Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological product...Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological productivity.Mimicking this natural process,photocatalysis has emerged as a promising strategy for harnessing solar energy to drive chemical reactions with minimal environmental impact.This versatile approach finds applications in pollutant degradation,water purification,energy conversion,and organic synthesis.However,a major limitation of single-component photocatalysts is the rapid recombination of photogenerated charge carriers,significantly reducing their efficiency.展开更多
Interface engineering is thought to be one of the most effective methods to reduce the recombination of electron and holes.Especially,the introduction of interfacial chemical bonds could greatly help to promote the ch...Interface engineering is thought to be one of the most effective methods to reduce the recombination of electron and holes.Especially,the introduction of interfacial chemical bonds could greatly help to promote the charge migration and separation.Interface chemical bonds are one kind of strong interactions between adjacent phases caused by the sharing of outer electrons,which could not only optimize the inter-facial electron distribution of different phases,but also pave electron-level channels like a"bridge"for charge transfer.It plays an important role in regulating photogenerated charge transfer,reactant adsorption,and the activation energy of catalytic reactions.Research in this area is the current focus for the PEC water splitting,CO_(2)reduction,organic catalysis and photodynamic antibacterial[1-3].展开更多
In quantum mechanics,when an electron is quickly ripped off from a molecule,a superposition of new eigenstates of the cation creates an electron wave packet that governs the charge flow inside,which has been called ch...In quantum mechanics,when an electron is quickly ripped off from a molecule,a superposition of new eigenstates of the cation creates an electron wave packet that governs the charge flow inside,which has been called charge migration(CM).Experimentally,extracting such dynamics at its natural(attosecond)timescale is quite difficult.We report the first such experiment in a linear carbon-chain molecule,butadiyne(C_(4)H_(2)),via high-harmonic spectroscopy(HHS).By employing advanced theoretical and computational tools,we showed that the wave packet and the CM of a single molecule are reconstructed from the harmonic spectra for each fixed-in-space angle of the molecule.For this onedimensional molecule,we calculate the center of charge <x>(t) to obtain v_(cm),to quantify the migration speed and how it depends on the orientation angle.The findings also uncover how the electron dynamics at the first few tens to hundreds of attoseconds depends on molecular structure.The method can be extended to other molecules where the HHS technique can be employed.展开更多
In particular, charge migration phenomena in DNA have attracted much interest because of relevance to the generation of damage and mutations which play important roles in most of life processes. In this paper a theory...In particular, charge migration phenomena in DNA have attracted much interest because of relevance to the generation of damage and mutations which play important roles in most of life processes. In this paper a theory method was presented in which the DNA chain was treated as a double-stranded system, and the charge migration in DNA based on the donor-bridge-acceptor system was investigated by this model. After having obtained the Hamiltonian, the effects of the surrounding were explained and calculated. The double-strand calculation could lead to good exponential decay curves and this time two different faUoff parameters were found respectively before and after 3 or 4 AT base pair bridge lengths as prediction. Lately theoretical study showed this result by addition of more parameter, and sequence effect was then concentrated on. The difference of transfer integral caused the different decay rate of unlike sequences, but bridge length was still proved to be the main factor on the decay rates.展开更多
Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is a...Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is an energy-intensive method involving multi-step reactions,producing harmful by-product wastes.Solar-driven H_(2)O_(2)production,an alternative route for H_(2)O_(2)generation,is a green and sustainable technology since it only utilizes water and oxygen as feedstock.However,the rapid recombination of charge carriers as well as insufficient redox capability limit the photocatalytic H_(2)O_(2)production performance.Constructing step-scheme(S-scheme)heterojunction photocatalysts has been regarded as an effective strategy to address these drawbacks because it not only achieves spatially separated charge carriers,but also preserves redox capability of the photocatalytic system.This paper covers the recent advances of S-scheme heterojunction photocatalysts for H_(2)O_(2)production in terms of basic principles,characterization techniques,and preparation strategies.Moreover,the mechanism and advantages of S-scheme heterojunction for photocatalytic H_(2)O_(2)generation are systematically discussed.The recent S-scheme heterojunction designs,including inorganic-organic heterojunction,inorganic-inorganic heterojunction,and organic-organic heterojunction,are summarized.Lastly,the challenges and research directions of S-scheme photocatalysts for H_(2)O_(2)generation are presented.展开更多
Photocatalytic oxygen reduction provides a sustainable method for on-site hydrogen peroxide(H_(2)O_(2))synthesis.However,most photocatalysts suffer from moderate kinetics due to sluggish electron transfer and ineffici...Photocatalytic oxygen reduction provides a sustainable method for on-site hydrogen peroxide(H_(2)O_(2))synthesis.However,most photocatalysts suffer from moderate kinetics due to sluggish electron transfer and inefficient oxygen adsorption and activation.Herein,sodium(Na)and potassium(K)are co-incorporated into graphitic carbon nitride(g-C_(3)N_(4))via a stepwise co-doping strategy combining sodium chloride-induced and molten salt-assisted polymerization.Experimental results and density functional theory calculations demonstrate that the synergistic interaction between intralayer Na+ions and interlayer K^(+)ions facilitates charge carrier separation and migration both within and between g-C_(3)N_(4)layers.Additionally,multiple heteroatom sites enhance surface charge polarization and introduce cyano groups,which synergistically promote oxygen molecule(O_(2))adsorption and elevate local proton coverage.Simultaneously,the energy barrier for H_(2)O_(2)desorption on the optimal photocatalyst(5Na/3.3K-CN)is lowered,thus improving H_(2)O_(2)production efficiency.Eventually,5Na/3.3K-CN exhibits an impressive H_(2)O_(2)yield of 2541.6μmol·g^(-1)·h^(-1) in an artificial reactor,which is 10.6 times higher than that of pure g-C_(3)N_(4)(240.2μmol·g^(-1)·h^(-1)).Under natural sunlight outdoors,5Na/3.3K-CN still maintains ultrahigh H_(2)O_(2)photosynthesis efficiency,achieving an H_(2)O_(2)photosynthesis rate of 2068.7μmol·g^(-1)·h^(-1).This work introduces a straightforward method to simultaneously optimize charge transfer and O_(2)activation for boosting H_(2)O_(2)photosynthesis,offering valuable insights toward the real-world deployment of g-C_(3)N_(4)-based photocatalysts in environmental protection and energy conversion.展开更多
Coherent superposition of electronic states induces attosecond electron motion in molecules.We theoretically investigate the strong-field ionization of this superposition state by numerically solving the time-dependen...Coherent superposition of electronic states induces attosecond electron motion in molecules.We theoretically investigate the strong-field ionization of this superposition state by numerically solving the time-dependent Schrodinger equation.In the obtained photoelectron momentum distribution,an intriguing bifurcation structure appears in the strong-field holographic interference pattern.We demonstrate that this bifurcation structure directly provides complete information about the status of the transient wave function of the superposition state:the horizontal location of the bifurcation in the momentum distribution reveals the relative phase of the involved components of the superposition state and the vertical position indicates the relative coefficient.Thus,this bifurcation structure takes a snapshot of the transient electron wave packet of the superposition state and provides an intuitive way to monitor electron motion in molecules.展开更多
