Layered oxides have attracted significant attention as cathodes for sodium-ion batteries(SIBs)due to their compositional versatility and tuneable electrochemical performance.However,these materials still face challeng...Layered oxides have attracted significant attention as cathodes for sodium-ion batteries(SIBs)due to their compositional versatility and tuneable electrochemical performance.However,these materials still face challenges such as structural phase transitions,Na^(+)/vacancy ordering,and Jahn–Teller distortion effect,resulting in severe capacity decay and sluggish ion kinetics.We develop a novel Cu/Y dual-doping strategy that leads to the formation of"Na–Y"interlayer aggregates,which act as structural pillars within alkali metal layers,enhancing structural stability and disrupting the ordered arrangement of Na^(+)/vacancies.This disruption leads to a unique coexistence of ordered and disordered Na^(+)/vacancy states with near-zero strain,which significantly improves Na^(+)diffusion kinetics.This structural innovation not only mitigates the unfavorable P2–O2 phase transition but also facilitates rapid ion transport.As a result,the doped material demonstrates exceptional electrochemical performance,including an ultra-long cycle life of 3000 cycles at 10 C and an outstanding high-rate capability of~70 mAh g^(−1)at 50 C.The discovery of this novel interlayer pillar,along with its role in modulating Na^(+)/vacancy arrangements,provides a fresh perspective on engineering layered oxides.It opens up promising new pathways for the structural design of advanced cathode materials toward efficient,stable,and high-rate SIBs.展开更多
CO_(2)hydrogenation to value-added light olefins(C_(2-4)=)is crucial for the utilization and cycling of global carbon resource.Moderate CO_(2)activation and carbon chain growth ability are key factors for iron-based c...CO_(2)hydrogenation to value-added light olefins(C_(2-4)=)is crucial for the utilization and cycling of global carbon resource.Moderate CO_(2)activation and carbon chain growth ability are key factors for iron-based catalysts for efficient CO_(2)conversion to target C_(2-4)=products.The electronic interaction and confinement effect of electron-deficient graphene inner surface on the active phase are effective to improve surface chemical properties and enhance the catalytic performance.Here,we report a core-shell FeCo alloy catalyst with graphene layers confinement prepared by a simple sol-gel method.The electron transfer from Fe species to curved graphene inner surface modifies the surface electronic structure of the active phaseχ-(Fe_(x)Co_(1-x))_(5)C_(2)and improves CO_(2)adsorption capacity,enhancing the efficient conversion of CO_(2)and moderate C-C coupling.Therefore,the catalyst FeCoK@C exhibits C_(2-4)=selectivity of 33.0%while maintaining high CO_(2)conversion of 52.0%.The high stability without obvious deactivation for over 100 h and unprecedented C_(2-4)=space time yield(STY)up to 52.9 mmolCO_(2)·g^(-1)·h^(-1)demonstrate its potential for practical application.This work provides an efficient strategy for the development of high-performance CO_(2)hydrogenation catalysts.展开更多
Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric fo...Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric for dynamic random access memory(DRAM)applications,offering a high dielectric constant with a remarkable leakage-lowering effect by Al acceptor doping.However,ATO fabrication via conventional supercycle-based ALD suffers from severe crystallinity loss during the growth of TiO_(2) upon Al doping owing to the dopant-induced lattice disorder.In addition,Al doping cannot reduce any inherent O vacancies(V_(O))of TiO_(2),although the original purpose of doping was to address the n-type nature caused by V_(O).To resolve these limitations,we propose a single-step,in-situ Ar/O_(2) post-doping plasma(PDP)process immediately after the Al dopant incorporation.Using the PDP process,simultaneous atomic-scale dopant migration-mediated crystallization and V_(O) annihilation were successfully initiated.Thus,the surface concentration of the dopant decreased,reducing the dopant-induced lattice distortion,while promoting the highly crystallized seed layer-like surface.Consequently,strong rutile-phase recovery was accompanied by enhanced lattice-matched growth.In addition,the PDP process significantly lowers the V_(O)-to-lattice oxygen ratio by facilitating the recombination between reactive O species and V_(O),increasing the corresponding 0.4 e V of conduction band offset(CBO).Despite the common trade-off between the dielectric constant and leakage,the Pt/PDP-ATO/Ru capacitor exhibited a simultaneous 30%increase in dielectric constant and up to a 1.6-order reduction in leakage current density.展开更多
Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from th...Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from the poor activity and remained in great challenge for real application.Herein,hydrothermally synthesized BiOCl with layered structure(BOC-NSs)was exfoliated into thickness reduced nanosheets(BOCNSs-w)and even atomic layers(BOCNSs-i)via ultrasonication in water and isopro-panol,respectively.In comparison with the pristine BOCNSs,the exfoli-ated BiOCl,especially BOCNSs-i with atomically layered structure,exhibits much improved photocatalytic activity forCO_(2)overall splitting to produce CO andO_(2) at a stoichiometric ratio of 2:1,with CO evolution rate reaching 134.8µmolg^(-1)h^(-1) under simulated solar light(1.7 suns).By surpassing the photocatalytic performances of the state-of-the-artBi_(l)O_(m)X_(n)(X:Cl,Br,I)based photocatalysts,the CO evolution rate is further increased by 99 times,reaching 13.3 mmolg^(-1)h^(-1) under concentrated solar irradiation(34 suns).This excellent photocatalytic performance achieved over BOCNSs-i should be benefited from the shortened transfer distance and the increased built-in electric field intensity,which acceler-ates the migration of photogenerated charge carriers to surface.Moreover,with oxygen vacancies(VO)introduced into the atomic layers,BOCNSs-i is exposed with the electrons enriched Bi active sites that could transfer electrons to activateCO_(2)molecules for highly efficient and selective CO production,by lowering the energy barrier of rate-determining step(RDS),*OH+*CO_(2)-→HCO_(3)-.It is also realized that theH_(2)O vapor supplied during photocatalytic reaction would exchange oxygen atoms withCO_(2),which could alter the reaction path-ways and further reduce the energy barrier of RDS,contributing to the dramatically improved photocatalytic performance forCO_(2)overall splitting to CO andO_(2).展开更多
Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolu...Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolution reaction(HER)by enhancing Volmer kinetics from rapid water dissociation and improving Tafel kinetics from efficient H*desorption.Atomic layer deposition of Ru with 50 process cycles results in a mixture of Ru SAs and 2.8-0.4 nm NPs present on TNT layers,and it emerges with the highest HER activity among all the electrodes synthesized.A detailed study of the Ti and Ru species using different high-resolution techniques confirmed the presence of Ti^(3+)states and the coexistence of Ru SAs and NPs.With insights from literature,the role of Ti^(3+),appropriate work functions of TNT layers and Ru,and the synergistic effect of Ru SAs and Ru NPs in improving the performance of alkaline HER were elaborated and justified.The aforementioned characteristics led to a remarkable performance by having 9mV onset potentials and 33 mV dec^(-1) of Tafel slopes and a higher turnover frequency of 1.72 H2 s^(-1) at 30 mV.Besides,a notable stability from 28 h staircase chronopotentiometric measurements for TNT@Ru surpasses TNT@Pt in comparison.展开更多
Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+d...Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.展开更多
As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we emp...As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we employed high-quality crystalline TiN/Al_(2)O_(3)/BaTiO_(3)/Pt RRAM with an optimized thin Al_(2)O_(3) interlayer around 12 nm thick prepared using atomic layer deposition since the thickness of the interlayer affects the memory window size. After insertion of the Al_(2)O_(3) interlayer, the novel RRAM exhibited outstanding uniform resistive switching voltage and the ON/OFF memory window drastically increased from 10 to 103 without any discernible decline in performance. Moreover, the low-resistance state and high-resistance state operating current values decreased by almost one order and three orders of magnitude, respectively, thereby decreasing the power consumption for the RESET and SET processes by more than three and almost one order of magnitude, respectively. The device also exhibits multilevel resistive switching behavior when varying the applied voltage. Finally, we also developed a 6 6 crossbar array which demonstrated consistent and reliable resistive switching behavior with minimal variation. Hence, our approach holds great promise for producing state-of-the-art non-volatile resistive switching devices.展开更多
VO_2 thin films were grown on silicon substrates using Al_2O_3 thin films as the buffer layers. Compared with direct deposition on silicon, VO_2 thin films deposited on Al_2O_3 buffer layers experience a significant i...VO_2 thin films were grown on silicon substrates using Al_2O_3 thin films as the buffer layers. Compared with direct deposition on silicon, VO_2 thin films deposited on Al_2O_3 buffer layers experience a significant improvement in their microstructures and physical properties. By optimizing the growth conditions, the resistance of VO_2 thin films can change by four orders of magnitude with a reduced thermal hysteresis of 4 °C at the phase transition temperature. The electrically driven phase transformation was measured in Pt/Si/Al_2O_3/VO_2/Au heterostructures. The introduction of a buffer layer reduces the leakage current and Joule heating during electrically driven phase transitions. The C–V measurement result indicates that the phase transformation of VO_2 thin films can be induced by an electrical field.展开更多
The effect of ultraviolet-ozone(UVO)irradiation on amorphous(am)SnO_(2) and its impact on the photoconversion efficiency of MAPbI3-based perovskite solar cells were investigated in detail.UVO treatment was found to in...The effect of ultraviolet-ozone(UVO)irradiation on amorphous(am)SnO_(2) and its impact on the photoconversion efficiency of MAPbI3-based perovskite solar cells were investigated in detail.UVO treatment was found to increase the amount of chemisorbed oxygen on the am-SnO_(2) surface,reducing the surface energy and contact angle.Physicochemical changes in the am-SnO_(2) surface lowered the Gibbs free energy for the densification of perovskite films and facilitated the formation of homogeneous perovskite grains.In addition,the Fermi energy of the UVO-treated am-SnO_(2) shifted upwards to achieve an ideal band offset for MAPbI3,which was verified by theoretical calculations based on the density functional theory.We achieved a champion efficiency of 19.01% with a statistical reproducibility of 17.01±1.34% owing to improved perovskite film densification and enhanced charge transport/extraction,which is considerably higher than the 13.78±2.15% of the counterpart.Furthermore,UVO-treated,am-SnO_(2)-based devices showed improved stability and less hysteresis,which is encouraging for the future application of up-scaled perovskite solar cells.展开更多
