Recent advances in geoscience have underscored the critical role of abiogenic processes in petroleum formation,especially the formation and polymerization of methane.However,whether a direct carbon-H_(2) reaction can ...Recent advances in geoscience have underscored the critical role of abiogenic processes in petroleum formation,especially the formation and polymerization of methane.However,whether a direct carbon-H_(2) reaction can produce C_(2+)hydrocarbons(e.g.,ethane and propane)beyond methane remains an open question.Here,we demonstrate the direct synthesis of ethane and propane via reactions between amorphous carbon and H_(2) under upper mantle conditions(2-10 GPa and 800-1200℃).A systematic investigation reveals that increasing structural disorder in carbon precursors,from graphite to glassy carbon-Ⅱ and carbon black,enhances the production of C_(2)-C_(3) hydrocarbons.Through integrated X-ray diffraction and reverse Monte Carlo simulations,we establish that the continuous random atomic network structures in amorphous carbon enable one-step synthesis of heavy hydrocarbons with H_(2).These models establish a direct link between atomic-scale carbon structures and the one-step synthesis of C_(2+)hydrocarbons under H2-rich,high-pressure,and high-temperature conditions—potentially revealing an efficient mechanism for the abiotic production of C_(2+)hydrocarbons in the upper mantle.展开更多
Although literature abounds with examples of formation of perhaloalkanes by photo-lytic or Lewis-acid induced halogen exchange reactions involving radical or carbocationintermediates,the procedures are seldom applicab...Although literature abounds with examples of formation of perhaloalkanes by photo-lytic or Lewis-acid induced halogen exchange reactions involving radical or carbocationintermediates,the procedures are seldom applicable to the preparation of perhaloalkanes ingood yields under mild conditions.Recently,we have reported the spontaneous reactionsof some perhalofluoroalkanes with various types of nucleophiles.All these reactions areinitiated by the halophilic attack of nucleophiles on C—Br or C—Cl bonds,followed byanionic chain steps involving carbanion as well as olefin intermediates.Notably,the latter areformed after the β-elimination of a good leaving group from the former.On the other hand,it is well known that halogenated carbanions can effectively make halophilic attacks on theC—X bonds of other halogenated substrates,e.g.,in the“halogen dance”of Bunnett.There-展开更多
Summary of main observation and conclusion A Cu(I)-catalyzed three-component reaction of terminal enynals/enynones,diazo compounds,and al kenes has been developed.With this method,a series of oxabicyclo[2.2.2]octanes ...Summary of main observation and conclusion A Cu(I)-catalyzed three-component reaction of terminal enynals/enynones,diazo compounds,and al kenes has been developed.With this method,a series of oxabicyclo[2.2.2]octanes were effectively synthesized in high yields under mild reaction condi-tions.This transformation is proposed to proceed through trapping of the cyclic vinyl-o-quinodimethanes(vinyI-o-QDMs)species,which were generated from terminal enynals/enynones and diazo compounds by alkenes.The obvious advantages of wide substrate scopes,mild reaction conditions,and high seteroselectivity and atom eficiency make this reaction highly appealing for construction of highly rigid[2.2.2]octane skeleton.展开更多
Chemical looping oxidative dehydrogenation(CL‐ODH)is a promising novel method to convert ethane into higher value‐added ethylene.In this study,perovskite‐type Co_(2)O_(3)/LaCoO_(3) was prepared by the one‐step cit...Chemical looping oxidative dehydrogenation(CL‐ODH)is a promising novel method to convert ethane into higher value‐added ethylene.In this study,perovskite‐type Co_(2)O_(3)/LaCoO_(3) was prepared by the one‐step citric acid‐gel method and applied as an oxygen carrier in the CL‐ODH process of ethane to ethylene;moreover,the effects of CuO,ZnO,and MgO as additives were investigated.The properties of the oxygen carriers were characterized using XRD,BET,XPS,H_(2)‐TPR,O_(2)‐TPD,and EPR.Characterization results showed that the addition of additives into Co_(2)O_(3)/LaCoO_(3) increased the amounts of surface chemisorbed oxygen and lattice oxygen.Co_(2)O_(3)/LaCoO_(3) had a strong ability to absorb and release oxygen after adding CuO,ZnO,and MgO,respectively.The performances of the oxygen carriers for CL‐ODH of ethane to ethylene were studied at a reaction temperature of 650℃,atmospheric pressure,and GHSV of 15,000 mL/g·h in eight redox cycles.All the oxygen carriers had 100%ethane conversion,and ZnO‐Co_(2)O_(3)/LaCoO_(3) exhibited the best ethylene selectivity of more than 70%in all the oxygen carriers.It was confirmed that lattice oxygen was mainly responsible for the selectivity of ethylene,and oxygen vacancies were conducive to the migration of lattice oxygen.Most of Zn^(2+) entered into the bulk phase of Co_(2)O_(3)/LaCoO_(3),and formed lots of oxygen vacancies.展开更多