As an ideal secondary energy source,hydrogen has the title of clean energy and the product of its complete combustion is only water,which is not polluting to the environment.Photocatalytic hydrogen production technolo...As an ideal secondary energy source,hydrogen has the title of clean energy and the product of its complete combustion is only water,which is not polluting to the environment.Photocatalytic hydrogen production technology is an environmentally friendly,safe,and low-cost strategy that requires only an inexhaustible amount of solar energy and water as feedstock.This paper provides a detailed and detailed review of S-scheme heterojunction photocatalysts for photocatalytic hydrogen production,mainly including TiO_(2)-based,Perovskite-based,CdS-based,Graphitic phase carbon nitride-based,COF-based graphdiyne-based,ZnO-based,and ZnIn_(2)S_(4)-based S-scheme heterojunction photocatalysts.The classification of S-scheme heterojunctions is summarized.What’s more,various characterizations for direct verification of the charge migration mechanism of S-scheme heterojunctions are outlined.Based on the present study,the future potential challenges and future research trends for S-scheme heterojunctions in photocatalytic hydrogen evolution technology are pointed out,which provides feasible strategies for the development and design of S-scheme heterojunction photocatalysts in the field of photocatalytic hydrogen evolution.展开更多
In natural photosynthesis,compartmentalized protein networks spatially orchestrate light-driven electron transfer for CO_(2)activation,offering a blueprint for artificial systems.Herein,we report the design and synthe...In natural photosynthesis,compartmentalized protein networks spatially orchestrate light-driven electron transfer for CO_(2)activation,offering a blueprint for artificial systems.Herein,we report the design and synthesis of a molecular compartmentalized photocatalyst for photocatalytic CO_(2)overall conversion,in which a nickel-substituted polyoxometalate(NiPOM)is confined within the inner channels of carbon nanotubes(CNTs),while Fe-porphyrin derivatives(FeTCPPOMe)are anchored onto the CNT exterior viaπ-πinteractions.This unique inside-outside configuration creates a highly ordered,vectorial electron transfer pathway whereby photoexcited electrons are generated at the FeTCPPOMe sites,swiftly injected into the CNT and then directly delivered to the encapsulated NiPOM.Under simulated solar illumination,the FeTCPPOMe-NiPOM@CNT composite exhibits good photocatalytic CO_(2)reduction performance,achieving a CO production rate of 42.7μmol g^(−1)h^(−1)with a 100%CO selectivity.In-situ DRIFTS,quasi in-situ XPS and in-situ illuminated Kelvin probe force microscopy(KPFM)combined with density functional theory calculations clearly elucidated the photoinduced electron transfer pathway.This work demonstrates that strategic nanoscale confinement and hierarchical assembly can dramatically enhance charge transport and catalytic efficiency,offering a promising blueprint for next-generation CO_(2)photoreduction systems.展开更多
The efficient utilization of visible light catalysts for organic reactions necessitates not only the effective separation of photogenerated electrons and holes to participate in the reaction,but also their ability to ...The efficient utilization of visible light catalysts for organic reactions necessitates not only the effective separation of photogenerated electrons and holes to participate in the reaction,but also their ability to form key intermediates with reactant molecules.The present study successfully synthesized a crusiform-like mesoporous structure of nitrogen-doped carbon-coated Cu_(2)O/Cu(Cu_(2)O/Cu/N-C)with a Cu_(2)O/dual electron acceptor interface using etched HKUST-1 as the precursor.A series of theoretical and experimental studies have demonstrated that the Cu_(2)O/Cu/N-C interface in the photocatalytic homo-coupling of terminal alkynes not only effectively enhances the separation of photogenerated electron−hole pairs,but also facilitates the formation of the key intermediate[Cu_(2)O/Cu/N-C]-phenylacetylide and promotes the rearrangement of its internal charges.As a result,the homo-coupling reaction can be effectively facilitated.The primary reason for the functional role of Cu_(2)O/Cu/N-C interface lies in the downward bending of energy band from Cu_(2)O to N-doped C layers,induced by the different work functions of Cu_(2)O,Cu and N-doped C layers.Consequently,Cu_(2)O/Cu/N-C photocatalysts demonstrate exceptional photocatalytic activity in the homo-coupling reaction of terminal alkynes under blue-light irradiation and air atmosphere.The present study presents a novel research methodology for the development of highly efficient visible light catalysts to facilitate organic reactions in future applications.展开更多
