Sulfide-based all-solid-state lithium batteries(ASSLBs) with nickel-rich oxide cathodes are emerging as primary contenders for the next generation rechargeable batteries,owing to their superior safety and energy densi...Sulfide-based all-solid-state lithium batteries(ASSLBs) with nickel-rich oxide cathodes are emerging as primary contenders for the next generation rechargeable batteries,owing to their superior safety and energy density.However,the all-solid-state batteries with nickel-rich oxide cathodes suffer from performance degradation due to the reactions between the highly reactive surface oxygen of the cathode and the electrolyte,as well as the instability of the bulk oxygen structure in the cathode.Herein,we propose a synergistic modification design scheme to adjust the oxygen activity from surface to bulk.The LiBO_(2)coating inhibits the reactivity of surface lattice oxygen ions.Meanwhile,Zr doping in the bulk phase forms strong Zr-O covalent bonds that stabilize the bulk lattice oxygen structure.The synergistic effect of these modifications prevents the release of oxygen,thus avoiding the degradation of the cathode/SE interface.Additionally,the regulation of surface-to-bulk oxygen activity establishes a highly stable interface,thereby enhancing the lithium ion diffusion kinetics and mechanical stability of the cathode.Consequently,cathodes modified with this synergistic strategy exhibit outstanding performance in sulfide-based ASSLBs,including an ultra-long cycle life of 100,000 cycles,ultra-high rate capability at 45C,and 85% high active material content in the composite cathode.Additionally,ASSLB exhibits stable cycling under high loading conditions of 82.82 mg cm^(-2),achieving an areal capacity of 17.90 mA h cm^(-2).These encouraging results pave the way for practical applications of ASSLBs in fast charging,long cycle life,and high energy density in the future.展开更多
The hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts hav...The hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts have been made to manipulate the p-d hybridization in TMOs by tailoring the spatial orbital overlap via structural engineering.Here,we demonstrate enhanced p-d hybridization in Ba^(2+)-doped LaNiO_(3)epitaxial films by simultaneously modifying both the spatial and energetic overlaps between the O-2p and Ni-3d orbitals.Combining x-ray absorption spectroscopy and firstprinciples calculations,we reveal that the enhanced hybridization stems from the synergistic effects of a reduced chargetransfer energy due to hole injection and an increased spatial orbital overlap due to straightening of Ni-O-Ni bonds.We further show that the enhanced p-d hybridization can be utilized to promote the oxygen evolution activity of LaNiO_(3).This work sheds new insights into the fine-tuning of the electronic structures of TMOs for enhanced functionalities.展开更多
Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we...Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we prepare two mixed-addendum polyoxometalate-based coordination polymers of the general formula[H_(x)M_(1-x)(i-PrIm)_(4)][H_(2)N(CH_(3))_(2)]_(4)[HPMo_(8)V_(6)O_(42)](M=Co 1,Ni,2;i-PrIm=1-isopropyl-1H-imidazole).Needing no additives,they can catalyze the selective oxidation of isochroman to isochromanone with O_(2)as an oxidant,with yields of 91.5%(1)and 46.8%(2),respectively.Mechanistic studies indicate that the excellent performance of catalyst 1 is attributed to the synergistic operation of[Co(i-Pr-Im)_(4))]complex and PMo_(8)V_(6)unit,and that the catalytic reaction is a radical pathway involving superoxide radicals.Additionally,the catalyst 1 can be recycled and reused at least four times with uncompromised performance.These results provide fundamental guidelines for designing efficient and multi-site heterogeneous catalysts for the selective oxidation of benzyl C(sp^(3))-H bonds by activating O_(2).展开更多
Singlet oxygen(^(1)O_(2)),as an electrophilic oxidant,is essential for the selective water decontamination of pollutants from water.Herein,we showcase a high-performing electrocatalytic filtration system composed of c...Singlet oxygen(^(1)O_(2)),as an electrophilic oxidant,is essential for the selective water decontamination of pollutants from water.Herein,we showcase a high-performing electrocatalytic filtration system composed of carbon nanotubes functionalized with CoFe alloy nanoparticles(CoFeCNT)to selectively facilitate the electrochemical activation of O_(2)to^(1)O_(2).Benefiting from the prominently featured bimetal active sites of CoFeCNT,nearly complete production of^(1)O_(2)is achieved by the electrocatalytic activation of O_(2).Additionally,the proposed system exhibits a consistent pollutant removal efficiency>90%in a flow-through reactor over 48 h of continuous operation without a noticeable decline in performance,highlighting the dependable stability of the system for practical applications.The flow-through configuration demonstrates a striking 8-fold enhancement in tetracycline oxidation compared to a conventional batch reactor.This work provides a molecular level understanding of the oxygen reduction reaction,showing promising potential for the selective removal of emerging organic contaminants from water.展开更多
A dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction was prepared by decomposition methods,and it displayed enhanced performance to degrade tetracycline hydrochloride with the ideal stability under di...A dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction was prepared by decomposition methods,and it displayed enhanced performance to degrade tetracycline hydrochloride with the ideal stability under different water substrates and ions.Comparing with three single components,as g-C_(3)N_(4),g-C_(3)N_(5),and Ag_(3)PO_(4),the dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction displayed 4.4-,3.4-,and 2.5-times enhancements in the tetracycline hydrochloride removal.Based on the dynamics analyses for charge carriers and band structure calculations,two channels of molecular oxygen activation(MOA)between Ag_(3)PO_(4)and g-C_(3)N_(4)(and g-C_(3)N_(5))were confirmed.More importantly,according to this double consumption process of excited electrons,dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) could suppress the charge recombination,which was the key point to boosting photocatalytic activity.Moreover,the determination of intermediates also supported the vital role of MOA during these photocatalytic reactions.this report of two reactive sites in MOA that generate reactive oxygen species in a“V”type band structure.The electronic dynamic in the reaction was also testified by several detections,indicating the enhanced charge separation and migration from internal field effect and electron trapping from dual S-scheme mechanism.This work provides a new research direction for the design and mechanism analysis of dual S-scheme photocatalysts.展开更多