The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior a...The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior activity,stability,and cost-effectiveness.Herein,tricoordinated cobalt atoms were successfully fabricated through an in-situ ligand-protected synthesis by introducing tungsten atoms into zeolite frameworks.These unsaturated Co species efficiently activate C-H bonds while suppressing C-C bond cleavage,resulting in exceptional catalytic activity and olefin selectivity in both propane and ethane dehydrogenation reactions.The optimized Co_(0.2%)@0.01W-S-1 catalyst demonstrated an impressive propylene formation rate of 15.2 molC_(3H6)gcC h^(-1)at 823 K and an ethylene formation rate of 240.3mol_(C2H4)g_(Co)^(-1)h^(-1)at 913 K,with propylene and ethylene selectivities of 99.0%and 97.5%,respectively.These results not only significantly surpass conventional tetracoordinated Co catalysts but also rival some Pt-based catalysts under similar conditions.Importantly,the catalyst exhibited excellent stability in dehydrogenation reactions,with no significant loss in catalytic activity after five consecutive regeneration cycles.This work offers valuable insights into the design of zeolite-supported non-precious metal catalysts with high activity and durability for efficient alkane dehydrogenation.展开更多
Ethan Wargo,9 years old,sets up a small table on his lawn each morning in Sycamore,Illinois,waiting for people to walk by so that he can offer a compliment to anyone who stops to talk.In mid‑July 2025,Ethan launched w...Ethan Wargo,9 years old,sets up a small table on his lawn each morning in Sycamore,Illinois,waiting for people to walk by so that he can offer a compliment to anyone who stops to talk.In mid‑July 2025,Ethan launched what he calls a“compliments stand”,spending up to five hours a day at his table.The idea was inspired by a scene in a recent graphic(绘画的)novel,where characters run a stand.He parked himself next to his twin sister,Claire,who sells her artwork at her own stand,but Ethan knew charging for compliments didn't feel right.“I didn't want people to pay to be happy,”he said.“Paying for something like that is very silly.”展开更多
Decabromodiphenyl ethane(DBDPE)is widely used as an additive flame retardant and has led to global pollution.Its has a large molecular mass and is prone to debromination and degradation under photothermal conditions,r...Decabromodiphenyl ethane(DBDPE)is widely used as an additive flame retardant and has led to global pollution.Its has a large molecular mass and is prone to debromination and degradation under photothermal conditions,resulting in smaller homologous compounds.Due to the lack of standard substances for debromination products,the in-depth study of DBDPE environmental geochemical behavior through debromination conversion has been hindered.Therefore,based on DBDPE photodegradation experiment,this study first analyzed and identified the brominated products of DBDPE using high-performance liquid chromatography-atmospheric pressure photoionization-time of flight mass spectrometry(HPLC-APPI-TOF/MS).Four debromination products-nonabromodiphenyl ethane(nonaBDPE),octabromodiphenyl ethane(octa-BDPE),heptabromodiphenyl ethane(hepta-BDPE)and hexabromodiphenyl ethane(hexa-BDPE)are identified based on the characteristic ion peak of[M-Br+O]^(-) in negative ion mode.Subsequently,using methanol as the mobile phase,four debromination products of DBDPE were separated and purified with a semi-preparative high-performance liquid chromatography(SP-HPLC)system equipped with an Agilent Zorbax Eclipse PAH column(4.6 mm×250 mm,5μm).The first-time acquisition of hexa-BDPE(60.00μg),octa-BDPE(19.40μg),hepta-BDPE(31.20μg)and octa-BDPE(isomer,45.20μg)with purity exceeding 90%has been achieved.Among them,the purity of one hepta-BDPE monomer is as high as 98.91%.This study indicates that based on photodegradation experiments,the combination of HPLC-APPI-TOF/MS and SP-HPLC techniques can rapidly identify and prepare DBDPE debrominated products.This approach meets the requirements for preliminary research on the pollution characteristics of DBDPE debrominated compounds and offers a feasible solution for the preparation of standard reference materials for emerging pollutants.展开更多
Ethylene(C_(2)H_(4))is a core raw material for the petrochemical industry.It is of economic and environmental significance to use C_(2)H_(6)as the fuel and proton-conducting solid oxide fuel cells(P-SOFC)as the reacto...Ethylene(C_(2)H_(4))is a core raw material for the petrochemical industry.It is of economic and environmental significance to use C_(2)H_(6)as the fuel and proton-conducting solid oxide fuel cells(P-SOFC)as the reactor to co-generate electricity and C_(2)H_(4).However,the large-sized Ni particles in the conventional Nicermet anode directly crack C_(2)H_(6);and oxide materials with a mild capability of breaking C-C bonds are generally limited to electrolyte-supported structures with high ohmic impedance.This research for the first time constructs an anode-supported cell using BZCY as the porous scaffold and impregnated double perovskite(PrBa)_(0.95)(Fe_(0.8)Ni_(0.2))_(1.8)Mo_(0.2)O_(6-δ)(PBFNM0.2)as the anode electrocatalysis.FeNi3 nanoparticles exsolve from PBFNM0.2 in H_(2) and uniformly distribute on the surface of perovskite substrate,acting as an active component for C_(2)H_(6)dehydrogenation and electrochemical performance enhancement.The cell with 30 wt%PBFNM0.2 impregnated anode showing a high power density of 508 and 386mW/cm^(2) with H_(2) and C_(2)H_(6)fuels,respectively;high C_(2)H_(6)conversion of 50.9%,C_(2)H_(4)selectivity of 92.1%,and C_(2)H_(4)yield of 46.9%are achieved at 750℃and 700mA/cm^(2),which outperforms all previously electrolyte-supported cells for co-generated electricity and ethylene.Moreover,the cell demonstrated excellent recoverability throughout three dehydrogenation-regeneration cycles.This work provides a practical way with broad application potential to create a novel anode-supported cell efficiently realizing the co-generation of electricity and C_(2)H_(4)from C_(2)H_(6).展开更多
