experimental observation and molecular dynamics simulations,which well identify candidates for(0001)twist boundary crack nucleation.It demonstrated that grain pairs combining a moderately high Schmid factor for basal slip and a well-orientated Burgers vector in the out-of-surface plane was the preferable location for surface(0001)twist-boundary crack initiation,and grain pairs combining a high Schmid factor for basal slip and a high normal stress on basal plane are perfect candidates for subsurface cracking.Based on this,phenomeno-logical models are proposed to explain the surface(0001)twist-boundary cracking mechanism from the perspective of surface extrusion-intrusion-induced micro-notches.
基金National Natural Science Foundation of China(No.81861138040)。
文摘F-B co-doped TiO_(2)nanosheets with exposed anatase(001)facets were synthesized via a one-pot solvothermal method,and their photocatalytic hydrogen evolution performance was investigated.Characterization results confirm that this method effectively promotes the growth of the highly active anatase(001)facets and enhances visible and infrared light absorption while inducing oxygen vacancies.Under optimal conditions,the hydrogen evolution reaches 20.57μmol after 10 h of ultraviolet-visible(UV-Vis)light irradiation,exceeding the commercial TiO_(2)nanoparticles Degussa P25 by more than 10 times.These findings highlight the potential of F-B co-doped TiO_(2)nanosheets for efficient photocatalysis.
基金supported by the Hebei Province Key R&D Technology Project(23314401D)2023 Hebei Province High-level Talent Team Construction Special Project(235A4401D)+6 种基金Hebei North University Youth Fund Project(XJ2024013)School-level Cultivation Research Project of Hebei North University(XJPY2024025)First Batch of School-level Scientific Research Projects of Hebei North University in 2023(B2023405004)Hebei North University High-level Talent Research Start-up Fund(BSJJ202303,BSJJ202313,BSJJ202421)Science and Technology Research Project of Higher Education Institutions in Hebei Province(QN2023222)Central Guided Local Science and Technology Development Funding Program(236Z4401G)Natural Science Foundation of Hebei Province(B2022405005).
文摘Lithium-sulfur(Li-S)batteries are promising for high-energy-density storage,but their performance is limited by sluggish lithium polysulfide(LiPS)conversion kinetics.Here,we tackle this issue by synthesizing ultrafine truncated octahedral TiO_(2) nanocrystals(P-O_(v)-TiO_(2)),featuring specific{101}facets and dual defects—phosphorus doping and oxygen vacancies.Acting as an efficient electrocatalyst in the separator,P-O_(v)-TiO_(2) exhibits superior catalytic properties,where oxygen vacancies modulate the electronic structure,enhancing electron enrichment and charge transfer;phosphorus doping tailors the d-band center of the catalyst,strengthening Ti-S interactions between the{101}facets and LiPSs.As a result,Li-S coin cells modified with P-O_(v)-TiO_(2) achieve a high specific capacity of 895 mAh g^(−1) at 5 C and exhibit a minimal decay rate of 0.14%per cycle over 200 cycles.Furthermore,Li-S pouch cells deliver a high capacity of 1004 mAh g^(−1) at 0.1 C under lean electrolyte conditions.This study elucidates the mechanisms of charge states on specific crystal planes and deepens our understanding of dual-defect engineering in Li-S electrochemistry,offering a promising approach for developing efficient and cost-effective catalysts for Li-S battery applications.
文摘The facets effect on the catalytic properties of inorganic compounds and metal-organic frameworks(MOFs)has been widely demonstrated,but the intrinsic facets effect free of interference of capping agents has not been discussed.Here we give a proof-of-concept illustration on the intrinsic facets effect by employing the popularly investigated NH2-MIL-125(Ti)MOFs with{001},{111}and{100}facets controllably exposed as model photocatalysts,which were synthesized via a simple supersaturation strategy free of any capping agents.Compared to conventional synthetic routes with capping agents employed,the NH2-MIL-125(Ti)MOFs obtained in this work exhibit remarkably different physical and chemical properties such as surface wettability,charge separation as well as trend of facets effect on photocatalytic water splitting performance.The main reason has been unraveled to originate from unavoidable residue/influence of capping agents during the conventional facets-controlled synthetic routes leading to changed local surface structural environment as well as distinct charge separation property.Our results demonstrate the importance and feasibility of facets-controllable synthesis free of capping agents in getting insight into the intrinsic facets effect of MOFs-related materials.
