Polycyclic Aromatic Hydrocarbons(PAHs),along with their derivatives nitro-PAHs and oxy-PAHs,are globally recognized toxic pollutants.This research conducted daily PM_(2.5)sampling in winter 2021 at three urban(YNCE,SW...Polycyclic Aromatic Hydrocarbons(PAHs),along with their derivatives nitro-PAHs and oxy-PAHs,are globally recognized toxic pollutants.This research conducted daily PM_(2.5)sampling in winter 2021 at three urban(YNCE,SWP,and NG)and three suburban sites(HC,CTV,and YNE)in the Ili River Valley(IRV).For the first time in the IRV,a comprehensive study on 39 PAHs and derivatives was carried out.The results showed that the average∑_(16)PAHs concentration was 130.21±98.94 ng/m^(3),with 16PAHs constituting the dominant fraction(112.51±86.48 ng/m^(3)).The mean BaP and the total BaP equivalent quotient(TEQ)concentrations were 10.28±8.85 ng/m^(3)and 19.74±16.70 ng/m^(3),respectively.Approximately 88%of the daily BaP averages and 98%of the daily TEQ averages exceeded the national daily average standard of BaP(2.5 ng/m^(3)),indicating severe local BaP pollution.Urban sites had notably higher∑PAHs and TEQ concentrations than suburban sites,attributed to increased vehicular traffic and coal combustion in urban areas.PMF results showed that traffic emissions(32.7%-60.5%),coal combustion(13.9%-24.3%)and secondary formation(14.7%-22.7%)were the primary contributors to∑PAHs.Urban sites experienced a greater influence from traffic,while suburban sites were more impacted by coal and biomass burning.On polluted days,traffic sources’contributions increased significantly at HC,YNE,NG and YNCE sites,and secondary formation sources’contributions grew at CTV and YNCE sites.The sourcedependent BaPeq results underscored the role of secondary-formed PAH derivatives in TEQ.展开更多
Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recen...Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recent years.In this study,the occurrence,distribution,source,and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry,normal,and flood seasons of 2018.The PAH concentrations ranged from 255 to 7298 ng/L and the NPAH concentrations ranged from not-detected(ND)to 212 ng/L.Among the target analytes,2-nitrofluorene(2-n Flu)was the predominant NPAH,with a detection frequency ranging from 85%to 90%and a maximum concentration of 56.2 ng/L.The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds.In terms of seasonal variation,the highest levels of the NPAHs and PAHs were in the dry season and flood season,respectively.Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion,whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion.The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model.The carcinogenic risk level of the targets ranged from 2.09×10^(-7)to 5.75×10^(-5)and some surface water samples posed a potential health risk.展开更多
Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,...Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,formation mechanism,and health risk assessment of them in heating season,particulate matter(PM)were collected in Beijing urban area from December 26,2017 to January 17,2018.PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS).Average daily concentrations of PAHs and NPAHs were(78±54)ng/m^(3)and(783±684)pg/m^(3),respectively.The concentrations of them were significantly higher at nighttime than at daytime,and NPAHs concentrations were 1-2 orders of magnitude lower than PAHs concentrations.In the heating season,the dominant species of PAHs include benzo[b]fluoranthene,fluoranthene,pyrene,and chrysene,while 9-nitroanthracene,2+3-nitrofluoranthene,and 2-nitropyrene were dominant species for NPAHs.NPAHs were found to have a single peak during heating and to be primarily distributed in the 0.4-0.7μm particle size.Primary emissions such as biomass burning,coal combustion,and traffic emissions were the major sources of PAHs.NPAHs were produced by the primary source of vehicle emissions and the secondary reaction triggered by OH radicals,as well as biomass burning during daytime.According to the health risk assessment,the total carcinogenic risk was higher in adults than in children.While upon oral ingestion,the carcinogenic risk in children was higher than that of adults,but the risk of adults was higher than children through skin contact and respiratory inhalation.展开更多
Intensive daytime and nighttime sampling was carried out from 23 Oct to 31 Dec 2008 to investigate the occurrence of nitrated polycyclic aromatic hydrocarbons （NPAHs） in PM1o at a roadside site in Xiamen, China. At ...Intensive daytime and nighttime sampling was carried out from 23 Oct to 31 Dec 2008 to investigate the occurrence of nitrated polycyclic aromatic hydrocarbons （NPAHs） in PM1o at a roadside site in Xiamen, China. At the same time, six PMt0 samples were collected from a nearby roadway tunnel for comparison. Six NPAHs, namely 9-nitroanthracene, 2- and 3-nitrofluoranthene, 1- nitropyrene, 7-nitrobenz[a]anthracene, and 6-nitrobenzo[a]pyrene, were identified and quantified using GC/MS in negative ion chemical ionization mode. The average total concentration of six NPAHs （~NPAHs） in the cold season （26 Nov-31 Dec） was 2.3 （daytime） and 9.9 （nighttime） times higher than those in the warm season. Significant statistical difference （p 〈 0.01, 2-tailed） of ∑NPAHs between daytime and nighttime was found during both the warm and cold seasons. NPAHs were significantly positively correlated with their parent PAHs and nitrogen dioxide but negatively correlated with ambient temperature. The ratio of 2 ＋ 3-nitrofluoranthene to 1- nitropyrene exhibited a similar diurnal pattern as ZNPAHs and was generally greater than 5, indicating the importance of secondary atmospheric formation. The diurnal variations of NPAHs were all influenced by the diurnal variations of PAHs, nitrogen dioxide, sunlight, and temperature. The daily inhalable exposure to the six NPAHs in the tunnel was much higher than the roadside values in the warm season but only slightly higher than those in the cold season.展开更多
Air pollutants can potentially lead to nitration of allergic proteins,thus promoting sensitization of these allergens.However,little is currently known about the nitration status of house dust mite(HDM)allergens.We id...Air pollutants can potentially lead to nitration of allergic proteins,thus promoting sensitization of these allergens.However,little is currently known about the nitration status of house dust mite(HDM)allergens.We identified the occurrence of nitrated products of two major HDM allergens Der f 1 and Der p 1 in dust samples collected from college dormitories in eastern China and assessed their associated health risk.The results showed that both non-nitrated and nitrated forms of the two allergens were detected in the dust in the range of non-detected(ND)-10.6,1.44-15.4,ND-22.4,ND-7.28μg/g for non-nitrated Der f 1,nitrated Der f 1,non-nitrated Der p 1 and nitrated Der p 1,respectively.The median rates of nitration were determined as 74.0%for Der f 1 and 20.4% for Der p 1 at consideration of one nitration site.Further analysis reveals that the levels of HDM allergens and their nitrated products were found to be generally higher during winter,in dormitories of lower altitude and with female occupants.Furthermore,the calculated risk indexes were at considerably high levels.Our findings suggest that nitrated HDM allergens have already accumulated in the environment at such significant levels and their associated health risk calls for our immediate attention.展开更多
