Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitro...Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitrogen removal efficiency.Herein,we compared traditional(control),biochar(BC), andβ-cyclodextrin-fu nctionalized biochar(BC@β-CD) CW systems to investigate nitrogen removal from influent with low C/N ratios,and the mechanisms that enhance this process.The highest nitrogen removal rates were observed in the BC@β-CD group,with rates 45.89% and 42.48% higher than those of the control,accompanied by a 70.57% and 85.45% decrease in nitrous oxide release,when the C/N ratio decreased from4 to 2,respectively.Metagenomic and enzymatic analyses indicated that BC@β-CD enhances nitrogen removal by coordinately promoting carbon metabolism and increasing denitrification enzyme activities,without affecting microbial species diversity in CWs.Structural equation modeling confirmed that the foremost advantages of BC@β-CD were effective electron generation and transportation resulting from increased activities of nicotinamide adenine dinucleotide(NADH) dehydrogenase and the electron transfer system(ETS),thereby strategically reallocating more carbon metabolic flow to support denitrification.Our results show that the application of BC@β-CD in CWs to optimize the reallocation of electrons from carbon metabolism is a feasible strategy to enhance denitrification under low C/N conditions.展开更多
Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nit...Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nitrogen addition in a Larix gmelinii forest was carried out to study the effects on soil carbon,nitrogen,and CO_(2)flux during the thawing,growing,and freezing periods.Our study found that warming(0-2.0℃)increased soil organic carbon(SOC)and total nitrogen(STN),dissolved organic carbon(DOC)and dissolved organic nitrogen(DON),and microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN).Warming played a direct role in regulating soil CO_(2)emissions,stimulated microbial and plant root respiration and soil CO_(2)flux rapidly increased.Rainfall increase initially increased soil carbon and nitrogen,but a 30%increase in mean annual rainfall caused losses of SOC,STN,DOC,and DON,while MBC and MBN accumulated.Soil CO_(2)emissions were regulated by MBC after an increase in rainfall,excess moisture inhibited microbial activity,and soil CO_(2)flux showed a trend of R2(20%rainfall increase)>R1(10%rainfall increase)>CK(control)>R3(30%rainfall increase).The addition of nitrogen increased SOC,STN,DOC,DON,MBC and MBN.Soil CO_(2)flux progressively decreased with nitrogen inputs(2.5,5.0 and 10.0 g m^(-2)a^(-1)),as more N intensified plant-microbe competition.Nitrogen addition indirectly regulated soil CO_(2)emissions by altering SOC and STN,with MBC and MBN acting as secondary regulators.The results highlight the role of cold-temperate coniferous forest soils in predicting carbon-climate feedback in high-latitude forest permafrost regions.展开更多
Nowadays,higher requirements are put forward to the storage and utilization of energy,and supercapacitor is a kind of energy storage electronic devices.The resulting CA-N,with a specific surface area of 320.6 m^(2)/g ...Nowadays,higher requirements are put forward to the storage and utilization of energy,and supercapacitor is a kind of energy storage electronic devices.The resulting CA-N,with a specific surface area of 320.6 m^(2)/g and a pore volume of 0.28 cm^(3)/g,demonstrated a remarkable supercapacitance of 283.3 F/g.As a mesoporous material,CA-N offers numerous channels for the diffusion and absorption of electrolyte ions.Furthermore,it exhibited an impressive capacity retention rate of 98.48% after 5000 charge-discharge cycles.These outstanding electrochemical properties highlight the potential of CA-N for applications in energy storage.展开更多
Zinc telluride(ZnTe)with high density and low cost is considered as promising anode for sodium-ion batteries.However,ZnTe suffers from continuous capacity degradation owing to the low electronic conductivity,large vol...Zinc telluride(ZnTe)with high density and low cost is considered as promising anode for sodium-ion batteries.However,ZnTe suffers from continuous capacity degradation owing to the low electronic conductivity,large volume expansion,and high ion-diffusion energy barriers.Herein,the nitrogen-doped carbon confined ZnTe polyhedron heterostructure(ZnTe/NC)is proposed,exploiting its orbital rehybridization and the realignment of energy level to improve storage performance.Systematic ex situ/in situ characterizations and simulations demonstrated that the elaborate ZnTe/NC offers abundant electron/ion transport pathways,accelerates Na^(+)diffusion kinetics,and alleviates huge volume expansion.Notably,the nitrogen-doped carbon-support interaction induced via electron transfer between ZnTe sites and support elevates the energy level of Zn 3d orbital,greatly enhancing ion adsorption capability and reducing the ion diffusion barrier.As a result,the ZnTe/NC anode delivers a high discharge capacity of 470.5 mAh g^(−1)and long cycling durability over 1000 cycles.This work uncovers that optimizing sodium ion adsorption and diffusion via d-orbital energy level modulation enabled by nitrogen-doped support interaction is an effective method for developing high-performance transition metal telluride anodes for alkali ion storage.展开更多
Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is ...Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is unknown.This study used a six-year(2017-2022)field study to explore the impacts of intercropping green manure with maize and reducing nitrogen fertilization on SOC stocks,while specifically focusing on the relationship between aggregate composition and carbon sequestration.Maize intercropped with common vetch(M/V),maize intercropped with rapeseed(M/R),and sole maize(M),were each tested at conventional(N2,360 kg ha^(-1))and reduced(N1,270 kg ha^(-1),25% reduced)N application rates.Soil was sampled in 2020,2021,and 2022.Compared with sole maize,intercropping with green manure(M/V and M/R)significantly increased SOC stocks which compensated for any negative effect due to the 25% reduction in N application.Based on 3-year averages,intercropping with M/V and M/R increased the SOC content compared to sole maize(M)by 12.1 and 9.1%,respectively,with intercropping further mitigating the negative impact of reduced nitrogen application.There was no significant difference between M/V and M/R.The SOC content at N1 was reduced by 9.3-10.5%compared to that at N2 in sole maize,but the differences in SOC stocks between N1 and N2 were not significant in the intercropping patterns(M/V and M/R).The intercropped M/V and M/R showed 20.9 and 16.3% higher SOC contents compared to sole maize at N1,with no differences at N2.Intercropping green manure led to a 5.3% greater SOC in the 0-20 cm depth soil in 2022 compared to that in 2020,due to the cumulative effect of two years of green manure intercropping.Intercropping green manure(M/V and M/R)increased the proportion of macroaggregates(>0.25 mm)and aggregate stability while reducing the proportion of microaggregates compared to sole maize under the N1 application.Structural equation modeling indicated that cropping patterns and nitrogen application levels mainly affect SOC indirectly by regulating the composition of macroaggregates and aggregate organic carbon(AOC).Correlation analysis further revealed that the composition of macroaggregates is significantly and positively correlated with the SOC content(R^(2)=0.64).In addition,intercropping green manure can maintain high crop yields by increasing SOC under reduced chemical nitrogen application.The results of this study show that intercropping green manure with grain crops can be a viable measure for increasing SOC sinks and maize productivity by optimizing the aggregate composition with reduced N application in the Hexi Oasis Irrigation Area.展开更多
Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(...Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.展开更多
Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and ...Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and the operation life of the catalyst.In this work,dahlia-like SWCNHs with N contents ranging from 2.1at%to 4.3at%are controllably synthesized via arc discharge and applied as a carrier of Pt nanoparticles(NPs),denoted as Pt/N-SWCNHs.Pt/N-SWCNHs-2:1(graphite and melamine with the mass ratio of 2:1)exhibits excellent electrocatalytic activity(onset potential=0.95 V).The half-wave potential of Pt/N-SWCNHs-2:1 is only reduced by 2 mV after 3000 cyclic voltammetry cycles.This can be attributed to the enhanced dispersion of Pt NPs and the strong electronic interaction between the N-SWCNHs and Pt,facilitated by the optimal nitrogen doping level.The results of this work offer important perspectives on the design and enhancement of Pt-based electrocatalysts for ORR applications,highlighting the critical role of the nitrogen doping level in balancing the electrocatalytic activity and long-term stability.展开更多
The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate ...The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate change on the structure,function,and services of the ecosystem.However,the spatial distribution and controlling factors of SOC and TN across various soil layers and vegetation types within this unique ecosystem remain inadequately understood.In this study,256 soil samples in 89 sites were collected from the Three River Headwaters Region(TRHR)in China to investigate SOC and TN and to explore the primary factors affecting their distribution,including soil,vegetation,climate,and geography factors.The results show that SOC and TN contents in 0-20,20-40,40-60,and 60-80 cm soil layers are 24.40,18.03,14.04,12.40 g/kg and 2.46,1.90,1.51,1.17 g/kg,respectively;with higher concentrations observed in the southeastern region compared to the northwest of the TRHR.One-way analysis of variance reveals that SOC and TN levels are elevated in the alpine meadow and the alpine shrub relative to the alpine steppe in the 0-60 cm soil layers.The structural equation model explores that soil water content is the main controlling factor affecting the variation of SOC and TN.Moreover,the geography,climate,and vegetation factors notably indirectly affect SOC and TN through soil factors.Therefore,it can effectively improve soil water and nutrient conditions through vegetation restoration,soil improvement,and grazing management,and the change of SOC and TN can be fully understood by establishing monitoring networks to better protect soil carbon and nitrogen.展开更多
Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NH...Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NHMC/Ni/NiO)nanocomposite for developing high-capacity LIBs anode materials through carbonization and selective etching strategies.The synthesized NMHC/Ni/NiO-0.33 composite exhibited a highly regular microstructure with well-dispersed Ni/NiO particles.The composite had a surface area of 408 m^(2)·g^(−1),a mesopore ratio of 75.0%,and a pyridine–nitrogen ratio of 58.9%.The introduction of nitrogen atoms reduced the disordered structure of lignin mesoporous carbon and enhanced its electrical conductivity,thus improving the lithium storage capabilities of the composite.Following 100 cycles at a current density of 0.2 A·g^(−1),the composite demonstrated enhanced Coulomb efficiency and rate performance,achieving a specific discharge capacity of 1230.9 mAh·g^(−1).At a high-current density of 1 A·g^(−1),the composite exhibited an excellent specific discharge capacity of 714.6 mAh·g^(−1).This study presents an innovative method for synthesizing high-performance anode materials of LIBs.展开更多
Herein,an external crosslinker facilitated the hypercrosslinking of ferrocene and a nitrogen heterocyclic compound(either melamine or imidazole)through a direct Friedel-Crafts reaction,which led to the formation of ni...Herein,an external crosslinker facilitated the hypercrosslinking of ferrocene and a nitrogen heterocyclic compound(either melamine or imidazole)through a direct Friedel-Crafts reaction,which led to the formation of nitrogen-containing hypercrosslinked fer-rocene polymer precursors(HCP-FCs).Subsequent carbonization of these precursors results in the production of iron-nitrogen-doped por-ous carbon absorbers(Fe-NPCs).The Fe-NPCs demonstrate a porous structure comprising aggregated nanotubes and nanospheres.The porosity of this structure can be modulated by adjusting the iron and nitrogen contents to optimize impedance matching.The uniform dis-tribution of Fe-N_(x)C,N dipoles,andα-Fe within the carbon matrix can be ensured by using hypercrosslinked ferrocenes in constructing porous carbon,providing the absorber with numerous polarization sites and a conductive network.The electromagnetic wave absorption performance of the specially designed Fe-NPC-M_(2)absorbers is satisfactory,revealing a minimum reflection loss of-55.3 dB at 2.5 mm and an effective absorption bandwidth of 6.00 GHz at 2.0 mm.By utilizing hypercrosslinked polymers(HCPs)as precursors,a novel method for developing highly efficient carbon-based absorbing agents is introduced in this research.展开更多
Nitrogen-doped activated carbon(N-AC)was successfully prepared by KOH-activation and nitrogen doping using ammonia(NH3)heat treatment.Coconut shell-derived activated carbon(AC)was heat-treated under NH3 gas in the tem...Nitrogen-doped activated carbon(N-AC)was successfully prepared by KOH-activation and nitrogen doping using ammonia(NH3)heat treatment.Coconut shell-derived activated carbon(AC)was heat-treated under NH3 gas in the temperature range of 700℃-900℃.Likewise,the mixture of potassium hydroxide(KOH)and AC was heated at 800℃,followed by heat treatment underNH3 gas at 800℃(hereafter referred to asKOH-N-AC800).Scanning electron microscopy(SEM),Raman spectroscopy,X-ray photoelectron spectroscopy(XPS)and Brunauer-Emmett-Teller(BET)method were utilized to analyze morphology,crystallinity,chemical bonding,chemical composition and surface area.The surface area and porosity of N-AC increased with increasing NH3 heat treatment.Similarly,the nitrogen content in the N-AC increased from 3.23%to 4.84 at%when the NH3 heat treatment was raised from 700℃ to 800℃.However,the nitrogen content of N-AC decreased to 3.40 at% after using NH3 heat treatment at 900℃.The nitrogen content of KOH-N-AC800 is 5.43 at%.KOH-N-AC800 and N-AC800 exhibited improvements of 33.66% and 26.24%,respectively,in CO_(2) adsorption compared with AC.The enhancement of CO_(2) adsorption of KOH-N-AC800 is attributed to the synergic effect of the nitrogen doping,high surface area,and porosity.The results exhibited that nitrogen sites on the surface play a more significant role in CO_(2) adsorption than surface area and porosity.This work proposes the potential synergistic effect of KOH-activation and nitrogen doping for enhancing the CO_(2) adsorption capacity of activated carbon.展开更多