In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit...In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit poor proton conductivity and limited catalytic activity.Herein,a novel Sr_(1.95)Fe_(1.4)Co_(0.1)Mo_(0.4)Zr_(0.1)O_(6-δ)(SFCMZ)anode is prepared as PCECs anode for EENDH.Zr doping increases the oxygen vacancies and enhances the proton conductivity of SFCMZ.Moreover,an alloy-oxide heterostructure(Co Fe@SFCMZ)is formed through in-situ exsolution of Co Fe alloy nanoparticles under reduction conditions,generating abundant oxygen vacancies and improving its catalytic activity.Co Fe@SFCMZ cell achieves an electrolysis current density of 0.87 A/cm^(2) at 700℃ under 1.6 V,with an ethane conversion rate of 34.22%and corresponding ethylene selectivity of 93.4%.These results demonstrate that Co Fe@SFCMZ anode exhibits excellent electrocatalytic activity,suggesting promising applications for EENDH.展开更多
Boron nitride containing hydroxyl groups efficiently catalysed oxidative dehydrogenation of ethane to ethylene,offering rather high selectivity（95%） but only small amount of CO2 formation（0.4%） at a given ethane c...Boron nitride containing hydroxyl groups efficiently catalysed oxidative dehydrogenation of ethane to ethylene,offering rather high selectivity（95%） but only small amount of CO2 formation（0.4%） at a given ethane conversion of 11%.Even at high conversion level of 63%,the selectivity of ethylene retained at 80%,which is competitive with the energy-demanding industrialized steam cracking route.A long-term test for 200 h resulted in stable conversion and product selectivity,showing the excellent catalytic stability.Both experimental and computational studies have identified that the hydrogen abstraction of B-OH groups by molecular oxygen dynamically generated the active sites and triggered ethane dehydrogenation.展开更多
This thesis aims to analysis the varied and meaningful symbols in Ethan Frome by Edith Wharton,which,without doubt,will help enhance the understanding of this classic novel.
Aim： To quantitatively study the histological changes of the testis and epididymis as a result of a drastic reduction of testosterone secretion. Methods： Fourteen adult Sprague-Dawley rats were injected intraperiton...Aim： To quantitatively study the histological changes of the testis and epididymis as a result of a drastic reduction of testosterone secretion. Methods： Fourteen adult Sprague-Dawley rats were injected intraperitoneally with ethane dimethane sulfonate （EDS, 75 mg/kg） and the same number of animals were injected with normal saline as a control. At days 7 and 12 （after treatment）, respectively, half of the animals from each group were killed. The testes and epididymides were removed and tissue blocks embedded in methacrylate resin. The cell number per testis was estimated using the stereological optical disector and some other parameters were obtained using other morphometric methods. Results： The EDS treatment resulted in an almost complete elimination of Leydig cells but had no effect on the numbers of Sertoli cells per testis. At day 7 after EDS treatment, many elongated spermatids were retained in the seminiferous epithelium and many round spermatids could be seen in the epididymal ducts. At day 12, a looser arrangement of spermatids and spermatocytes became evident, with apparent narrow empty spaces being formed between germ cells in an approximately radial direction towards the tubule lumen; the numbers （per testis） of non-type B spermatogonia and spermatocytes were similar to controls, whereas that of type B spermatogonia increased by 59%, and that of early round, elongating and late elongated spermatids decreased by 37%, 72% and 52%, respectively. Conclusion： The primary spermatogenic lesions following EDS administration were （i） spermiation failure and （ii） detachment of spermatids and spermatocytes associated with impairment in spermiogenesis and meiosis.展开更多
Objective This study aimed to evaluate the hepatotoxicity, metabolic disturbance activity and endocrine disrupting activity of mice treated by Decabromodiphenyl ethane （DBDPE）. Methods In this study, Balb/C mice wer...Objective This study aimed to evaluate the hepatotoxicity, metabolic disturbance activity and endocrine disrupting activity of mice treated by Decabromodiphenyl ethane （DBDPE）. Methods In this study, Balb/C mice were treated orally by gavage with various doses of DBDPE. After 30 days of treatment, mice were sacrificed; blood, livers and thyroid glands were obtained, and hepatic microsomes were isolated. Biochemical parameters including 8 clinical chemistry parameters, blood glucose and hormone levels including insulin and thyroid hormone were assayed. The effects of DBDPE on hepatic cytochrome P450 （CYP） levels and activities and uridinediphosphate-glucuronosyltransferase （UDPGT） activities were investigated. Liver and thyroid glands were observed. Results There were no obvious signs of toxicity and no significant treatment effect on body weight, or liver-to-body weight ratios between treatment groups. The levels of ALT and AST of higher dose treatment groups were markedly increased. Blood glucose levels of treatment groups were higher than those of control group. There was also an induction in TSH, T3, and f T3. UDPGT, PROD, and EROD activities were found to have been increased significantly in the high dose group. Histopathologic liver changes were characterized by hepatocyte hypertrophy and cytoplasmic vacuolization. Our findings suggest that DBDPE can cause a certain degree of mouse liver damage and insufficiency. Conclusion DBDPE has the activity of endocrine disruptors in Bal/C mice, which may induce drug-metabolizing enzymes including CYPs and UDPGT, and interfere with thyroid hormone levels mediated by Ah R and CAR signaling pathways. Endocrine disrupting activity of DBDPE could also affect the glucose metabolism homeostasis.展开更多