This work presents a comprehensive analysis of 3D cylindrical junction-less charge trapping memory device performance regarding continuous scaling of the structure dimensions. The key device performance, such as progr...This work presents a comprehensive analysis of 3D cylindrical junction-less charge trapping memory device performance regarding continuous scaling of the structure dimensions. The key device performance, such as program/erase speed, vertical charge loss, and lateral charge migration under high temperature are intensively studied using the Sentaurus 3 D device simulator. Although scaling of channel radius is beneficial for operation speed improvement, it leads to a retention challenge due to vertical leakage, especially enhanced charge loss through TPO. Scaling of gate length not only decreases the program/erase speed but also leads to worse lateral charge migration. Scaling of spacer length is critical for the interference of adjacent cells and should be carefully optimized according to specific cell operation conditions. The gate stack shape is also found to be an important factor affecting the lateral charge migration. Our results provide guidance for high density and high reliability 3D CTM integration.展开更多
Accelerated margin loss during read after delay(RAD)is a newly discovered reliability concern in HfO2-based ferroelectric random access memories(FeRAMs),which significantly impacts the lifetime of the memory device.Un...Accelerated margin loss during read after delay(RAD)is a newly discovered reliability concern in HfO2-based ferroelectric random access memories(FeRAMs),which significantly impacts the lifetime of the memory device.Unlike conventional fatigue effect,this issue is closely linked to the coercive field(Ec)shift,or imprint,during bipolar electrical field cycling at intermediate frequency.The precise cause of imprint during RAD,however,remains elusive.To investigate,we employed customized electrical testing to examine the charge transfer behavior in static imprint(SI)and continuous read/write(CRW)scenarios,which can be viewed as RAD performed at minimum and maximum frequencies.Our findings reveal that interfacial charge injection is the primary mechanism for imprint in SI,while bulk charge drives the imprint in asymmetric CRW.Further exploration with a SPICE-based charge transfer model suggests that RAD-related imprint is the result of bulk charge migration,driven by the periodically restored depolarization field after read/write-back operation.Experimental verification supports this theory,highlighting the importance of interface engineering to enhance bound charge screening and element doping to elevate the migration barrier for bulk charges in addressing the RAD problem.展开更多
The investigation of charge carrier kinetics has long been a cornerstone of polymer photocatalysis research.However,the role of proton transport behavior in photocatalytic processes has often been underappreciated,des...The investigation of charge carrier kinetics has long been a cornerstone of polymer photocatalysis research.However,the role of proton transport behavior in photocatalytic processes has often been underappreciated,despite its fundamental importance in proton-coupled electron-transfer reactions.Addressing this gap,we present a novel BF_(2)-bridged covalent organic framework(C2-COF-BF2) that undergoes post-synthetic modification with boron trifluoride,designed to confer a dual functional advantage.Specifically,the incorporated BF_(2) moieties are engineered to induce a donor-acceptor effect and potentially serve as continuous supply sites for activated protons.This bifunctional role not only enhances charge separation and migration while suppressing electron-hole recombination but also facilitates proton transport,thereby enabling improved performance in both photocatalytic hydrogen evolution reaction(HER) and H_(2) O_(2) production.Remarkably,the photocatalytic HER performance of C2-COF-BF2(AQY_(450 nm)= 8.78%) ranks among the highest efficiencies reported for COF-based photocatalysts to date.These findings highlight an innovative pathway for advancing the rational design of COF photocatalysts,offering a synergistic optimization of charge carrier kinetics and mass transfer processes to achieve unprecedented photocatalytic efficiency.展开更多
文摘Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological productivity.Mimicking this natural process,photocatalysis has emerged as a promising strategy for harnessing solar energy to drive chemical reactions with minimal environmental impact.This versatile approach finds applications in pollutant degradation,water purification,energy conversion,and organic synthesis.However,a major limitation of single-component photocatalysts is the rapid recombination of photogenerated charge carriers,significantly reducing their efficiency.
