Pyridinic-N doping carbon layers coupled with tensile strain of FeNi alloy for activating water and urea oxidation

Exploitation of oxygen evolution reaction(OER)and urea oxidation reaction(UOR)catalysts with high activity and stability at large current density is a major challenge for energy-saving H_(2) production in water electrolysis.Herein,we use the pyridinic-N doping carbon layers coupled with tensile strain of FeNi alloy activated by NiFe_(2)O_(4)(FeNi/NiFe_(2)O_(4)@NC)for efficiently increasing the performance of water and urea oxidation.Due to the tensile strain effect on FeNi/NiFe_(2)O_(4)@NC,it provides a favorable modulation on the electronic properties of the active center,thus enabling amazing OER(η_(100)=196 mV)and UOR(E_(10)=1.32 V)intrinsic activity.Besides,the carbon-coated layers can be used as armor to prevent FeNi alloy from being corroded by the electrolyte for enhancing the OER/UOR stability at large current density,showing high industrial practicability.This work thus provides a simple way to prepare high-efficiency catalyst for activating water and urea oxidation.

Turnip mosaic virus pathogenesis and host resistance mechanisms in Brassica

Turnip mosaic virus(TuMV)is a devastating potyvirus pathogen that infects a wide variety of both cultivated and wild Brassicaceae plants.We urgently need more information and understanding of TuMV pathogenesis and the host responses involved in disease development in cruciferous crops.TuMV displays great versatility in viral pathogenesis,especially in its replication and intercellular movement.Moreover,in the coevolutionary arms races between TuMV and its hosts,the virus has evolved to co-opt host factors to facilitate its infection and counter host defense responses.This review mainly focuses on recent advances in understanding the viral factors that contribute to the TuMV infection cycle and the host resistance mechanism in Brassica.Finally,we propose some future research directions on TuMV pathogenesis and control strategies to design durable TuMV-resistant Brassica crops.

Coupling interface engineering with electronic interaction toward high-efficiency H_(2) evolution in pH-universal electrolytes

Herein,the merits of heterojunction,CeO_(2),and W are employed to design and prepare the PtCoW@CeO_(2)heterojunction catalyst,which can accelerate water dissociation and improve the desorption of OHad,displaying efficient hydrogen evolution reaction(HER)performance in pH-universal conditions.Density functional theory calculation results reveal that the electronic structure of Pt is regulated by CeO_(2)and W,which tunes the Pt-Hadbond strength to boost HER intrinsic activity.Consequently,electrochemical results display that it has low potentials of-26,-25,and-23 mV at-10 mA cm^(-2)in alkaline,neutral,and acidic solutions,respectively,and it can stably cycle for 50,000 cycles.Thus,this work provides the guidance for developing high-performance Pt-based catalysts in pH-universal environments.

Tailoring the selective adsorption sites of NiMoO by Ni particles for biomass upgrading assisted hydrogen production

5-Hydroxymethylfurfural electrooxidation reaction(HMFOR)is a promising route to produce valueadded chemicals from biomass.Since it involves HMF adsorption and C-H/O-H cleavage,understanding the adsorption behavior and catalytic process of organic molecules on catalysts is important.Herein,the selective adsorption sites of NiMoO are tuned by Ni particles for HMFOR-assisted H2production.Experimental and theoretical calculation results indicate that the synergistic interaction between Ni and NiMoO optimizes the adsorption/desorption of HMF/intermediates/2,5-furandicarboxylic acid(FDCA)and promotes the C-H/O-H bond cleavage,thereby improving the HMFOR kinetics(kNiMoO-Ni/kNiMoO=1.97)and FDCA selectivity(99.3%).When coupled as a two-electrode system,it can drive efficient HMF conversion(FDCA yield:98.5%)and H2production(Faradaic efficiency:99.1%)at 1.45 V.This work thus offers a strategy to tune the adsorption sites of catalyst for efficient HMFOR-assisted H2production.

Strong electronic coupling of CoNi and N-doped-carbon for efficient urea-assisted H2 production at a large current density

Exploiting efficient urea oxidation reaction(UOR)and hydrogen evolution reaction(HER)catalysts are significant for energy-saving H2 production through urea-assisted water electrolysis,but it is still challenging.Herein,carbon-encapsulated CoNi coupled with CoNiMoO(CoNi@CN-CoNiMoO)is prepared by solvothermal method and calcination to enhance the activity/stability of urea-assisted water electrolysis at large current density.It exhibits good activity for UOR(E10/1,000=1.29/1.40 V)and HER(E-10/-1000=-45/-245 mV)in 1.0 M KOH+0.5 M urea solution.For the UOR||HER system,CoNi@CN-CoNiMoO only needs 1.58 V at 500 mA cm-2 and shows good stability.Density functional theory calculation suggests that the strong electronic interaction at the interface between NiCo alloy and N-doping-carbon layers can optimize the adsorption/desorption energy of UOR/HER intermediates and accelerate the water dissociation,which can expedite urea decomposition and Volmer step,thus increasing the UOR and HER activity,respectively.This work provides a new solution to design UOR/HER catalysts for H2 production through urea-assisted water electrolysis.