Harnessing the redox potential of biochar to activate airborne O_(2)for contaminant removal is challenging.In this study,ferrihydrite(Fh)modified the boron(B),nitrogen(N)co-doped biochars(BCs)composites(Fh/B(n)NC)were...Harnessing the redox potential of biochar to activate airborne O_(2)for contaminant removal is challenging.In this study,ferrihydrite(Fh)modified the boron(B),nitrogen(N)co-doped biochars(BCs)composites(Fh/B(n)NC)were developed for enhancing the degradation of a model pollutant,tetracycline(TC),merely by airborne O_(2).Fh/B(3)NC showed excellent O_(2)activation activity for efficient TC degradation with a apparent TC degradation rate of 5.54,6.88,and 22.15 times that of B(3)NC,Fh,and raw BCs,respectively,where 1O_(2)and H_(2)O_(2)were identified as the dominant ROS for TC degradation.The B incorporation into the carbon lattice of Fh/B(3)NC promoted the generation of electron donors,sp2 C and the reductive B species,hence boosting Fe(III)reduction and 1O_(2)generation.O_(2)adsorption was enhanced due to the positively charged adsorption sites(C-B+and N-C+).And 1O_(2)was generated via Fe(II)catalyzed low-efficient successive one-electron transfer(O_(2)→O_(2)·−→1O_(2),H_(2)O_(2)),as well as biochar catalyzed high-efficient two-electron transfer(O_(2)→H_(2)O_(2)→1O_(2))that does not involve.O_(2)−as the intermediate.Moreover,Fh/B,N co-doped biochar showed a wide pH range,remarkable anti-interference capabilities,and effective detoxification.These findings shed new light on the development of environmentally benign BCs materials capable of degradading organic pollutants.展开更多
Microbial oxidation and the mechanism of Sb(Ⅲ)are key governing elements in biogeochemical cycling.A novel Sb oxidizing bacterium,Klebsiella aerogenes HC10,was attracted early and revealed that extracellular metaboli...Microbial oxidation and the mechanism of Sb(Ⅲ)are key governing elements in biogeochemical cycling.A novel Sb oxidizing bacterium,Klebsiella aerogenes HC10,was attracted early and revealed that extracellular metabolites were the main fractions driving Sb oxidation.However,linkages between the extracellular metabolite driven Sb oxidation process and mechanism remain elusive.Here,model phenolic and quinone compounds,i.e.,anthraquinone-2,6-disulfonate(AQDS)and hydroquinone(HYD),representing extracellular oxidants secreted by K.aerogenes HC10,were chosen to further study the Sb(Ⅲ)oxidation mechanism.N_(2)purging and free radical quenching showed that oxygen-induced oxidation accounted for 36.78%of Sb(Ⅲ)in the metabolite reaction system,while hydroxyl free radicals(·OH)accounted for 15.52%.·OH and H_(2)O_(2)are the main driving factors for Sb oxidation.Radical quenching,methanol purification and electron paramagnetic resonance(EPR)analysis revealed that·OH,superoxide radical(O_(2)^(•-))and semiquinone(SQ-•)were reactive intermediates of the phenolic induced oxidation process.Phenolic-induced ROS are one of the main oxidants in metabolites.Cyclic voltammetry(CV)showed that electron transfer of quinone also mediated Sb(Ⅲ)oxidation.Part of Sb(V)was scavenged by the formation of the secondary Sb(V)-bearing mineral mopungite[NaSb(OH)6]in the incubation system.Our study demonstrates the microbial role of oxidation detoxification and mineralization of Sb and provides scientific references for the biochemical remediation of Sb-contaminated soil.展开更多
NO catalytic oxidation is the key performance of the diesel oxidation catalyst(DOC).We present a facile deposition method for the core-shell rare-earth manganese-zirconium composite oxide that shows the Mn mullite pha...NO catalytic oxidation is the key performance of the diesel oxidation catalyst(DOC).We present a facile deposition method for the core-shell rare-earth manganese-zirconium composite oxide that shows the Mn mullite phase uniform loading on the surface of zirconium-based composite(YMO/CYZO),which demonstrates a superior NO oxidation catalytic performance in simulated diesel combustion conditions and better thermal stability than mullite phase YMn_(2)O_(5)oxide.The NO oxidation at 250℃over YMO/CYZO-a approaches 25.2%in contrast to 13.52%over YMn_(2)O_(5)-a.Then the catalytic performance of YMO/CYZO,YMO and commercial 1 wt%Pt/Al_(2)O_(3)in a NO+O_(2)atmosphere was compared.The maximum conversion rate of YMO/CYZO to NO oxidation is 89.6%at 274℃with a GHSV of 50000 h^(-1),and the performance is superior to that of YMO(82.8%at 293℃)and 1 wt%Pt/Al_(2)O_(3)(68.6%,335℃).The NO-temperature programmed desorption(NO-TPD)and diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)results reveal that YMO/CYZO has multiple NO adsorption sites and high storage capacity.Furthermore,density functional theory(DFT)calculation indicates that YMO/CYZO has lower oxygen vacancy formation energies(E_(v)=0.93 eV)and favorable NO adsorption energies(E_(ads)=2.1 eV).Moreover,in situ X-ray photoelectron spectroscopy(XPS)characterization shows that the core-shell structure of YMO/CYZO has the potential to transmit active oxygen species to help realize Mn3+to Mn4+during the reaction process to enhance the conversion of NO*molecules,while NO oxidation reactions follow the MvK mechanism.展开更多
During the course of mungbean (Phaseolus radiatus L.) germination, the rate of ethylene production and the activity of ACC synthase (1_aminocyclopropane_1_carboxylic acid synthase, EC4.4.1.4) began to increase in the ...During the course of mungbean (Phaseolus radiatus L.) germination, the rate of ethylene production and the activity of ACC synthase (1_aminocyclopropane_1_carboxylic acid synthase, EC4.4.1.4) began to increase in the 5th day of germination, and reached its peak in the 10th day and then decreased. The ethylene production and the activity of ACC synthase were obviously promoted by 10 μmol/L exogenous IAA (indole_3_acetic acid). The production of superoxide radical (O -· 2) and hydrogen peroxide (H 2O 2) were also promoted by exogenous IAA, suggesting that there was some relationship between active oxygen production and the activity of ACC synthase induced by exogenous IAA. The production of ethylene and the activity of ACC synthase increased dramatically when the seedlings were treated with exogenous O -· 2, whereas the exogenous H 2O 2 had no effects on the production of ethylene and the activity of ACC synthase. Exogenous SOD (superoxide dismutase, one scavenger of O -· 2) could inhibit the production of ethylene and the activity of ACC synthase, but exogenous CAT (catalase) could not. So it was possible that IAA would stimulate the activity of ACC synthase by inducing the production of O -· 2 in germinating mungbean seedlings, and this might be one of the regulating mechanism of ethylene synthesis in higher plants; the production of H 2O 2 induced by IAA was not the cause of the increase of the activity of ACC synthase and the production of ethylene.展开更多