基金supported by the National Natural Science Foundation of China(Nos.52172174,and 51872002)the Program of Anhui Scientific and Technical Leaders Reserve Candidates(2018RH168).
文摘Interface engineering is thought to be one of the most effective methods to reduce the recombination of electron and holes.Especially,the introduction of interfacial chemical bonds could greatly help to promote the charge migration and separation.Interface chemical bonds are one kind of strong interactions between adjacent phases caused by the sharing of outer electrons,which could not only optimize the inter-facial electron distribution of different phases,but also pave electron-level channels like a"bridge"for charge transfer.It plays an important role in regulating photogenerated charge transfer,reactant adsorption,and the activation energy of catalytic reactions.Research in this area is the current focus for the PEC water splitting,CO_(2)reduction,organic catalysis and photodynamic antibacterial[1-3].
基金supported by the National Key Research and Development Program of China (No. 2019YFA0308300)the National Natural Science Foundation of China (Nos. 91950202, 12225406, 12074136, 12021004, and 11934006)+2 种基金the Natural Science Foundation of Hubei Province (No. 2021CFB330)supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (No. DE-FG0286ER13491)supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences (No. DE-SC0023192)
文摘In quantum mechanics,when an electron is quickly ripped off from a molecule,a superposition of new eigenstates of the cation creates an electron wave packet that governs the charge flow inside,which has been called charge migration(CM).Experimentally,extracting such dynamics at its natural(attosecond)timescale is quite difficult.We report the first such experiment in a linear carbon-chain molecule,butadiyne(C_(4)H_(2)),via high-harmonic spectroscopy(HHS).By employing advanced theoretical and computational tools,we showed that the wave packet and the CM of a single molecule are reconstructed from the harmonic spectra for each fixed-in-space angle of the molecule.For this onedimensional molecule,we calculate the center of charge <x>(t) to obtain v_(cm),to quantify the migration speed and how it depends on the orientation angle.The findings also uncover how the electron dynamics at the first few tens to hundreds of attoseconds depends on molecular structure.The method can be extended to other molecules where the HHS technique can be employed.
基金Project supported by the Natural Science Foundation of Shanghai Science and Technology Committee （No. 02DJ14023）.
文摘In particular, charge migration phenomena in DNA have attracted much interest because of relevance to the generation of damage and mutations which play important roles in most of life processes. In this paper a theory method was presented in which the DNA chain was treated as a double-stranded system, and the charge migration in DNA based on the donor-bridge-acceptor system was investigated by this model. After having obtained the Hamiltonian, the effects of the surrounding were explained and calculated. The double-strand calculation could lead to good exponential decay curves and this time two different faUoff parameters were found respectively before and after 3 or 4 AT base pair bridge lengths as prediction. Lately theoretical study showed this result by addition of more parameter, and sequence effect was then concentrated on. The difference of transfer integral caused the different decay rate of unlike sequences, but bridge length was still proved to be the main factor on the decay rates.
文摘Hydrogen peroxide(H_(2)O_(2)),as an essential and green chemical,is extensively used in energy and environmental applications.However,the production of H_(2)O_(2)primarily relies on the anthraquinone method,which is an energy-intensive method involving multi-step reactions,producing harmful by-product wastes.Solar-driven H_(2)O_(2)production,an alternative route for H_(2)O_(2)generation,is a green and sustainable technology since it only utilizes water and oxygen as feedstock.However,the rapid recombination of charge carriers as well as insufficient redox capability limit the photocatalytic H_(2)O_(2)production performance.Constructing step-scheme(S-scheme)heterojunction photocatalysts has been regarded as an effective strategy to address these drawbacks because it not only achieves spatially separated charge carriers,but also preserves redox capability of the photocatalytic system.This paper covers the recent advances of S-scheme heterojunction photocatalysts for H_(2)O_(2)production in terms of basic principles,characterization techniques,and preparation strategies.Moreover,the mechanism and advantages of S-scheme heterojunction for photocatalytic H_(2)O_(2)generation are systematically discussed.The recent S-scheme heterojunction designs,including inorganic-organic heterojunction,inorganic-inorganic heterojunction,and organic-organic heterojunction,are summarized.Lastly,the challenges and research directions of S-scheme photocatalysts for H_(2)O_(2)generation are presented.