文摘ASEAN’s major power balancing strategy refers to the balancing strategy adopted by ASEAN and its member states to seek national and regional security and development by maintaining multi-faceted friendship and impartiality with surrounding major powers.The evolution of this strategy is a process of dynamic adjustment,with ASEAN and its members being the implementing subjects,major powers the objects.
基金Advanced Research Center for Chemical Building Blocks,ARC CBBC,which is co-foundedco-financed by the Dutch Research Council(NWO)and the Netherlands Ministry of Economic Affairs and Climate Policy.
文摘Photocatalysis is a promising technology for purification of indoor air by oxidation of volatile organic compounds.This study provides a comprehensive analysis of the adsorption and photo-oxidation of surface-adsorbed acetone on three SrTiO_(3)morphologies:cubes(for which exclusively{100}facets are exposed),{110}-truncated cubes,and{100}-truncated rhombic dodecahedrons,respectively,all prepared by hydrothermal synthesis.In situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy shows that cubic crystals contain a high quantity of surface-OH groups,enabling significant quantities of adsorbed acetone in the form ofη^(1)-enolate when exposed to gas phase acetone.Contrary,{110}facets exhibit fewer surface-OH groups,resulting in relatively small quantities of adsorbedη^(1)-acetone,without observable quantities of enolate.Interestingly,acetate and formate signatures appear in the spectra of cubic,surfaceη^(1)-enolate containing,SrTiO_(3)upon illumination,while besides acetate and formate,the formation of(surface)formaldehyde was observed on truncated cubes,and dodecahedrons,by conversion of adsorbedη^(1)-acetone.Time-Resolved Photoluminescence studies demonstrate that the lifetimes of photogenerated charge carriers vary with crystal morphology.The shortest carrier lifetime(τ_(1)=33±0.1 ps)was observed in{110}-truncated cube SrTiO_(3),likely due to a relatively strong built-in electric field promoting electron transport to{100}facets and hole transport to{110}facets.The second lifetime(τ_(2)=259±1 ps)was also the shortest for this morphology,possibly due to a higher amount of surface trap states.Our results demonstrate that SrTiO_(3)crystal morphology can be tuned to optimize performance in photocatalytic oxidation.
基金supported by National Natural Science Fund for Excellent Young Scholars(22222813)the National Natural Science Foundation of China(22078338)+2 种基金the National Key Research and Development Program of China(2023YFA1506803)the Postdoctoral Fellowship Program of CPSF(GZC20232700)the“Special Research Assistant Project”of the Chinese Academy of Sciences.
文摘Nanostructured ceria has attracted much attention in the field of redox catalysts due to the numerous active sites with excellent redox ability.Based on the acidic medium etching strategy,we constructed the strong binding centers(hydroxyl sites and strong acid sites)on the surfaces of nanostructured ceria,which regulate the adsorption process of KA-Oil(the mixture of cyclohexanol and cyclohexanone)and to promote high KA-Oil selectivity in cyclohexane oxidation.The three CeO_(2)(nanocube,nanorod and nanopolyhedron)with different exposed crystal planes were treated by acid etching to change the surface sites and catalytic properties.The transition behavior of surface sites during etching was revealed,abundant strong binding centers were proved to be constructed successfully.And especially for the nanorod treated by acid(Acid@CeO_(2)-NR)with the strongest response for sulfuric acid etching,the strong adsorption of cyclohexanone by strong binding centers was confirmed based on the in-situ DRIFTs.The sulfuric acid etching strategy to enhance the selective oxidation of cyclohexane based on the construction of strong binding centers was proved to be feasible and effective,Acid@CeO_(2)-NR with strongest etching response achieved the dramatic promotion of KA-Oil selectivity from 64.1%to 92.3%.