The changes in content of Ca2 + and CaM, Ca2 + -ATPase activity and active oxygen metabolism during strawberry (Fragaria ananassa Duch. cv. Chunxing) fruits maturation and senescence were investigated in this study. T...The changes in content of Ca2 + and CaM, Ca2 + -ATPase activity and active oxygen metabolism during strawberry (Fragaria ananassa Duch. cv. Chunxing) fruits maturation and senescence were investigated in this study. The results showed that the soluble Ca2+ content and SOD activity in fruits tended to decline and O2 production rate to increase, the Ca2 + -ATPase activity peaked at first and then declined during fruits maturation and senescence. There were the highest CaM content at white stage in preharvest fruits and at marked senescence stage in postharvest ones. The above biochemical changes in fruits stored at low temperature (4℃)were slower than those stored at normal temperature(25℃). Thus, it indicated that the stimulation of calcium messenger system and accumulation of active oxygen free radical were closely related to fruits maturation and senescence.展开更多
A spinel oxide NiCo204 prepared by thermal decomposition is of very high activity for the oxygen evolution reaction(OER)in alkaline solution.The oxygen evolution overpotential on NiCo204 is 0.252-0.262V in 10 M NaOH s...A spinel oxide NiCo204 prepared by thermal decomposition is of very high activity for the oxygen evolution reaction(OER)in alkaline solution.The oxygen evolution overpotential on NiCo204 is 0.252-0.262V in 10 M NaOH solution at 343K and current density 100 mAcm^(-2).展开更多
Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness o...Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium（SDBS） assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction（OER）. Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method（noted as Co3O4-T） and commercial IrO2 catalyst for OER in 0.1M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.展开更多
In order to understand the role of active oxygen species in mediating plant injuries induced by far-UV radiation, seedlings of Taxus cuspidata Sieb. et Zucc. were irradiated by far-UV rays in laboratory for 4 weeks. T...In order to understand the role of active oxygen species in mediating plant injuries induced by far-UV radiation, seedlings of Taxus cuspidata Sieb. et Zucc. were irradiated by far-UV rays in laboratory for 4 weeks. The production of organic free-radicals in detached needles, and the production of O-2(radical anion) and O-1(2) in isolated chloroplasts were detected weekly by electron spin resonance (ESR) to evaluate their relative importance. The results show that the cumulative effect of far-UV irradiation, is best indicated by the production of organic free radicals in the needles, O-2(radical anion) production in chloroplasts is the next. The enhancement of O-1(2) production in chloroplasts by the cumulative far-UV irradiation seems to be not so important as O-2(radical anion) in mediating injuries induced by, far-UV radiation because of its high background value.展开更多
The article uses the method of regression statistics to obtain the regression formula of iron fluid nodule ratio Q and compacted graphite ratio R, through rare earth magnesium treatment. At the same time it has given ...The article uses the method of regression statistics to obtain the regression formula of iron fluid nodule ratio Q and compacted graphite ratio R, through rare earth magnesium treatment. At the same time it has given thejudging figure of Q and R, considering oxygen activity and temperature. When using oxygen activity to judgenodule ratio and compacted graphite ratio of the ironfluid treated by rare earth magnesium alloy, its limit value changes with the change of temperature.展开更多
Palladium-based catalysts have long been considered the benchmark for methane combustion;however,the authentic phase of catalytic active sites remains a subject of ongoing debate.Additionally,challenges like water-poi...Palladium-based catalysts have long been considered the benchmark for methane combustion;however,the authentic phase of catalytic active sites remains a subject of ongoing debate.Additionally,challenges like water-poisoning and long-term stability need to be addressed to advance catalyst performance.Herein,we investigate Pd on Co_(3)O_(4) nanorods as a highly effective catalyst for catalytic oxidation of methane,demonstrating long-term stability and water tolerance during a 100-h continuous operation at 350℃.Comprehensive characterizations reveal the presence of an active Pd-oxygen vacancy(Ov)-cobalt interface in Pd/Co_(3)O_(4),which effectively adsorbs molecular O_(2).The absorbed oxygen species on this interface are activated and directly participate in methane combustion.Moreover,near-ambient pressure X-ray photoelectron spectroscopy demonstrates that Pd nanoparticles undergo a rapid phase transition and predominantly remain in the metallic state during the reaction.This behavior is attributed to the electronic metal-support interaction between Pd and Co_(3)O_(4).Furthermore,in situ Fourier transformed infrared spectrum reveals that under reaction conditions,HCO3*species are formed initially and subsequently transformed into formate species,indicating that the formate pathway is the dominant mechanism for CH_(4) oxidation.展开更多