基金supported by the Program for New Century Talents in University(No.NCET-11-0951)from the Ministry of Education of ChinaKey Laboratory Project Fund of CAS(No.2005DP173065-2016-04).
文摘Photocatalytic oxygen reduction provides a sustainable method for on-site hydrogen peroxide(H_(2)O_(2))synthesis.However,most photocatalysts suffer from moderate kinetics due to sluggish electron transfer and inefficient oxygen adsorption and activation.Herein,sodium(Na)and potassium(K)are co-incorporated into graphitic carbon nitride(g-C_(3)N_(4))via a stepwise co-doping strategy combining sodium chloride-induced and molten salt-assisted polymerization.Experimental results and density functional theory calculations demonstrate that the synergistic interaction between intralayer Na+ions and interlayer K^(+)ions facilitates charge carrier separation and migration both within and between g-C_(3)N_(4)layers.Additionally,multiple heteroatom sites enhance surface charge polarization and introduce cyano groups,which synergistically promote oxygen molecule(O_(2))adsorption and elevate local proton coverage.Simultaneously,the energy barrier for H_(2)O_(2)desorption on the optimal photocatalyst(5Na/3.3K-CN)is lowered,thus improving H_(2)O_(2)production efficiency.Eventually,5Na/3.3K-CN exhibits an impressive H_(2)O_(2)yield of 2541.6μmol·g^(-1)·h^(-1) in an artificial reactor,which is 10.6 times higher than that of pure g-C_(3)N_(4)(240.2μmol·g^(-1)·h^(-1)).Under natural sunlight outdoors,5Na/3.3K-CN still maintains ultrahigh H_(2)O_(2)photosynthesis efficiency,achieving an H_(2)O_(2)photosynthesis rate of 2068.7μmol·g^(-1)·h^(-1).This work introduces a straightforward method to simultaneously optimize charge transfer and O_(2)activation for boosting H_(2)O_(2)photosynthesis,offering valuable insights toward the real-world deployment of g-C_(3)N_(4)-based photocatalysts in environmental protection and energy conversion.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11874163,11604108,and 11604388)the Program for HUST Academic Frontier Youth Teamthe Fundamental Research Funds for the Central Universities,China(HUST No.2017KFXKJC002)。
文摘Coherent superposition of electronic states induces attosecond electron motion in molecules.We theoretically investigate the strong-field ionization of this superposition state by numerically solving the time-dependent Schrodinger equation.In the obtained photoelectron momentum distribution,an intriguing bifurcation structure appears in the strong-field holographic interference pattern.We demonstrate that this bifurcation structure directly provides complete information about the status of the transient wave function of the superposition state:the horizontal location of the bifurcation in the momentum distribution reveals the relative phase of the involved components of the superposition state and the vertical position indicates the relative coefficient.Thus,this bifurcation structure takes a snapshot of the transient electron wave packet of the superposition state and provides an intuitive way to monitor electron motion in molecules.
基金supported by the Chinese National Natural Science Foundation(No.22062001).
文摘As an ideal secondary energy source,hydrogen has the title of clean energy and the product of its complete combustion is only water,which is not polluting to the environment.Photocatalytic hydrogen production technology is an environmentally friendly,safe,and low-cost strategy that requires only an inexhaustible amount of solar energy and water as feedstock.This paper provides a detailed and detailed review of S-scheme heterojunction photocatalysts for photocatalytic hydrogen production,mainly including TiO_(2)-based,Perovskite-based,CdS-based,Graphitic phase carbon nitride-based,COF-based graphdiyne-based,ZnO-based,and ZnIn_(2)S_(4)-based S-scheme heterojunction photocatalysts.The classification of S-scheme heterojunctions is summarized.What’s more,various characterizations for direct verification of the charge migration mechanism of S-scheme heterojunctions are outlined.Based on the present study,the future potential challenges and future research trends for S-scheme heterojunctions in photocatalytic hydrogen evolution technology are pointed out,which provides feasible strategies for the development and design of S-scheme heterojunction photocatalysts in the field of photocatalytic hydrogen evolution.