基金supported by the National Natural Science Foundation of China(Nos.52100087,52170079,U20A20322)Science and Technology Development Program of Jilin Province,China(Nos.20220508100RC,20230402035GH).
文摘Rational tuning of crystallographic surface and metal doping were effective to enhance the catalytic performance of metal organic frameworks,but limited work has been explored for achieving modulation of crystal facets and metal doping in a single system.MIL-68(In)was promising for photocatalytic applications due to its low toxicity and excellent photoresponsivity.However,its catalytic activity was constrained by severe carrier recombination and a lack of active sites.Herein,increased(001)facet ratio and active sites exposure were simultaneously realized by cobalt doping in MIL-68(In)through a one-pot solvothermal strategy.Optimized MIL-68(In/Co)-2.5 exhibited remarkable catalytic performance in comparison with pristine MIL-68(In)and other MIL-68(In/Co).The reaction kinetic constant and degradation efficiency of MIL-68(In/Co)were approximately twice and 17%higher than the pristine MIL-68(In)in 36 min reaction,respectively.Density functional theory calculations revealed that Co dopant could modulate the orientation of MIL-68(In)facets,facilitate the exchange of electrons and reduce the adsorption energy of peroxymonosulfate(PMS).This work provides a novel pathway for improvement of In-based MOFs in PMS/vis system,it also promotes the profound comprehension of the correlation between crystal facet regulation and catalytic activation in the PMS/vis system.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFB1506400)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB43000000)+3 种基金the CAS Project for Young Scientists in Basic Research(YSBR-090)the National Natural Science Foundation of China(Contract Nos.U20A20206,51972300,62274155,and 62304219)support from the Youth Innovation Promotion Association,the Chi-nese Academy of Sciences(No.2020114)Beijing Natural Sci-ence Foundation(Grant No.JQ24029).
文摘Developing high-performance narrow-bandgap (NBG) perovskite solar cells based on tin-lead (Sn-Pb) perovskite is critical for the advancement of all-perovskite tandem solar cells. However, the limitations of the device current density and efficiency are magnified by the issues concerning poor carrier transport caused by a substantial number of defects in thick NBG films. This problem is further exacerbated by the quality of film crystallization, which is associated with the rapid and uncontrolled crystallization of Sn-rich perovskite chemistry using the antisolvent approach. We regulate the crystallization of Sn-contained perovskite with a mild gas-quench approach to fabricate a highly crystal-oriented and well-arranged NBG perovskite absorber. This strategy effectively boosts electron transport and light absorption of the NBG perovskite. Consequently, the average power conversion efficiency (PCE) of the NBG perovskite solar cells increases from 19.50% to 21.18%, with the best device achieving an excellent PCE of 21.84%. Furthermore, when combined with a wide-bandgap perovskite subcell to form an all-perovskite tandem solar cell, a PCE of 25.23% is achieved. After being stored in the glovebox for 1000 h, the unencapsulated device maintains over 90% of its initial PCE, demonstrating long-term stability and durability. This work presents a promising approach for developing high-efficiency NBG perovskite solar cells.