Adaptive Neural Control for Nonlinear MIMO Function Constraint Systems

Dear Editor,In this letter,a novel adaptive control design problem for uncertain nonlinear multi-input-multi-output(MIMO)systems with time-varying full state constraints is proposed,where the considered systems consist of various subsystems,and the states of each subsystem are interconnected tightly.It is universally acknowledged that in the existing researches with state constraints,system constraint bounds are always constants or time-varying functions.

N‑Doped Graphene‑Decorated NiCo Alloy Coupled with Mesoporous NiCoMoO Nano‑sheet Heterojunction for Enhanced Water Electrolysis Activity at High Current Density

Developing highly effective and stable non-noble metalbased bifunctional catalyst working at high current density is an urgent issue for water electrolysis(WE).Herein,we prepare the N-doped graphene-decorated NiCo alloy coupled with mesoporous NiCoMoO nano-sheet grown on 3D nickel foam(NiCo@C-NiCoMoO/NF)for water splitting.NiCo@C-NiCoMoO/NF exhibits outstanding activity with low overpotentials for hydrogen and oxygen evolution reaction(HER:39/266 mV;OER:260/390 mV)at±10 and±1000 mA cm^(−2).More importantly,in 6.0 M KOH solution at 60℃ for WE,it only requires 1.90 V to reach 1000 mA cm−2 and shows excellent stability for 43 h,exhibiting the potential for actual application.The good performance can be assigned to N-doped graphene-decorated NiCo alloy and mesoporous NiCoMoO nano-sheet,which not only increase the intrinsic activity and expose abundant catalytic activity sites,but also enhance its chemical and mechanical stability.This work thus could provide a promising material for industrial hydrogen production.

Three-Phase Heterojunction NiMo-Based Nano-Needle for Water Splitting at Industrial Alkaline Condition

Constructing heterojunction is an effective strategy to develop high-performance non-preciousmetal-based catalysts for electrochemical water splitting(WS).Herein,we design and prepare an N-doped-carbon-encapsulated Ni/MoO_(2) nano-needle with three-phase heterojunction(Ni/MoO_(2)@CN)for accelerating the WS under industrial alkaline condition.Density functional theory calculations reveal that the electrons are redistributed at the three-phase heterojunction interface,which optimizes the adsorption energy of H-and O-containing intermediates to obtain the best ΔG_(H*) for hydrogen evolution reaction(HER)and decrease the ΔG value of ratedetermining step for oxygen evolution reaction(OER),thus enhancing the HER/OER catalytic activity.Electrochemical results confirm that Ni/MoO_(2)@CN exhibits good activity for HER(ƞ_(-10)=33 mV,ƞ_(-1000)=267 mV)and OER(ƞ_(10)=250 mV,ƞ_(1000)=420 mV).It shows a low potential of 1.86 V at 1000 mA cm^(−2) for WS in 6.0 M KOH solution at 60℃ and can steadily operate for 330 h.This good HER/OER performance can be attributed to the three-phase heterojunction with high intrinsic activity and the self-supporting nano-needle with more active sites,faster mass diffusion,and bubbles release.This work provides a unique idea for designing high efficiency catalytic materials for WS.

Hybrid Reduced Graphene Oxide with Special Magnetoresistance for Wireless Magnetic Field Sensor

Very few materials show large magnetoresistance(MR)under a low magnetic field at room temperature,which causes the barrier to the development of magnetic field sensors for detecting low-level electromagnetic radiation in real-time.Here,a hybrid reduced graphene oxide(rGO)-based magnetic field sensor is produced by in situ deposition of FeCo nanoparticles(NPs)on reduced graphene oxide(rGO).Special quantum magnetoresistance(MR)of the hybrid rGO is observed,which unveils that Abrikosov's quantum model for layered materials can occur in hybrid rGO;meanwhile,the MR value can be tunable by adjusting the particle density of FeCo NPs on rGO nanosheets.Very high MR value up to 21.02±5.74%at 10 kOe at room temperature is achieved,and the average increasing rate of resistance per kOe is up to 0.9282ΩkOe^-1.In this paper,we demonstrate that the hybrid rGO-based magnetic field sensor can be embedded in a wireless system for real-time detection of low-level electromagnetic radiation caused by a working mobile phone.We believe that the two-dimensional nanomaterials with controllable MR can be integrated with a wireless system for the future connected society.