Broadband transparent films play a pivotal role in various applications such as lenses and solar cells,particularly porous structured transparent films exhibit significant potential.This study investigates a porous Si...Broadband transparent films play a pivotal role in various applications such as lenses and solar cells,particularly porous structured transparent films exhibit significant potential.This study investigates a porous SiO_(2) refractive index gradient anti-reflective film prepared by atomic layer deposition(ALD).A porous SiO_(2) film with gradual porosity was obtained by phosphoric acid etching of Al_(2)O_(3)/SiO_(2) multilayers with gradient Al2O3 ratios,achieving a gradual decrease in refractive index from the substrate to the surface.The film exhibited an average transmittance as high as 97.8%within the wavelength range from 320 nm to 1200 nm.The environmental adaptability was further enhanced by surface modification using rare earth oxide(REO)La_(2)O_(3),resulting in formation of a lotus leaf-like structure and achieving a water contact angle of 100.0°.These data proved that the modification significantly improved hydrophobic self-cleaning capability while maintaining exceptional transparency of the film.The surface structure of the modified film remained undamaged even after undergoing wipe testing,demonstrating its excellent surface durability.展开更多
MgO thin films with different textures are fabricated by the ion beam assisted （IBAD） method on the Y2O3/Al2O3 buffered C276 tape. Then a CaO2 layer is directly grown on the IBAD-MgO film by the pulsed laser deposit...MgO thin films with different textures are fabricated by the ion beam assisted （IBAD） method on the Y2O3/Al2O3 buffered C276 tape. Then a CaO2 layer is directly grown on the IBAD-MgO film by the pulsed laser deposition （PLD） method. Effects of lBAD-MgO texture, substrata temperature and thickness on the grain alignment of the CeO2 layer are investigated. Film characterization is performed by x-ray diffraction and atomic force microscopy. It is found that the orientation and texture degree of the CaO2 layer are very sensitive to the IBAD-MgO texture. By optimizing the IBAD-MgO texture, CeO2 has pure （002） orientation and excellent biaxial texture deposited in a broad substrata temperature range. In addition, the PLD-CeO2 layer has a thickness effect. Under the optimized experimental condition, the PLD-CeO2 layer has a high in-plane texture of △φ = 2.9° and a smooth surface with an rms surface roughness of less than 2nm. The critical current density Jc of a 0.4μm-thick YBCO film deposited on the CeO2 layer is 6.25 × 106 A/cm2 at 77K and a self-field.展开更多
Engineering an efficient interface is a trustworthy strategy for designing advanced photocatalytic systems for solar energy conversion.Herein,oxygen-deficient Bi_(2)WO_(6)atomic layers without organic residues were su...Engineering an efficient interface is a trustworthy strategy for designing advanced photocatalytic systems for solar energy conversion.Herein,oxygen-deficient Bi_(2)WO_(6)atomic layers without organic residues were successfully fabricated via a facile solvothermal strategy by the multifunctional regulatory mechanism of introduced chloridion.Both DFT calculations and speciation determination revealed that chloridion displayed a more pronounced effect in the controllable synthesis of oxygen-deficient Bi_(2)WO_(6)atomic layers without organic residues:ultrathinning and defect-engineering.This built-in multi-cooperative interface endowed Bi_(2)WO_(6)with intriguing photoelectrochemical properties,O_(2) activation ability,and ultrahigh activity in visible-light powered deep oxidation of NO.A reasonable photocatalytic mechanism was proposed based on in situ infrared spectroscopy analysis and theoretical calculations.We believe that this multi-cooperative interface engineering of oxygen-deficient Bi_(2)WO_(6)atomic layers without organic residues could provide new insights into the design of two-dimensional(2D)layered materials with efficient active sites and pave the way for efficient NO photooxidation systems.展开更多
Modulating the interface between the electron transport layer(ETL)and perovskite to minimize interfacial recombination is pivotal for developing efficient and stable perovskite solar cells.Here,we introduce an ultra-t...Modulating the interface between the electron transport layer(ETL)and perovskite to minimize interfacial recombination is pivotal for developing efficient and stable perovskite solar cells.Here,we introduce an ultra-thin ZrO_(2)insulating interface layer onto the inner surface of the mesoporous TiO_(2)ETL via the chemical bath deposition in the zirconium n-butoxide solution,which alters the interface characteristics between TiO_(2)and perovskite for the printable hole-conductor-free mesoscopic perovskite solar cells(p-MPSCs).The insulating ZrO_(2)interface layer reduces interface defects and suppresses interfacial non-radiative recombination.Furthermore,the ZrO_(2)interface layer improves the wettability of the mesoporous TiO_(2)ETL,which favors the crystallization of perovskite within the mesoporous scaffold.Meanwhile,the device performance presents thickness dependence on the interface layer.While increased thickness improves the open-circuit voltage,excessive thickness negatively impacts both the short-circuit current density and fill factor.Consequently,an improved power conversion efficiency of 19.9% was achieved for p-MPSCs with the ZrO_(2)interface layer at its optimized thickness.展开更多
The rapid evolution of hypersonic vehicle technologies necessitates robust thermal protection systems capable of withstanding extreme oxidative ablation.This study introduces a novel gradient-architected ZrB_(2)-MoSi_...The rapid evolution of hypersonic vehicle technologies necessitates robust thermal protection systems capable of withstanding extreme oxidative ablation.This study introduces a novel gradient-architected ZrB_(2)-MoSi_(2)-SiC dense layer embedded within a lightweight three-dimensional(3D)needled carbon fiber composite.Utilizing the volatility of ethanol and polycarbosilane,the ceramic slurry is selectively infused into targeted regions of the fibrous structure,optimizing the ZrB_(2)to MoSi_(2)ratio to enhance performance.The resulting dense layer exhibits exceptional emissivity,surpassing 0.90 in the 1-3μm range and exceeding 0.87 in the 2-14μm range.Moreover,it demonstrates remarkable oxidative ablation resistance.Specifically,at an optimized ZrB_(2)to MoSi_(2)ratio of 6:4,the dense layer achieves a minimal linear ablation rate of 0.015μm·s^(-1) under a 1.5 MW·m^(-2)oxyacetylene flame for 1000 s.Even after exposure to oxyacetylene ablation at surface temperatures of approximately 1750℃for 1000 s,the dense layer retains its structural integrity,highlighting its enduring oxidation resistance.The incorporation of MoSi_(2)not only enhances emissivity but also fortifies the ZrO_(2)and SiO_(2)oxide layers,crucial for environments with elevated oxygen levels,thereby mitigating the active oxidation of SiC.This combination of high emissivity and long-term oxidation resistance at ultra-high temperatures positions the ZrB_(2)-MoSi_(2)-SiC dense layer as an exceptionally promising candidate for advanced thermal protection in hypersonic vehicles.展开更多