基金the National Natural Science Foundation of China(NSFC,Nos.51908218 and 21905092)the Youth Elite Sailing Program of Shanghai Institute of Technology(No.1021GK240006002-A07)+2 种基金Scientific Research Foundation of Shanghai Institute of Technology(No.10120K226156-A06-YJ2022-62)Shanghai Higher Education Institution Young Teacher Training Funding Program(No.ZZ202312031)the Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse(Nanjing University of Science and Technology)。
文摘The facet effect of metal-organic frameworks(MOF)on regulating the property of loaded co-catalysts is an important but unexplored issue in the field of photocatalysis.In this work,a series of MIL-125-NH_(2)polyhedrons(MIL=Materials Institute Lavoisier)with facet exposure of{001},{001}/{111}and{111}are synthesized and used to load Pd-based co-catalysts for photocatalytic oxygen reduction reaction(ORR)toward H_(2)O_(2)production.The different facets with distinct chemical environments(Ti-O clusters on{111}facets and carboxyl ligands on{001}facets)result in the selective loading of Pd0and PdO dominated cocatalysts on{001}and{111}facets,respectively.The{001}/{111}co-exposed MIL-125-NH_(2)thus enables the spatially separated loading of Pd0and Pd O dual cocatalysts respectively.Pd0efficiently traps the photoexcited electrons and PdO trends to capture the holes,collaboratively promoting the directional separation of photogenerated electron-hole pairs.As a result,the photocatalytic ORR activity is significantly enhanced with a H_(2)O_(2)production rate of 128.6 mmol L^(-1)g^(-1)h^(-1),superior than pristine and single cocatalyst modified MIL-125-NH_(2)samples.Our findings provide new insight into the design of high-performance photocatalysts.
文摘Photocatalytic ozonation holds promise for advanced water purification,yet its development has been hindered by a limited understanding of ozone activation mechanisms and its related photogenerated electron transfer dynamics.Herein,we employed in-situ DRIFTS and Raman spectroscopy to elucidate the distinct adsorption and activation behaviors of ozone(O_(3))on the{001}and{110}crystal facets of Bi_(2)O_(2)CO_(3)(BOC)nanosheets.BOC-{001}demonstrates superior photocatalytic ozonation performance,with 85%phenol mineralization and excellent durability,significantly outperforming the 53%mineralization rate of BOC-{110}.This enhanced activity is attributed to non-dissociative ozone adsorption and favorable adsorption energy over{001}facet,which facilitate the one-electron O_(3) reduction pathway.Furthermore,crystal facet engineering strengthens the built-in electric field,promoting exciton dissociation and the generation of localized charge carriers.The synergistic effects of optimized electron availability and ozone adsorption significantly boost the production of reactive oxygen species.These findings provide a deeper understanding of the critical roles of O_(3) adsorption and electron transfer in radical generation,which could provide some guidance for the strategic development of highly effective photocatalytic ozonation catalysts.
文摘The electrochemical CO_(2)reduction(ECR)to hydrocarbon products is an attractive pathway to decrease CO_(2)emission and advance a carbon-neutral process.Among the products of ECR,methane(CH_(4))stands out due to its high calorific value,serving as the main component of natural gas.However,the development of ECR catalysts capable of producing CH_(4)with both high activity and stability remains critically urgent.This review summarizes and explores the research progress and future application strategies for ECR toward CH_(4)production.Combining experiments,in-situ characterizations,and theoretical calculations,this review examines mechanism of CH_(4)formation in ECR.It then clarifies key factors affecting Cu-based catalysts for CH_(4)production,including facet dependence,size effects,and valence states.Next,this review details emerging strategies such as sub-nanoscale catalysts,Cu/oxides interface engineering,and Cu surface modification.Finally,future directions highlight in-situ characterization,reactor design,and high-throughput screening,guiding industrial CH_(4)production.
文摘针对基于CT(computed tomography)图像检测分析中的点云提取精度与完整性问题,提出一种基于预分割轮廓的高精度、高完整性的亚体素表面检测方法。首先采用Otsu分割算法提取CT图像的体素级轮廓点集,并以此作为粗定位轮廓自适应地生成用于亚体素表面检测的完备感兴趣区域(region of interest,ROI);然后提出一种基于梯度非极大值抑制的表面体素判定方法,避免了梯度阈值选择难题;最后基于3D Facet模型定位亚体素级表面点位置。实验结果表明,该方法能有效改善传统亚体素检测方法的轮廓丢失、伪边严重等问题,轮廓定位误差小于0.2个体素,同时能够取得3倍以上的计算加速比。