Bifunctional interstitial phosphorous doping strategy boosts platinum-zinc alloy for efficient ammonia oxidation reaction and hydrogen evolution reaction

It is still a lack of bifunctional catalysts for ammonia oxidation reaction(AOR)and hydrogen evolution reaction(HER)due to their different reaction mechanisms.In this work,P is doped into PtZn alloy by calcination with NaH_(2)PO_(2) as P source to induce the lattice tensile strain of Pt and the electronic interaction between P and Zn,which optimizes the AOR and HER activity simultaneously.The sample with the optimal P content can drive the AOR peak current density of 293.6 mA·mgPt^(-1),which is almost 2.7 times of Pt.For HER,the overpotential at^(-1)0 mA·cm^(-2) is only 23 mV with Tafel slope of 34.1 mV·dec^(-1).Furthermore,only 0.59 V is needed to obtain 50 mA·mgPt^(-1) for ammonia electrolysis under a two-electrode system.Therefore,this work shows an ingenious method to design bifunctional catalysts for ammonia electrolysis.

Integrated in-memory sensor and computing of artificial vision system based on reversible bonding transition-induced nitrogen-doped carbon quantum dots (N-CQDs)

Carbon quantum dots (CQDs) have been used in memristors due to their attractive optical and electronic properties, which are considered candidates for brain-inspired computing devices. In this work, the performance of CQDs-based memristors is improved by utilizing nitrogen-doping. In contrast, nitrogen-doped CQDs (N-CQDs)-based optoelectronic memristors can be driven with smaller programming voltages (−0.6 to 0.7 V) and exhibit lower powers (78 nW/0.29 µW). The physical mechanism can be attributed to the reversible transition between C–N and C=N with lower binding energy induced by the electric field and the generation of photogenerated carriers by ultraviolet light irradiation, which adjusts the conductivity of the initial N-CQDs to implement resistance switching. Importantly, the convolutional image processing based on various cross kernels is efficiently demonstrated by stable multi-level storage properties. An N-CQDs-based optoelectronic reservoir computing implements impressively high accuracy in both no noise and various noise modes when recognizing the Modified National Institute of Standards and Technology (MNIST) dataset. It illustrates that N-CQDs-based memristors provide a novel strategy for developing artificial vision system with integrated in-memory sensor and computing.

The resistance switching performance of the memristor improved effectively by inserting carbon quantum dots(CQDs)for digital information processing

As an emerging information device that adapts to development of the big data era,memristor has attracted much attention due to its advantage in processing massive data.However,the nucleation and growth of conductive filaments often exhibit randomness and instability,which undoubtedly leads to a wide and discrete range of switching parameters,damaging the electrical performance of device.In this work,a strategy of inserting carbon quantum dots(CQDs)into graphene oxide(GO)resistance layer is utilized to improve the stability of the switching parameters and the reliability of the device is improved.Compared with GO-based devices,GO/CQDs/GO-based devices exhibit a more stable resistance switching curve,low power,lower and more concentrated threshold voltage parameters with lower variation coefficient,faster switching speed,and more stable retention and endurance.The cause-inducing performance improvement may be attributed to the local electric field generated by CQDs in resistance switching that effectively guides the formation and rupture of conductive filaments,which optimizes the effective migration distance of Ag^(+),thereby improving the uniformity of resistance switching.Additionally,a convolutional neural network model is constructed to identify the CIFAR-10 data set,showing the high recognition accuracy of online and offline learning.The cross-kernel structure is used to further implement convolutional image processing through multiplication and accumulation operations.This work provides a solution to improve the performance of memristors,which can contribute to developing digital information processing.

Te-doped Fe_(3)O_(4) flower enabling low overpotential cycling of Li-CO_(2) batteries at high current density

Li-CO_(2)batteries(LCBs)suffer from high overpotentials caused by sluggish CO_(2)reaction kinetics.This work designs a Te-doped Fe_(3)O_(4)(Te-Fe_(3)O_(4))flower-like microsphere catalyst to lower the overpotential and improve the reversibility of LCBs.Experimental results reveal that Te doping modifies the electronic structure of Fe_(3)O_(4)and reduces the overpotential.The stable Te-O bond between Te and C_(2)O^(2-)_(4)could effectively inhibit the dispro-portionation reaction of the latter,enabling the Te-Fe_(3)O_(4)cathodes to exhibit a remarkable capacity(9485 mAh g^(-1))and a long cycling life(155 cycles)with an overpotential of 1.21 V and an energy efficiency of about 80%at a high current density(2000 mA g^(-1)).Through the interaction between Te and Li_(2)C_(2)O_(4)to inhibit the dispro-portionation reaction,this work successfully achieves long-term cycling of LCBs with low overpotential at high current density.