Normally,a transparent inert film is coated on the surface of TiO_(2) particles to enhance the weatherability of the pigment.Liquid-phase coating process is mainly used in industry,which difficult to get really unifor...Normally,a transparent inert film is coated on the surface of TiO_(2) particles to enhance the weatherability of the pigment.Liquid-phase coating process is mainly used in industry,which difficult to get really uniform films.This work combining nanoparticle fluidization technology with atomic layer deposition(ALD) technology to achieve precise surface modification of a large number of micro-nano particles.First,we explored the fluidization characteristics of TiO_(2) nanoparticles in a home-made atmospheric fluidized bed ALD reactor(FB-ALD) to ensure the uniform fluidization of a large number of nanoparticles.Then TiCl_(4) and H_(2)O were used as precursors to deposit amorphous TiO_(2) films on the surface of TiO_(2) nanoparticles at 80℃ under atmospheric pressure,and the growth per cycle was about 0.109 nm per cycle.After 30 ALD cycles,the film thickness was about 3.1 nm,which could almost fully suppress the photocatalytic activity of TiO_(2).Compared with other traditional coating materials,amorphous TiO_(2) has higher light refractive index,and realizes the suppression of the photocatalytic activity of TiO_(2) without introducing other substances,demonstrating greater application potential in TiO_(2) pigment coating field.The process is a gas-phase coating method,which is efficient,no waste water,and easy to scale up.This work shown the excellent property of interface engineering in improving pigment weatherability and can also provide guidance for the nanoparticle surface modification.展开更多
The metal organic deposition(MOD)method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer.The material phase and the macro-orientatio...The metal organic deposition(MOD)method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer.The material phase and the macro-orientations were analyzed by XRD.The surface morphology and the blocking performance of the buffer layer were investigated by SEM and AES.The grain orientation and the crystallographic growth mode of the CeO2 layer were first characterized by electron backscattering diffraction(EBSD).The uniformly distributed islanded LZO seed layer optimized both the in-plan and the out-plan orientation of the CeO2/LZO buffer layers,and the CeO2/LZO buffer layers with a thickness of 175 nm acted as an efficient Ni,W barrier.The EBSD analysis indicated that the crystallographic orientation of each layer can be obtained at various accelerating voltages for the multilayer sample,the percentage of{001}<110>rotated cube texture of CeO2 layer reaching 97.4%at the accelerating voltage of 15 kV,thus showing epitaxial deposition with a high texture.展开更多
The electron transport layer(ETL)plays an important role on the performance and stability of perovskite solar cells(PSCs).Developing double ETL is a promising strategy to take the advantages of different ETL materials...The electron transport layer(ETL)plays an important role on the performance and stability of perovskite solar cells(PSCs).Developing double ETL is a promising strategy to take the advantages of different ETL materials and avoid their drawbacks.Here,an ultrathin SnO_(2)layer of~5 nm deposited by atomic layer deposit(ALD)was used to construct a TiO_(2)/SnO_(2)double ETL,improving the power conversion efficiency(PCE)from 18.02%to 21.13%.The ultrathin SnO_(2)layer enhances the electrical conductivity of the double layer ETLs and improves band alignment at the ETL/perovskite interface,promoting charge extraction and transfer.The ultrathin SnO_(2)layer also passivates the ETL/perovskite interface,suppressing nonradiative recombination.The double ETL achieves outstanding stability compared with PSCs with TiO_(2)only ETL.The PSCs with double ETL retains 85%of its initial PCE after 900 hours illumination.Our work demonstrates the prospects of using ultrathin metal oxide to construct double ETL for high-performance PSCs.展开更多
基金supported by the “Pioneer” and “Leading Goose” R&D Program of Zhejiang Province of China (No. 2024C01056)the support from London South Bank University
文摘Layered oxides have attracted significant attention as cathodes for sodium-ion batteries(SIBs)due to their compositional versatility and tuneable electrochemical performance.However,these materials still face challenges such as structural phase transitions,Na^(+)/vacancy ordering,and Jahn–Teller distortion effect,resulting in severe capacity decay and sluggish ion kinetics.We develop a novel Cu/Y dual-doping strategy that leads to the formation of"Na–Y"interlayer aggregates,which act as structural pillars within alkali metal layers,enhancing structural stability and disrupting the ordered arrangement of Na^(+)/vacancies.This disruption leads to a unique coexistence of ordered and disordered Na^(+)/vacancy states with near-zero strain,which significantly improves Na^(+)diffusion kinetics.This structural innovation not only mitigates the unfavorable P2–O2 phase transition but also facilitates rapid ion transport.As a result,the doped material demonstrates exceptional electrochemical performance,including an ultra-long cycle life of 3000 cycles at 10 C and an outstanding high-rate capability of~70 mAh g^(−1)at 50 C.The discovery of this novel interlayer pillar,along with its role in modulating Na^(+)/vacancy arrangements,provides a fresh perspective on engineering layered oxides.It opens up promising new pathways for the structural design of advanced cathode materials toward efficient,stable,and high-rate SIBs.