K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require f...K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require further investigation.In this study,novel N-doped multichannel carbon nanofibers(h-NMCNFs)with hierarchical porous structures were successfully synthesized as efficient cathode hosts for K–Se batteries through the carbonization of two electrospun immiscible polymer nanofibers and subsequent chemical activation.Mesopores originated from the decomposition of the polymer embedded in the carbon nanofibers,and micropores were introduced via KOH activation.During the activation step,hierarchical porous carbon nanofibers with enhanced pore volumes were formed because of the micropores in the carbon nanofibers.Owing to the mesopores that enabled easy access to the electrolyte and the high utilization of chain-like Se within the micropores,the Se-loaded hierarchical porous carbon nanofibers(60 wt%Se)exhibited a high discharge capacity and excellent rate performance.The discharge capacity of the nanofibers at the 1,000th cycle was 210.8 mA.h.g^(-1)at a current density of 0.5C.The capacity retention after the initial activation was 64%.In addition,a discharge capacity of 165 mA.h.g^(-1)was obtained at an extremely high current density of 3.0C.展开更多
Widespread soil acidification driven by nitrogen(N)fertilization and precipitation challenges the conventional notion of the long-term stability of soil inorganic carbon(SIC)in agroecosystems.However,the changes in SI...Widespread soil acidification driven by nitrogen(N)fertilization and precipitation challenges the conventional notion of the long-term stability of soil inorganic carbon(SIC)in agroecosystems.However,the changes in SIC with precipitation and N fertilization remain ambiguous.Based on 4,000+soil samples collected in the 1980s and 2010s and by developing machine learning models to fill the missing SIC of soil samples,this study generated 3,697 paired soil samples between the two periods and then investigated the cropland SIC change and explored its relationship with precipitation and N fertilization across the Sichuan Basin,China.The results showed an overall SIC loss,with a decline of the mean SIC by 15.73%.SIC change varied with initial soil pH and initial SIC and exhibited an exponential relationship with soil pH change,indicating the changing role of carbonates in providing acid-buffering capacity.There was a parabolical relationship between the magnitude of SIC decline and N fertilizer rates,and low N fertilizer rates contributed to a reduction in SIC loss,while SIC loss was promoted by N fertilization occurred when N fertilizing rates exceeded 250 kg ha^(-1) yr^(-1).The change in SIC showed a sinusoidal variation with precipitation,with 950 mm being the threshold controlling whether SIC increased or decreased.Meanwhile,N fertilization did not alter the sinusoidal relationship between SIC change and precipitation.In areas with rainfall<950 mm,the high N fertilizer rate did not cause SIC loss,while higher precipitation could also cause larger SIC loss in areas with lower N fertilizer rates.These results suggest that SIC dynamics are jointly driven by precipitation and N fertilization and are controlled by acid-buffering mechanisms associated with initial pH and SIC,with precipitation being the predominant driver.These findings emphasize the need for more regional soil observations and in-depth studies of SIC change and its mechanisms for accurately estimating SIC change.展开更多
Carbon nanotubes(CNTs)are widely used in various fields owing to their unique properties.In this study,three different types of nitrogen-doped CNT heterojunctions were constructed:parallel-doped(PCNT),vertically doped...Carbon nanotubes(CNTs)are widely used in various fields owing to their unique properties.In this study,three different types of nitrogen-doped CNT heterojunctions were constructed:parallel-doped(PCNT),vertically doped(VCNT),and mesh-doped(MCNT).Non-equilibrium molecular dynamics(NEMD)simulations were conducted to investigate their heat flux and thermal rectification(TR)effects.The results show that heat flux preferentially flows from nitrogen-doped regions to undoped regions,exhibiting distinct thermal rectification behavior,with PCNT showing the most pronounced effect.Interestingly,the TR ratio of the zigzag PCNT is significantly higher than that of the armchair PCNT.Subsequently,we examined the effects of system length and diameter on the TR ratio of the PCNT and found that the TR ratio increases and then decreases with increasing model length.In addition,the effect of defect density on the heat flux of the PCNT is peculiar.The phonon density of states,phonon dispersion,participation ratio,and phonon spectral heat flux were analyzed to elucidate the thermal transport behavior of phonons in the nanotubes.This study provides insights into the development and design of nitrogen-doped CNT thermal rectifiers.展开更多
The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-d...The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-doped carbon nitride composite ultraviolet-activated Ce-UiO-66 catalysts,denoted as RECNactMOF,for efficient nitrogen fixation.Rare earth doping modulates the band structure of carbon nitride,facilitating the formation of a type-I heterojunction with Ce-UiO-66 and promoting photocarrier generation at nitrogen fixation sites.Among these,Sm-doped SmCN-actMOF exhibits high visible-light absorption and efficient utilization of photocarriers,resulting in an apparent quantum efficiency(AQE)of 1.58%under 495 nm light irradiation.This study provides a pathway for enhancing the nitrogen fixation efficiency of photocatalysts through the incorporation of rare earth elements,and expanding the potential applications of rare earth materials in the field of photocatalysis.展开更多
Increasing anthropogenic nitrogen(N)inputs has profoundly altered soil microbial necromass carbon(MNC),which serves as a key source of soil organic carbon(SOC).Yet,the response pattern of MNC and its contribution to S...Increasing anthropogenic nitrogen(N)inputs has profoundly altered soil microbial necromass carbon(MNC),which serves as a key source of soil organic carbon(SOC).Yet,the response pattern of MNC and its contribution to SOC across a wide range of N addition rates,remain elusive.In a temperate grassland with six years'consecutive N addition spanning seven rates(0-50 g N/(m^(2)·year))in Inner Mongolia,China,we explored the responses of soil MNC and its contribution to SOC.The soil MNC showed a hump-shaped pattern to increasing N addition rates,with the N saturation threshold at 18.07 g N/(m^(2)·year).The soil MNC was driven by nematode abundance and the ratio of bacterial to fungal biomass below the N threshold,and by plant biomass allocation pattern and diversity above the N threshold.The contribution of soil MNC to SOC declined with increasing N addition rates,and was mainly regulated by the ratio of MNC to mineral-associated organic carbon and plant diversity and the ratio of bacterial to fungal biomass.In addition,the soil MNC and SOC differentially responded to N addition and were mediated by disparate biological and geochemical mechanisms,leading to the decoupled MNC production from SOC formation.Together,in this N-enriched temperate grassland,the soilmicrobial necro-mass production tends to be insufficient as a general explanation linking SOC formation.This study expands the mechanistic comprehension of the connections between external N input and soil carbon sequestration.展开更多