光驱动Rh/InGaN_(1-x)O_(x)纳米组装体甲烷干重整制合成气

Light-driven dry reforming of methane toward syngas presents a proper solution for alleviating climate change and for the sustainable supply of transportation fuels and chemicals.Herein,Rh/InGaN_(1-x)O_(x) nanowires supported by silicon wafer are explored as an ideal platform for loading Rh nanoparticles,thus assembling a new nanoarchitecture for this grand topic.In combination with the remarkable photothermal synergy,the O atoms in Rh/InGaN_(1-x)O_(x) can significantly lower the apparent activation energy of dry reforming of methane from 2.96 eV downward to 1.70 eV.The as-designed Rh/InGaN_(1-x)O_(x) NWs nanoarchitecture thus demonstrates a measurable syngas evolution rate of 180.9 mmol g_(cat)^(-1) h^(-1) with a marked selectivity of 96.3% under concentrated light illumination of 6 W cm^(-2).What is more,a high turnover number(TON)of 4182 mol syngas per mole Rh has been realized after six reuse cycles without obvious activity degradation.The correlative 18O isotope labeling experiments,in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)and in-situ diffuse reflectance Fourier transform infrared spectroscopy characterizations,as well as density functional theory calculations reveal that under light illumination,Rh/InGaN_(1-x)O_(x) NWs facilitate releasing^(*)CH_(3) and H^(+)from CH_(4) by holes,followed by H_(2) evolution from H^(+)reduction with electrons.Subsequently,the O atoms in Rh/InGaN_(1-x)O_(x) can directly participate in CO generation by reacting with the ^(*)C species from CH_(4) dehydrogenation and contributes to the coke elimination,in concurrent formation of O vacancies.The resultant O vacancies are then replenished by CO_(2),showing an ideal chemical loop.This work presents a green strategy for syngas production via light-driven dry reforming of methane.

Modulating metal-support interaction between Pt_(3)Ni and unsaturated WOx to selectively regulate the ORR performance

Tuning strong metal-support interaction between Pt-based alloys and metal oxides is an effective strategy for modulating the performance of oxygen reduction reaction(ORR).Herein,Pt_(3)Ni alloy anchored on WO_(x) with different content of oxygen vacancies is synthesized,and the effect of unsaturated WO_(x) on ORR activity/stability is revealed.Electrochemical results indicate that ORR activity is positively correlated with oxygen vacancy concentration,while durability presents the opposite trend.Density functional theory(DFT)calculation results suggest that controlling the content of oxygen vacancies can usefully adjust the charge redistribution between Pt_(3)Ni and WO_(x),which can optimize the adsorption/activation of reactants,thus obtaining good ORR activity.This study uncovers the effect of unsaturated WO_(x) on ORR performance for Pt-based alloys and provides a promising strategy to design efficient and stable ORR catalysts.

Synergized oxygen vacancies with Mn_(2)O_(3)@CeO_(2)heterojunction as high current density catalysts for Li-O_(2)batteries

The application of Li-O_(2)batteries(LOBs)with ultra-high theoretical energy density is limited due to the slow redox kinetics and serious side reactions,especially in high-rate cycles.Herein,CeO_(2)is constructed on the surface of Mn_(2)O_(3)through an interface engineering strategy,and Mn_(2)O_(3)@CeO_(2)heterojunction with good activity and stability at high current density is prepared.The interfacial properties of catalyst and formation mechanism of Li_(2)O_(2)are deeply studied by density functional theory(DFT)and experiments,revealing the charge-discharge reaction mechanism of LOBs.The results show that the strong electron coupling between Mn_(2)O_(3)and CeO_(2)can promote the formation of oxygen vacancies.Heterojunction combined with oxygen vacancy can improve the affinity for O_(2)and LiO_(2)reaction intermediates,inducing the formation of thin-film Li_(2)O_(2)with low potential and easy decomposition,thus improving the cycle stability at high current density.Consequently,it achieved a high specific capacity of 12545 at 1000 mA g^(-1)and good cyclability of 120 cycles at 4000 mA g^(-1).This work thus sheds light on designing efficient and stable catalysts for LOBs under high current density.