Abstract Objective To investigate the toxic effects of decabromodiphenyl ethane （DBDPE）, used as an alternative to decabromodiphenyl ether in vitro. Methods HepG2 cells were cultured in the presence of DBDPE at vari...Abstract Objective To investigate the toxic effects of decabromodiphenyl ethane （DBDPE）, used as an alternative to decabromodiphenyl ether in vitro. Methods HepG2 cells were cultured in the presence of DBDPE at various concentrations （3.125-100.0 mg/L） for 24, 48, and 72 h respectively and the toxic effect of DBDPE was studied. Results As evaluated by the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase assays and nuclear morphological changes, DBDPE inhibited HepG2 viability in a time- and dose-dependent manner within a range of 12.5 mg/L to 100 mg/L and for 48 h and 72 h. Induction of apoptosis was detected at 12.5-100 mg/L at 48 h and 72 h by propidium iodide staining, accompanied with overproduction of reactive oxygen species （ROS）. Furthermore, N-acetyI-L-cysteine, a widely used ROS scavenger, significantly reduced DBDPE-induced ROS levels and increased HepG2 cells viability. Conclusion DBDPE has cytotoxic and anti-proliferation effect and can induce apoptosis in which ROS plays an important role展开更多
Separation of ethane from ethylene is a very important but challenging process in the petrochemical industry.Finding an alternative method would reduce the energy needed to make 170 million tons of ethylene manufactur...Separation of ethane from ethylene is a very important but challenging process in the petrochemical industry.Finding an alternative method would reduce the energy needed to make 170 million tons of ethylene manufactured worldwide each year.Adsorptive separation using C2H6-selective porous materials to directly produce high-purity C2H4 is more energy-efficient.We herein report the"reversed C2H6/C2H4 adsorption"in a metal–organic framework Cr-BTC via the introduction of oxygen on its open metal sites.The oxidized Cr-BTC(O2)can bind C2H6 over C2H4 through the active Cr-superoxo sites,which was elucidated by the gas sorption isotherms and density functional theory calculations.This material thus exhibits a good performance for the separation of 50/50 C2H6/C2H4 mixtures to produce 99.99%pure C2H4 in a single separation operation.展开更多
Gold(Au)as co-catalyst is remarkable for activating methane(CH4),especially atomically dispersed Au with maximized exposing active sites and specific electronic structure.Furthermore,singlet oxygen(^(1)O_(2))typically...Gold(Au)as co-catalyst is remarkable for activating methane(CH4),especially atomically dispersed Au with maximized exposing active sites and specific electronic structure.Furthermore,singlet oxygen(^(1)O_(2))typically manifests a mild redox capacity with a high selectivity to attack organic substrates.Peroxomonosulfate(PMS)favors to produce oxidative species 102 during the photocatalytic reactions.Thus,combining atomic Au as co-catalyst and ^(1)O_(2) as oxidant is an effective strategy to selectively convert CH4.Herein,we synthesized atomically dispersed Au on WO_(3)(Au/WO_(3)),where Au was in the forms of single atoms and clusters.At room temperature,such Au/WO_(3) exhibited enhanced photocata lytic conversion of CH4 to CH3 CH3 with a selectivity,up to 94%,under visible light.The radicals-pathway mechanism of CH4 coupling has also been investigated through detection and trapping experiment of active species.Theoretical calculations further interpret the electronic structure of Au/WO_(3) and tip-enhanced local electric field at the Au sites for promoting CH4 conversion.展开更多
Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction...Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction （XRD）, nitrogen adsorption （N2） and X-ray photoelectron spectroscopy （XPS）. The results reveal that Cu-MCM-48 with mass fraction of copper up to 10 % can still retain the uniform mesoporous framework of MCM-48. The copper in the framework of MCM-48 was easily auto-reduced to Cu（I） in N2 at high temperature, which did not alter the mesoporous structure of MCM-48. The adsorption equilibrium isotherms of ethylene and ethane on these molecular sieve adsorbents have been measured at 30℃. At 100 kPa, the adsorption capacities of ethylene on 5Cu-MCM-48 and 10Cu-MCM-48 are higher than those on MCM-48. The 10Cu-MCM-48 molecular sieve adsorbent has a higher selective adsorption ratio of ethylene to ethane, the separation factor is 3.8, and the amount of ethylene adsorbed is 11.1 ml·g ^-1.展开更多
基金supported by the Natural Science Foundation of China(Grant Nos.52288102,52090020,and 52372261)the Natural Science Foundation of Hebei Province(Grant No.E202403045)+2 种基金the S&T Program of Hebei(Grant No.225A1102D)the Ministry of Education Chang Jiang Scholar Professor Program(Grant No.T2022241)supported by the User Experiment Assist System at SSRF.
