The metal-support interaction is of critical importance to enhance the catalytic activity and selectivity.However,it is still challenging to construct an appropriate interaction starting from the catalyst fabrication ...The metal-support interaction is of critical importance to enhance the catalytic activity and selectivity.However,it is still challenging to construct an appropriate interaction starting from the catalyst fabrication and/or activation.We herein established low-temperature treatment of Ni^(2+)ions impregnated on ceria in reductive atmosphere and reduction-oxidation cycles as effective approachs to regulate the metal-support interaction and raise the catalytic performance in the CO_(2)methanation.The proposed construction approach yielded Ni/Ce O_(2)that displayed highly dispersed Ni nanoparticles in contact with Ce O_(2)(111)and(100)facet,higher density of surface oxygen vacancies and larger amounts of weak basic sites relative to the reference samples,which increased the capacity for H2 and CO_(2)adsorption/activation.The interaction resulted in appreciably(2-3 fold)higher activity in the CO_(2)methanation with maintaining almost full selectivity to CH4 and high stability.Coverage of Ni surface by Ce O_(2)-x thin layer as a typical structure of strong metal-support interaction resulting from high-temperature reduction,can be alleviated via reduction-oxidation cycles.We also demonstrate the activation treatment-determined metalsupport interaction effect can generally extend to(Ti O_(2)and Zr O_(2))supported Ni catalysts.展开更多
Distribution of Paleogene lacustrine high-quality source rocks in the Bozhong sag in Bohai Bay Basin is analyzed through data of geochemistry,geology and well logging,and its differences under the control of climate a...Distribution of Paleogene lacustrine high-quality source rocks in the Bozhong sag in Bohai Bay Basin is analyzed through data of geochemistry,geology and well logging,and its differences under the control of climate and tectonics is also well discussed.Distribution characteristics of the high-quality source rocks developed in the saline environment controlled by the climate are quite different from that developed in the rapid subsidence environment controlled by tectonics.The high-quality source rocks in Member 1 of Shahejie Formation developed in the saline environment account for 81.9%of total subsag area,and are distributed widely and extensively.The high-quality source rocks in Member 3 of Shahejie Formation and Member 3 of Dongying Formation is developed in the tectonic subsidence environment,and horizontally,the subsag subsidence rates has a positive correlation with the area proportion of the high-quality source rocks in the sag;vertically,the reduction-oxidation interface of the lake controls the enrichment of highquality source rocks.Controlled by the saline environment and rapid subsidence environment,the highquality source rocks in the Bozhong sag and adjacent areas have three types of development condition:the saline water,the tectonic subsidence,and joint control of the saline water and the tectonic subsidence.The humid climate and low subsidence rate are not favorable for development of high-quality source rocks.展开更多
Surface characterization of metal nanoparticles is a critical need in nanocatalysis for in-depth understanding of the structure-function relationships.The surface structure of nanoparticles is often different from the...Surface characterization of metal nanoparticles is a critical need in nanocatalysis for in-depth understanding of the structure-function relationships.The surface structure of nanoparticles is often different from the subsurface,and it is challenging to separately characterize the surface and the subsurface.In this work,theoretical calculations and extended X-ray absorption fine structure(EXAFS)analysis illustrate that the surface atoms of noble metals(Pt and Pd)are oxidized in the air,while the subsurface atoms are not easily oxidized.Taking advantage of the oxidation properties,we suggest a stepwise reduction-oxidation approach to determine the surface atomic arrangement of noble metal nanoparticles,and confirm the rationality of this approach by identifying the surface structure of typical 2-3 nm Pt and Pd nanoparticles.The reduction-oxidation approach is applied to characterize the surface structure of model Pd-Sb bimetallic catalyst,which illustrates that the surface Pd is well isolated by Sb atoms with short bond distance at 2.70Å,while there are still Pd-Pd bonds in the subsurface.Density functional theory(DFT)calculations and Pd L edge X-ray absorption near edge structure(XANES)indicate that the isolation of surface Pd significantly decreases the adsorption energies of Pd-hydrocarbon,which leads to the high propylene selectivity and turnover frequency Pd-Sb bimetallic catalyst for propane dehydrogenation.展开更多