Transition metal sulfides have great potential as anode mterials for sodium-ion batteries(SIBs)due to their high theoretical specific capacities.However,the inferior intrinsic conductivity and large volume variation d...Transition metal sulfides have great potential as anode mterials for sodium-ion batteries(SIBs)due to their high theoretical specific capacities.However,the inferior intrinsic conductivity and large volume variation during sodiation-desodiation processes seriously affect its high-rate and long-cyde performance,unbeneficial for the application as fast-charging and long-cycling SIBs anode.Herein,the three-dimensional porous Cu_(1.81)S/nitrogen-doped carbon frameworks(Cu_(1.81)S/NC)are synthesized by the simple and facile sol-gel and annealing processes,which can accommodate the volumetric expansion of Cu_(1.81)S nanoparticles and accelerate the transmission of ions and electrons during Na^(+)insertion/extraction processes,exhibiting the excellent rate capability(250.6 mA·g^(-1)at 20.0 A·g^(-1))and outstanding cycling stability(70% capacity retention for 6000 cycles at 10.0 A·g^(-1))for SIBs.Moreover,the Na-ion full cells coupled with Na_(3)V_(2)(PO_(4))_(3)/C cathode also demonstrate the satisfactory reversible specific capacity of 330.5 mAh·g^(-1)at 5.0 A·g^(-1)and long-cycle performance with the 86.9% capacity retention at 2.0 A·g^(-1)after 750 cycles.This work proposes a promising way for the conversionbased metal sulfides for the applications as fast-charging sodium-ion battery anode.展开更多
Improving rice yield and nitrogen use efficiency(NUE)are crucial challenges for coordinating food production and environmental health.However,little is known about the physiological mechanisms underlying the synergist...Improving rice yield and nitrogen use efficiency(NUE)are crucial challenges for coordinating food production and environmental health.However,little is known about the physiological mechanisms underlying the synergistic effects of high yield and NUE in rice.Using two near-isogenic rice lines(named DEP1 and dep1),a two-year field experiment was conducted to assess agronomic characteristics and the physiological characteristics of carbon and nitrogen translocation under three nitrogen levels.Compared with DEP1,dep1 had higher grain yield,grain filling percentage,nitrogen(N)uptake,and NUE.More non-structural carbohydrates(NSCs)and N in the stems were translocated to grains during grain filling in dep1 than in DEP1.Furthermore,stem NSCs translocation was significantly positively correlated with grain yield,while stem N translocation was significantly positively correlated with NUE.Key carbon metabolism enzyme activities(α-amylase,β-amylase and sucrose-phosphate synthase in stems,and sucrose synthase,ADP-glucose pyrophosphorylase and starch synthase in grains)and stem sucrose transporter gene(OsSUT1 and OsSWEET13)expression were higher in dep1 than in DEP1.This contributed to high stem NSCs translocation.Higher N translocation in the stems occurred due to the higher expression of OsNPF2.4.Moreover,the higher values of root morphological traits(root dry weight,root surface area,root length and root volume)and structural characteristics(stele diameter,cortical thickness and vessel section area)in dep1 explained its high nitrogen uptake.In addition,higher expression of OsNADH-GOGAT1 and OsGS1.3 promoted the assimilation of ammonium and contributed to higher nitrogen uptake in dep1.The application of N reduced carbon translocation but enhanced N translocation by regulating the corresponding metabolic enzyme activities and gene expression.Overall,these findings highlighted the roles of nitrogen uptake,and carbon and nitrogen translocation from stems as crucial characteristics for synergistically improving yield and NUE in the dep1 rice line.展开更多
Chromium is one of the heavy metal pollutants. Heavy metal chromium-contaminated water will seriously endanger human health after use. There are many ways to remove chromium-containing sewage, and the adsorption metho...Chromium is one of the heavy metal pollutants. Heavy metal chromium-contaminated water will seriously endanger human health after use. There are many ways to remove chromium-containing sewage, and the adsorption method is the most effective and convenient method. The adsorption amount of traditional activated carbon is limited, so it needs to be modified to improve the adsorption rate. This experiment determined a reasonable modification method, and the calcination method was selected for the modification. This paper mainly compares the surface morphological characteristics of activated carbon before and after modification. The modified X-ray diffraction peak is increased and the infrared ray absorption peak increased, and the results show that the surface of the modified activated carbon is more rough than that of the modified activated carbon, the functional groups are increased, and the sulfur and nitrogen are doped on the activated carbon. Therefore, the modified activated carbon has a high removal rate and the best performance under acidic conditions.展开更多
In the past century,industrial and economic growth relied heavily on fossil fuels such as coal,oil,and natural gas.As the society energy demands continue to grow,these fossil fuel reserves are depleted,leading to sign...In the past century,industrial and economic growth relied heavily on fossil fuels such as coal,oil,and natural gas.As the society energy demands continue to grow,these fossil fuel reserves are depleted,leading to significant environmental issues[1].Currently,sustainable biomass resources have attracted much attention as potential substitutes to fossil fuels for producing biofuels and commodity chemicals[2].展开更多
基金supported by the National Natural Science Foundation of China(52321005)the Guangdong Basic and Applied Basic Research Foundation(2023A1515012383 and 2024A1515030138)+1 种基金the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology,2021TS30)the Shenzhen Science and Technology Program(KQTD20190929172630447 and KCXFZ20211020163404007).
文摘Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitrogen removal efficiency.Herein,we compared traditional(control),biochar(BC), andβ-cyclodextrin-fu nctionalized biochar(BC@β-CD) CW systems to investigate nitrogen removal from influent with low C/N ratios,and the mechanisms that enhance this process.The highest nitrogen removal rates were observed in the BC@β-CD group,with rates 45.89% and 42.48% higher than those of the control,accompanied by a 70.57% and 85.45% decrease in nitrous oxide release,when the C/N ratio decreased from4 to 2,respectively.Metagenomic and enzymatic analyses indicated that BC@β-CD enhances nitrogen removal by coordinately promoting carbon metabolism and increasing denitrification enzyme activities,without affecting microbial species diversity in CWs.Structural equation modeling confirmed that the foremost advantages of BC@β-CD were effective electron generation and transportation resulting from increased activities of nicotinamide adenine dinucleotide(NADH) dehydrogenase and the electron transfer system(ETS),thereby strategically reallocating more carbon metabolic flow to support denitrification.Our results show that the application of BC@β-CD in CWs to optimize the reallocation of electrons from carbon metabolism is a feasible strategy to enhance denitrification under low C/N conditions.