Nutrition plays a vital role in human health,particularly through the type and quality of dietary fats.While excessive saturated fatty acid(SFA)intake is associated with negative cardiovascular outcomes,unsaturated fa...Nutrition plays a vital role in human health,particularly through the type and quality of dietary fats.While excessive saturated fatty acid(SFA)intake is associated with negative cardiovascular outcomes,unsaturated fats especially monounsaturated(MUFA)and polyunsaturated fatty acids(PUFA)offer protective benefits.Among the bioactive lipids derived from unsaturated fats are nitrated fatty acids(NO2-FAs),electrophilic signaling molecules formed naturally during inflammation or via dietary interactions between nitrite-rich vegetables and unsaturated lipids.NO2-FAs have been shown to exert anti-inflammatory,antioxidant,and antiplatelet effects,influencing metabolic pathways involved in cardiometabolic health.This review explores the formation,meta-bolism,and biological actions of NO2-FAs from dietary sources,emphasizing their role within dietary patterns like the Mediterranean diet.By bridging lipid biochemistry and nutritional science,we underscore the therapeutic potential of NO2-FAs as diet-derived agents for disease prevention and treatment in metabolic and cardiovascular disorders.展开更多
Previous studies documented increased nitrative stress and susceptibility to air pollution among individuals with chronic inflammatory conditions.This study examines the role of anti-inflammatory and cardioprotective ...Previous studies documented increased nitrative stress and susceptibility to air pollution among individuals with chronic inflammatory conditions.This study examines the role of anti-inflammatory and cardioprotective nitrated fatty acids(i.e.,NO2-cLA)in chronic obstructive pulmonary disease(COPD)'s and ischemic heart disease(IHD)'s susceptibility to air pollution.In a randomized crossover study,40 healthy,40 COPD,and 39 IHD adults underwent a 2 h walk in a more polluted street or a less polluted park.We measured urinary NO2-cLA before and 24 h after the walk,as well as respiratory inflammatory biomarkers,lung function,airway resistance,and arterial stiffness.Baseline NO2-cLA levels were 2.56(95%CI:1.20-5.43)-fold higher among COPD participants than healthy participants,which can be explained by higher fractional exhaled nitric oxide and sputum myeloperoxidase levels.Among COPD but not healthy or IHD participants,the street walk,compared to park,led to a 57.7%(95%CI:7.6-80.6%)decrease in NO2-cLA levels and sputum biomarker changes indicative of decreased neutrophil inflammation and proresolving responses.Decreased NO2-cLA levels were associated with exposure to black carbon and ultrafine particles and worsened lung function and arterial stiffness.Taken together,nitrated fatty acids partially mediate COPD patients'cardiorespiratory responses to air pollution,explaining their susceptibility.展开更多
Cmyc,a proto-oncogene,is expressed at extremely low levels in mature neurons and is traditionally thought to have no function in these cells.However,recent studies suggest that Cmyc may play a crucial role in maintain...Cmyc,a proto-oncogene,is expressed at extremely low levels in mature neurons and is traditionally thought to have no function in these cells.However,recent studies suggest that Cmyc may play a crucial role in maintaining the health and function of mature dopaminergic neurons.This study assessed the role of Cmyc in dopaminergic neurons and its significance in Parkinson’s disease.We used a conditional knockout approach to specifically delete Cmyc in substantia nigra dopaminergic neurons of adult mice.Our findings showed that Cmyc deletion led to progressive neuron loss,Parkinson’s disease-like symptoms,downregulation of Klotho,and upregulation of senescence-associated inflammatory factors,along with enhanced oxidative stress and nitrated alpha-synuclein accumulation,ultimately causing neuronal death.In vitro experiments confirmed increased senescence in C-MYC knockout cells,which was partially reversible by KLOTHO overexpression.We conclude that low-level Cmyc expression is essential for maintaining the health of mature dopaminergic neurons and preventing neurodegeneration,and suggest the c-Myc/Klotho axis as a potential therapeutic target for age-related neurodegenerative diseases,including Parkinson’s disease.Our study introduces a novel mouse model for Parkinson’s disease that replicates a condition associated with normal aging,offering a valuable tool for future research into disease mechanisms and therapeutic strategies.展开更多
Ammonium toxicity in plants remains poorly understood despite extensive research.While nitrate is known to benefit plant growth,the synergistic effects of nitrate in mitigating ammonium toxicity,even at low concentrat...Ammonium toxicity in plants remains poorly understood despite extensive research.While nitrate is known to benefit plant growth,the synergistic effects of nitrate in mitigating ammonium toxicity,even at low concentrations,are not fully elucidated.This review delves into the physiological and molecular nature of this phenomenon.To date,nitrate-dependent alleviation of ammonium toxicity is the result of cumulative consequences of the role of nitrate as a nutrient and signal in plant performance.The ability to counteract the ammonium-induced acidification through nitrate uptake and metabolism,the enhancement of potassium uptake as an essential nitrate counterion,and the nitratedependent signaling of key factors involved in ammonium assimilation,ROS scavenging,and growth hormone biosynthesis,are the most relevant hallmarks.In addition,evidence suggests that the availability of nitrate and ammonium has driven ecological selection in plants,determining current N preferences,and may have led to the selection of nitrate-dependent and ammonium-sensitive domesticated crops and the inefficient use of N fertilizers in agriculture.As ammonium toxicity limits N fertilization options and reduces agricultural yields,when it could be a more sustainable and cheaper alternative to nitrate,this review provides a better understanding of how plants use nitrate to counteract the problematic aspects of ammonium nutrition.展开更多
Nitrate pollution is a severe threat to the fragile ecosystems in karst regions.However,our knowledge of the sources and transformations of nitrate in karst cave groundwater is still limited.This study aimed to invest...Nitrate pollution is a severe threat to the fragile ecosystems in karst regions.However,our knowledge of the sources and transformations of nitrate in karst cave groundwater is still limited.This study aimed to investigate the temporal and spatial patterns of nitrate dynamics in the underground water of karst caves located on the south bank of the Qingjiang River in central China,through a comprehensive application of multiple approaches,such as hydrochemistry,nitrogen and oxygen isotope compositions of nitrate,and a Bayesian isotope mixing model(SIMMR).During the sampling period(from December 2018 to December 2019),the nitrate concentration did not show an apparent temporal variation;meanwhile,no water samples in this study had a nitrate concentration higher than the limit for drinking water,but the nitrate concentration in karst underground rivers is significantly higher than that in surface water.The results of the comprehensive analyses revealed that the predominant nitrate sources included nitrification in soil and chemical fertilizer,which had mean percentages of 43%and 32%,respectively.The source contribution varied in the outlet water among different caves.The soil-derived nitrate in the underground water from the Shizi Cave accounted for the highest proportion(49%),while chemical-fertilizer-derived nitrate in the underground water from the Mishui Cave accounted for the highest proportion(36%).The dualisotope signatures of nitrate supported a major influence on nitrogen dynamics in the cave underground from nitrification.These findings suggest that nitrate carried by underground rivers in karst caves should be alerted when making the nitrate balance in rivers flowing through karst areas.展开更多
