With rapid advancement and deep integration of artificial intelligence and the internet-of-things,artificial intelligence of things has emerged as a promising technology changing people’s daily life.Massive growth of...With rapid advancement and deep integration of artificial intelligence and the internet-of-things,artificial intelligence of things has emerged as a promising technology changing people’s daily life.Massive growth of data generated from the devices challenges the AIoT systems from information collection,storage,processing and communication.In the review,we introduce volatile threshold switching memristors,which can be roughly classified into three types:metallic conductive filament-based TS devices,amorphous chalcogenide-based ovonic threshold switching devices,and metal-insulator transition based TS devices.They play important roles in high-density storage,energy efficient computing and hardware security for AIoT systems.Firstly,a brief introduction is exhibited to describe the categories(materials and characteristics)of volatile TS devices.And then,switching mechanisms of the three types of TS devices are discussed and systematically summarized.After that,attention is focused on the applications in 3D cross-point memory technology with high storage-density,efficient neuromorphic computing,hardware security(true random number generators and physical unclonable functions),and others(steep subthreshold slope transistor,logic devices,etc.).Finally,the major challenges and future outlook of volatile threshold switching memristors are presented.展开更多
The energy storage behaviors of MnO_(2) for aqueous Zn-MnO_(2) batteries mainly depend on the Zn^(2+)/H^(+)intercalation but are limited by poor ion/electron migration dynamics and stability.Herein,a strategy is propo...The energy storage behaviors of MnO_(2) for aqueous Zn-MnO_(2) batteries mainly depend on the Zn^(2+)/H^(+)intercalation but are limited by poor ion/electron migration dynamics and stability.Herein,a strategy is proposed that promoting proton migration kinetics ameliorates H^(+)storage activity by introducing Ni^(2+)intoγ-MnO_(2)(Ni-MnO_(2)).Ni^(2+)can lower the diffusion barrier of H^(+)and selectively induce the ion intercalation,thereby alleviating the electrostatic interaction with the lattice.Moreover,Ni^(2+)enables the adjacent[MnO6]octahedrons to have better electron conductivity.The Ni-MnO_(2) exhibits superior rate performance(nearly four times specific capacity compared with MnO_(2))and ultra-long-cycle stability(100%of capacity retention after 11000 cycles at 3.0 A g^(-1)).The calculation indicates that the Ni-MnO_(2) allows H^(+)migrate rapidly along the one-dimensional tunnel due to reduction of the activation energy caused by Ni^(2+)regulating,thus achieving excellent reaction kinetics.This work brings great potential for the development of high-performance aqueous Zn-MnO_(2) batteries.展开更多
Perovskite crystal facets greatly impact the performance and stability of their corresponding photovoltaic devices.Compared to the(001)facet,the(011)facet yields better photoelectric properties,including higher conduc...Perovskite crystal facets greatly impact the performance and stability of their corresponding photovoltaic devices.Compared to the(001)facet,the(011)facet yields better photoelectric properties,including higher conductivity and enhanced charge carrier mobility.Thus,achieving(011)facet-exposed films is a promising way to improve device performance.However,the growth of(011)facets is energetically unfavorable in FAPbI_(3) perovskites due to the influence of methylammonium chloride additive.Here,1-butyl-4-methylpyridinium chloride([4MBP]Cl)was used to expose(011)facets.The[4MBP]^(+)cation selectively decreases the surface energy of the(011)facet enabling the growth of the(011)plane.The[4MBP]^(+)cation causes the perovskite nuclei to rotate by 45°such that(011)crystal facets stack along the out-of-plane direction.The(011)facet has excellent charge transport properties and can achieve better-matched energy level alignment.In addition,[4MBP]Cl increases the activation energy barrier for ion migration,suppressing decomposition of the perovskite.As a result,a small-size device(0.06 cm2)and a module(29.0 cm2)based on exposure of the(011)facet achieved power conversion efficiencies of 25.24%and 21.12%,respectively.展开更多
Inspired by the recently predicted 2D MX_(2)Y_(6)(M=metal element;X=Si/Ge/Sn;Y=S/Se/Te),we explore the possible applications of alkaline earth metal(using magnesium as example)in this family based on the idea of eleme...Inspired by the recently predicted 2D MX_(2)Y_(6)(M=metal element;X=Si/Ge/Sn;Y=S/Se/Te),we explore the possible applications of alkaline earth metal(using magnesium as example)in this family based on the idea of element replacement and valence electron balance.Herein,we report a new family of 2D quaternary compounds,namely MgMX_(2)Y_(6)(M=Ti/Zr/Hf;X=Si/Ge;Y=S/Se/Te)monolayers,with superior kinetic,thermodynamic and mechanical stability.In addition,our results indicate that MgMX_(2)Y_(6)monolayers are all indirect band gap semiconductors with band gap values ranging from 0.870 to 2.500 eV.Moreover,the band edges and optical properties of 2D MgMX_(2)Y_(6)are suitable for constructing multifunctional optoelectronic devices.Furthermore,for comparison,the mechanical,electronic and optical properties of In_(2)X_(2)Y_(6)monolayers have been discussed in detail.The success of introducing Mg into the 2D MX_(2)Y_(6)family indicates that more potential materials,such as Caand Sr-based 2D MX_(2)Y_(6)monolayers,may be discovered in the future.Therefore,this work not only broadens the existing family of 2D semiconductors,but it also provides beneficial results for the future.展开更多