基金supported by the National Natural Science Foundation of China(22472071,22075119,and 22209017)the Natural Science Foundation of Gansu Province(21JR7RA440)the Fundamental Research Funds for the Central Universities(lzuibky2024-ou01)。
文摘In natural photosynthesis,compartmentalized protein networks spatially orchestrate light-driven electron transfer for CO_(2)activation,offering a blueprint for artificial systems.Herein,we report the design and synthesis of a molecular compartmentalized photocatalyst for photocatalytic CO_(2)overall conversion,in which a nickel-substituted polyoxometalate(NiPOM)is confined within the inner channels of carbon nanotubes(CNTs),while Fe-porphyrin derivatives(FeTCPPOMe)are anchored onto the CNT exterior viaπ-πinteractions.This unique inside-outside configuration creates a highly ordered,vectorial electron transfer pathway whereby photoexcited electrons are generated at the FeTCPPOMe sites,swiftly injected into the CNT and then directly delivered to the encapsulated NiPOM.Under simulated solar illumination,the FeTCPPOMe-NiPOM@CNT composite exhibits good photocatalytic CO_(2)reduction performance,achieving a CO production rate of 42.7μmol g^(−1)h^(−1)with a 100%CO selectivity.In-situ DRIFTS,quasi in-situ XPS and in-situ illuminated Kelvin probe force microscopy(KPFM)combined with density functional theory calculations clearly elucidated the photoinduced electron transfer pathway.This work demonstrates that strategic nanoscale confinement and hierarchical assembly can dramatically enhance charge transport and catalytic efficiency,offering a promising blueprint for next-generation CO_(2)photoreduction systems.
基金supported by the Xuzhou Key Research and Development Program(Social Development)(No.KC23298)the National Natural Science Foundation of China(No.22271122)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20211549)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_2903).
文摘The efficient utilization of visible light catalysts for organic reactions necessitates not only the effective separation of photogenerated electrons and holes to participate in the reaction,but also their ability to form key intermediates with reactant molecules.The present study successfully synthesized a crusiform-like mesoporous structure of nitrogen-doped carbon-coated Cu_(2)O/Cu(Cu_(2)O/Cu/N-C)with a Cu_(2)O/dual electron acceptor interface using etched HKUST-1 as the precursor.A series of theoretical and experimental studies have demonstrated that the Cu_(2)O/Cu/N-C interface in the photocatalytic homo-coupling of terminal alkynes not only effectively enhances the separation of photogenerated electron−hole pairs,but also facilitates the formation of the key intermediate[Cu_(2)O/Cu/N-C]-phenylacetylide and promotes the rearrangement of its internal charges.As a result,the homo-coupling reaction can be effectively facilitated.The primary reason for the functional role of Cu_(2)O/Cu/N-C interface lies in the downward bending of energy band from Cu_(2)O to N-doped C layers,induced by the different work functions of Cu_(2)O,Cu and N-doped C layers.Consequently,Cu_(2)O/Cu/N-C photocatalysts demonstrate exceptional photocatalytic activity in the homo-coupling reaction of terminal alkynes under blue-light irradiation and air atmosphere.The present study presents a novel research methodology for the development of highly efficient visible light catalysts to facilitate organic reactions in future applications.