文摘Recent advances in geoscience have underscored the critical role of abiogenic processes in petroleum formation,especially the formation and polymerization of methane.However,whether a direct carbon-H_(2) reaction can produce C_(2+)hydrocarbons(e.g.,ethane and propane)beyond methane remains an open question.Here,we demonstrate the direct synthesis of ethane and propane via reactions between amorphous carbon and H_(2) under upper mantle conditions(2-10 GPa and 800-1200℃).A systematic investigation reveals that increasing structural disorder in carbon precursors,from graphite to glassy carbon-Ⅱ and carbon black,enhances the production of C_(2)-C_(3) hydrocarbons.Through integrated X-ray diffraction and reverse Monte Carlo simulations,we establish that the continuous random atomic network structures in amorphous carbon enable one-step synthesis of heavy hydrocarbons with H_(2).These models establish a direct link between atomic-scale carbon structures and the one-step synthesis of C_(2+)hydrocarbons under H2-rich,high-pressure,and high-temperature conditions—potentially revealing an efficient mechanism for the abiotic production of C_(2+)hydrocarbons in the upper mantle.
基金the National Natural Science Foundation of China.
文摘Although literature abounds with examples of formation of perhaloalkanes by photo-lytic or Lewis-acid induced halogen exchange reactions involving radical or carbocationintermediates,the procedures are seldom applicable to the preparation of perhaloalkanes ingood yields under mild conditions.Recently,we have reported the spontaneous reactionsof some perhalofluoroalkanes with various types of nucleophiles.All these reactions areinitiated by the halophilic attack of nucleophiles on C—Br or C—Cl bonds,followed byanionic chain steps involving carbanion as well as olefin intermediates.Notably,the latter areformed after the β-elimination of a good leaving group from the former.On the other hand,it is well known that halogenated carbanions can effectively make halophilic attacks on theC—X bonds of other halogenated substrates,e.g.,in the“halogen dance”of Bunnett.There-
基金We appreciate financial support from Ministry of Science and Technology of the People's Republic of China(2016YFA0602900)the National Natural Science Foundation of China(21871096,21672071)+1 种基金Guangdong Science and Technology Department(20188030308007,2018A030310359,2016A030310433)the Science and Technology Program of Guangzhou(201707010316,201707010168).
文摘Summary of main observation and conclusion A Cu(I)-catalyzed three-component reaction of terminal enynals/enynones,diazo compounds,and al kenes has been developed.With this method,a series of oxabicyclo[2.2.2]octanes were effectively synthesized in high yields under mild reaction condi-tions.This transformation is proposed to proceed through trapping of the cyclic vinyl-o-quinodimethanes(vinyI-o-QDMs)species,which were generated from terminal enynals/enynones and diazo compounds by alkenes.The obvious advantages of wide substrate scopes,mild reaction conditions,and high seteroselectivity and atom eficiency make this reaction highly appealing for construction of highly rigid[2.2.2]octane skeleton.
文摘Chemical looping oxidative dehydrogenation(CL‐ODH)is a promising novel method to convert ethane into higher value‐added ethylene.In this study,perovskite‐type Co_(2)O_(3)/LaCoO_(3) was prepared by the one‐step citric acid‐gel method and applied as an oxygen carrier in the CL‐ODH process of ethane to ethylene;moreover,the effects of CuO,ZnO,and MgO as additives were investigated.The properties of the oxygen carriers were characterized using XRD,BET,XPS,H_(2)‐TPR,O_(2)‐TPD,and EPR.Characterization results showed that the addition of additives into Co_(2)O_(3)/LaCoO_(3) increased the amounts of surface chemisorbed oxygen and lattice oxygen.Co_(2)O_(3)/LaCoO_(3) had a strong ability to absorb and release oxygen after adding CuO,ZnO,and MgO,respectively.The performances of the oxygen carriers for CL‐ODH of ethane to ethylene were studied at a reaction temperature of 650℃,atmospheric pressure,and GHSV of 15,000 mL/g·h in eight redox cycles.All the oxygen carriers had 100%ethane conversion,and ZnO‐Co_(2)O_(3)/LaCoO_(3) exhibited the best ethylene selectivity of more than 70%in all the oxygen carriers.It was confirmed that lattice oxygen was mainly responsible for the selectivity of ethylene,and oxygen vacancies were conducive to the migration of lattice oxygen.Most of Zn^(2+) entered into the bulk phase of Co_(2)O_(3)/LaCoO_(3),and formed lots of oxygen vacancies.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1506000)Gusu Innovation and Entrepreneurship Leading Talents Program(ZXL2022497)+5 种基金Jiangsu Distinguished Professor programfinancial support by National Natural Science Foundation of China(Grant No.22301057)Natural Science Foundation of Hebei Province(Grant No.B2023201065)Science Research Project of Hebei Education Department(Grant No.BJK2024103)supported by the Open Research Fund of Shanghai Key Laboratory of High-resolution Electron MicroscopyOpen Project of State Key Laboratory of Supramolecular Structure and Materials(sklssm2024019),ShanghaiTech University。
文摘The dehydrogenation of alkanes has emerged as a vital complementary process to address the increasing global demand for olefins.A key challenge remains in the construction of novel active centers that offer superior activity,stability,and cost-effectiveness.Herein,tricoordinated cobalt atoms were successfully fabricated through an in-situ ligand-protected synthesis by introducing tungsten atoms into zeolite frameworks.These unsaturated Co species efficiently activate C-H bonds while suppressing C-C bond cleavage,resulting in exceptional catalytic activity and olefin selectivity in both propane and ethane dehydrogenation reactions.The optimized Co_(0.2%)@0.01W-S-1 catalyst demonstrated an impressive propylene formation rate of 15.2 molC_(3H6)gcC h^(-1)at 823 K and an ethylene formation rate of 240.3mol_(C2H4)g_(Co)^(-1)h^(-1)at 913 K,with propylene and ethylene selectivities of 99.0%and 97.5%,respectively.These results not only significantly surpass conventional tetracoordinated Co catalysts but also rival some Pt-based catalysts under similar conditions.Importantly,the catalyst exhibited excellent stability in dehydrogenation reactions,with no significant loss in catalytic activity after five consecutive regeneration cycles.This work offers valuable insights into the design of zeolite-supported non-precious metal catalysts with high activity and durability for efficient alkane dehydrogenation.