Sparse coding is a prevalent method for image inpainting and feature extraction,which can repair corrupted images or improve data processing efficiency,and has numerous applications in computer vision and signal proce...Sparse coding is a prevalent method for image inpainting and feature extraction,which can repair corrupted images or improve data processing efficiency,and has numerous applications in computer vision and signal processing.Recently,sev-eral memristor-based in-memory computing systems have been proposed to enhance the efficiency of sparse coding remark-ably.However,the variations and low precision of the devices will deteriorate the dictionary,causing inevitable degradation in the accuracy and reliability of the application.In this work,a digital-analog hybrid memristive sparse coding system is pro-posed utilizing a multilevel Pt/Al_(2)O_(3)/AlO_(x)/W memristor,which employs the forward stagewise regression algorithm:The approxi-mate cosine distance calculation is conducted in the analog part to speed up the computation,followed by high-precision coeffi-cient updates performed in the digital portion.We determine that four states of the aforementioned memristor are sufficient for the processing of natural images.Furthermore,through dynamic adjustment of the mapping ratio,the precision require-ment for the digit-to-analog converters can be reduced to 4 bits.Compared to the previous system,our system achieves higher image reconstruction quality of the 38 dB peak-signal-to-noise ratio.Moreover,in the context of image inpainting,images containing 50%missing pixels can be restored with a reconstruction error of 0.0424 root-mean-squared error.展开更多
Under the complex external reaction conditions,uncovering the true structural evolution of the catalyst is of profound significance for the establishment of relevant structure–activity relationships and the rational ...Under the complex external reaction conditions,uncovering the true structural evolution of the catalyst is of profound significance for the establishment of relevant structure–activity relationships and the rational design of electrocatalysts.Here,the surface reconstruction of the catalyst was characterized by ex-situ methods and in-situ Raman spectroscopy in CO_(2)electroreduction.The final results showed that the Bi_(2)O_(3) nanoparticles were transformed into Bi/Bi_(2)O_(3) two-dimensional thin-layer nanosheets(NSs).It is considered to be the active phase in the electrocatalytic process.The Bi/Bi_(2)O_(3) NSs showed good catalytic performance with a Faraday efficiency(FE)of 94.8%for formate and a current density of 26 mA cm^(−2) at−1.01 V.While the catalyst maintained a 90%FE in a wide potential range(−0.91 V to−1.21 V)and long-term stability(24 h).Theoretical calculations support the theory that the excellent performance originates from the enhanced bonding state of surface Bi-Bi,which stabilized the adsorption of the key intermediate OCHO^(∗) and thus promoted the production of formate.展开更多
Increasing both clean water and green energy demands for survival and development are the grand challenges of our age.Here,we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane(3D-GCM)...Increasing both clean water and green energy demands for survival and development are the grand challenges of our age.Here,we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane(3D-GCM)with active metal nanoparticles(AMNs)loading for simultaneously obtaining the water purification and clean energy generation,via a“green”one-step laser scribing technology.The as-prepared 3D-GCM shows high porosity and uniform distribution with AMNs,which exhibits high permeated fluxes(over 100 L m^(−2) h^(−1))and versatile super-adsorption capacities for the removal of tricky organic pollutants from wastewater under ultra-low pressure-driving(0.1 bar).After adsorption saturating,the AMNs in 3D-GCM actuates the advanced oxidization process to self-clean the fouled membrane via the catalysis,and restores the adsorption capacity well for the next time membrane separation.Most importantly,the 3D-GCM with the welding of laser scribing overcomes the lateral shear force damaging during the long-term separation.Moreover,the 3D-GCM could emit plentiful of hot electrons from AMNs under light irradiation,realizing the membrane catalytic hydrolysis reactions for hydrogen energy generation.This“green”precision manufacturing with laser scribing technology provides a feasible technology to fabricate high-efficient and robust 3D-GCM microreactor in the tricky wastewater purification and sustainable clean energy production as well.展开更多