基金Project supported by the National Natural Science Foundation of China(Nos.61474137,61176073,61306107)
文摘This work presents a comprehensive analysis of 3D cylindrical junction-less charge trapping memory device performance regarding continuous scaling of the structure dimensions. The key device performance, such as program/erase speed, vertical charge loss, and lateral charge migration under high temperature are intensively studied using the Sentaurus 3 D device simulator. Although scaling of channel radius is beneficial for operation speed improvement, it leads to a retention challenge due to vertical leakage, especially enhanced charge loss through TPO. Scaling of gate length not only decreases the program/erase speed but also leads to worse lateral charge migration. Scaling of spacer length is critical for the interference of adjacent cells and should be carefully optimized according to specific cell operation conditions. The gate stack shape is also found to be an important factor affecting the lateral charge migration. Our results provide guidance for high density and high reliability 3D CTM integration.
基金supported by the National Natural Science Foundation of China under Grants 62025406。
文摘Accelerated margin loss during read after delay(RAD)is a newly discovered reliability concern in HfO2-based ferroelectric random access memories(FeRAMs),which significantly impacts the lifetime of the memory device.Unlike conventional fatigue effect,this issue is closely linked to the coercive field(Ec)shift,or imprint,during bipolar electrical field cycling at intermediate frequency.The precise cause of imprint during RAD,however,remains elusive.To investigate,we employed customized electrical testing to examine the charge transfer behavior in static imprint(SI)and continuous read/write(CRW)scenarios,which can be viewed as RAD performed at minimum and maximum frequencies.Our findings reveal that interfacial charge injection is the primary mechanism for imprint in SI,while bulk charge drives the imprint in asymmetric CRW.Further exploration with a SPICE-based charge transfer model suggests that RAD-related imprint is the result of bulk charge migration,driven by the periodically restored depolarization field after read/write-back operation.Experimental verification supports this theory,highlighting the importance of interface engineering to enhance bound charge screening and element doping to elevate the migration barrier for bulk charges in addressing the RAD problem.
基金supported by the National Natural Science Foundation of China(21975110,22378219,22302106)the Technology Support Program for the Youth Innovation Team of Shandong Higher Education Institutions(2023KJ225)the support from Taishan Youth Scholar Program of Shandong Province。
基金supported by the National Natural Science Foundation of China (21972021,22271281,22325109,22171263,62227815,91961115,22494633,22422508)the Natural Science Foundation of Fujian Province (2024J01238,2022J06032,2021J02017)+5 种基金the Scientific Research and Equipment Development Project of Chinese Academy of Sciences (YJKYQ20210024)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China (2021ZR101)the Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences (CXZX-2022-GH09,CXZX-2023-GS03,CXZX-2022-JQ03)the Key Research Project of Chinese Academy of Sciences(KGFZD-145-25-21)the Strategic Priority Research Program of Chinese Academy of Sciences (XDB1170000)the 111 Project (D16008)。
文摘The investigation of charge carrier kinetics has long been a cornerstone of polymer photocatalysis research.However,the role of proton transport behavior in photocatalytic processes has often been underappreciated,despite its fundamental importance in proton-coupled electron-transfer reactions.Addressing this gap,we present a novel BF_(2)-bridged covalent organic framework(C2-COF-BF2) that undergoes post-synthetic modification with boron trifluoride,designed to confer a dual functional advantage.Specifically,the incorporated BF_(2) moieties are engineered to induce a donor-acceptor effect and potentially serve as continuous supply sites for activated protons.This bifunctional role not only enhances charge separation and migration while suppressing electron-hole recombination but also facilitates proton transport,thereby enabling improved performance in both photocatalytic hydrogen evolution reaction(HER) and H_(2) O_(2) production.Remarkably,the photocatalytic HER performance of C2-COF-BF2(AQY_(450 nm)= 8.78%) ranks among the highest efficiencies reported for COF-based photocatalysts to date.These findings highlight an innovative pathway for advancing the rational design of COF photocatalysts,offering a synergistic optimization of charge carrier kinetics and mass transfer processes to achieve unprecedented photocatalytic efficiency.