Lithium-rich manganese-based cathodes(LRMs)have garnered significant attention as promising candidates for highenergy-density batteries due to their exceptional specific capacity exceeding 300 mAh/g,achieved through s...Lithium-rich manganese-based cathodes(LRMs)have garnered significant attention as promising candidates for highenergy-density batteries due to their exceptional specific capacity exceeding 300 mAh/g,achieved through synergistic anionic and cationic redox reactions.However,these materials face challenges including oxygen release-induced structural degradation and consequent capacity fading.To address these issues,strategies such as surface modification and bulk phase engineering have been explored.In this study,we developed a facile and cost-effective quenching approach that simultaneously modifies both surface and bulk characteristics.Multi-scale characterization and computational analysis reveal that rapid cooling partially preserves the high-temperature disordered phase in the bulk structure,thereby enhancing the structural stability.Concurrently,Li^(+)/H^(+)exchange at the surface forms a robust rock-salt/spinel passivation layer,effectively suppressing oxygen evolution and mitigating interfacial side reactions.This dual modification strategy demonstrates a synergistic stabilization effect.The enhanced oxygen redox activity coexists with the improved structural integrity,leading to superior electrochemical performance.The optimized cathode delivers an initial discharge capacity approaching 307.14 mAh/g at 0.1 C and remarkable cycling stability with 94.12%capacity retention after 200 cycles at 1 C.This study presents a straightforward and economical strategy for concurrent surface–bulk modification,offering valuable insights for designing high-capacity LRM cathodes with extended cycle life.展开更多
Oxidative coupling of methane (OCM) is one of the most promising approaches to produce ethylene and ethane (C_(2)-hydrocarbons) in the post-oil era.The MnO_(x)-Na_(2)WO_(4)/SiO_(2) system shows promising OCM performan...Oxidative coupling of methane (OCM) is one of the most promising approaches to produce ethylene and ethane (C_(2)-hydrocarbons) in the post-oil era.The MnO_(x)-Na_(2)WO_(4)/SiO_(2) system shows promising OCM performance,which can be further enhanced by cofed steam.However,the positive effect of steam on C_(2)-hydrocarbons selectivity practically disappears above 800℃.In the present study,we demonstrate that the use of SiC as a support for MnO_(x)-Na_(2)WO_(4) is beneficial for achieving high selectivity up to 850℃.Our sophisticated kinetic tests using feeds without and with steam revealed that the steam-mediated improvement in selectivity to C_(2)-hydrocarbons is due to the inhibition of the direct CH_(4) oxidation to carbon oxides because of the different enhancing effects of steam on the rates of CH_(4) conversion to C_(2)H_(6) and CO/CO_(2).Other descriptors of the selectivity improvement are MnO_(x) dispersion and the catalyst specific surface area.The knowledge gained herein may be useful for optimizing OCM performance through catalyst design and reactor operation.展开更多
Different from reversible agonist-stimulated receptor activation,singlet oxygen oxidation activates permanently G protein-coupled receptor(GPCR)cholecystokinin 1(CCK1R)in type II photodynamic action,with soluble photo...Different from reversible agonist-stimulated receptor activation,singlet oxygen oxidation activates permanently G protein-coupled receptor(GPCR)cholecystokinin 1(CCK1R)in type II photodynamic action,with soluble photosensitizer dyes(sulphonated aluminum phthalocyanine,λmax 675 nm)or genetically encoded protein photosensitizers(KillerRedλmax 585 nm;mini singlet oxygen generatorλmax 450 nm),together with a pulse of light(37 mW/cm2,1-2 minutes).Three lines of evidence shed light on the mechanism of GPCR activated by singlet oxygen(GPCR-ABSO):(1)CCK1R is quantitatively converted from dimer to monomer;(2)Transmembrane domain 3,a pharmacophore for permanent photodynamic CCK1R activation,can be transplanted to non-susceptible M3 acetylcholine receptor;and(3)Larger size of disordered region in intracellular loop 3 correlates with higher sensitivity to photodynamic CCK1R activation.GPCR-ABSO will add to the arsenal of engineered designer GPCR such as receptors activated solely by synthetic ligands and designer receptors exclusively activated by designer drugs,but show some clear advantages:Enhanced selectivity(double selectivity of localized photosensitizer and light illumination),long-lasting activation with no need for repeated drug administration,antagonist-binding site remains intact when needed,ease to apply to multiple GPCR.This type of permanent photodynamic activation may be applied to functional proteins other than GPCR.展开更多
Peach fruits [Prumus persica （L.） Batsch, cv. Yuhuasanhao] were used as materials to investigate the changes of reactive oxygen species （ROS） and related enzymes in mitochondria respiration during storage and then...Peach fruits [Prumus persica （L.） Batsch, cv. Yuhuasanhao] were used as materials to investigate the changes of reactive oxygen species （ROS） and related enzymes in mitochondria respiration during storage and then their influence on senescence of harvested Peach fruits was studied. The results showed that low temperature （5℃） strongly inhibited the reduction of firmness and the increase in respiration rate. During storage at ambient temperature （20℃）, ROS had a cumulative process while malondialdehye （MDA） content continued to increase in associated with enhanced membrane lipid peroxidation. Lipoxygenase （LOX） activity was strongly inhibited under the low temperature condition. The activities of succinic dehydrogenase （SDH）, cytochrome C oxidase （CCO）, and Ca^2＋-ATPase declined to a certain extent at ambient temperature, while they showed higher activities at low temperature, which may be related to lower membrane lipid peroxidation at low temperature. Higher Ca^2＋ content at ambient temperature may be responsible for impairment of mitochondrial function, thus, leading to fruit senescence. The results showed that under low temperature condition, the low accumulation of ROS and the low level of membrane lipid peroxidation could maintain the function of mitochondria that would help to delay the senescence of peach fruits. These suggested a close relationship existed between ROS metabolism and mitochondrial respiration. It can be inferred that the low temperature helps to delay senescence of peach fruits via suppression of ROS and related enzymes, maintain better homeostasis of Ca^2＋ in mitochondria and thus better mitochondrial functions.展开更多
Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in...Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mgPt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst （0.20 A/mgPt）. Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst.展开更多
基金financially supported by the National Natural Science Foundation of China (52474338,22109084 and 52304338)the Hunan Provincial Key Research and Development Program (2024JK2093,2023GK2016)supported in part by the High Performance Computing Center of Central South University.