Atmospheric water harvesting offers a powerful and promising solution to address the problem of global freshwater scarcity.In the past decade,significant progress has been achieved in utilizing hydrolytically stable m...Atmospheric water harvesting offers a powerful and promising solution to address the problem of global freshwater scarcity.In the past decade,significant progress has been achieved in utilizing hydrolytically stable metal-organic frameworks as recyclable water-sorbent materials under low relative humidity,especially in those arid areas.Recently,Yaghi's group has employed a combined crystallographic and theoretical technique to decipher the water filling mechanism in MOF-303,where the polar organic linkers rather than the inorganic units of MOF are demonstrated as the key factor.Hence,the hydrophilic strength of the water-binding pocket in MOFs can be optimized through the approach of multivariate modulations,resulting in enhanced water harvesting properties.展开更多
Similarity search,that is,finding similar items in massive data,is a fundamental computing problem in many fields such as data mining and information retrieval.However,for large-scale and high-dimension data,it suffer...Similarity search,that is,finding similar items in massive data,is a fundamental computing problem in many fields such as data mining and information retrieval.However,for large-scale and high-dimension data,it suffers from high computational complexity,requiring tremendous computation resources.Here,based on the low-power self-selective memristors,for the first time,we propose an in-memory search(IMS)system with two innovative designs.First,by exploiting the natural distribution law of the devices resistance,a hardware locality sensitive hashing encoder has been designed to transform the realvalued vectors into more efficient binary codes.Second,a compact memristive ternary content addressable memory is developed to calculate the Hamming distances between the binary codes in parallel.Our IMS system demonstrated a 168energy efficiency improvement over all-transistors counterparts in clustering and classification tasks,while achieving a software-comparable accuracy,thus providing a low-complexity and low-power solution for in-memory data mining applications.展开更多
The recent development of three-dimensional semiconductor integration technology demands a key component-the ovonic threshold switching(OTS)selector to suppress the current leakage in the high-density memory chips.Yet...The recent development of three-dimensional semiconductor integration technology demands a key component-the ovonic threshold switching(OTS)selector to suppress the current leakage in the high-density memory chips.Yet,the unsatisfactory performance of existing OTS materials becomes the bottleneck of the industrial advancement.The sluggish development of OTS materials,which are usually made from chalcogenide glass,should be largely attributed to the insufficient understanding of the electronic structure in these materials,despite of intensive research in the past decade.Due to the heavy first-principles computation on disordered systems,a universal theory to explain the origin of mid-gap states(MGS),which are the key feature leading to the OTS behavior,is still lacking.To avoid the formidable computational tasks,we adopt machine learning method to understand and predict MGS in typical OTS materials.We build hundreds of chalcogenide glass models and collect major structural features from both short-range order(SRO)and medium-range order(MRO)of the amorphous cells.After training the artificial neural network using these features,the accuracy has reached~95%when it recognizes MGS in new glass.By analyzing the synaptic weights of the input structural features,we discover that the bonding and coordination environments from SRO and particularly MRO are closely related to MGS.The trained model could be used in many other OTS chalcogenides after minor modification.The intelligent machine learning allows us to understand the OTS mechanism from vast amount of structural data without heavy computational tasks,providing a new strategy to design functional amorphous materials from first principles.展开更多
In this letter,the Ti-doped NbO_(x)-based selector is applied to SiNOx-based resistive random-access memory(RRAM),forming Pt/NbOx(Ti-doped)/SiNO_(x)/Ti one selector-one RRAM device(1S1R),to suppress the sneak path cur...In this letter,the Ti-doped NbO_(x)-based selector is applied to SiNOx-based resistive random-access memory(RRAM),forming Pt/NbOx(Ti-doped)/SiNO_(x)/Ti one selector-one RRAM device(1S1R),to suppress the sneak path current.The fabricated 1S1R exhibits stable direct current(DC)endurance(>200 cycles),suitable memory window(>40),matched selectivity(>40)and high uniformity of switching parameters.展开更多
With the rapid growth of computer science and big data,the traditional von Neumann architecture suffers the aggravating data communication costs due to the separated structure of the processing units and memories.Memr...With the rapid growth of computer science and big data,the traditional von Neumann architecture suffers the aggravating data communication costs due to the separated structure of the processing units and memories.Memristive in-memory computing paradigm is considered as a prominent candidate to address these issues,and plentiful applications have been demonstrated and verified.These applications can be broadly categorized into two major types:soft computing that can tolerant uncertain and imprecise results,and hard computing that emphasizes explicit and precise numerical results for each task,leading to different requirements on the computational accuracies and the corresponding hardware solutions.In this review,we conduct a thorough survey of the recent advances of memristive in-memory computing applications,both on the soft computing type that focuses on artificial neural networks and other machine learning algorithms,and the hard computing type that includes scientific computing and digital image processing.At the end of the review,we discuss the remaining challenges and future opportunities of memristive in-memory computing in the incoming Artificial Intelligence of Things era.展开更多