文摘CO_(2)hydrogenation to value-added light olefins(C_(2-4)=)is crucial for the utilization and cycling of global carbon resource.Moderate CO_(2)activation and carbon chain growth ability are key factors for iron-based catalysts for efficient CO_(2)conversion to target C_(2-4)=products.The electronic interaction and confinement effect of electron-deficient graphene inner surface on the active phase are effective to improve surface chemical properties and enhance the catalytic performance.Here,we report a core-shell FeCo alloy catalyst with graphene layers confinement prepared by a simple sol-gel method.The electron transfer from Fe species to curved graphene inner surface modifies the surface electronic structure of the active phaseχ-(Fe_(x)Co_(1-x))_(5)C_(2)and improves CO_(2)adsorption capacity,enhancing the efficient conversion of CO_(2)and moderate C-C coupling.Therefore,the catalyst FeCoK@C exhibits C_(2-4)=selectivity of 33.0%while maintaining high CO_(2)conversion of 52.0%.The high stability without obvious deactivation for over 100 h and unprecedented C_(2-4)=space time yield(STY)up to 52.9 mmolCO_(2)·g^(-1)·h^(-1)demonstrate its potential for practical application.This work provides an efficient strategy for the development of high-performance CO_(2)hydrogenation catalysts.
基金supported by the Samsung Electronics Co.,Ltd.(ISO230414-05954-01)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF2021R1A6A1A03039981)+2 种基金the Korea Institute for Advancement of Technology(KIAT)Grant,funded by the Korea Government(MOTIE)(P0023703,HRD Program for Industrial Innovation)The computations were performed at the Korea Institute of Science and Technology Information(KISTI)National Supercomputing Center(KSC-2024-CRE-0316)the UNIST Supercomputing Center。
文摘Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric for dynamic random access memory(DRAM)applications,offering a high dielectric constant with a remarkable leakage-lowering effect by Al acceptor doping.However,ATO fabrication via conventional supercycle-based ALD suffers from severe crystallinity loss during the growth of TiO_(2) upon Al doping owing to the dopant-induced lattice disorder.In addition,Al doping cannot reduce any inherent O vacancies(V_(O))of TiO_(2),although the original purpose of doping was to address the n-type nature caused by V_(O).To resolve these limitations,we propose a single-step,in-situ Ar/O_(2) post-doping plasma(PDP)process immediately after the Al dopant incorporation.Using the PDP process,simultaneous atomic-scale dopant migration-mediated crystallization and V_(O) annihilation were successfully initiated.Thus,the surface concentration of the dopant decreased,reducing the dopant-induced lattice distortion,while promoting the highly crystallized seed layer-like surface.Consequently,strong rutile-phase recovery was accompanied by enhanced lattice-matched growth.In addition,the PDP process significantly lowers the V_(O)-to-lattice oxygen ratio by facilitating the recombination between reactive O species and V_(O),increasing the corresponding 0.4 e V of conduction band offset(CBO).Despite the common trade-off between the dielectric constant and leakage,the Pt/PDP-ATO/Ru capacitor exhibited a simultaneous 30%increase in dielectric constant and up to a 1.6-order reduction in leakage current density.
基金the financial support from the National Key R&D Program of China(2024YFF0506100)the National Natural Science Foundation of China(52225606 and 52488201).
文摘Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from the poor activity and remained in great challenge for real application.Herein,hydrothermally synthesized BiOCl with layered structure(BOC-NSs)was exfoliated into thickness reduced nanosheets(BOCNSs-w)and even atomic layers(BOCNSs-i)via ultrasonication in water and isopro-panol,respectively.In comparison with the pristine BOCNSs,the exfoli-ated BiOCl,especially BOCNSs-i with atomically layered structure,exhibits much improved photocatalytic activity forCO_(2)overall splitting to produce CO andO_(2) at a stoichiometric ratio of 2:1,with CO evolution rate reaching 134.8µmolg^(-1)h^(-1) under simulated solar light(1.7 suns).By surpassing the photocatalytic performances of the state-of-the-artBi_(l)O_(m)X_(n)(X:Cl,Br,I)based photocatalysts,the CO evolution rate is further increased by 99 times,reaching 13.3 mmolg^(-1)h^(-1) under concentrated solar irradiation(34 suns).This excellent photocatalytic performance achieved over BOCNSs-i should be benefited from the shortened transfer distance and the increased built-in electric field intensity,which acceler-ates the migration of photogenerated charge carriers to surface.Moreover,with oxygen vacancies(VO)introduced into the atomic layers,BOCNSs-i is exposed with the electrons enriched Bi active sites that could transfer electrons to activateCO_(2)molecules for highly efficient and selective CO production,by lowering the energy barrier of rate-determining step(RDS),*OH+*CO_(2)-→HCO_(3)-.It is also realized that theH_(2)O vapor supplied during photocatalytic reaction would exchange oxygen atoms withCO_(2),which could alter the reaction path-ways and further reduce the energy barrier of RDS,contributing to the dramatically improved photocatalytic performance forCO_(2)overall splitting to CO andO_(2).