文摘Sulfide-based all-solid-state lithium batteries(ASSLBs) with nickel-rich oxide cathodes are emerging as primary contenders for the next generation rechargeable batteries,owing to their superior safety and energy density.However,the all-solid-state batteries with nickel-rich oxide cathodes suffer from performance degradation due to the reactions between the highly reactive surface oxygen of the cathode and the electrolyte,as well as the instability of the bulk oxygen structure in the cathode.Herein,we propose a synergistic modification design scheme to adjust the oxygen activity from surface to bulk.The LiBO_(2)coating inhibits the reactivity of surface lattice oxygen ions.Meanwhile,Zr doping in the bulk phase forms strong Zr-O covalent bonds that stabilize the bulk lattice oxygen structure.The synergistic effect of these modifications prevents the release of oxygen,thus avoiding the degradation of the cathode/SE interface.Additionally,the regulation of surface-to-bulk oxygen activity establishes a highly stable interface,thereby enhancing the lithium ion diffusion kinetics and mechanical stability of the cathode.Consequently,cathodes modified with this synergistic strategy exhibit outstanding performance in sulfide-based ASSLBs,including an ultra-long cycle life of 100,000 cycles,ultra-high rate capability at 45C,and 85% high active material content in the composite cathode.Additionally,ASSLB exhibits stable cycling under high loading conditions of 82.82 mg cm^(-2),achieving an areal capacity of 17.90 mA h cm^(-2).These encouraging results pave the way for practical applications of ASSLBs in fast charging,long cycle life,and high energy density in the future.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1402902)the National Natural Science Foundation of China(Grant Nos.12374179,12074119,12374145,051B22001,12104157,12134003,and 12304218)the Shanghai Pujiang Program(Grant No.23PJ1402200).
文摘The hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts have been made to manipulate the p-d hybridization in TMOs by tailoring the spatial orbital overlap via structural engineering.Here,we demonstrate enhanced p-d hybridization in Ba^(2+)-doped LaNiO_(3)epitaxial films by simultaneously modifying both the spatial and energetic overlaps between the O-2p and Ni-3d orbitals.Combining x-ray absorption spectroscopy and firstprinciples calculations,we reveal that the enhanced hybridization stems from the synergistic effects of a reduced chargetransfer energy due to hole injection and an increased spatial orbital overlap due to straightening of Ni-O-Ni bonds.We further show that the enhanced p-d hybridization can be utilized to promote the oxygen evolution activity of LaNiO_(3).This work sheds new insights into the fine-tuning of the electronic structures of TMOs for enhanced functionalities.
基金financially supported by the National Natural Science Foundation of China(Nos.22171122 and 22201123)Liaoning Revitalization Talents Program(No.XLYC 2007130)+1 种基金Fundamental Research Project(No.LJ212410148038)of the Educational Department of Liaoning ProvinceTalent Scientific Research Fund of Liaoning Petrochemical University(No.2016XJJL–019)。
文摘Attaining the selective oxidation of isochroman into isochromanone in a molecular oxygen(O_(2))environment without any additives,via a heterogeneous oxidation process,is highly desirable and challenging work.Herein,we prepare two mixed-addendum polyoxometalate-based coordination polymers of the general formula[H_(x)M_(1-x)(i-PrIm)_(4)][H_(2)N(CH_(3))_(2)]_(4)[HPMo_(8)V_(6)O_(42)](M=Co 1,Ni,2;i-PrIm=1-isopropyl-1H-imidazole).Needing no additives,they can catalyze the selective oxidation of isochroman to isochromanone with O_(2)as an oxidant,with yields of 91.5%(1)and 46.8%(2),respectively.Mechanistic studies indicate that the excellent performance of catalyst 1 is attributed to the synergistic operation of[Co(i-Pr-Im)_(4))]complex and PMo_(8)V_(6)unit,and that the catalytic reaction is a radical pathway involving superoxide radicals.Additionally,the catalyst 1 can be recycled and reused at least four times with uncompromised performance.These results provide fundamental guidelines for designing efficient and multi-site heterogeneous catalysts for the selective oxidation of benzyl C(sp^(3))-H bonds by activating O_(2).
基金supported by the Natural Science Foundation of Shanghai(No.23ZR1401300)the National Natural Science Foundation of China(No.52170068).
文摘Singlet oxygen(^(1)O_(2)),as an electrophilic oxidant,is essential for the selective water decontamination of pollutants from water.Herein,we showcase a high-performing electrocatalytic filtration system composed of carbon nanotubes functionalized with CoFe alloy nanoparticles(CoFeCNT)to selectively facilitate the electrochemical activation of O_(2)to^(1)O_(2).Benefiting from the prominently featured bimetal active sites of CoFeCNT,nearly complete production of^(1)O_(2)is achieved by the electrocatalytic activation of O_(2).Additionally,the proposed system exhibits a consistent pollutant removal efficiency>90%in a flow-through reactor over 48 h of continuous operation without a noticeable decline in performance,highlighting the dependable stability of the system for practical applications.The flow-through configuration demonstrates a striking 8-fold enhancement in tetracycline oxidation compared to a conventional batch reactor.This work provides a molecular level understanding of the oxygen reduction reaction,showing promising potential for the selective removal of emerging organic contaminants from water.