水系可充电锌/二氧化锰电池因其成本低廉、能量密度高而引起了广泛关注.然而,缓慢的反应动力学和MnO_(2)阴极的歧化反应以及不可逆的相变现象对其发展造成了严重阻碍.在此,我们选用了Mo掺杂α-MnO_(2)(Mo–MnO_(2))作为阴极材料,通过铵...水系可充电锌/二氧化锰电池因其成本低廉、能量密度高而引起了广泛关注.然而,缓慢的反应动力学和MnO_(2)阴极的歧化反应以及不可逆的相变现象对其发展造成了严重阻碍.在此,我们选用了Mo掺杂α-MnO_(2)(Mo–MnO_(2))作为阴极材料,通过铵根离子插层机制所形成的N–H···O强键合作用来稳定Mo–MnO_(2)的2×2隧道结构,并且有效抑制了Mn^(3+)溶解,在质子插入/脱出过程中不会引起晶格的畸变,进一步提高了其循环稳定性.获得的Mo–MnO_(2)正极在100 mA g^(−1)时表现出265.2 mA h g^(−1)的高比容量和364.3 W h kg^(−1)的能量密度.在2.0 A g^(−1)下1000次循环后,容量保持率达95.2%.这项工作有助于深入了解非金属阳离子在电极主体材料间的键合作用,为设计具有高能量密度和长期循环能力的水系锌离子电池提供了新思路.展开更多
Finding and designing cathode oxygen reduction reaction(ORR) catalysts with high activity and stability in acidic electrolyte is essential for the large-scale application of fuel cells and metal-air batteries.Pt-based...Finding and designing cathode oxygen reduction reaction(ORR) catalysts with high activity and stability in acidic electrolyte is essential for the large-scale application of fuel cells and metal-air batteries.Pt-based alloys have emerged as potential electrocatalysts for the oxygen reduction reaction.Herein,we adapted a simple pyrolytic reduction method to grow FePt nanoalloys on hollow mesoporous carbon supports.Benefiting from the ultra-high specific surface of the hollow mesoporous carbon,the in situ formed FePt NPs were homogenously deposited on the carbon supports with size smaller than5 nm.The optimized FePt-HMCS showed a remarkably increased mass activity(MA) of 0.582 A·mg^(-1)_(Pt) at 0.75 V in ORR,being 6.3 times higher than that of commercial Pt/C(0.093 A·mg^(-1)_(Pt)).Meanwhile,the FePt NPs showed negligible decay in mass activity with 21 mV of negative shift in the half-wave potential after 5000 electrochemical cycles,which is more stable than that of commercial Pt/C(6.6% decay in MA with 30 mV of negative shift).The study demonstrated a simple strategy for controlling the alloy size with enhanced metal-support interactions to boost their promising application in fuel cells.展开更多
Covalent organic framework(COF)nanocrystals are useful in biological applications;however,their hydrophobic nature makes them aggregate into clusters in aqueous media.In this work,we show that by modifying the crystal...Covalent organic framework(COF)nanocrystals are useful in biological applications;however,their hydrophobic nature makes them aggregate into clusters in aqueous media.In this work,we show that by modifying the crystal surface with hydrophilic functional groups,these nanocrystals can maintain in the monodispersed form in aqueous solution.Specifically,three COFs,TPB-DMTP COF,TAPB-PDA COF and TAPB-BPDA COF were synthesized using organic Lewis acid as the catalyst,to generate nanoparticles with the size ranging from 180 nm to 1μm.2-Aminoethanesulfonic acid(AESA)was applied to react with the terminal aldehyde functional groups exposed at the surface of COF nanocrystals.The resulting negatively charged surface keeps these nanocrystals apart from each other in aqueous solution for at least 48 h.The mesopore of these COF nanocrystals allows the entering of single-strand DNA molecules and the release in the presence of complementary DNA.展开更多
基金supported by the STI 2030—Major Projects(Grant No.2021ZD0201201)National Natural Science Foundation of China(Grant No.92064012)Hubei Province Postdoctoral Innovation Research Program(Grant No.0106182103)。
文摘With rapid advancement and deep integration of artificial intelligence and the internet-of-things,artificial intelligence of things has emerged as a promising technology changing people’s daily life.Massive growth of data generated from the devices challenges the AIoT systems from information collection,storage,processing and communication.In the review,we introduce volatile threshold switching memristors,which can be roughly classified into three types:metallic conductive filament-based TS devices,amorphous chalcogenide-based ovonic threshold switching devices,and metal-insulator transition based TS devices.They play important roles in high-density storage,energy efficient computing and hardware security for AIoT systems.Firstly,a brief introduction is exhibited to describe the categories(materials and characteristics)of volatile TS devices.And then,switching mechanisms of the three types of TS devices are discussed and systematically summarized.After that,attention is focused on the applications in 3D cross-point memory technology with high storage-density,efficient neuromorphic computing,hardware security(true random number generators and physical unclonable functions),and others(steep subthreshold slope transistor,logic devices,etc.).Finally,the major challenges and future outlook of volatile threshold switching memristors are presented.