基金funded by the Science and Technology Programme of Inner Mongolia Autonomous Region(Grant No.:2023YFDZ0026 and 2024KYPT0003)the 2024 Postgraduate Research and Innovation Programme of Inner Mongolia Agricultural University。
文摘Changes in the soil environment induced by major global changes in climate are affecting carbon emissions in cold-temperate coniferous forests.A randomized block experiment simulating warming,rainfall increase and nitrogen addition in a Larix gmelinii forest was carried out to study the effects on soil carbon,nitrogen,and CO_(2)flux during the thawing,growing,and freezing periods.Our study found that warming(0-2.0℃)increased soil organic carbon(SOC)and total nitrogen(STN),dissolved organic carbon(DOC)and dissolved organic nitrogen(DON),and microbial biomass carbon(MBC)and microbial biomass nitrogen(MBN).Warming played a direct role in regulating soil CO_(2)emissions,stimulated microbial and plant root respiration and soil CO_(2)flux rapidly increased.Rainfall increase initially increased soil carbon and nitrogen,but a 30%increase in mean annual rainfall caused losses of SOC,STN,DOC,and DON,while MBC and MBN accumulated.Soil CO_(2)emissions were regulated by MBC after an increase in rainfall,excess moisture inhibited microbial activity,and soil CO_(2)flux showed a trend of R2(20%rainfall increase)>R1(10%rainfall increase)>CK(control)>R3(30%rainfall increase).The addition of nitrogen increased SOC,STN,DOC,DON,MBC and MBN.Soil CO_(2)flux progressively decreased with nitrogen inputs(2.5,5.0 and 10.0 g m^(-2)a^(-1)),as more N intensified plant-microbe competition.Nitrogen addition indirectly regulated soil CO_(2)emissions by altering SOC and STN,with MBC and MBN acting as secondary regulators.The results highlight the role of cold-temperate coniferous forest soils in predicting carbon-climate feedback in high-latitude forest permafrost regions.
基金supported by Shenzhen Science and Technology Program(No.JCYJ20240813103608012)State Key Laboratory of New Textile Materials andAdvanced Processing Technologies(No.FZ2024019)National Natural Science Foundation of China(No.22104117).
文摘Nowadays,higher requirements are put forward to the storage and utilization of energy,and supercapacitor is a kind of energy storage electronic devices.The resulting CA-N,with a specific surface area of 320.6 m^(2)/g and a pore volume of 0.28 cm^(3)/g,demonstrated a remarkable supercapacitance of 283.3 F/g.As a mesoporous material,CA-N offers numerous channels for the diffusion and absorption of electrolyte ions.Furthermore,it exhibited an impressive capacity retention rate of 98.48% after 5000 charge-discharge cycles.These outstanding electrochemical properties highlight the potential of CA-N for applications in energy storage.
基金supported by the National Natural Science Foundation of China(52402298,52172224,52302240)Science and Technology Correspondent Project of Tianjin(24YDTPJC00240)+1 种基金the Macao Young Scholars Program(AM2023011)the Yuanguang Scholars Program,Hebei University of Technology(282022554).
文摘Zinc telluride(ZnTe)with high density and low cost is considered as promising anode for sodium-ion batteries.However,ZnTe suffers from continuous capacity degradation owing to the low electronic conductivity,large volume expansion,and high ion-diffusion energy barriers.Herein,the nitrogen-doped carbon confined ZnTe polyhedron heterostructure(ZnTe/NC)is proposed,exploiting its orbital rehybridization and the realignment of energy level to improve storage performance.Systematic ex situ/in situ characterizations and simulations demonstrated that the elaborate ZnTe/NC offers abundant electron/ion transport pathways,accelerates Na^(+)diffusion kinetics,and alleviates huge volume expansion.Notably,the nitrogen-doped carbon-support interaction induced via electron transfer between ZnTe sites and support elevates the energy level of Zn 3d orbital,greatly enhancing ion adsorption capability and reducing the ion diffusion barrier.As a result,the ZnTe/NC anode delivers a high discharge capacity of 470.5 mAh g^(−1)and long cycling durability over 1000 cycles.This work uncovers that optimizing sodium ion adsorption and diffusion via d-orbital energy level modulation enabled by nitrogen-doped support interaction is an effective method for developing high-performance transition metal telluride anodes for alkali ion storage.
基金supported by the National Key Research and Development Program of China(2021YFD1700204)the National Natural Science Foundation of China(U21A20218 and 32372238)+1 种基金the Modern Agro-Industry Technology Research System of China(CARS-22-G-12)the“Innovation Star”Program of Graduate Students in 2025 of Gansu Province,China(2025CXZX-749)。
文摘Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is unknown.This study used a six-year(2017-2022)field study to explore the impacts of intercropping green manure with maize and reducing nitrogen fertilization on SOC stocks,while specifically focusing on the relationship between aggregate composition and carbon sequestration.Maize intercropped with common vetch(M/V),maize intercropped with rapeseed(M/R),and sole maize(M),were each tested at conventional(N2,360 kg ha^(-1))and reduced(N1,270 kg ha^(-1),25% reduced)N application rates.Soil was sampled in 2020,2021,and 2022.Compared with sole maize,intercropping with green manure(M/V and M/R)significantly increased SOC stocks which compensated for any negative effect due to the 25% reduction in N application.Based on 3-year averages,intercropping with M/V and M/R increased the SOC content compared to sole maize(M)by 12.1 and 9.1%,respectively,with intercropping further mitigating the negative impact of reduced nitrogen application.There was no significant difference between M/V and M/R.The SOC content at N1 was reduced by 9.3-10.5%compared to that at N2 in sole maize,but the differences in SOC stocks between N1 and N2 were not significant in the intercropping patterns(M/V and M/R).The intercropped M/V and M/R showed 20.9 and 16.3% higher SOC contents compared to sole maize at N1,with no differences at N2.Intercropping green manure led to a 5.3% greater SOC in the 0-20 cm depth soil in 2022 compared to that in 2020,due to the cumulative effect of two years of green manure intercropping.Intercropping green manure(M/V and M/R)increased the proportion of macroaggregates(>0.25 mm)and aggregate stability while reducing the proportion of microaggregates compared to sole maize under the N1 application.Structural equation modeling indicated that cropping patterns and nitrogen application levels mainly affect SOC indirectly by regulating the composition of macroaggregates and aggregate organic carbon(AOC).Correlation analysis further revealed that the composition of macroaggregates is significantly and positively correlated with the SOC content(R^(2)=0.64).In addition,intercropping green manure can maintain high crop yields by increasing SOC under reduced chemical nitrogen application.The results of this study show that intercropping green manure with grain crops can be a viable measure for increasing SOC sinks and maize productivity by optimizing the aggregate composition with reduced N application in the Hexi Oasis Irrigation Area.
基金financially supported by National Natural Science Foundation of China(22466010)Guizhou Provincial Basic Research Program(Natural Science)ZK[2023]47 and key program ZD[2025]075+6 种基金Innovation and Entrepreneurship Project for overseas Talents in Guizhou Province[2022]02Specific Natural Science Foundation of Guizhou University(X202207)the national undergraduate innovation and entrepreneurship training program(gzugc2023006gzusc2024012)SRT project of Guizhou university(2023SRT0292023SRT024)supported by Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University。
文摘Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.