基金funded by the National Natural Science Foundation of China(No.22106042)Hunan Provincial Natural Science Foundation of China(Nos.2024JJ5124,2024JJ5126)the Scientific Research Foundation of Hunan Provincial Education Department(No.23B0564)。
文摘A dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction was prepared by decomposition methods,and it displayed enhanced performance to degrade tetracycline hydrochloride with the ideal stability under different water substrates and ions.Comparing with three single components,as g-C_(3)N_(4),g-C_(3)N_(5),and Ag_(3)PO_(4),the dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) heterojunction displayed 4.4-,3.4-,and 2.5-times enhancements in the tetracycline hydrochloride removal.Based on the dynamics analyses for charge carriers and band structure calculations,two channels of molecular oxygen activation(MOA)between Ag_(3)PO_(4)and g-C_(3)N_(4)(and g-C_(3)N_(5))were confirmed.More importantly,according to this double consumption process of excited electrons,dual S-scheme g-C_(3)N_(4)/Ag_(3)PO_(4)/g-C_(3)N_(5) could suppress the charge recombination,which was the key point to boosting photocatalytic activity.Moreover,the determination of intermediates also supported the vital role of MOA during these photocatalytic reactions.this report of two reactive sites in MOA that generate reactive oxygen species in a“V”type band structure.The electronic dynamic in the reaction was also testified by several detections,indicating the enhanced charge separation and migration from internal field effect and electron trapping from dual S-scheme mechanism.This work provides a new research direction for the design and mechanism analysis of dual S-scheme photocatalysts.
基金supported by the National Natural Science Foundation of China(No.U21A20293).
文摘Harnessing the redox potential of biochar to activate airborne O_(2)for contaminant removal is challenging.In this study,ferrihydrite(Fh)modified the boron(B),nitrogen(N)co-doped biochars(BCs)composites(Fh/B(n)NC)were developed for enhancing the degradation of a model pollutant,tetracycline(TC),merely by airborne O_(2).Fh/B(3)NC showed excellent O_(2)activation activity for efficient TC degradation with a apparent TC degradation rate of 5.54,6.88,and 22.15 times that of B(3)NC,Fh,and raw BCs,respectively,where 1O_(2)and H_(2)O_(2)were identified as the dominant ROS for TC degradation.The B incorporation into the carbon lattice of Fh/B(3)NC promoted the generation of electron donors,sp2 C and the reductive B species,hence boosting Fe(III)reduction and 1O_(2)generation.O_(2)adsorption was enhanced due to the positively charged adsorption sites(C-B+and N-C+).And 1O_(2)was generated via Fe(II)catalyzed low-efficient successive one-electron transfer(O_(2)→O_(2)·−→1O_(2),H_(2)O_(2)),as well as biochar catalyzed high-efficient two-electron transfer(O_(2)→H_(2)O_(2)→1O_(2))that does not involve.O_(2)−as the intermediate.Moreover,Fh/B,N co-doped biochar showed a wide pH range,remarkable anti-interference capabilities,and effective detoxification.These findings shed new light on the development of environmentally benign BCs materials capable of degradading organic pollutants.
基金supported by the National Natural Science Foundation of China(No.42267001)the College Young and Middle-aged Teachers’Basic Ability Improvement Project of Guangxi,China(No.2023KY0393).
文摘Microbial oxidation and the mechanism of Sb(Ⅲ)are key governing elements in biogeochemical cycling.A novel Sb oxidizing bacterium,Klebsiella aerogenes HC10,was attracted early and revealed that extracellular metabolites were the main fractions driving Sb oxidation.However,linkages between the extracellular metabolite driven Sb oxidation process and mechanism remain elusive.Here,model phenolic and quinone compounds,i.e.,anthraquinone-2,6-disulfonate(AQDS)and hydroquinone(HYD),representing extracellular oxidants secreted by K.aerogenes HC10,were chosen to further study the Sb(Ⅲ)oxidation mechanism.N_(2)purging and free radical quenching showed that oxygen-induced oxidation accounted for 36.78%of Sb(Ⅲ)in the metabolite reaction system,while hydroxyl free radicals(·OH)accounted for 15.52%.·OH and H_(2)O_(2)are the main driving factors for Sb oxidation.Radical quenching,methanol purification and electron paramagnetic resonance(EPR)analysis revealed that·OH,superoxide radical(O_(2)^(•-))and semiquinone(SQ-•)were reactive intermediates of the phenolic induced oxidation process.Phenolic-induced ROS are one of the main oxidants in metabolites.Cyclic voltammetry(CV)showed that electron transfer of quinone also mediated Sb(Ⅲ)oxidation.Part of Sb(V)was scavenged by the formation of the secondary Sb(V)-bearing mineral mopungite[NaSb(OH)6]in the incubation system.Our study demonstrates the microbial role of oxidation detoxification and mineralization of Sb and provides scientific references for the biochemical remediation of Sb-contaminated soil.
基金supported by National Natural Science Foundation of China(52204376)Open Project of Yunnan Precious Metals Laboratory Co.(YPML-2023050266)Youth Foundation of Hebei Province(E2022103007)。
文摘NO catalytic oxidation is the key performance of the diesel oxidation catalyst(DOC).We present a facile deposition method for the core-shell rare-earth manganese-zirconium composite oxide that shows the Mn mullite phase uniform loading on the surface of zirconium-based composite(YMO/CYZO),which demonstrates a superior NO oxidation catalytic performance in simulated diesel combustion conditions and better thermal stability than mullite phase YMn_(2)O_(5)oxide.The NO oxidation at 250℃over YMO/CYZO-a approaches 25.2%in contrast to 13.52%over YMn_(2)O_(5)-a.Then the catalytic performance of YMO/CYZO,YMO and commercial 1 wt%Pt/Al_(2)O_(3)in a NO+O_(2)atmosphere was compared.The maximum conversion rate of YMO/CYZO to NO oxidation is 89.6%at 274℃with a GHSV of 50000 h^(-1),and the performance is superior to that of YMO(82.8%at 293℃)and 1 wt%Pt/Al_(2)O_(3)(68.6%,335℃).The NO-temperature programmed desorption(NO-TPD)and diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)results reveal that YMO/CYZO has multiple NO adsorption sites and high storage capacity.Furthermore,density functional theory(DFT)calculation indicates that YMO/CYZO has lower oxygen vacancy formation energies(E_(v)=0.93 eV)and favorable NO adsorption energies(E_(ads)=2.1 eV).Moreover,in situ X-ray photoelectron spectroscopy(XPS)characterization shows that the core-shell structure of YMO/CYZO has the potential to transmit active oxygen species to help realize Mn3+to Mn4+during the reaction process to enhance the conversion of NO*molecules,while NO oxidation reactions follow the MvK mechanism.