基金supported by the National Natural Science Foundation of China(No.52002122)the Science and Technology Department of Hubei Province(No.2019AAA038)+1 种基金the Project funded by China Postdoctoral Science Foundation(No.2021M690947)the Wuhan Yellow Crane Talent Program(No.2017-02).
文摘The energy storage behaviors of MnO_(2) for aqueous Zn-MnO_(2) batteries mainly depend on the Zn^(2+)/H^(+)intercalation but are limited by poor ion/electron migration dynamics and stability.Herein,a strategy is proposed that promoting proton migration kinetics ameliorates H^(+)storage activity by introducing Ni^(2+)intoγ-MnO_(2)(Ni-MnO_(2)).Ni^(2+)can lower the diffusion barrier of H^(+)and selectively induce the ion intercalation,thereby alleviating the electrostatic interaction with the lattice.Moreover,Ni^(2+)enables the adjacent[MnO6]octahedrons to have better electron conductivity.The Ni-MnO_(2) exhibits superior rate performance(nearly four times specific capacity compared with MnO_(2))and ultra-long-cycle stability(100%of capacity retention after 11000 cycles at 3.0 A g^(-1)).The calculation indicates that the Ni-MnO_(2) allows H^(+)migrate rapidly along the one-dimensional tunnel due to reduction of the activation energy caused by Ni^(2+)regulating,thus achieving excellent reaction kinetics.This work brings great potential for the development of high-performance aqueous Zn-MnO_(2) batteries.
基金This work was funded by the European Union’s Horizon 2020 program,through a FET Proactive research and innovation action under grant agreement No.101084124(DIAMOND)supported by the 111 Project(B16016),and the Project of Scientific and Technological Support Program in Jiang Su Province(BE2022026-2)+2 种基金K.Z.thanks to the China Scholarship Council(no.202206730056)X.F.Z.thanks to the China Scholarship Council(no.202206730058)R.W.acknowledges the grant(LD22E020002)by the Natural Science Foundation of Zhejiang Province of China.
文摘Perovskite crystal facets greatly impact the performance and stability of their corresponding photovoltaic devices.Compared to the(001)facet,the(011)facet yields better photoelectric properties,including higher conductivity and enhanced charge carrier mobility.Thus,achieving(011)facet-exposed films is a promising way to improve device performance.However,the growth of(011)facets is energetically unfavorable in FAPbI_(3) perovskites due to the influence of methylammonium chloride additive.Here,1-butyl-4-methylpyridinium chloride([4MBP]Cl)was used to expose(011)facets.The[4MBP]^(+)cation selectively decreases the surface energy of the(011)facet enabling the growth of the(011)plane.The[4MBP]^(+)cation causes the perovskite nuclei to rotate by 45°such that(011)crystal facets stack along the out-of-plane direction.The(011)facet has excellent charge transport properties and can achieve better-matched energy level alignment.In addition,[4MBP]Cl increases the activation energy barrier for ion migration,suppressing decomposition of the perovskite.As a result,a small-size device(0.06 cm2)and a module(29.0 cm2)based on exposure of the(011)facet achieved power conversion efficiencies of 25.24%and 21.12%,respectively.
基金supported by the National Natural Science Foundation of China (Grant No. 61974049, 62222404 61974050)National Key Research and Development Plan of China (Grant No. 2021YFB3601200)
文摘Inspired by the recently predicted 2D MX_(2)Y_(6)(M=metal element;X=Si/Ge/Sn;Y=S/Se/Te),we explore the possible applications of alkaline earth metal(using magnesium as example)in this family based on the idea of element replacement and valence electron balance.Herein,we report a new family of 2D quaternary compounds,namely MgMX_(2)Y_(6)(M=Ti/Zr/Hf;X=Si/Ge;Y=S/Se/Te)monolayers,with superior kinetic,thermodynamic and mechanical stability.In addition,our results indicate that MgMX_(2)Y_(6)monolayers are all indirect band gap semiconductors with band gap values ranging from 0.870 to 2.500 eV.Moreover,the band edges and optical properties of 2D MgMX_(2)Y_(6)are suitable for constructing multifunctional optoelectronic devices.Furthermore,for comparison,the mechanical,electronic and optical properties of In_(2)X_(2)Y_(6)monolayers have been discussed in detail.The success of introducing Mg into the 2D MX_(2)Y_(6)family indicates that more potential materials,such as Caand Sr-based 2D MX_(2)Y_(6)monolayers,may be discovered in the future.Therefore,this work not only broadens the existing family of 2D semiconductors,but it also provides beneficial results for the future.
基金This work was supported by the National Key R&D Program of China(Grant No.2019YFB2205100)in part by Hubei Key Laboratory of Advanced Memories.