利用界面工程来调控铁电隧道忆阻器的生物突触行为

界面工程一直是调节铁电隧道结忆阻器(FTM)行为的重要途径,且直接影响其生物突触特性.为了研究界面对人工突触性能的影响,本工作中,我们研究了具有Pt/BaTiO_(3)/La_(0.67)Sr_(0.33)MnO_(3)结构的忆阻器.其中可以通过控制SrTiO_(3)(STO)衬底的终止层和BaTiO_(3)(BTO)薄膜层状生长模式来控制忆阻器器件的界面.由于BTO薄膜相反的铁电极化方向以及与之对应的不同的能带结构,具有不同界面的FTM呈现出相反的电阻开关行为.更重要的是,FTM的突触学习特性也可以通过控制界面来调整.具有不同接口终端的FTM可以调节长时程增强、长时程抑制、尖峰时间依赖性可塑性和配对脉冲促进的不同特性.基于这两种接口工程FTM的突触行为,可以构建人工神经网络系统来完成手写数字图像识别过程,两者的准确率都接近90%.我们的结果为通过纳米级界面工程调整忆阻器的功能提供了有用的参考.

Low-power memristors based on layered 2D SnSe/graphene materials

The emerging two-terminal memristor with a conductance-adjustable function under external stimulation is considered a strong candidate for use in artificial memory and electronic synapses. However, the stability, uniformity, and power consumption of memristors are still challenging in neuromorphic computing. Here an Au/SnSe/graphene/SiO_(2)/Si memristor was fabricated, incorporating two-dimensional graphene with high thermal conductivity. The device not only exhibits excellent electrical characteristics(e.g., high stability,good uniformity and a high ROFF/RON ratio), but also can implement biological synaptic functions such as paired-pulse facilitation, short-term plasticity and long-term plasticity. Its set and reset power values can be as low as 16.7 and 2.3 nW,respectively. Meanwhile, the resistance switching mechanism for the device, which might be associated with the formation and rupture of a filamentary conducting path consisting of Sn vacancies, was confirmed by high-resolution transmission electron microscopy observations. The proposed device is an excellent candidate for use in high-density storage and lowpower neuromorphic computing applications.

Hf_(0.5)Zr_(0.5)O_(2)-based ferroelectric memristor with multilevel storage potential and artificial synaptic plasticity

Memristors are designed to mimic the brain’s integrated functions of storage and computing,thus breaking through the von Neumann framework.However,the formation and breaking of the conductive filament inside a conventional memristor is unstable,which makes it difficult to realistically mimic the function of a biological synapse.This problem has become a main factor that hinders memristor applications.The ferroelectric memristor overcomes the shortcomings of the traditional memristor because its resistance variation depends on the polarization direction of the ferroelectric thin film.In this work,an Au/Hf0.5Zr0.5O2/p+-Si ferroelectric memristor is proposed,which is capable of achieving resistive switching characteristics.In particular,the proposed device realizes the stable characteristics of multilevel storage,which possesses the potential to be applied to multi-level storage.Through polarization,the resistance of the proposed memristor can be gradually modulated by flipping the ferroelectric domains.Additionally,a plurality of resistance states can be obtained in bidirectional continuous reversibility,which is similar to the changes in synaptic weights.Furthermore,the proposed memristor is able to successfully mimic biological synaptic functions such as long-term depression,long-term potentiation,paired-pulse facilitation,and spike-timing-dependent plasticity.Consequently,it constitutes a promising candidate for a breakthrough in the von Neumann framework.

Analysis of Expression Profiles of Long Noncoding RNAs and mRNAs in A549 Cells Infected with H3N2 Swine Influenza Virus by RNA Sequencing

Long noncoding RNAs(lncRNAs)participate in regulating many biological processes.However,their roles in influenza A virus(IAV)pathogenicity are largely unknown.Here,we analyzed the expression profiles of lncRNAs and mRNAs in H3N2-infected cells and mock-infected cells by high-throughput sequencing.The results showed that 6129 lncRNAs and 50,031 mRNA transcripts in A549 cells displayed differential expression after H3N2 infection compared with mock infection.Among the differentially expressed lncRNAs,4963 were upregulated,and 1166 were downregulated.Functional annotation and enrichment analysis using gene ontology and Kyoto Encyclopedia of Genes and Genomes databases(KEGG)suggested that target genes of the differentially expressed lncRNAs were enriched in some biological processes,such as cellular metabolism and autophagy.The up-or downregulated lncRNAs were selected and further verified by quantitative real-time polymerase chain reaction(RT-qPCR)and reverse transcription PCR(RT-PCR).To the best of our knowledge,this is the first report of a comparative expression analysis of lncRNAs in A549 cells infected with H3N2.Our results support the need for further analyses of the functions of differentially expressed lncRNAs during H3N2 infection.