Electrochemical nitrate reduction reaction(NO_(3)RR)is a sustainable strategy to treat wastewater and produce ammonia.However,it is still a challenge to prepare electrocatalysts with high activity and selectivity.Here...Electrochemical nitrate reduction reaction(NO_(3)RR)is a sustainable strategy to treat wastewater and produce ammonia.However,it is still a challenge to prepare electrocatalysts with high activity and selectivity.Herein,the CuO_(x) nanowires supported Ru nanoclusters(Ru-CuO_(x))were fabricated via a three-step procedure for efficient nitrate conversion and highly selective ammonia generation.The prepared RuCuO_(x) shows a high ammonia yield rate of 2286.5μg h^(-1) cm^(-2) at-0.7 V vs.RHE and Faradaic efficiency(FE)of 80.1%at-0.4 V vs.RHE.Additionally,the nitrate conversion rate exceeds 90%at the potential range from-0.2 to-0.7 V vs.RHE,and the ammonia selectivity can reach 97.7%at-0.7 V vs.RHE in100 mg L^(-1) NaNO_(3) solution.The systematic characterizations clarify that the introduction of Ru not only regulates the electronic structure of CuO_(x) and accelerates the reconstruction of CuO_(x) to Cu but also promotes H2O dissociation to generate active hydrogen.Moreover.in-situ Raman spectroscopy reveals that the formed Ru-Cu is considered the actual active species during the NO_(3)RR.Density functional theory(DFT)calculations further prove that the obtained Ru-Cu facilitates the adsorption of nitrate and lowers the Gibbs free energy of the rate-determining step,thus improving the NO_(3)RR performance.展开更多
In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry bet...In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry between corresponding building blocks and linking units in addition to the unmanageable packing of 1D organic chains once formed.Herein,two novel imide-linked 1D COFs with phthalocyanine building blocks,namely NiPc-CZDM-COF and NiPc-CZDL-COF,were fabricated from the hydrothermal synthesis reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato nickel(II)(NiPc(COOH)_(8))with 9H-carbazole-3,6-diamine(CZDM)and 4,4′-(9H-carbazole-3,6-diyl)dianiline(CZDL),respectively.Two COFs have high crystallinity on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy.Due to their high ratio of exposed active centers on the edge sites of porous ribbons,both NiPc-CZDM-COF and NiPc-CZDL-COF electrodes display high utilization efficiency of NiPc electroactive sites of 8.0%and 7.5% according to the electrochemical measurement,resulting in their excellent capacity toward electrocatalytic nitrate reduction with the nitrate-to-NH3 Faradaic efficiency of nearly 100%.In particular,NiPc-CZDM-COF electrode exhibits superior electrocatalytic performance with high NH_(3) partial current density of−246 mA/cm^(2),ammonia yield rate of 19.5 mg cm^(−2) h^(−1),and turnover frequency of 5.8 s^(−1) at−1.2 V in an H-type cell associated with its higher conductivity.This work reveals the good potential of 1D porous crystalline materials in electrocatalysis.展开更多
Artificial photosynthesis of hydrogen peroxide(H_(2)O_(2))from earth-abundant water and oxygen is a sustainable approach,however current photocatalysts suffer from low production rate and solar-to-chemical conversion ...Artificial photosynthesis of hydrogen peroxide(H_(2)O_(2))from earth-abundant water and oxygen is a sustainable approach,however current photocatalysts suffer from low production rate and solar-to-chemical conversion efficiency(<1.5%).Herein,we report that nickelchromium layered double hydroxide with intercalated nitrate(NiCrOOH-NO_(3))and a thickness of~4.4 nm is an efficient photocatalyst,enabling a H_(2)O_(2)production yield of 28.7 mmol g^(-1)h^(-1)under visible light irradiation with3.92%solar-to-chemical conversion efficiency.Experimental and computational studies have revealed an inherent facet-dependent reduction-oxidation reaction behavior and spatial separation of photogenerated electrons and holes.An unexpected role of intercalated nitrate is demonstrated,which promotes excited electron—hole spatial separation and facilitates the electron transfer to oxygen intermediate via delocalization.This work provides understandings in the impact of nanostructure and anion in the design of advanced photocatalysts,paving the way toward practical synthesis of H_(2)O_(2)using fully solar-driven renewable energy.展开更多
Exploring high-performance electrocatalysts for the nitrate reduction reaction(NO_(3)RR)is crucial for environmental nitrate removal and ammonia synthesis.Single-atom collaboration with cluster can provide sufficient ...Exploring high-performance electrocatalysts for the nitrate reduction reaction(NO_(3)RR)is crucial for environmental nitrate removal and ammonia synthesis.Single-atom collaboration with cluster can provide sufficient active sites for catalysts to promote NO_(3)RR,yet the unclear synergistic effect between the two hinders their rational design.Herein,a series of Ir_(3)clusters and metal single atoms co-embedded in graphitic carbon nitride(g-CN)catalysts(Ir_(3)M1)were constructed,and the synergistic effects of Ir_(3)clusters and M1 single atoms on the NO_(3)RR catalytic mechanism and activity were systematically explored using density functional theory(DFT)calculations combined with machine learning.Comprehensive evaluations of structural stability and catalytic activity demonstrate that the synergy between single atoms and clusters effectively balances the adsorption energies of key intermediates,yielding exceptional catalytic performance(the limiting potential of Ir_(3)Ti_(1)can reach−0.22 V).Machine learning models further clarify the synergistic mechanism,where the geometric configurations of clusters serve as critical features for modulating the catalytic activity of single-atom sites,whereas the electronic structures of single atoms directly govern the reactivity of cluster sites.This DFT-machine learning approach provides theoretical guidelines for catalyst design and a predictive framework for efficient NO_(3)RR electrocatalysts.展开更多
Springs are vital freshwater sources for rural communities,yet they are increasingly threatened by nutrient enrichment,microbial contamination,and declining ecological integrity.This study assessed the water quality o...Springs are vital freshwater sources for rural communities,yet they are increasingly threatened by nutrient enrichment,microbial contamination,and declining ecological integrity.This study assessed the water quality of Sumber Suko Spring in East Java,Indonesia,through an integrated ecological approach combining physicochemical,microbiological,biological,and hydrological parameters across wet and dry seasons.Physicochemical results showed stable temperature(24.1–26.7°C),near-neutral pH(6.4–6.9),and adequate dissolved oxygen(6.2–7.4 mg/L).However,nitrate concentrations were elevated(39.37–48.16 mg/L),exceeding natural background levels and indicating agricultural leaching,while phosphate values ranged between 0.12–0.21 mg/L.Microbial analysis revealed high total coliform counts(24 CFU/100mL),far above WHO standards,although E.coli was not detected.Plankton analysis identified 10 genera,with Microcystis aeruginosa dominating,particularly in the dry season,signaling risks of eutrophication.Shannon-Wiener diversity indices(H’)ranged from 1.25 to 1.67,with evenness values between 0.43 and 0.56,reflecting low-to-moderate community stability.Hydrological measurements showed seasonal discharge fluctuations from 14.6 L/s in the wet season to 7.8 L/s in the dry season,strongly correlated with rainfall.Overall,the integration of nutrient enrichment,coliform contamination,and cyanobacterial dominance indicates that Sumber Suko Spring is under ecological stress and does not meet drinking water standards without treatment.The findings highlight the urgent need for source protection,disinfection,and continuous monitoring within a water safety plan framework.This study provides evidence-based insights to support local policy alignment with WHO guidelines and emphasizes the importance of community participation in sustaining spring ecosystems for long-term water security.展开更多