文摘Sparse coding is a prevalent method for image inpainting and feature extraction,which can repair corrupted images or improve data processing efficiency,and has numerous applications in computer vision and signal processing.Recently,sev-eral memristor-based in-memory computing systems have been proposed to enhance the efficiency of sparse coding remark-ably.However,the variations and low precision of the devices will deteriorate the dictionary,causing inevitable degradation in the accuracy and reliability of the application.In this work,a digital-analog hybrid memristive sparse coding system is pro-posed utilizing a multilevel Pt/Al_(2)O_(3)/AlO_(x)/W memristor,which employs the forward stagewise regression algorithm:The approxi-mate cosine distance calculation is conducted in the analog part to speed up the computation,followed by high-precision coeffi-cient updates performed in the digital portion.We determine that four states of the aforementioned memristor are sufficient for the processing of natural images.Furthermore,through dynamic adjustment of the mapping ratio,the precision require-ment for the digit-to-analog converters can be reduced to 4 bits.Compared to the previous system,our system achieves higher image reconstruction quality of the 38 dB peak-signal-to-noise ratio.Moreover,in the context of image inpainting,images containing 50%missing pixels can be restored with a reconstruction error of 0.0424 root-mean-squared error.
基金the National Natural Science Foundation of China(12025503,U1932134,U1867215 and 12105208)the Fundamental Research Funds for the Central Universities(2042021kf0068,2042022kf1181)China Postdoctoral Science Foundation(No.2020M682469)。
文摘Under the complex external reaction conditions,uncovering the true structural evolution of the catalyst is of profound significance for the establishment of relevant structure–activity relationships and the rational design of electrocatalysts.Here,the surface reconstruction of the catalyst was characterized by ex-situ methods and in-situ Raman spectroscopy in CO_(2)electroreduction.The final results showed that the Bi_(2)O_(3) nanoparticles were transformed into Bi/Bi_(2)O_(3) two-dimensional thin-layer nanosheets(NSs).It is considered to be the active phase in the electrocatalytic process.The Bi/Bi_(2)O_(3) NSs showed good catalytic performance with a Faraday efficiency(FE)of 94.8%for formate and a current density of 26 mA cm^(−2) at−1.01 V.While the catalyst maintained a 90%FE in a wide potential range(−0.91 V to−1.21 V)and long-term stability(24 h).Theoretical calculations support the theory that the excellent performance originates from the enhanced bonding state of surface Bi-Bi,which stabilized the adsorption of the key intermediate OCHO^(∗) and thus promoted the production of formate.
基金supported by the National Scientific Foundation of China(No.61974050,61704061,51805184,61974049)Key Laboratory of Non-ferrous Metals and New Materials Processing Technology of Ministry of Education/Guangxi Key Laboratory of Optoelectronic Materials and Devices open Fund(20KF-9)+2 种基金the Natural Science Foundation of Hunan Province of China(No.2018TP2003)Excellent youth project of Hunan Provincial Department of Education(No.18B111)State Key Laboratory of Crop Germplasm Innovation and Resource Utilization(No.17KFXN02).The authors thank the technical support from Analytical and Testing Center at Huazhong University of Science and Technology.
文摘Increasing both clean water and green energy demands for survival and development are the grand challenges of our age.Here,we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane(3D-GCM)with active metal nanoparticles(AMNs)loading for simultaneously obtaining the water purification and clean energy generation,via a“green”one-step laser scribing technology.The as-prepared 3D-GCM shows high porosity and uniform distribution with AMNs,which exhibits high permeated fluxes(over 100 L m^(−2) h^(−1))and versatile super-adsorption capacities for the removal of tricky organic pollutants from wastewater under ultra-low pressure-driving(0.1 bar).After adsorption saturating,the AMNs in 3D-GCM actuates the advanced oxidization process to self-clean the fouled membrane via the catalysis,and restores the adsorption capacity well for the next time membrane separation.Most importantly,the 3D-GCM with the welding of laser scribing overcomes the lateral shear force damaging during the long-term separation.Moreover,the 3D-GCM could emit plentiful of hot electrons from AMNs under light irradiation,realizing the membrane catalytic hydrolysis reactions for hydrogen energy generation.This“green”precision manufacturing with laser scribing technology provides a feasible technology to fabricate high-efficient and robust 3D-GCM microreactor in the tricky wastewater purification and sustainable clean energy production as well.
基金supported by the National Natural Science Foundation of China(Grant Nos.21471118,21971199,22025106,51202127,91545205,and 91622103)National Key Research and Development Project of China(2018YFA0704000)+1 种基金Natural Science Foundation of Hubei Province(2016CFB382)Fundamental Research Funds for the Central Universities(2042017kf0227,2042019kf0205)。
文摘Atmospheric water harvesting offers a powerful and promising solution to address the problem of global freshwater scarcity.In the past decade,significant progress has been achieved in utilizing hydrolytically stable metal-organic frameworks as recyclable water-sorbent materials under low relative humidity,especially in those arid areas.Recently,Yaghi's group has employed a combined crystallographic and theoretical technique to decipher the water filling mechanism in MOF-303,where the polar organic linkers rather than the inorganic units of MOF are demonstrated as the key factor.Hence,the hydrophilic strength of the water-binding pocket in MOFs can be optimized through the approach of multivariate modulations,resulting in enhanced water harvesting properties.