基金financially supported by the National Natural Science Foundation of China(Nos.12175089 and 12205127)the Key Research and Development Program of Yunnan Province,China(Nos.202301AU070064 and 202103AF140006)the Yunnan Industrial Innovative Talents Program for“Xingdian Talent Support Plan”,China(No.KKXY202252001).
文摘Nitrogen-doped single-walled carbon nanohorns(N-SWCNHs)can serve as an effective carrier for platinum(Pt)catalysts,which has the potential to improve the electrocatalytic activity of oxygen reduction reaction(ORR)and the operation life of the catalyst.In this work,dahlia-like SWCNHs with N contents ranging from 2.1at%to 4.3at%are controllably synthesized via arc discharge and applied as a carrier of Pt nanoparticles(NPs),denoted as Pt/N-SWCNHs.Pt/N-SWCNHs-2:1(graphite and melamine with the mass ratio of 2:1)exhibits excellent electrocatalytic activity(onset potential=0.95 V).The half-wave potential of Pt/N-SWCNHs-2:1 is only reduced by 2 mV after 3000 cyclic voltammetry cycles.This can be attributed to the enhanced dispersion of Pt NPs and the strong electronic interaction between the N-SWCNHs and Pt,facilitated by the optimal nitrogen doping level.The results of this work offer important perspectives on the design and enhancement of Pt-based electrocatalysts for ORR applications,highlighting the critical role of the nitrogen doping level in balancing the electrocatalytic activity and long-term stability.
基金supported by the National Science Foundation for Distinguished Young Scholars(No.42425107)Ecological Civilization Special Project of Key Research&and Development Program in Gansu Province(No.24YFFA009)the Top Talent Project of Gansu Province,Chinese Academy of Sciences Young Crossover Team Project(No.JCTD-2022-18)。
文摘The alpine ecosystem has great potential for carbon sequestration.Soil organic carbon(SOC)and total nitrogen(TN)are highly sensitive to climate change,and their dynamics are crucial to revealing the effect of climate change on the structure,function,and services of the ecosystem.However,the spatial distribution and controlling factors of SOC and TN across various soil layers and vegetation types within this unique ecosystem remain inadequately understood.In this study,256 soil samples in 89 sites were collected from the Three River Headwaters Region(TRHR)in China to investigate SOC and TN and to explore the primary factors affecting their distribution,including soil,vegetation,climate,and geography factors.The results show that SOC and TN contents in 0-20,20-40,40-60,and 60-80 cm soil layers are 24.40,18.03,14.04,12.40 g/kg and 2.46,1.90,1.51,1.17 g/kg,respectively;with higher concentrations observed in the southeastern region compared to the northwest of the TRHR.One-way analysis of variance reveals that SOC and TN levels are elevated in the alpine meadow and the alpine shrub relative to the alpine steppe in the 0-60 cm soil layers.The structural equation model explores that soil water content is the main controlling factor affecting the variation of SOC and TN.Moreover,the geography,climate,and vegetation factors notably indirectly affect SOC and TN through soil factors.Therefore,it can effectively improve soil water and nutrient conditions through vegetation restoration,soil improvement,and grazing management,and the change of SOC and TN can be fully understood by establishing monitoring networks to better protect soil carbon and nitrogen.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22278092,22078116 and 22222805)Guangdong Provincial Key Research and Development Program(No.2020B1111380002)+2 种基金Science and Technology Research Project of Guangzhou(Nos.2023A03J0034,2023A04J0077 and 202102020467)State Key Laboratory of Pulp and Paper Engineering(No.202313)Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.202255464).
文摘Developing high-capacity carbon-based anode materials is crucial for enhancing the performance of lithium-ion batteries(LIBs).In this study,we presented a nitrogen-doped lignin mesoporous carbon/nickel/nickel oxide(NHMC/Ni/NiO)nanocomposite for developing high-capacity LIBs anode materials through carbonization and selective etching strategies.The synthesized NMHC/Ni/NiO-0.33 composite exhibited a highly regular microstructure with well-dispersed Ni/NiO particles.The composite had a surface area of 408 m^(2)·g^(−1),a mesopore ratio of 75.0%,and a pyridine–nitrogen ratio of 58.9%.The introduction of nitrogen atoms reduced the disordered structure of lignin mesoporous carbon and enhanced its electrical conductivity,thus improving the lithium storage capabilities of the composite.Following 100 cycles at a current density of 0.2 A·g^(−1),the composite demonstrated enhanced Coulomb efficiency and rate performance,achieving a specific discharge capacity of 1230.9 mAh·g^(−1).At a high-current density of 1 A·g^(−1),the composite exhibited an excellent specific discharge capacity of 714.6 mAh·g^(−1).This study presents an innovative method for synthesizing high-performance anode materials of LIBs.
基金supported by the National Natural Science Foundation of China(No.51803041)the University and Local Integration Development Project of Yantai,China(No.2022 XDRHXMXK08).
文摘Herein,an external crosslinker facilitated the hypercrosslinking of ferrocene and a nitrogen heterocyclic compound(either melamine or imidazole)through a direct Friedel-Crafts reaction,which led to the formation of nitrogen-containing hypercrosslinked fer-rocene polymer precursors(HCP-FCs).Subsequent carbonization of these precursors results in the production of iron-nitrogen-doped por-ous carbon absorbers(Fe-NPCs).The Fe-NPCs demonstrate a porous structure comprising aggregated nanotubes and nanospheres.The porosity of this structure can be modulated by adjusting the iron and nitrogen contents to optimize impedance matching.The uniform dis-tribution of Fe-N_(x)C,N dipoles,andα-Fe within the carbon matrix can be ensured by using hypercrosslinked ferrocenes in constructing porous carbon,providing the absorber with numerous polarization sites and a conductive network.The electromagnetic wave absorption performance of the specially designed Fe-NPC-M_(2)absorbers is satisfactory,revealing a minimum reflection loss of-55.3 dB at 2.5 mm and an effective absorption bandwidth of 6.00 GHz at 2.0 mm.By utilizing hypercrosslinked polymers(HCPs)as precursors,a novel method for developing highly efficient carbon-based absorbing agents is introduced in this research.
基金funded by Burapha University,grant number SDG 4/2568.