To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrat...To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones(NVZs)delineation through optimization of hydrogeological parameters.Based on detailed hydrogeological and hydrochemical investigations,the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability.The model selected hydrogeological parameters(depth of groundwater,lithology of the vadose zone,topographic slope,aquifer water yield property),one climatic parameter(precipitation),and two anthropogenic parameters(land use type and population density)as assessment indicators.The results of the groundwater nitrate vulnerability assessment showed that the low,relatively low,relatively high,and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%,35.44%,53.74%and 4.86%of the total area,respectively.Groundwater nitrate vulnerability was most strongly influenced by human activities,followed by groundwater depth and topographic slope.The high vulnerability zone is mainly affected by domestic and industrial wastewater,whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities.Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index(DI)and nitrate concentration(ρ(NO3−)).The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning,guiding the development of targeted measures in the NVZs to prevent groundwater contamination.展开更多
Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt...Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt-based electrocatalysts,emphasizing their structural engineering for enhanced the performance of electrocatalytic nitrate reduction reaction(NO3RR)through dimensional control,compositional tuning,and coordination microenvironment modulation.Notably,by critically analyzing metallic cobalt,cobalt alloys,cobalt compounds,cobalt single atom and molecular catalyst configurations,we firstly establish correlations between atomic-scale structural features and catalytic performance in a coordination environment perspective for NO3RR,including the dynamic reconstruction during operation and its impact on active site.Synergizing experimental breakthroughs with computational modeling,we decode mechanisms underlying competitive hydrogen evolution suppression,intermediate adsorption-energy optimization,and durability enhancement in complex aqueous environments.The development of cobalt-based catalysts was summarized and prospected,and the emerging opportunities of machine learning in accelerating the research and development of high-performance catalysts and the configuration of series reactors for scalable nitrate-to-ammonia systems were also introduced.Bridging surface science and applications,it outlines a framework for designing multifunctional electrocatalysts to restore nitrogen cycle balance sustainably.展开更多
The electrode structures in ignition devices for Electrically Controlled Solid Propellants(ECSP) can be classified into fixed and movable types. In movable electrode structures, springs are typically used to push the ...The electrode structures in ignition devices for Electrically Controlled Solid Propellants(ECSP) can be classified into fixed and movable types. In movable electrode structures, springs are typically used to push the electrodes and the propellant. The effects of spring pressure on the ignition and combustion of propellants have not yet been studied. In this paper, a universal testing machine and an electrochemical workstation were firstly utilized to investigate the compressive mechanical property and conductivity of Hydroxylamine Nitrate(HAN)-ECSP. The maximum pressure at which the propellant undergoes elastic deformation is 65 kPa. When the spring pressure increased from 5.1 k Pa to 20.4 kPa, the propellant resistance decreased from 56.8 Ω to 36.8 Ω.Various observation methods were employed to study the process of electrical energy injection and the ignition and combustion characteristics under constant voltage. Appropriately increasing the spring pressure can accelerate the injection of electrical energy into the propellant, increase the electrification current, and thus reduce the initial ignition delay time of the propellant. When the spring pressure is 20.4 kPa, the squeezing speed of the propellant is too fast, making it difficult for the propellant to be adequately heated at the electrode interface, which is unfavorable for ignition. Excessive spring pressure also leads to the accumulation of a large amount of combustion residue on the electrode plate, hindering the mixing and diffusion of hot gases during the second ignition process, preventing the gaseous flame of the propellant. When the spring pressure is 5.1 kPa, improving the working voltage can enhance the repeated ignition characteristics of the propellant.展开更多
The electrocatalytic reduction of nitrate to ammonia(NO_(3)^(−)RR)offers a sustainable alternative to energy-intensive industrial NH3 synthesis.Tandem catalysis has shown promise in overcoming the multi-step complexit...The electrocatalytic reduction of nitrate to ammonia(NO_(3)^(−)RR)offers a sustainable alternative to energy-intensive industrial NH3 synthesis.Tandem catalysis has shown promise in overcoming the multi-step complexity of NO_(3)^(−)RR,yet challenges remain in optimizing performance and elucidating tandem mechanisms.Herein,we report a Cu@Co/CoFe-P tandem electrocatalyst featuring a phosphorus-doped heterostructure with dual active sites(Cu-P and Co/CoFe-P).This catalyst achieves an exceptional NH_(3)yield of 175.40 mg h^(−1)cm^(−2)and a record-high current density exceeding 2 A cm^(−2),with the electro-synthesized NH3 directly converted into NH4Cl.In situ spectroscopic analysis and density functional theory(DFT)calculations reveal a novel desorption-reactivation tandem mechanism:(1)the Cu-P domain preferentially reduces NO_(3)^(−)to*NO_(2),which desorbs as stable NO_(2)^(−);(2)the Co/CoFe-P domain subsequently reactivates NO_(2)^(−),and converts it efficiently into NH3.Moreover,phosphorus doping enhances*H supply,while Fe alloying with Co promotes NO_(2)^(−)hydrogenation,ensuring an efficient and synchronized tandem pathway for NO_(3)^(−)RR.The proposed*NO_(2)desorption-reactivation mechanism deepens the understanding of NO_(3)^(−)RR tandem process,thereby paving the way for designing more efficient tandem electrocatalysts.展开更多
基金supported by the National Key R&D Program of China(No.2017YFC0212501)the Fundamental Research Funds for the Central Universities(No.2021YJSMT09)the research project on deep source apportionment of urban air pollution and pollution control strategies in the core area of the Ili River Valley。
文摘Polycyclic Aromatic Hydrocarbons(PAHs),along with their derivatives nitro-PAHs and oxy-PAHs,are globally recognized toxic pollutants.This research conducted daily PM_(2.5)sampling in winter 2021 at three urban(YNCE,SWP,and NG)and three suburban sites(HC,CTV,and YNE)in the Ili River Valley(IRV).For the first time in the IRV,a comprehensive study on 39 PAHs and derivatives was carried out.The results showed that the average∑_(16)PAHs concentration was 130.21±98.94 ng/m^(3),with 16PAHs constituting the dominant fraction(112.51±86.48 ng/m^(3)).The mean BaP and the total BaP equivalent quotient(TEQ)concentrations were 10.28±8.85 ng/m^(3)and 19.74±16.70 ng/m^(3),respectively.Approximately 88%of the daily BaP averages and 98%of the daily TEQ averages exceeded the national daily average standard of BaP(2.5 ng/m^(3)),indicating severe local BaP pollution.Urban sites had notably higher∑PAHs and TEQ concentrations than suburban sites,attributed to increased vehicular traffic and coal combustion in urban areas.PMF results showed that traffic emissions(32.7%-60.5%),coal combustion(13.9%-24.3%)and secondary formation(14.7%-22.7%)were the primary contributors to∑PAHs.Urban sites experienced a greater influence from traffic,while suburban sites were more impacted by coal and biomass burning.On polluted days,traffic sources’contributions increased significantly at HC,YNE,NG and YNCE sites,and secondary formation sources’contributions grew at CTV and YNCE sites.The sourcedependent BaPeq results underscored the role of secondary-formed PAH derivatives in TEQ.