基金National Key Research and Development Plan of MOST of China,Grant/Award Numbers:2019YFB2205100,2021ZD0201201National Natural Science Foundation of China,Grant/Award Number:92064012+1 种基金Hubei Engineering Research Center on MicroelectronicsChua Memristor Institute。
文摘Similarity search,that is,finding similar items in massive data,is a fundamental computing problem in many fields such as data mining and information retrieval.However,for large-scale and high-dimension data,it suffers from high computational complexity,requiring tremendous computation resources.Here,based on the low-power self-selective memristors,for the first time,we propose an in-memory search(IMS)system with two innovative designs.First,by exploiting the natural distribution law of the devices resistance,a hardware locality sensitive hashing encoder has been designed to transform the realvalued vectors into more efficient binary codes.Second,a compact memristive ternary content addressable memory is developed to calculate the Hamming distances between the binary codes in parallel.Our IMS system demonstrated a 168energy efficiency improvement over all-transistors counterparts in clustering and classification tasks,while achieving a software-comparable accuracy,thus providing a low-complexity and low-power solution for in-memory data mining applications.
基金supported by the Natural Science Foundation of Hubei Province (2022CFB402)the Science and Technology Major Project of Wuhan (2021012002023423)the Science and Technology Major Project of Hubei (2022AEA001)。
基金National Key R&D Plan of China(Grant No.2019YFB2205100,2017YFB0701700)National Science and Technology Major Project of China(Grant No.2017ZX02301007-002)+2 种基金National Natural Science Foundation of China(Grant No.62174060)Fundamental Research Funds for the Central Universities,HUST(No.2021GCRC051)Hubei Key Laboratory of Advanced Memories.
文摘The recent development of three-dimensional semiconductor integration technology demands a key component-the ovonic threshold switching(OTS)selector to suppress the current leakage in the high-density memory chips.Yet,the unsatisfactory performance of existing OTS materials becomes the bottleneck of the industrial advancement.The sluggish development of OTS materials,which are usually made from chalcogenide glass,should be largely attributed to the insufficient understanding of the electronic structure in these materials,despite of intensive research in the past decade.Due to the heavy first-principles computation on disordered systems,a universal theory to explain the origin of mid-gap states(MGS),which are the key feature leading to the OTS behavior,is still lacking.To avoid the formidable computational tasks,we adopt machine learning method to understand and predict MGS in typical OTS materials.We build hundreds of chalcogenide glass models and collect major structural features from both short-range order(SRO)and medium-range order(MRO)of the amorphous cells.After training the artificial neural network using these features,the accuracy has reached~95%when it recognizes MGS in new glass.By analyzing the synaptic weights of the input structural features,we discover that the bonding and coordination environments from SRO and particularly MRO are closely related to MGS.The trained model could be used in many other OTS chalcogenides after minor modification.The intelligent machine learning allows us to understand the OTS mechanism from vast amount of structural data without heavy computational tasks,providing a new strategy to design functional amorphous materials from first principles.
基金financially supported by the National Natural Science Foundation of China(No.61904050)the Science and Technology Major Project of Hubei(Nos.2020AAA005 and 2020AEA017)+1 种基金the Scientific Research Project of Education Department of Hubei Province(No.Q20181009)Hubei Key Laboratory of Advanced Memories。
文摘In this letter,the Ti-doped NbO_(x)-based selector is applied to SiNOx-based resistive random-access memory(RRAM),forming Pt/NbOx(Ti-doped)/SiNO_(x)/Ti one selector-one RRAM device(1S1R),to suppress the sneak path current.The fabricated 1S1R exhibits stable direct current(DC)endurance(>200 cycles),suitable memory window(>40),matched selectivity(>40)and high uniformity of switching parameters.
基金This work was financially supported by the National Key R&D Program of China(Nos.2019YFB2205100 and 2021ZD0201201)the National Natural Science Foundation of China(Grant Nos.92064012 and 61874164).
文摘With the rapid growth of computer science and big data,the traditional von Neumann architecture suffers the aggravating data communication costs due to the separated structure of the processing units and memories.Memristive in-memory computing paradigm is considered as a prominent candidate to address these issues,and plentiful applications have been demonstrated and verified.These applications can be broadly categorized into two major types:soft computing that can tolerant uncertain and imprecise results,and hard computing that emphasizes explicit and precise numerical results for each task,leading to different requirements on the computational accuracies and the corresponding hardware solutions.In this review,we conduct a thorough survey of the recent advances of memristive in-memory computing applications,both on the soft computing type that focuses on artificial neural networks and other machine learning algorithms,and the hard computing type that includes scientific computing and digital image processing.At the end of the review,we discuss the remaining challenges and future opportunities of memristive in-memory computing in the incoming Artificial Intelligence of Things era.