基金support from the European Union Horizon 2020 program(project HERMES,nr.952184)the Ministry of Education,Youth and Sports of the Czech Republic for supporting CEMNAT(LM2023037)+1 种基金Czech-NanoLab(LM2023051)infrastructures for providing ALD,SEM,EDX,XPS,TEM,and XRDCzech Science Foundation(project 23-08019X,EXPRO).
文摘Synergistic interplays involving multiple active centers originating from TiO2 nanotube layers(TNT)and ruthenium(Ru)species comprising of both single atoms(SAs)and nanoparticles(NPs)augment the alkaline hydrogen evolution reaction(HER)by enhancing Volmer kinetics from rapid water dissociation and improving Tafel kinetics from efficient H*desorption.Atomic layer deposition of Ru with 50 process cycles results in a mixture of Ru SAs and 2.8-0.4 nm NPs present on TNT layers,and it emerges with the highest HER activity among all the electrodes synthesized.A detailed study of the Ti and Ru species using different high-resolution techniques confirmed the presence of Ti^(3+)states and the coexistence of Ru SAs and NPs.With insights from literature,the role of Ti^(3+),appropriate work functions of TNT layers and Ru,and the synergistic effect of Ru SAs and Ru NPs in improving the performance of alkaline HER were elaborated and justified.The aforementioned characteristics led to a remarkable performance by having 9mV onset potentials and 33 mV dec^(-1) of Tafel slopes and a higher turnover frequency of 1.72 H2 s^(-1) at 30 mV.Besides,a notable stability from 28 h staircase chronopotentiometric measurements for TNT@Ru surpasses TNT@Pt in comparison.
基金supported by the National Natural Science Foundation of China(No.21805018)by Sichuan Science and Technology Program(Nos.2022ZHCG0018,2023NSFSC0117 and 2023ZHCG0060)Yibin Science and Technology Program(No.2022JB005)and China Postdoctoral Science Foundation(No.2022M722704).
文摘Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.
基金supported by the National Research Foundation of Korea funded by the Korean Government(grant No.RS-2023-00208801).
文摘As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we employed high-quality crystalline TiN/Al_(2)O_(3)/BaTiO_(3)/Pt RRAM with an optimized thin Al_(2)O_(3) interlayer around 12 nm thick prepared using atomic layer deposition since the thickness of the interlayer affects the memory window size. After insertion of the Al_(2)O_(3) interlayer, the novel RRAM exhibited outstanding uniform resistive switching voltage and the ON/OFF memory window drastically increased from 10 to 103 without any discernible decline in performance. Moreover, the low-resistance state and high-resistance state operating current values decreased by almost one order and three orders of magnitude, respectively, thereby decreasing the power consumption for the RESET and SET processes by more than three and almost one order of magnitude, respectively. The device also exhibits multilevel resistive switching behavior when varying the applied voltage. Finally, we also developed a 6 6 crossbar array which demonstrated consistent and reliable resistive switching behavior with minimal variation. Hence, our approach holds great promise for producing state-of-the-art non-volatile resistive switching devices.
基金financially supported by the National Natural Science Foundation of China (Nos. 51401046, 51572042, 61131005, 61021061, and 61271037)International Cooperation Projects (Nos. 2013HH0003 and 2015DFR50870)+3 种基金the 111 Project (No. B13042)the Sichuan Province S&T program (Nos. 2014GZ0003, 2015GZ0091, and 2015GZ0069)Fundamental Research Funds for the Central Universitiesthe start-up fund from the University of Electronic Science and Technology of China
文摘VO_2 thin films were grown on silicon substrates using Al_2O_3 thin films as the buffer layers. Compared with direct deposition on silicon, VO_2 thin films deposited on Al_2O_3 buffer layers experience a significant improvement in their microstructures and physical properties. By optimizing the growth conditions, the resistance of VO_2 thin films can change by four orders of magnitude with a reduced thermal hysteresis of 4 °C at the phase transition temperature. The electrically driven phase transformation was measured in Pt/Si/Al_2O_3/VO_2/Au heterostructures. The introduction of a buffer layer reduces the leakage current and Joule heating during electrically driven phase transitions. The C–V measurement result indicates that the phase transformation of VO_2 thin films can be induced by an electrical field.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2020R1F1A1068664)supported by the Defense Challengeable Future Technology Program of the Agency for Defense Development,Republic of Korea.
文摘The effect of ultraviolet-ozone(UVO)irradiation on amorphous(am)SnO_(2) and its impact on the photoconversion efficiency of MAPbI3-based perovskite solar cells were investigated in detail.UVO treatment was found to increase the amount of chemisorbed oxygen on the am-SnO_(2) surface,reducing the surface energy and contact angle.Physicochemical changes in the am-SnO_(2) surface lowered the Gibbs free energy for the densification of perovskite films and facilitated the formation of homogeneous perovskite grains.In addition,the Fermi energy of the UVO-treated am-SnO_(2) shifted upwards to achieve an ideal band offset for MAPbI3,which was verified by theoretical calculations based on the density functional theory.We achieved a champion efficiency of 19.01% with a statistical reproducibility of 17.01±1.34% owing to improved perovskite film densification and enhanced charge transport/extraction,which is considerably higher than the 13.78±2.15% of the counterpart.Furthermore,UVO-treated,am-SnO_(2)-based devices showed improved stability and less hysteresis,which is encouraging for the future application of up-scaled perovskite solar cells.