基金supported by the National Natural Science Foundation of China(No.41671493)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF17030)the National Major Project of the Science and Technology Ministry of China(No.2017ZX07202-004 and 2017X07301002-3)。
文摘Nitrated polycyclic aromatic hydrocarbons(NPAHs)have toxic potentials that are higher than those of their corresponding parent polycyclic aromatic hydrocarbons(PAHs)and thus have received increasing attention in recent years.In this study,the occurrence,distribution,source,and human health risk assessment of 15 NPAHs and 16 PAHs were investigated in the surface water from 20 sampling sites of Lake Taihu during the dry,normal,and flood seasons of 2018.The PAH concentrations ranged from 255 to 7298 ng/L and the NPAH concentrations ranged from not-detected(ND)to 212 ng/L.Among the target analytes,2-nitrofluorene(2-n Flu)was the predominant NPAH,with a detection frequency ranging from 85%to 90%and a maximum concentration of 56.2 ng/L.The three-ringed and four-ringed NPAHs and PAHs comprised the majority of the detected compounds.In terms of seasonal variation,the highest levels of the NPAHs and PAHs were in the dry season and flood season,respectively.Diagnostic ratio analysis indicated that the prime source of NPAHs was direct combustion,whereas in the case of PAHs the contribution was predominantly from a mixed pattern including pollution from unburned petroleum and petroleum combustion.The human health risk of NPAHs and PAHs was evaluated using a lifetime carcinogenic risk assessment model.The carcinogenic risk level of the targets ranged from 2.09×10^(-7)to 5.75×10^(-5)and some surface water samples posed a potential health risk.
基金supported by the National Natural Science Foundation of China(No.41907197)the Fundamental Research Funds for Central Public Welfare Scientific Research Institutes of China,Chinese Research Academy of Environmental Sciences(No.2019YSKY-018)+1 种基金the National Key R&D Program of China(No.2019YFC0214800)the Standard System and Key Standards Research of National Ecological Environment Protection and Risk Prevention(No.2020YFC18063)。
文摘Polycyclic aromatic hydrocarbons(PAHs)and their nitrated derivatives(NPAHs)attract continuous attention due to their outstanding carcinogenicity and mutagenicity.In order to investigate the diurnal variations,sources,formation mechanism,and health risk assessment of them in heating season,particulate matter(PM)were collected in Beijing urban area from December 26,2017 to January 17,2018.PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS).Average daily concentrations of PAHs and NPAHs were(78±54)ng/m^(3)and(783±684)pg/m^(3),respectively.The concentrations of them were significantly higher at nighttime than at daytime,and NPAHs concentrations were 1-2 orders of magnitude lower than PAHs concentrations.In the heating season,the dominant species of PAHs include benzo[b]fluoranthene,fluoranthene,pyrene,and chrysene,while 9-nitroanthracene,2+3-nitrofluoranthene,and 2-nitropyrene were dominant species for NPAHs.NPAHs were found to have a single peak during heating and to be primarily distributed in the 0.4-0.7μm particle size.Primary emissions such as biomass burning,coal combustion,and traffic emissions were the major sources of PAHs.NPAHs were produced by the primary source of vehicle emissions and the secondary reaction triggered by OH radicals,as well as biomass burning during daytime.According to the health risk assessment,the total carcinogenic risk was higher in adults than in children.While upon oral ingestion,the carcinogenic risk in children was higher than that of adults,but the risk of adults was higher than children through skin contact and respiratory inhalation.
基金supported by the National Natural Science Foundation of China (No. 40971257,41171365)the Environmental Nonprofit Research and Special Project of China (No. 201009004)the Program for Changjiang Scholars and Innovative Research Team in University (No.IRT0941)
文摘Intensive daytime and nighttime sampling was carried out from 23 Oct to 31 Dec 2008 to investigate the occurrence of nitrated polycyclic aromatic hydrocarbons （NPAHs） in PM1o at a roadside site in Xiamen, China. At the same time, six PMt0 samples were collected from a nearby roadway tunnel for comparison. Six NPAHs, namely 9-nitroanthracene, 2- and 3-nitrofluoranthene, 1- nitropyrene, 7-nitrobenz[a]anthracene, and 6-nitrobenzo[a]pyrene, were identified and quantified using GC/MS in negative ion chemical ionization mode. The average total concentration of six NPAHs （~NPAHs） in the cold season （26 Nov-31 Dec） was 2.3 （daytime） and 9.9 （nighttime） times higher than those in the warm season. Significant statistical difference （p 〈 0.01, 2-tailed） of ∑NPAHs between daytime and nighttime was found during both the warm and cold seasons. NPAHs were significantly positively correlated with their parent PAHs and nitrogen dioxide but negatively correlated with ambient temperature. The ratio of 2 ＋ 3-nitrofluoranthene to 1- nitropyrene exhibited a similar diurnal pattern as ZNPAHs and was generally greater than 5, indicating the importance of secondary atmospheric formation. The diurnal variations of NPAHs were all influenced by the diurnal variations of PAHs, nitrogen dioxide, sunlight, and temperature. The daily inhalable exposure to the six NPAHs in the tunnel was much higher than the roadside values in the warm season but only slightly higher than those in the cold season.
基金financially supported by the National Natural Science Foundation of China (No. 41977341)Natural Science Foundation of Zhejiang Province, China (No. LGF21B070007)Research Center for Air Pollution and Health, Zhejiang University (No. I21405-11)
文摘Air pollutants can potentially lead to nitration of allergic proteins,thus promoting sensitization of these allergens.However,little is currently known about the nitration status of house dust mite(HDM)allergens.We identified the occurrence of nitrated products of two major HDM allergens Der f 1 and Der p 1 in dust samples collected from college dormitories in eastern China and assessed their associated health risk.The results showed that both non-nitrated and nitrated forms of the two allergens were detected in the dust in the range of non-detected(ND)-10.6,1.44-15.4,ND-22.4,ND-7.28μg/g for non-nitrated Der f 1,nitrated Der f 1,non-nitrated Der p 1 and nitrated Der p 1,respectively.The median rates of nitration were determined as 74.0%for Der f 1 and 20.4% for Der p 1 at consideration of one nitration site.Further analysis reveals that the levels of HDM allergens and their nitrated products were found to be generally higher during winter,in dormitories of lower altitude and with female occupants.Furthermore,the calculated risk indexes were at considerably high levels.Our findings suggest that nitrated HDM allergens have already accumulated in the environment at such significant levels and their associated health risk calls for our immediate attention.
基金the support of ANID-FONDECYT POSDOCTORAL 3220099,ANID-FONDECYT REGULAR No 1220339,FOVI240019 and FOVI240035,ANID/FONDEQUIP N°EQM200049ANID/DOCTORATE No.21221883CSIC-Uruguay,INIA-Fpta-Uruguay,and Programa de Desarrollo de las Ciencias B´asicas(PEDECIBA,Uruguay).