文摘Ethan Wargo,9 years old,sets up a small table on his lawn each morning in Sycamore,Illinois,waiting for people to walk by so that he can offer a compliment to anyone who stops to talk.In mid‑July 2025,Ethan launched what he calls a“compliments stand”,spending up to five hours a day at his table.The idea was inspired by a scene in a recent graphic(绘画的)novel,where characters run a stand.He parked himself next to his twin sister,Claire,who sells her artwork at her own stand,but Ethan knew charging for compliments didn't feel right.“I didn't want people to pay to be happy,”he said.“Paying for something like that is very silly.”
基金supported by the National Natural Science Foundation of China(Nos.42107284 and 22078177)the Postdoctoral Fellowship Program of CPSF(No.GZB20240410)。
文摘Decabromodiphenyl ethane(DBDPE)is widely used as an additive flame retardant and has led to global pollution.Its has a large molecular mass and is prone to debromination and degradation under photothermal conditions,resulting in smaller homologous compounds.Due to the lack of standard substances for debromination products,the in-depth study of DBDPE environmental geochemical behavior through debromination conversion has been hindered.Therefore,based on DBDPE photodegradation experiment,this study first analyzed and identified the brominated products of DBDPE using high-performance liquid chromatography-atmospheric pressure photoionization-time of flight mass spectrometry(HPLC-APPI-TOF/MS).Four debromination products-nonabromodiphenyl ethane(nonaBDPE),octabromodiphenyl ethane(octa-BDPE),heptabromodiphenyl ethane(hepta-BDPE)and hexabromodiphenyl ethane(hexa-BDPE)are identified based on the characteristic ion peak of[M-Br+O]^(-) in negative ion mode.Subsequently,using methanol as the mobile phase,four debromination products of DBDPE were separated and purified with a semi-preparative high-performance liquid chromatography(SP-HPLC)system equipped with an Agilent Zorbax Eclipse PAH column(4.6 mm×250 mm,5μm).The first-time acquisition of hexa-BDPE(60.00μg),octa-BDPE(19.40μg),hepta-BDPE(31.20μg)and octa-BDPE(isomer,45.20μg)with purity exceeding 90%has been achieved.Among them,the purity of one hepta-BDPE monomer is as high as 98.91%.This study indicates that based on photodegradation experiments,the combination of HPLC-APPI-TOF/MS and SP-HPLC techniques can rapidly identify and prepare DBDPE debrominated products.This approach meets the requirements for preliminary research on the pollution characteristics of DBDPE debrominated compounds and offers a feasible solution for the preparation of standard reference materials for emerging pollutants.
基金financially supported by the National Natural Science Foundation of China(Nos.52072134,52272205)Hubei Province(Nos.2021BCA149,2021CFA072,2022BAA087)the special fund for Science and Technology Innovation Teams of Shanxi Province(No.202304051001007)。
文摘Ethylene(C_(2)H_(4))is a core raw material for the petrochemical industry.It is of economic and environmental significance to use C_(2)H_(6)as the fuel and proton-conducting solid oxide fuel cells(P-SOFC)as the reactor to co-generate electricity and C_(2)H_(4).However,the large-sized Ni particles in the conventional Nicermet anode directly crack C_(2)H_(6);and oxide materials with a mild capability of breaking C-C bonds are generally limited to electrolyte-supported structures with high ohmic impedance.This research for the first time constructs an anode-supported cell using BZCY as the porous scaffold and impregnated double perovskite(PrBa)_(0.95)(Fe_(0.8)Ni_(0.2))_(1.8)Mo_(0.2)O_(6-δ)(PBFNM0.2)as the anode electrocatalysis.FeNi3 nanoparticles exsolve from PBFNM0.2 in H_(2) and uniformly distribute on the surface of perovskite substrate,acting as an active component for C_(2)H_(6)dehydrogenation and electrochemical performance enhancement.The cell with 30 wt%PBFNM0.2 impregnated anode showing a high power density of 508 and 386mW/cm^(2) with H_(2) and C_(2)H_(6)fuels,respectively;high C_(2)H_(6)conversion of 50.9%,C_(2)H_(4)selectivity of 92.1%,and C_(2)H_(4)yield of 46.9%are achieved at 750℃and 700mA/cm^(2),which outperforms all previously electrolyte-supported cells for co-generated electricity and ethylene.Moreover,the cell demonstrated excellent recoverability throughout three dehydrogenation-regeneration cycles.This work provides a practical way with broad application potential to create a novel anode-supported cell efficiently realizing the co-generation of electricity and C_(2)H_(4)from C_(2)H_(6).