文摘Broadband transparent films play a pivotal role in various applications such as lenses and solar cells,particularly porous structured transparent films exhibit significant potential.This study investigates a porous SiO_(2) refractive index gradient anti-reflective film prepared by atomic layer deposition(ALD).A porous SiO_(2) film with gradual porosity was obtained by phosphoric acid etching of Al_(2)O_(3)/SiO_(2) multilayers with gradient Al2O3 ratios,achieving a gradual decrease in refractive index from the substrate to the surface.The film exhibited an average transmittance as high as 97.8%within the wavelength range from 320 nm to 1200 nm.The environmental adaptability was further enhanced by surface modification using rare earth oxide(REO)La_(2)O_(3),resulting in formation of a lotus leaf-like structure and achieving a water contact angle of 100.0°.These data proved that the modification significantly improved hydrophobic self-cleaning capability while maintaining exceptional transparency of the film.The surface structure of the modified film remained undamaged even after undergoing wipe testing,demonstrating its excellent surface durability.
基金Supported by the ITER Project of the Ministry of Science and Technology of China under Grant No 2011GB113004the Shanghai Commission of Science and Technology under Grant Nos 09DZ1206000 and 11DZ1100402the Youth Fund of Natural Science Foundation of China under Grant No 11204174
文摘MgO thin films with different textures are fabricated by the ion beam assisted （IBAD） method on the Y2O3/Al2O3 buffered C276 tape. Then a CaO2 layer is directly grown on the IBAD-MgO film by the pulsed laser deposition （PLD） method. Effects of lBAD-MgO texture, substrata temperature and thickness on the grain alignment of the CeO2 layer are investigated. Film characterization is performed by x-ray diffraction and atomic force microscopy. It is found that the orientation and texture degree of the CaO2 layer are very sensitive to the IBAD-MgO texture. By optimizing the IBAD-MgO texture, CeO2 has pure （002） orientation and excellent biaxial texture deposited in a broad substrata temperature range. In addition, the PLD-CeO2 layer has a thickness effect. Under the optimized experimental condition, the PLD-CeO2 layer has a high in-plane texture of △φ = 2.9° and a smooth surface with an rms surface roughness of less than 2nm. The critical current density Jc of a 0.4μm-thick YBCO film deposited on the CeO2 layer is 6.25 × 106 A/cm2 at 77K and a self-field.
文摘Engineering an efficient interface is a trustworthy strategy for designing advanced photocatalytic systems for solar energy conversion.Herein,oxygen-deficient Bi_(2)WO_(6)atomic layers without organic residues were successfully fabricated via a facile solvothermal strategy by the multifunctional regulatory mechanism of introduced chloridion.Both DFT calculations and speciation determination revealed that chloridion displayed a more pronounced effect in the controllable synthesis of oxygen-deficient Bi_(2)WO_(6)atomic layers without organic residues:ultrathinning and defect-engineering.This built-in multi-cooperative interface endowed Bi_(2)WO_(6)with intriguing photoelectrochemical properties,O_(2) activation ability,and ultrahigh activity in visible-light powered deep oxidation of NO.A reasonable photocatalytic mechanism was proposed based on in situ infrared spectroscopy analysis and theoretical calculations.We believe that this multi-cooperative interface engineering of oxygen-deficient Bi_(2)WO_(6)atomic layers without organic residues could provide new insights into the design of two-dimensional(2D)layered materials with efficient active sites and pave the way for efficient NO photooxidation systems.
基金financial support from the National Natural Science Foundation of China(22439001,52172198,51902117)supported by the Innovation Fund of Wuhan National Laboratory for Optoelectronicsthe Analytical and Testing Center of Huazhong University of Science and Technology(HUST)for performing various characterizations。
文摘Modulating the interface between the electron transport layer(ETL)and perovskite to minimize interfacial recombination is pivotal for developing efficient and stable perovskite solar cells.Here,we introduce an ultra-thin ZrO_(2)insulating interface layer onto the inner surface of the mesoporous TiO_(2)ETL via the chemical bath deposition in the zirconium n-butoxide solution,which alters the interface characteristics between TiO_(2)and perovskite for the printable hole-conductor-free mesoscopic perovskite solar cells(p-MPSCs).The insulating ZrO_(2)interface layer reduces interface defects and suppresses interfacial non-radiative recombination.Furthermore,the ZrO_(2)interface layer improves the wettability of the mesoporous TiO_(2)ETL,which favors the crystallization of perovskite within the mesoporous scaffold.Meanwhile,the device performance presents thickness dependence on the interface layer.While increased thickness improves the open-circuit voltage,excessive thickness negatively impacts both the short-circuit current density and fill factor.Consequently,an improved power conversion efficiency of 19.9% was achieved for p-MPSCs with the ZrO_(2)interface layer at its optimized thickness.
基金supported by the National Natural Science Foundation of China(Nos.52272060,51902067,51872066 and 52172041)the Key Program of National Natural Science Foundation of China(No.52032003)+5 种基金the Young Elite Scientists Sponsorship Program by CAST(No.2020QNRC001)China Postdoctoral Science Foundation(Nos.2019M651282 and 2022T150157)Heilongjiang Provincial Postdoctoral Science Foundation(Nos.LBH-Z19022 and LBH-TZ2207)Heilongjiang Touyan Innovation Team Program,Shanghai Aerospace Science and Technology Innovation Fund(No.SAST2019-012)the Fundamental Research Funds for the Central Universities(No.FRFCU5710051022)the Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(No.JCKYS2022603C011).