文摘Nutrition plays a vital role in human health,particularly through the type and quality of dietary fats.While excessive saturated fatty acid(SFA)intake is associated with negative cardiovascular outcomes,unsaturated fats especially monounsaturated(MUFA)and polyunsaturated fatty acids(PUFA)offer protective benefits.Among the bioactive lipids derived from unsaturated fats are nitrated fatty acids(NO2-FAs),electrophilic signaling molecules formed naturally during inflammation or via dietary interactions between nitrite-rich vegetables and unsaturated lipids.NO2-FAs have been shown to exert anti-inflammatory,antioxidant,and antiplatelet effects,influencing metabolic pathways involved in cardiometabolic health.This review explores the formation,meta-bolism,and biological actions of NO2-FAs from dietary sources,emphasizing their role within dietary patterns like the Mediterranean diet.By bridging lipid biochemistry and nutritional science,we underscore the therapeutic potential of NO2-FAs as diet-derived agents for disease prevention and treatment in metabolic and cardiovascular disorders.
基金funded by the British Heart Foundation(PGF/10/82/28608).
文摘Previous studies documented increased nitrative stress and susceptibility to air pollution among individuals with chronic inflammatory conditions.This study examines the role of anti-inflammatory and cardioprotective nitrated fatty acids(i.e.,NO2-cLA)in chronic obstructive pulmonary disease(COPD)'s and ischemic heart disease(IHD)'s susceptibility to air pollution.In a randomized crossover study,40 healthy,40 COPD,and 39 IHD adults underwent a 2 h walk in a more polluted street or a less polluted park.We measured urinary NO2-cLA before and 24 h after the walk,as well as respiratory inflammatory biomarkers,lung function,airway resistance,and arterial stiffness.Baseline NO2-cLA levels were 2.56(95%CI:1.20-5.43)-fold higher among COPD participants than healthy participants,which can be explained by higher fractional exhaled nitric oxide and sputum myeloperoxidase levels.Among COPD but not healthy or IHD participants,the street walk,compared to park,led to a 57.7%(95%CI:7.6-80.6%)decrease in NO2-cLA levels and sputum biomarker changes indicative of decreased neutrophil inflammation and proresolving responses.Decreased NO2-cLA levels were associated with exposure to black carbon and ultrafine particles and worsened lung function and arterial stiffness.Taken together,nitrated fatty acids partially mediate COPD patients'cardiorespiratory responses to air pollution,explaining their susceptibility.
基金supported by the National Natural Science Foundation of China,No.81671263(to XX)Scientific Research and Innovation Team,Education Department of Anhui Province,China,No.2023AH010072(to XX)+1 种基金the Natural Science Foundation of Anhui Province,No.2208085MH221(to XX)The Key Projects for National Science Research of Education Department of Anhui Province,No.KJ2021A0851(to YD).
文摘Cmyc,a proto-oncogene,is expressed at extremely low levels in mature neurons and is traditionally thought to have no function in these cells.However,recent studies suggest that Cmyc may play a crucial role in maintaining the health and function of mature dopaminergic neurons.This study assessed the role of Cmyc in dopaminergic neurons and its significance in Parkinson’s disease.We used a conditional knockout approach to specifically delete Cmyc in substantia nigra dopaminergic neurons of adult mice.Our findings showed that Cmyc deletion led to progressive neuron loss,Parkinson’s disease-like symptoms,downregulation of Klotho,and upregulation of senescence-associated inflammatory factors,along with enhanced oxidative stress and nitrated alpha-synuclein accumulation,ultimately causing neuronal death.In vitro experiments confirmed increased senescence in C-MYC knockout cells,which was partially reversible by KLOTHO overexpression.We conclude that low-level Cmyc expression is essential for maintaining the health of mature dopaminergic neurons and preventing neurodegeneration,and suggest the c-Myc/Klotho axis as a potential therapeutic target for age-related neurodegenerative diseases,including Parkinson’s disease.Our study introduces a novel mouse model for Parkinson’s disease that replicates a condition associated with normal aging,offering a valuable tool for future research into disease mechanisms and therapeutic strategies.
基金funding from Deutsche Forschungsgemeinschaft (DFG)supported by an MCIN Ry C Programme MCIN/ AEI/10.13039/501100011033+2 种基金by the ‘European Union Next Generation EU/PRTR’ under grant no. RYC2021-032345-Isupported by the AEI (grant no. PID2019-107463RJ-I00/ AEI/10.13039/501100011033)the Regional Research and Development Programme of the Government of Navarre (call 2019, project Nitro Healthy, PC068)
文摘Ammonium toxicity in plants remains poorly understood despite extensive research.While nitrate is known to benefit plant growth,the synergistic effects of nitrate in mitigating ammonium toxicity,even at low concentrations,are not fully elucidated.This review delves into the physiological and molecular nature of this phenomenon.To date,nitrate-dependent alleviation of ammonium toxicity is the result of cumulative consequences of the role of nitrate as a nutrient and signal in plant performance.The ability to counteract the ammonium-induced acidification through nitrate uptake and metabolism,the enhancement of potassium uptake as an essential nitrate counterion,and the nitratedependent signaling of key factors involved in ammonium assimilation,ROS scavenging,and growth hormone biosynthesis,are the most relevant hallmarks.In addition,evidence suggests that the availability of nitrate and ammonium has driven ecological selection in plants,determining current N preferences,and may have led to the selection of nitrate-dependent and ammonium-sensitive domesticated crops and the inefficient use of N fertilizers in agriculture.As ammonium toxicity limits N fertilization options and reduces agricultural yields,when it could be a more sustainable and cheaper alternative to nitrate,this review provides a better understanding of how plants use nitrate to counteract the problematic aspects of ammonium nutrition.
基金supported by the National Natural Science Foundation of China(Nos.42372355,42530706)。
文摘Nitrate pollution is a severe threat to the fragile ecosystems in karst regions.However,our knowledge of the sources and transformations of nitrate in karst cave groundwater is still limited.This study aimed to investigate the temporal and spatial patterns of nitrate dynamics in the underground water of karst caves located on the south bank of the Qingjiang River in central China,through a comprehensive application of multiple approaches,such as hydrochemistry,nitrogen and oxygen isotope compositions of nitrate,and a Bayesian isotope mixing model(SIMMR).During the sampling period(from December 2018 to December 2019),the nitrate concentration did not show an apparent temporal variation;meanwhile,no water samples in this study had a nitrate concentration higher than the limit for drinking water,but the nitrate concentration in karst underground rivers is significantly higher than that in surface water.The results of the comprehensive analyses revealed that the predominant nitrate sources included nitrification in soil and chemical fertilizer,which had mean percentages of 43%and 32%,respectively.The source contribution varied in the outlet water among different caves.The soil-derived nitrate in the underground water from the Shizi Cave accounted for the highest proportion(49%),while chemical-fertilizer-derived nitrate in the underground water from the Mishui Cave accounted for the highest proportion(36%).The dualisotope signatures of nitrate supported a major influence on nitrogen dynamics in the cave underground from nitrification.These findings suggest that nitrate carried by underground rivers in karst caves should be alerted when making the nitrate balance in rivers flowing through karst areas.