文摘Nitrogen-doped activated carbon(N-AC)was successfully prepared by KOH-activation and nitrogen doping using ammonia(NH3)heat treatment.Coconut shell-derived activated carbon(AC)was heat-treated under NH3 gas in the temperature range of 700℃-900℃.Likewise,the mixture of potassium hydroxide(KOH)and AC was heated at 800℃,followed by heat treatment underNH3 gas at 800℃(hereafter referred to asKOH-N-AC800).Scanning electron microscopy(SEM),Raman spectroscopy,X-ray photoelectron spectroscopy(XPS)and Brunauer-Emmett-Teller(BET)method were utilized to analyze morphology,crystallinity,chemical bonding,chemical composition and surface area.The surface area and porosity of N-AC increased with increasing NH3 heat treatment.Similarly,the nitrogen content in the N-AC increased from 3.23%to 4.84 at%when the NH3 heat treatment was raised from 700℃ to 800℃.However,the nitrogen content of N-AC decreased to 3.40 at% after using NH3 heat treatment at 900℃.The nitrogen content of KOH-N-AC800 is 5.43 at%.KOH-N-AC800 and N-AC800 exhibited improvements of 33.66% and 26.24%,respectively,in CO_(2) adsorption compared with AC.The enhancement of CO_(2) adsorption of KOH-N-AC800 is attributed to the synergic effect of the nitrogen doping,high surface area,and porosity.The results exhibited that nitrogen sites on the surface play a more significant role in CO_(2) adsorption than surface area and porosity.This work proposes the potential synergistic effect of KOH-activation and nitrogen doping for enhancing the CO_(2) adsorption capacity of activated carbon.
基金financially supported by the Materials/Parts Technology Development Program(No.RS-202400456324)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)by the National Research Foundation(NRF)of Korea grant(No.RS-2024-00454367)funded by the Ministry of Science and ICT(MSIT,Korea)。
文摘K–Se batteries have been identified as promising energy storage systems owing to their high energy density and cost-effectiveness.However,challenges such as substantial volume changes and low Se utilization require further investigation.In this study,novel N-doped multichannel carbon nanofibers(h-NMCNFs)with hierarchical porous structures were successfully synthesized as efficient cathode hosts for K–Se batteries through the carbonization of two electrospun immiscible polymer nanofibers and subsequent chemical activation.Mesopores originated from the decomposition of the polymer embedded in the carbon nanofibers,and micropores were introduced via KOH activation.During the activation step,hierarchical porous carbon nanofibers with enhanced pore volumes were formed because of the micropores in the carbon nanofibers.Owing to the mesopores that enabled easy access to the electrolyte and the high utilization of chain-like Se within the micropores,the Se-loaded hierarchical porous carbon nanofibers(60 wt%Se)exhibited a high discharge capacity and excellent rate performance.The discharge capacity of the nanofibers at the 1,000th cycle was 210.8 mA.h.g^(-1)at a current density of 0.5C.The capacity retention after the initial activation was 64%.In addition,a discharge capacity of 165 mA.h.g^(-1)was obtained at an extremely high current density of 3.0C.
基金supported by the National Natural Science Foundation of China(42330707 and 41930647)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(72221002)the Science and Technology Plan of Sichuan Province,China(2022NSFSC0104).
文摘Widespread soil acidification driven by nitrogen(N)fertilization and precipitation challenges the conventional notion of the long-term stability of soil inorganic carbon(SIC)in agroecosystems.However,the changes in SIC with precipitation and N fertilization remain ambiguous.Based on 4,000+soil samples collected in the 1980s and 2010s and by developing machine learning models to fill the missing SIC of soil samples,this study generated 3,697 paired soil samples between the two periods and then investigated the cropland SIC change and explored its relationship with precipitation and N fertilization across the Sichuan Basin,China.The results showed an overall SIC loss,with a decline of the mean SIC by 15.73%.SIC change varied with initial soil pH and initial SIC and exhibited an exponential relationship with soil pH change,indicating the changing role of carbonates in providing acid-buffering capacity.There was a parabolical relationship between the magnitude of SIC decline and N fertilizer rates,and low N fertilizer rates contributed to a reduction in SIC loss,while SIC loss was promoted by N fertilization occurred when N fertilizing rates exceeded 250 kg ha^(-1) yr^(-1).The change in SIC showed a sinusoidal variation with precipitation,with 950 mm being the threshold controlling whether SIC increased or decreased.Meanwhile,N fertilization did not alter the sinusoidal relationship between SIC change and precipitation.In areas with rainfall<950 mm,the high N fertilizer rate did not cause SIC loss,while higher precipitation could also cause larger SIC loss in areas with lower N fertilizer rates.These results suggest that SIC dynamics are jointly driven by precipitation and N fertilization and are controlled by acid-buffering mechanisms associated with initial pH and SIC,with precipitation being the predominant driver.These findings emphasize the need for more regional soil observations and in-depth studies of SIC change and its mechanisms for accurately estimating SIC change.
基金supported by the National Natural Science Foundation of China(Grant No.52476071)the Natural Science Foundation of Hebei Province(Grant No.A2024502008).
文摘Carbon nanotubes(CNTs)are widely used in various fields owing to their unique properties.In this study,three different types of nitrogen-doped CNT heterojunctions were constructed:parallel-doped(PCNT),vertically doped(VCNT),and mesh-doped(MCNT).Non-equilibrium molecular dynamics(NEMD)simulations were conducted to investigate their heat flux and thermal rectification(TR)effects.The results show that heat flux preferentially flows from nitrogen-doped regions to undoped regions,exhibiting distinct thermal rectification behavior,with PCNT showing the most pronounced effect.Interestingly,the TR ratio of the zigzag PCNT is significantly higher than that of the armchair PCNT.Subsequently,we examined the effects of system length and diameter on the TR ratio of the PCNT and found that the TR ratio increases and then decreases with increasing model length.In addition,the effect of defect density on the heat flux of the PCNT is peculiar.The phonon density of states,phonon dispersion,participation ratio,and phonon spectral heat flux were analyzed to elucidate the thermal transport behavior of phonons in the nanotubes.This study provides insights into the development and design of nitrogen-doped CNT thermal rectifiers.
基金Project supported by the National Natural Science Foundation of China(22102141)。
文摘The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-doped carbon nitride composite ultraviolet-activated Ce-UiO-66 catalysts,denoted as RECNactMOF,for efficient nitrogen fixation.Rare earth doping modulates the band structure of carbon nitride,facilitating the formation of a type-I heterojunction with Ce-UiO-66 and promoting photocarrier generation at nitrogen fixation sites.Among these,Sm-doped SmCN-actMOF exhibits high visible-light absorption and efficient utilization of photocarriers,resulting in an apparent quantum efficiency(AQE)of 1.58%under 495 nm light irradiation.This study provides a pathway for enhancing the nitrogen fixation efficiency of photocatalysts through the incorporation of rare earth elements,and expanding the potential applications of rare earth materials in the field of photocatalysis.
基金supported by the National Natural Science Foundation of China(Nos.42130515 and 32301450)the Open Foundation of State Key Laboratory of Desert and Oasis Ecology,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences.