文摘The rapid evolution of hypersonic vehicle technologies necessitates robust thermal protection systems capable of withstanding extreme oxidative ablation.This study introduces a novel gradient-architected ZrB_(2)-MoSi_(2)-SiC dense layer embedded within a lightweight three-dimensional(3D)needled carbon fiber composite.Utilizing the volatility of ethanol and polycarbosilane,the ceramic slurry is selectively infused into targeted regions of the fibrous structure,optimizing the ZrB_(2)to MoSi_(2)ratio to enhance performance.The resulting dense layer exhibits exceptional emissivity,surpassing 0.90 in the 1-3μm range and exceeding 0.87 in the 2-14μm range.Moreover,it demonstrates remarkable oxidative ablation resistance.Specifically,at an optimized ZrB_(2)to MoSi_(2)ratio of 6:4,the dense layer achieves a minimal linear ablation rate of 0.015μm·s^(-1) under a 1.5 MW·m^(-2)oxyacetylene flame for 1000 s.Even after exposure to oxyacetylene ablation at surface temperatures of approximately 1750℃for 1000 s,the dense layer retains its structural integrity,highlighting its enduring oxidation resistance.The incorporation of MoSi_(2)not only enhances emissivity but also fortifies the ZrO_(2)and SiO_(2)oxide layers,crucial for environments with elevated oxygen levels,thereby mitigating the active oxidation of SiC.This combination of high emissivity and long-term oxidation resistance at ultra-high temperatures positions the ZrB_(2)-MoSi_(2)-SiC dense layer as an exceptionally promising candidate for advanced thermal protection in hypersonic vehicles.
基金supported by the National Natural Science Foundation of China(21808214)Research Project Supported by Shanxi Scholarship Council of China(2023-126)Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(20220013)。
文摘Normally,a transparent inert film is coated on the surface of TiO_(2) particles to enhance the weatherability of the pigment.Liquid-phase coating process is mainly used in industry,which difficult to get really uniform films.This work combining nanoparticle fluidization technology with atomic layer deposition(ALD) technology to achieve precise surface modification of a large number of micro-nano particles.First,we explored the fluidization characteristics of TiO_(2) nanoparticles in a home-made atmospheric fluidized bed ALD reactor(FB-ALD) to ensure the uniform fluidization of a large number of nanoparticles.Then TiCl_(4) and H_(2)O were used as precursors to deposit amorphous TiO_(2) films on the surface of TiO_(2) nanoparticles at 80℃ under atmospheric pressure,and the growth per cycle was about 0.109 nm per cycle.After 30 ALD cycles,the film thickness was about 3.1 nm,which could almost fully suppress the photocatalytic activity of TiO_(2).Compared with other traditional coating materials,amorphous TiO_(2) has higher light refractive index,and realizes the suppression of the photocatalytic activity of TiO_(2) without introducing other substances,demonstrating greater application potential in TiO_(2) pigment coating field.The process is a gas-phase coating method,which is efficient,no waste water,and easy to scale up.This work shown the excellent property of interface engineering in improving pigment weatherability and can also provide guidance for the nanoparticle surface modification.
基金National Basic Research Program"973"of China(2006CB601005)National Natural Science Foundation of China(50771003)National High Technology Research and Development Program of"863"(2009AA032401)
文摘The metal organic deposition(MOD)method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer.The material phase and the macro-orientations were analyzed by XRD.The surface morphology and the blocking performance of the buffer layer were investigated by SEM and AES.The grain orientation and the crystallographic growth mode of the CeO2 layer were first characterized by electron backscattering diffraction(EBSD).The uniformly distributed islanded LZO seed layer optimized both the in-plan and the out-plan orientation of the CeO2/LZO buffer layers,and the CeO2/LZO buffer layers with a thickness of 175 nm acted as an efficient Ni,W barrier.The EBSD analysis indicated that the crystallographic orientation of each layer can be obtained at various accelerating voltages for the multilayer sample,the percentage of{001}<110>rotated cube texture of CeO2 layer reaching 97.4%at the accelerating voltage of 15 kV,thus showing epitaxial deposition with a high texture.
基金supported by the National Key R&D Program of China(Grant No.2019YFB1503201)the National Natural Science Foundation of China(Grant Nos.52172238,52102304,51902264,and 51902177)+3 种基金the Natural Science Foundation of Shanxi Province,China(Grant No.2020JM093)Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University(Grant No.2020GXLH-Z-014)Science Technology and Innovation Commission of Shenzhen Municipality(Grant No.JCYJ20190807111605472)the Fundamental Research Funds for the Central Universities,China(Grant Nos.3102019JC0005 and G2021KY05103)。
文摘The electron transport layer(ETL)plays an important role on the performance and stability of perovskite solar cells(PSCs).Developing double ETL is a promising strategy to take the advantages of different ETL materials and avoid their drawbacks.Here,an ultrathin SnO_(2)layer of~5 nm deposited by atomic layer deposit(ALD)was used to construct a TiO_(2)/SnO_(2)double ETL,improving the power conversion efficiency(PCE)from 18.02%to 21.13%.The ultrathin SnO_(2)layer enhances the electrical conductivity of the double layer ETLs and improves band alignment at the ETL/perovskite interface,promoting charge extraction and transfer.The ultrathin SnO_(2)layer also passivates the ETL/perovskite interface,suppressing nonradiative recombination.The double ETL achieves outstanding stability compared with PSCs with TiO_(2)only ETL.The PSCs with double ETL retains 85%of its initial PCE after 900 hours illumination.Our work demonstrates the prospects of using ultrathin metal oxide to construct double ETL for high-performance PSCs.