基金supported by the National Key Research and Development Program of China(2021YFA1200500)the National Natural Science Foundation of China(61925402,62090032,62104039,and 62304042)+5 种基金the Science and Technology Commission of Shanghai Municipality(19JC1416600)China Postdoctoral Science Foundation(2022M720032)Shanghai Post-Doctoral Excellence Program(2022091)Sailing Program(23YF1402100)the Natural Science Foundation of Shanghai(21ZR1405700)the Shanghai Science and Technology Commission “Explorer Project”(22TS1401500)。
基金supported in part by the National Science and Technology Major Project of China(2017ZX02301007-002)Xu M acknowledges the National Natural Science Foundation of China(62174060)Miao X acknowledges the funding for Hubei Key Laboratory of Advanced Memories。
基金supported by the National Natural Science Foundation of China(22109163 and 52002122)China Postdoctoral Science Foundation(2021M690947).
文摘水系可充电锌/二氧化锰电池因其成本低廉、能量密度高而引起了广泛关注.然而,缓慢的反应动力学和MnO_(2)阴极的歧化反应以及不可逆的相变现象对其发展造成了严重阻碍.在此,我们选用了Mo掺杂α-MnO_(2)(Mo–MnO_(2))作为阴极材料,通过铵根离子插层机制所形成的N–H···O强键合作用来稳定Mo–MnO_(2)的2×2隧道结构,并且有效抑制了Mn^(3+)溶解,在质子插入/脱出过程中不会引起晶格的畸变,进一步提高了其循环稳定性.获得的Mo–MnO_(2)正极在100 mA g^(−1)时表现出265.2 mA h g^(−1)的高比容量和364.3 W h kg^(−1)的能量密度.在2.0 A g^(−1)下1000次循环后,容量保持率达95.2%.这项工作有助于深入了解非金属阳离子在电极主体材料间的键合作用,为设计具有高能量密度和长期循环能力的水系锌离子电池提供了新思路.
基金financially supported by the National Natural Science Foundation of China (No.22174133)。
文摘Finding and designing cathode oxygen reduction reaction(ORR) catalysts with high activity and stability in acidic electrolyte is essential for the large-scale application of fuel cells and metal-air batteries.Pt-based alloys have emerged as potential electrocatalysts for the oxygen reduction reaction.Herein,we adapted a simple pyrolytic reduction method to grow FePt nanoalloys on hollow mesoporous carbon supports.Benefiting from the ultra-high specific surface of the hollow mesoporous carbon,the in situ formed FePt NPs were homogenously deposited on the carbon supports with size smaller than5 nm.The optimized FePt-HMCS showed a remarkably increased mass activity(MA) of 0.582 A·mg^(-1)_(Pt) at 0.75 V in ORR,being 6.3 times higher than that of commercial Pt/C(0.093 A·mg^(-1)_(Pt)).Meanwhile,the FePt NPs showed negligible decay in mass activity with 21 mV of negative shift in the half-wave potential after 5000 electrochemical cycles,which is more stable than that of commercial Pt/C(6.6% decay in MA with 30 mV of negative shift).The study demonstrated a simple strategy for controlling the alloy size with enhanced metal-support interactions to boost their promising application in fuel cells.
基金supported by the National Natural Science Foundation of China(NSFC)(22025106 and 21971199)the National Key Research and Development Program of China(2022YFA1502902)。
文摘Covalent organic framework(COF)nanocrystals are useful in biological applications;however,their hydrophobic nature makes them aggregate into clusters in aqueous media.In this work,we show that by modifying the crystal surface with hydrophilic functional groups,these nanocrystals can maintain in the monodispersed form in aqueous solution.Specifically,three COFs,TPB-DMTP COF,TAPB-PDA COF and TAPB-BPDA COF were synthesized using organic Lewis acid as the catalyst,to generate nanoparticles with the size ranging from 180 nm to 1μm.2-Aminoethanesulfonic acid(AESA)was applied to react with the terminal aldehyde functional groups exposed at the surface of COF nanocrystals.The resulting negatively charged surface keeps these nanocrystals apart from each other in aqueous solution for at least 48 h.The mesopore of these COF nanocrystals allows the entering of single-strand DNA molecules and the release in the presence of complementary DNA.
基金supported by the National Natural Science Foundation of China(62174065)the Key Research and Development Plan of Hubei Province(2020BAB007)+1 种基金Hubei Provincial Natural Science Foundation(2021CFA038)the support from Hubei Key Laboratory of Advanced Memories&Hubei Engineering Research Center on Microelectronics。