基金financially supported by the National Natural Science Foundation of China(Nos.52272190 and 22178023)the National Key R&D Program of China(No.2021YFB4001401)。
文摘In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit poor proton conductivity and limited catalytic activity.Herein,a novel Sr_(1.95)Fe_(1.4)Co_(0.1)Mo_(0.4)Zr_(0.1)O_(6-δ)(SFCMZ)anode is prepared as PCECs anode for EENDH.Zr doping increases the oxygen vacancies and enhances the proton conductivity of SFCMZ.Moreover,an alloy-oxide heterostructure(Co Fe@SFCMZ)is formed through in-situ exsolution of Co Fe alloy nanoparticles under reduction conditions,generating abundant oxygen vacancies and improving its catalytic activity.Co Fe@SFCMZ cell achieves an electrolysis current density of 0.87 A/cm^(2) at 700℃ under 1.6 V,with an ethane conversion rate of 34.22%and corresponding ethylene selectivity of 93.4%.These results demonstrate that Co Fe@SFCMZ anode exhibits excellent electrocatalytic activity,suggesting promising applications for EENDH.
基金supported by the National Natural Science Foundation of China (21225312, U1462120, 21473206)Cheung Kong Scholars Programme of China (T2015036)~~
文摘Boron nitride containing hydroxyl groups efficiently catalysed oxidative dehydrogenation of ethane to ethylene,offering rather high selectivity（95%） but only small amount of CO2 formation（0.4%） at a given ethane conversion of 11%.Even at high conversion level of 63%,the selectivity of ethylene retained at 80%,which is competitive with the energy-demanding industrialized steam cracking route.A long-term test for 200 h resulted in stable conversion and product selectivity,showing the excellent catalytic stability.Both experimental and computational studies have identified that the hydrogen abstraction of B-OH groups by molecular oxygen dynamically generated the active sites and triggered ethane dehydrogenation.
文摘This thesis aims to analysis the varied and meaningful symbols in Ethan Frome by Edith Wharton,which,without doubt,will help enhance the understanding of this classic novel.
文摘Aim： To quantitatively study the histological changes of the testis and epididymis as a result of a drastic reduction of testosterone secretion. Methods： Fourteen adult Sprague-Dawley rats were injected intraperitoneally with ethane dimethane sulfonate （EDS, 75 mg/kg） and the same number of animals were injected with normal saline as a control. At days 7 and 12 （after treatment）, respectively, half of the animals from each group were killed. The testes and epididymides were removed and tissue blocks embedded in methacrylate resin. The cell number per testis was estimated using the stereological optical disector and some other parameters were obtained using other morphometric methods. Results： The EDS treatment resulted in an almost complete elimination of Leydig cells but had no effect on the numbers of Sertoli cells per testis. At day 7 after EDS treatment, many elongated spermatids were retained in the seminiferous epithelium and many round spermatids could be seen in the epididymal ducts. At day 12, a looser arrangement of spermatids and spermatocytes became evident, with apparent narrow empty spaces being formed between germ cells in an approximately radial direction towards the tubule lumen; the numbers （per testis） of non-type B spermatogonia and spermatocytes were similar to controls, whereas that of type B spermatogonia increased by 59%, and that of early round, elongating and late elongated spermatids decreased by 37%, 72% and 52%, respectively. Conclusion： The primary spermatogenic lesions following EDS administration were （i） spermiation failure and （ii） detachment of spermatids and spermatocytes associated with impairment in spermiogenesis and meiosis.
基金supported by the National Natural Science Foundation[No.21407179]
文摘Objective This study aimed to evaluate the hepatotoxicity, metabolic disturbance activity and endocrine disrupting activity of mice treated by Decabromodiphenyl ethane （DBDPE）. Methods In this study, Balb/C mice were treated orally by gavage with various doses of DBDPE. After 30 days of treatment, mice were sacrificed; blood, livers and thyroid glands were obtained, and hepatic microsomes were isolated. Biochemical parameters including 8 clinical chemistry parameters, blood glucose and hormone levels including insulin and thyroid hormone were assayed. The effects of DBDPE on hepatic cytochrome P450 （CYP） levels and activities and uridinediphosphate-glucuronosyltransferase （UDPGT） activities were investigated. Liver and thyroid glands were observed. Results There were no obvious signs of toxicity and no significant treatment effect on body weight, or liver-to-body weight ratios between treatment groups. The levels of ALT and AST of higher dose treatment groups were markedly increased. Blood glucose levels of treatment groups were higher than those of control group. There was also an induction in TSH, T3, and f T3. UDPGT, PROD, and EROD activities were found to have been increased significantly in the high dose group. Histopathologic liver changes were characterized by hepatocyte hypertrophy and cytoplasmic vacuolization. Our findings suggest that DBDPE can cause a certain degree of mouse liver damage and insufficiency. Conclusion DBDPE has the activity of endocrine disruptors in Bal/C mice, which may induce drug-metabolizing enzymes including CYPs and UDPGT, and interfere with thyroid hormone levels mediated by Ah R and CAR signaling pathways. Endocrine disrupting activity of DBDPE could also affect the glucose metabolism homeostasis.