基金the Natural Science Foundation of China(Grant No.NSFC-22072062,22202098)the Science and Technology Project of China Northern Rare Earth(BFXT-2023-D-0048 and BFXT-2022-D-0078)。
文摘Electrochemical nitrate reduction reaction(NO_(3)RR)is a sustainable strategy to treat wastewater and produce ammonia.However,it is still a challenge to prepare electrocatalysts with high activity and selectivity.Herein,the CuO_(x) nanowires supported Ru nanoclusters(Ru-CuO_(x))were fabricated via a three-step procedure for efficient nitrate conversion and highly selective ammonia generation.The prepared RuCuO_(x) shows a high ammonia yield rate of 2286.5μg h^(-1) cm^(-2) at-0.7 V vs.RHE and Faradaic efficiency(FE)of 80.1%at-0.4 V vs.RHE.Additionally,the nitrate conversion rate exceeds 90%at the potential range from-0.2 to-0.7 V vs.RHE,and the ammonia selectivity can reach 97.7%at-0.7 V vs.RHE in100 mg L^(-1) NaNO_(3) solution.The systematic characterizations clarify that the introduction of Ru not only regulates the electronic structure of CuO_(x) and accelerates the reconstruction of CuO_(x) to Cu but also promotes H2O dissociation to generate active hydrogen.Moreover.in-situ Raman spectroscopy reveals that the formed Ru-Cu is considered the actual active species during the NO_(3)RR.Density functional theory(DFT)calculations further prove that the obtained Ru-Cu facilitates the adsorption of nitrate and lowers the Gibbs free energy of the rate-determining step,thus improving the NO_(3)RR performance.
基金supported by the Natural Science Foundation(NSF)of China(Nos.22205015,22175020,and 22235001)the National Postdoctoral Program for Innovative Talents(No.BX20220032)+2 种基金the China Postdoctoral Science Foundation Funded Project(No.2022BG013)the Fundamental Research Funds for the Central Universities(Nos.00007709,00007770,and FRFBR-23-02B)University of Science and Technology Beijing is gratefully acknowledged.
文摘In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry between corresponding building blocks and linking units in addition to the unmanageable packing of 1D organic chains once formed.Herein,two novel imide-linked 1D COFs with phthalocyanine building blocks,namely NiPc-CZDM-COF and NiPc-CZDL-COF,were fabricated from the hydrothermal synthesis reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato nickel(II)(NiPc(COOH)_(8))with 9H-carbazole-3,6-diamine(CZDM)and 4,4′-(9H-carbazole-3,6-diyl)dianiline(CZDL),respectively.Two COFs have high crystallinity on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy.Due to their high ratio of exposed active centers on the edge sites of porous ribbons,both NiPc-CZDM-COF and NiPc-CZDL-COF electrodes display high utilization efficiency of NiPc electroactive sites of 8.0%and 7.5% according to the electrochemical measurement,resulting in their excellent capacity toward electrocatalytic nitrate reduction with the nitrate-to-NH3 Faradaic efficiency of nearly 100%.In particular,NiPc-CZDM-COF electrode exhibits superior electrocatalytic performance with high NH_(3) partial current density of−246 mA/cm^(2),ammonia yield rate of 19.5 mg cm^(−2) h^(−1),and turnover frequency of 5.8 s^(−1) at−1.2 V in an H-type cell associated with its higher conductivity.This work reveals the good potential of 1D porous crystalline materials in electrocatalysis.
基金support from the National Natural Science Foundation of China(NSFC 21905092,22475072 and 22075085)the Fundamental Research Funds for the Central Universities+1 种基金supported by the Shanghai Frontiers Science Center of Molecule Intelligent SynthesesEast China Normal University Multifunctional Platform for Innovation(004)。
文摘Artificial photosynthesis of hydrogen peroxide(H_(2)O_(2))from earth-abundant water and oxygen is a sustainable approach,however current photocatalysts suffer from low production rate and solar-to-chemical conversion efficiency(<1.5%).Herein,we report that nickelchromium layered double hydroxide with intercalated nitrate(NiCrOOH-NO_(3))and a thickness of~4.4 nm is an efficient photocatalyst,enabling a H_(2)O_(2)production yield of 28.7 mmol g^(-1)h^(-1)under visible light irradiation with3.92%solar-to-chemical conversion efficiency.Experimental and computational studies have revealed an inherent facet-dependent reduction-oxidation reaction behavior and spatial separation of photogenerated electrons and holes.An unexpected role of intercalated nitrate is demonstrated,which promotes excited electron—hole spatial separation and facilitates the electron transfer to oxygen intermediate via delocalization.This work provides understandings in the impact of nanostructure and anion in the design of advanced photocatalysts,paving the way toward practical synthesis of H_(2)O_(2)using fully solar-driven renewable energy.
基金the financial support from the Shandong Province colleges and universities youth innovation technology plan innovation team project(2022KJ285)the Natural Science Foundation of Shandong Province(ZR2022QE076)+1 种基金the National Natural Science Foundation of China(52202092)the Science and Technology Support Plan for Youth Innovation of Colleges and Universities of Shandong Province of China(2023KJ104).
文摘Exploring high-performance electrocatalysts for the nitrate reduction reaction(NO_(3)RR)is crucial for environmental nitrate removal and ammonia synthesis.Single-atom collaboration with cluster can provide sufficient active sites for catalysts to promote NO_(3)RR,yet the unclear synergistic effect between the two hinders their rational design.Herein,a series of Ir_(3)clusters and metal single atoms co-embedded in graphitic carbon nitride(g-CN)catalysts(Ir_(3)M1)were constructed,and the synergistic effects of Ir_(3)clusters and M1 single atoms on the NO_(3)RR catalytic mechanism and activity were systematically explored using density functional theory(DFT)calculations combined with machine learning.Comprehensive evaluations of structural stability and catalytic activity demonstrate that the synergy between single atoms and clusters effectively balances the adsorption energies of key intermediates,yielding exceptional catalytic performance(the limiting potential of Ir_(3)Ti_(1)can reach−0.22 V).Machine learning models further clarify the synergistic mechanism,where the geometric configurations of clusters serve as critical features for modulating the catalytic activity of single-atom sites,whereas the electronic structures of single atoms directly govern the reactivity of cluster sites.This DFT-machine learning approach provides theoretical guidelines for catalyst design and a predictive framework for efficient NO_(3)RR electrocatalysts.