文摘During the course of mungbean (Phaseolus radiatus L.) germination, the rate of ethylene production and the activity of ACC synthase (1_aminocyclopropane_1_carboxylic acid synthase, EC4.4.1.4) began to increase in the 5th day of germination, and reached its peak in the 10th day and then decreased. The ethylene production and the activity of ACC synthase were obviously promoted by 10 μmol/L exogenous IAA (indole_3_acetic acid). The production of superoxide radical (O -· 2) and hydrogen peroxide (H 2O 2) were also promoted by exogenous IAA, suggesting that there was some relationship between active oxygen production and the activity of ACC synthase induced by exogenous IAA. The production of ethylene and the activity of ACC synthase increased dramatically when the seedlings were treated with exogenous O -· 2, whereas the exogenous H 2O 2 had no effects on the production of ethylene and the activity of ACC synthase. Exogenous SOD (superoxide dismutase, one scavenger of O -· 2) could inhibit the production of ethylene and the activity of ACC synthase, but exogenous CAT (catalase) could not. So it was possible that IAA would stimulate the activity of ACC synthase by inducing the production of O -· 2 in germinating mungbean seedlings, and this might be one of the regulating mechanism of ethylene synthesis in higher plants; the production of H 2O 2 induced by IAA was not the cause of the increase of the activity of ACC synthase and the production of ethylene.
基金the National Natural Science Foundation of China ( No.30270933).
文摘The changes in content of Ca2 + and CaM, Ca2 + -ATPase activity and active oxygen metabolism during strawberry (Fragaria ananassa Duch. cv. Chunxing) fruits maturation and senescence were investigated in this study. The results showed that the soluble Ca2+ content and SOD activity in fruits tended to decline and O2 production rate to increase, the Ca2 + -ATPase activity peaked at first and then declined during fruits maturation and senescence. There were the highest CaM content at white stage in preharvest fruits and at marked senescence stage in postharvest ones. The above biochemical changes in fruits stored at low temperature (4℃)were slower than those stored at normal temperature(25℃). Thus, it indicated that the stimulation of calcium messenger system and accumulation of active oxygen free radical were closely related to fruits maturation and senescence.
文摘A spinel oxide NiCo204 prepared by thermal decomposition is of very high activity for the oxygen evolution reaction(OER)in alkaline solution.The oxygen evolution overpotential on NiCo204 is 0.252-0.262V in 10 M NaOH solution at 343K and current density 100 mAcm^(-2).
基金supported by the Youth Innovation Promotion Association(no.2015147)CAS and National Program on Key Basic Research Project(973 Program,2012CB215500)+1 种基金the Outstanding Youngest Scientist FoundationChinese Academy of Sciences(CAS)
文摘Oxygen evolution reaction（OER） is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells（URFCs）. However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium（SDBS） assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction（OER）. Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method（noted as Co3O4-T） and commercial IrO2 catalyst for OER in 0.1M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.
文摘In order to understand the role of active oxygen species in mediating plant injuries induced by far-UV radiation, seedlings of Taxus cuspidata Sieb. et Zucc. were irradiated by far-UV rays in laboratory for 4 weeks. The production of organic free-radicals in detached needles, and the production of O-2(radical anion) and O-1(2) in isolated chloroplasts were detected weekly by electron spin resonance (ESR) to evaluate their relative importance. The results show that the cumulative effect of far-UV irradiation, is best indicated by the production of organic free radicals in the needles, O-2(radical anion) production in chloroplasts is the next. The enhancement of O-1(2) production in chloroplasts by the cumulative far-UV irradiation seems to be not so important as O-2(radical anion) in mediating injuries induced by, far-UV radiation because of its high background value.
文摘The article uses the method of regression statistics to obtain the regression formula of iron fluid nodule ratio Q and compacted graphite ratio R, through rare earth magnesium treatment. At the same time it has given thejudging figure of Q and R, considering oxygen activity and temperature. When using oxygen activity to judgenodule ratio and compacted graphite ratio of the ironfluid treated by rare earth magnesium alloy, its limit value changes with the change of temperature.
文摘Palladium-based catalysts have long been considered the benchmark for methane combustion;however,the authentic phase of catalytic active sites remains a subject of ongoing debate.Additionally,challenges like water-poisoning and long-term stability need to be addressed to advance catalyst performance.Herein,we investigate Pd on Co_(3)O_(4) nanorods as a highly effective catalyst for catalytic oxidation of methane,demonstrating long-term stability and water tolerance during a 100-h continuous operation at 350℃.Comprehensive characterizations reveal the presence of an active Pd-oxygen vacancy(Ov)-cobalt interface in Pd/Co_(3)O_(4),which effectively adsorbs molecular O_(2).The absorbed oxygen species on this interface are activated and directly participate in methane combustion.Moreover,near-ambient pressure X-ray photoelectron spectroscopy demonstrates that Pd nanoparticles undergo a rapid phase transition and predominantly remain in the metallic state during the reaction.This behavior is attributed to the electronic metal-support interaction between Pd and Co_(3)O_(4).Furthermore,in situ Fourier transformed infrared spectrum reveals that under reaction conditions,HCO3*species are formed initially and subsequently transformed into formate species,indicating that the formate pathway is the dominant mechanism for CH_(4) oxidation.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB2502200)the National Natural Science Foundation of China(Grant Nos.52325207,22239003,and 22393904).