基金supported by the NSFC(No.20877102)"973"project(No.2010CB933904)
文摘Abstract Objective To investigate the toxic effects of decabromodiphenyl ethane （DBDPE）, used as an alternative to decabromodiphenyl ether in vitro. Methods HepG2 cells were cultured in the presence of DBDPE at various concentrations （3.125-100.0 mg/L） for 24, 48, and 72 h respectively and the toxic effect of DBDPE was studied. Results As evaluated by the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase assays and nuclear morphological changes, DBDPE inhibited HepG2 viability in a time- and dose-dependent manner within a range of 12.5 mg/L to 100 mg/L and for 48 h and 72 h. Induction of apoptosis was detected at 12.5-100 mg/L at 48 h and 72 h by propidium iodide staining, accompanied with overproduction of reactive oxygen species （ROS）. Furthermore, N-acetyI-L-cysteine, a widely used ROS scavenger, significantly reduced DBDPE-induced ROS levels and increased HepG2 cells viability. Conclusion DBDPE has cytotoxic and anti-proliferation effect and can induce apoptosis in which ROS plays an important role
基金the financial support from the National Natural Science Foundation of China(Nos.21606163 and 21878205)Coal Bed Methane Joint Foundation of Shanxi(2016012006)+2 种基金Foundation of State Key Laboratory of Coal Conversion(J18-19-610)Welch Foundation(grant AX-1730)the Distinguished Scientist Fellowship Program(DSFP)at KSU.
文摘Separation of ethane from ethylene is a very important but challenging process in the petrochemical industry.Finding an alternative method would reduce the energy needed to make 170 million tons of ethylene manufactured worldwide each year.Adsorptive separation using C2H6-selective porous materials to directly produce high-purity C2H4 is more energy-efficient.We herein report the"reversed C2H6/C2H4 adsorption"in a metal–organic framework Cr-BTC via the introduction of oxygen on its open metal sites.The oxidized Cr-BTC(O2)can bind C2H6 over C2H4 through the active Cr-superoxo sites,which was elucidated by the gas sorption isotherms and density functional theory calculations.This material thus exhibits a good performance for the separation of 50/50 C2H6/C2H4 mixtures to produce 99.99%pure C2H4 in a single separation operation.
基金sponsored by Shanghai Pujiang Program(No.19PJ1405200)the Startup Fund for Youngman Research at SJTU(SFYR at SJTU,No.WF220516003)。
文摘Gold(Au)as co-catalyst is remarkable for activating methane(CH4),especially atomically dispersed Au with maximized exposing active sites and specific electronic structure.Furthermore,singlet oxygen(^(1)O_(2))typically manifests a mild redox capacity with a high selectivity to attack organic substrates.Peroxomonosulfate(PMS)favors to produce oxidative species 102 during the photocatalytic reactions.Thus,combining atomic Au as co-catalyst and ^(1)O_(2) as oxidant is an effective strategy to selectively convert CH4.Herein,we synthesized atomically dispersed Au on WO_(3)(Au/WO_(3)),where Au was in the forms of single atoms and clusters.At room temperature,such Au/WO_(3) exhibited enhanced photocata lytic conversion of CH4 to CH3 CH3 with a selectivity,up to 94%,under visible light.The radicals-pathway mechanism of CH4 coupling has also been investigated through detection and trapping experiment of active species.Theoretical calculations further interpret the electronic structure of Au/WO_(3) and tip-enhanced local electric field at the Au sites for promoting CH4 conversion.
基金Supported by the National Natural Science Foundation of China （20276029） and the Specialized Research Fund for the Doctoral Program of Higher Education of China （20040291005）.
文摘Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction （XRD）, nitrogen adsorption （N2） and X-ray photoelectron spectroscopy （XPS）. The results reveal that Cu-MCM-48 with mass fraction of copper up to 10 % can still retain the uniform mesoporous framework of MCM-48. The copper in the framework of MCM-48 was easily auto-reduced to Cu（I） in N2 at high temperature, which did not alter the mesoporous structure of MCM-48. The adsorption equilibrium isotherms of ethylene and ethane on these molecular sieve adsorbents have been measured at 30℃. At 100 kPa, the adsorption capacities of ethylene on 5Cu-MCM-48 and 10Cu-MCM-48 are higher than those on MCM-48. The 10Cu-MCM-48 molecular sieve adsorbent has a higher selective adsorption ratio of ethylene to ethane, the separation factor is 3.8, and the amount of ethylene adsorbed is 11.1 ml·g ^-1.