文摘Springs are vital freshwater sources for rural communities,yet they are increasingly threatened by nutrient enrichment,microbial contamination,and declining ecological integrity.This study assessed the water quality of Sumber Suko Spring in East Java,Indonesia,through an integrated ecological approach combining physicochemical,microbiological,biological,and hydrological parameters across wet and dry seasons.Physicochemical results showed stable temperature(24.1–26.7°C),near-neutral pH(6.4–6.9),and adequate dissolved oxygen(6.2–7.4 mg/L).However,nitrate concentrations were elevated(39.37–48.16 mg/L),exceeding natural background levels and indicating agricultural leaching,while phosphate values ranged between 0.12–0.21 mg/L.Microbial analysis revealed high total coliform counts(24 CFU/100mL),far above WHO standards,although E.coli was not detected.Plankton analysis identified 10 genera,with Microcystis aeruginosa dominating,particularly in the dry season,signaling risks of eutrophication.Shannon-Wiener diversity indices(H’)ranged from 1.25 to 1.67,with evenness values between 0.43 and 0.56,reflecting low-to-moderate community stability.Hydrological measurements showed seasonal discharge fluctuations from 14.6 L/s in the wet season to 7.8 L/s in the dry season,strongly correlated with rainfall.Overall,the integration of nutrient enrichment,coliform contamination,and cyanobacterial dominance indicates that Sumber Suko Spring is under ecological stress and does not meet drinking water standards without treatment.The findings highlight the urgent need for source protection,disinfection,and continuous monitoring within a water safety plan framework.This study provides evidence-based insights to support local policy alignment with WHO guidelines and emphasizes the importance of community participation in sustaining spring ecosystems for long-term water security.
基金supported by the National Key Research and Development Program of China(No.2022YFF1301301)the Natural Science Foundation of Xiamen Municipality(No.3502Z202472047)the Geological Survey Program of China Geological Survey(DD20190303).
文摘To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions,this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones(NVZs)delineation through optimization of hydrogeological parameters.Based on detailed hydrogeological and hydrochemical investigations,the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability.The model selected hydrogeological parameters(depth of groundwater,lithology of the vadose zone,topographic slope,aquifer water yield property),one climatic parameter(precipitation),and two anthropogenic parameters(land use type and population density)as assessment indicators.The results of the groundwater nitrate vulnerability assessment showed that the low,relatively low,relatively high,and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%,35.44%,53.74%and 4.86%of the total area,respectively.Groundwater nitrate vulnerability was most strongly influenced by human activities,followed by groundwater depth and topographic slope.The high vulnerability zone is mainly affected by domestic and industrial wastewater,whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities.Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index(DI)and nitrate concentration(ρ(NO3−)).The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning,guiding the development of targeted measures in the NVZs to prevent groundwater contamination.
基金supported by the National Natural Science Foundation of China(Grant Nos.:21825201,52401244 and 52201227)Henan Province Key Research and Development and Promotion Program(Scientific and Technological Breakthrough Project:232102240088 and 252102230078)+3 种基金the Key Research&Development and Promotion of Special Project(Scientific Problem Tackling)of Henan Province(252102230078)Doctoral Research Startup Fund Project of Henan Open University(BSJH-2025-04)Zhejiang Provincial Natural Science Foundation of China(LQ24B020005,LQ23B030001)China Postdoctoral Science Foundation(2024M762442).
文摘Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt-based electrocatalysts,emphasizing their structural engineering for enhanced the performance of electrocatalytic nitrate reduction reaction(NO3RR)through dimensional control,compositional tuning,and coordination microenvironment modulation.Notably,by critically analyzing metallic cobalt,cobalt alloys,cobalt compounds,cobalt single atom and molecular catalyst configurations,we firstly establish correlations between atomic-scale structural features and catalytic performance in a coordination environment perspective for NO3RR,including the dynamic reconstruction during operation and its impact on active site.Synergizing experimental breakthroughs with computational modeling,we decode mechanisms underlying competitive hydrogen evolution suppression,intermediate adsorption-energy optimization,and durability enhancement in complex aqueous environments.The development of cobalt-based catalysts was summarized and prospected,and the emerging opportunities of machine learning in accelerating the research and development of high-performance catalysts and the configuration of series reactors for scalable nitrate-to-ammonia systems were also introduced.Bridging surface science and applications,it outlines a framework for designing multifunctional electrocatalysts to restore nitrogen cycle balance sustainably.
基金supported by the National Natural Science Foundation of China(Nos.T222100,22205258,52302485 and 2024JJ5404).
文摘The electrode structures in ignition devices for Electrically Controlled Solid Propellants(ECSP) can be classified into fixed and movable types. In movable electrode structures, springs are typically used to push the electrodes and the propellant. The effects of spring pressure on the ignition and combustion of propellants have not yet been studied. In this paper, a universal testing machine and an electrochemical workstation were firstly utilized to investigate the compressive mechanical property and conductivity of Hydroxylamine Nitrate(HAN)-ECSP. The maximum pressure at which the propellant undergoes elastic deformation is 65 kPa. When the spring pressure increased from 5.1 k Pa to 20.4 kPa, the propellant resistance decreased from 56.8 Ω to 36.8 Ω.Various observation methods were employed to study the process of electrical energy injection and the ignition and combustion characteristics under constant voltage. Appropriately increasing the spring pressure can accelerate the injection of electrical energy into the propellant, increase the electrification current, and thus reduce the initial ignition delay time of the propellant. When the spring pressure is 20.4 kPa, the squeezing speed of the propellant is too fast, making it difficult for the propellant to be adequately heated at the electrode interface, which is unfavorable for ignition. Excessive spring pressure also leads to the accumulation of a large amount of combustion residue on the electrode plate, hindering the mixing and diffusion of hot gases during the second ignition process, preventing the gaseous flame of the propellant. When the spring pressure is 5.1 kPa, improving the working voltage can enhance the repeated ignition characteristics of the propellant.
基金supported financially by the Key Project of the National Ministry of Science and Technology (No.2022YFC3705005)the Open Foundation of Key Laboratory of Industrial Ecology and Environmental Engineering,MOE (KLIEEE-22-05)
文摘The electrocatalytic reduction of nitrate to ammonia(NO_(3)^(−)RR)offers a sustainable alternative to energy-intensive industrial NH3 synthesis.Tandem catalysis has shown promise in overcoming the multi-step complexity of NO_(3)^(−)RR,yet challenges remain in optimizing performance and elucidating tandem mechanisms.Herein,we report a Cu@Co/CoFe-P tandem electrocatalyst featuring a phosphorus-doped heterostructure with dual active sites(Cu-P and Co/CoFe-P).This catalyst achieves an exceptional NH_(3)yield of 175.40 mg h^(−1)cm^(−2)and a record-high current density exceeding 2 A cm^(−2),with the electro-synthesized NH3 directly converted into NH4Cl.In situ spectroscopic analysis and density functional theory(DFT)calculations reveal a novel desorption-reactivation tandem mechanism:(1)the Cu-P domain preferentially reduces NO_(3)^(−)to*NO_(2),which desorbs as stable NO_(2)^(−);(2)the Co/CoFe-P domain subsequently reactivates NO_(2)^(−),and converts it efficiently into NH3.Moreover,phosphorus doping enhances*H supply,while Fe alloying with Co promotes NO_(2)^(−)hydrogenation,ensuring an efficient and synchronized tandem pathway for NO_(3)^(−)RR.The proposed*NO_(2)desorption-reactivation mechanism deepens the understanding of NO_(3)^(−)RR tandem process,thereby paving the way for designing more efficient tandem electrocatalysts.