文摘Lithium-rich manganese-based cathodes(LRMs)have garnered significant attention as promising candidates for highenergy-density batteries due to their exceptional specific capacity exceeding 300 mAh/g,achieved through synergistic anionic and cationic redox reactions.However,these materials face challenges including oxygen release-induced structural degradation and consequent capacity fading.To address these issues,strategies such as surface modification and bulk phase engineering have been explored.In this study,we developed a facile and cost-effective quenching approach that simultaneously modifies both surface and bulk characteristics.Multi-scale characterization and computational analysis reveal that rapid cooling partially preserves the high-temperature disordered phase in the bulk structure,thereby enhancing the structural stability.Concurrently,Li^(+)/H^(+)exchange at the surface forms a robust rock-salt/spinel passivation layer,effectively suppressing oxygen evolution and mitigating interfacial side reactions.This dual modification strategy demonstrates a synergistic stabilization effect.The enhanced oxygen redox activity coexists with the improved structural integrity,leading to superior electrochemical performance.The optimized cathode delivers an initial discharge capacity approaching 307.14 mAh/g at 0.1 C and remarkable cycling stability with 94.12%capacity retention after 200 cycles at 1 C.This study presents a straightforward and economical strategy for concurrent surface–bulk modification,offering valuable insights for designing high-capacity LRM cathodes with extended cycle life.
基金supported by the National Key Research and Development Program (Nos.2020YFA0210903)the National Natural Science Foundation of China (Grant Nos.22225807,21961132026,22021004)DFG within joint Sino-German project (KO 2261/11-1)。
文摘Oxidative coupling of methane (OCM) is one of the most promising approaches to produce ethylene and ethane (C_(2)-hydrocarbons) in the post-oil era.The MnO_(x)-Na_(2)WO_(4)/SiO_(2) system shows promising OCM performance,which can be further enhanced by cofed steam.However,the positive effect of steam on C_(2)-hydrocarbons selectivity practically disappears above 800℃.In the present study,we demonstrate that the use of SiC as a support for MnO_(x)-Na_(2)WO_(4) is beneficial for achieving high selectivity up to 850℃.Our sophisticated kinetic tests using feeds without and with steam revealed that the steam-mediated improvement in selectivity to C_(2)-hydrocarbons is due to the inhibition of the direct CH_(4) oxidation to carbon oxides because of the different enhancing effects of steam on the rates of CH_(4) conversion to C_(2)H_(6) and CO/CO_(2).Other descriptors of the selectivity improvement are MnO_(x) dispersion and the catalyst specific surface area.The knowledge gained herein may be useful for optimizing OCM performance through catalyst design and reactor operation.
基金Supported by the National Natural Science Foundation of China,No.32271278 and No.31971170.
文摘Different from reversible agonist-stimulated receptor activation,singlet oxygen oxidation activates permanently G protein-coupled receptor(GPCR)cholecystokinin 1(CCK1R)in type II photodynamic action,with soluble photosensitizer dyes(sulphonated aluminum phthalocyanine,λmax 675 nm)or genetically encoded protein photosensitizers(KillerRedλmax 585 nm;mini singlet oxygen generatorλmax 450 nm),together with a pulse of light(37 mW/cm2,1-2 minutes).Three lines of evidence shed light on the mechanism of GPCR activated by singlet oxygen(GPCR-ABSO):(1)CCK1R is quantitatively converted from dimer to monomer;(2)Transmembrane domain 3,a pharmacophore for permanent photodynamic CCK1R activation,can be transplanted to non-susceptible M3 acetylcholine receptor;and(3)Larger size of disordered region in intracellular loop 3 correlates with higher sensitivity to photodynamic CCK1R activation.GPCR-ABSO will add to the arsenal of engineered designer GPCR such as receptors activated solely by synthetic ligands and designer receptors exclusively activated by designer drugs,but show some clear advantages:Enhanced selectivity(double selectivity of localized photosensitizer and light illumination),long-lasting activation with no need for repeated drug administration,antagonist-binding site remains intact when needed,ease to apply to multiple GPCR.This type of permanent photodynamic activation may be applied to functional proteins other than GPCR.
基金funded by the National Natural Science Fundation of China (30840016)the Natural Science Fundation of Jiangsu Province, China (BK 2010310)the Natural Science Fundation for Colleges and Universities in Jiangsu Province, China (10KJB550004)
文摘Peach fruits [Prumus persica （L.） Batsch, cv. Yuhuasanhao] were used as materials to investigate the changes of reactive oxygen species （ROS） and related enzymes in mitochondria respiration during storage and then their influence on senescence of harvested Peach fruits was studied. The results showed that low temperature （5℃） strongly inhibited the reduction of firmness and the increase in respiration rate. During storage at ambient temperature （20℃）, ROS had a cumulative process while malondialdehye （MDA） content continued to increase in associated with enhanced membrane lipid peroxidation. Lipoxygenase （LOX） activity was strongly inhibited under the low temperature condition. The activities of succinic dehydrogenase （SDH）, cytochrome C oxidase （CCO）, and Ca^2＋-ATPase declined to a certain extent at ambient temperature, while they showed higher activities at low temperature, which may be related to lower membrane lipid peroxidation at low temperature. Higher Ca^2＋ content at ambient temperature may be responsible for impairment of mitochondrial function, thus, leading to fruit senescence. The results showed that under low temperature condition, the low accumulation of ROS and the low level of membrane lipid peroxidation could maintain the function of mitochondria that would help to delay the senescence of peach fruits. These suggested a close relationship existed between ROS metabolism and mitochondrial respiration. It can be inferred that the low temperature helps to delay senescence of peach fruits via suppression of ROS and related enzymes, maintain better homeostasis of Ca^2＋ in mitochondria and thus better mitochondrial functions.
基金This work is supported by Collaborative Innovation Center of Suzhou Nano Science and Technology, Ministry of Science and Technology of China （No.2014CB932700）, the National Natural Science Foundation of China （No.21603208, No.21573206, and No.51371164）, the China Postdoctoral Science Foundation （No.2015M580536, No.2016T90569）, Key Research Program of Frontier Sciences, CAS （QYZDBSSW- SLH017）, Strategic Priority Research Program B of the CAS （No.XDB01020000）, Hefei Science Center, CAS （No.2015HSC-UP016）, and Fundamental Research Funds for the Central Universities.
文摘Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mgPt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst （0.20 A/mgPt）. Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst.