文摘Increasing anthropogenic nitrogen(N)inputs has profoundly altered soil microbial necromass carbon(MNC),which serves as a key source of soil organic carbon(SOC).Yet,the response pattern of MNC and its contribution to SOC across a wide range of N addition rates,remain elusive.In a temperate grassland with six years'consecutive N addition spanning seven rates(0-50 g N/(m^(2)·year))in Inner Mongolia,China,we explored the responses of soil MNC and its contribution to SOC.The soil MNC showed a hump-shaped pattern to increasing N addition rates,with the N saturation threshold at 18.07 g N/(m^(2)·year).The soil MNC was driven by nematode abundance and the ratio of bacterial to fungal biomass below the N threshold,and by plant biomass allocation pattern and diversity above the N threshold.The contribution of soil MNC to SOC declined with increasing N addition rates,and was mainly regulated by the ratio of MNC to mineral-associated organic carbon and plant diversity and the ratio of bacterial to fungal biomass.In addition,the soil MNC and SOC differentially responded to N addition and were mediated by disparate biological and geochemical mechanisms,leading to the decoupled MNC production from SOC formation.Together,in this N-enriched temperate grassland,the soilmicrobial necro-mass production tends to be insufficient as a general explanation linking SOC formation.This study expands the mechanistic comprehension of the connections between external N input and soil carbon sequestration.
基金financially supported by the National Natural Science Foundation of China(Nos.U1904173 and 52272219)the Key Research Projects of Henan Provincial Department of Education(No.19A150043)+2 种基金the Natural Science Foundation of Henan Province(Nos.202300410330 and 222300420276)the Nanhu Scholars Program for Young Scholars of Xinyang Normal Universitythe Xinyang Normal University Analysis&Testing Center。
文摘Transition metal sulfides have great potential as anode mterials for sodium-ion batteries(SIBs)due to their high theoretical specific capacities.However,the inferior intrinsic conductivity and large volume variation during sodiation-desodiation processes seriously affect its high-rate and long-cyde performance,unbeneficial for the application as fast-charging and long-cycling SIBs anode.Herein,the three-dimensional porous Cu_(1.81)S/nitrogen-doped carbon frameworks(Cu_(1.81)S/NC)are synthesized by the simple and facile sol-gel and annealing processes,which can accommodate the volumetric expansion of Cu_(1.81)S nanoparticles and accelerate the transmission of ions and electrons during Na^(+)insertion/extraction processes,exhibiting the excellent rate capability(250.6 mA·g^(-1)at 20.0 A·g^(-1))and outstanding cycling stability(70% capacity retention for 6000 cycles at 10.0 A·g^(-1))for SIBs.Moreover,the Na-ion full cells coupled with Na_(3)V_(2)(PO_(4))_(3)/C cathode also demonstrate the satisfactory reversible specific capacity of 330.5 mAh·g^(-1)at 5.0 A·g^(-1)and long-cycle performance with the 86.9% capacity retention at 2.0 A·g^(-1)after 750 cycles.This work proposes a promising way for the conversionbased metal sulfides for the applications as fast-charging sodium-ion battery anode.
基金funded by the National Natural Science Foundation of China(32272200 and 31901425)the Jiangsu Provincial Key Research and Development Program,China(BE2021361)+2 种基金the Jiangsu Provincial Carbon Peak and Carbon Neutrality Technology Innovation Special Fund Project,China(BE2022425)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)the Lv Yang Jin Feng Talent Plan of Yangzhou City,China(YZLYJFJH2022YXBS020)。
文摘Improving rice yield and nitrogen use efficiency(NUE)are crucial challenges for coordinating food production and environmental health.However,little is known about the physiological mechanisms underlying the synergistic effects of high yield and NUE in rice.Using two near-isogenic rice lines(named DEP1 and dep1),a two-year field experiment was conducted to assess agronomic characteristics and the physiological characteristics of carbon and nitrogen translocation under three nitrogen levels.Compared with DEP1,dep1 had higher grain yield,grain filling percentage,nitrogen(N)uptake,and NUE.More non-structural carbohydrates(NSCs)and N in the stems were translocated to grains during grain filling in dep1 than in DEP1.Furthermore,stem NSCs translocation was significantly positively correlated with grain yield,while stem N translocation was significantly positively correlated with NUE.Key carbon metabolism enzyme activities(α-amylase,β-amylase and sucrose-phosphate synthase in stems,and sucrose synthase,ADP-glucose pyrophosphorylase and starch synthase in grains)and stem sucrose transporter gene(OsSUT1 and OsSWEET13)expression were higher in dep1 than in DEP1.This contributed to high stem NSCs translocation.Higher N translocation in the stems occurred due to the higher expression of OsNPF2.4.Moreover,the higher values of root morphological traits(root dry weight,root surface area,root length and root volume)and structural characteristics(stele diameter,cortical thickness and vessel section area)in dep1 explained its high nitrogen uptake.In addition,higher expression of OsNADH-GOGAT1 and OsGS1.3 promoted the assimilation of ammonium and contributed to higher nitrogen uptake in dep1.The application of N reduced carbon translocation but enhanced N translocation by regulating the corresponding metabolic enzyme activities and gene expression.Overall,these findings highlighted the roles of nitrogen uptake,and carbon and nitrogen translocation from stems as crucial characteristics for synergistically improving yield and NUE in the dep1 rice line.
文摘Chromium is one of the heavy metal pollutants. Heavy metal chromium-contaminated water will seriously endanger human health after use. There are many ways to remove chromium-containing sewage, and the adsorption method is the most effective and convenient method. The adsorption amount of traditional activated carbon is limited, so it needs to be modified to improve the adsorption rate. This experiment determined a reasonable modification method, and the calcination method was selected for the modification. This paper mainly compares the surface morphological characteristics of activated carbon before and after modification. The modified X-ray diffraction peak is increased and the infrared ray absorption peak increased, and the results show that the surface of the modified activated carbon is more rough than that of the modified activated carbon, the functional groups are increased, and the sulfur and nitrogen are doped on the activated carbon. Therefore, the modified activated carbon has a high removal rate and the best performance under acidic conditions.
基金funded by the Master,PhD Scholarship Programme of Vingroup Innovation Foundation(VINIF),code VINIF.2024.TS.035funded by Vietnam National University,Ho Chi Minh City(VNUHCM)under grant number NCM2024-18-01。
文摘In the past century,industrial and economic growth relied heavily on fossil fuels such as coal,oil,and natural gas.As the society energy demands continue to grow,these fossil fuel reserves are depleted,leading to significant environmental issues[1].Currently,sustainable biomass resources have attracted much attention as potential substitutes to fossil fuels for producing biofuels and commodity chemicals[2].