One hind leg(about 7% TBSA)of a rat was scalded and the changes of thereduction-oxidation state and protein degradation in the soleus muscle were observed inthe 72nd h after scalding both in vitro and in vivo.It was f...One hind leg(about 7% TBSA)of a rat was scalded and the changes of thereduction-oxidation state and protein degradation in the soleus muscle were observed inthe 72nd h after scalding both in vitro and in vivo.It was found that the lactate/pyruvate(L/P)and malate/pyruvate(M/P)ratios in the soleus muscle were significantly lower andthe protein degradation rate significantly higher in the scalded rats than those in the controland in the unscalded legs.After the addition of insulin to the medium,significant eleva-tion of L/P and M/P ratios and reduction of the protein degradation rate were observedin the soleus muscle.These findings suggest that there is a good correlation between thechanges of the reduction-oxidation and the protein degradation rate in the cytosol of thesoleus muscle after scalding in rats.展开更多
An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures： low-temperature roasting of vanadium-bearing titanomagnetite and water lea...An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures： low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70 wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.展开更多
Microbes are well-known for their great diversity and abundance in modern natural environments.They also are believed to pro-vide critical links among higher organisms and their associated environments.However,the low...Microbes are well-known for their great diversity and abundance in modern natural environments.They also are believed to pro-vide critical links among higher organisms and their associated environments.However,the low diversity of morphological fea-tures and structures of ancient microbes preserved in sediments and rocks make them difficult to identify and classify.This diffi-culty greatly hinders the investigation of geomicrobes throughout Earth history.Thus,most previous paleontological studies have focused on faunal and floral fossils.Here,geomicrobial functional groups(GFGs),or a collection of microbes featured in specific ecological,physiological or biogeochemical functions,are suggested to provide a way to overcome the difficulties of ancient mi-crobe investigations.GFGs are known for their great diversity in ecological,physiological and biogeochemical functions.In addi-tion,GFGs may be preserved as the biogeochemical,mineralogical and sedimentological records in sediments and rocks.We reviewed the functions,origins and identification diagnostics of some important GFGs involved in the elemental cycles of carbon,sulfur,nitrogen and iron.GFGs were further discussed with respect to their significant impacts on paleoclimate,sulfur chemistry of ancient seawater,nutritional status of geological environments,and the deposition of Precambrian banded iron formations.展开更多
基金financially supported by the Tianjin Key Science and Technology Project(19ZXNCGX00030)。
文摘The metal-support interaction is of critical importance to enhance the catalytic activity and selectivity.However,it is still challenging to construct an appropriate interaction starting from the catalyst fabrication and/or activation.We herein established low-temperature treatment of Ni^(2+)ions impregnated on ceria in reductive atmosphere and reduction-oxidation cycles as effective approachs to regulate the metal-support interaction and raise the catalytic performance in the CO_(2)methanation.The proposed construction approach yielded Ni/Ce O_(2)that displayed highly dispersed Ni nanoparticles in contact with Ce O_(2)(111)and(100)facet,higher density of surface oxygen vacancies and larger amounts of weak basic sites relative to the reference samples,which increased the capacity for H2 and CO_(2)adsorption/activation.The interaction resulted in appreciably(2-3 fold)higher activity in the CO_(2)methanation with maintaining almost full selectivity to CH4 and high stability.Coverage of Ni surface by Ce O_(2)-x thin layer as a typical structure of strong metal-support interaction resulting from high-temperature reduction,can be alleviated via reduction-oxidation cycles.We also demonstrate the activation treatment-determined metalsupport interaction effect can generally extend to(Ti O_(2)and Zr O_(2))supported Ni catalysts.
基金supported by the National Science and Technology Major Project of China(No.2016ZX05024-002).
文摘Distribution of Paleogene lacustrine high-quality source rocks in the Bozhong sag in Bohai Bay Basin is analyzed through data of geochemistry,geology and well logging,and its differences under the control of climate and tectonics is also well discussed.Distribution characteristics of the high-quality source rocks developed in the saline environment controlled by the climate are quite different from that developed in the rapid subsidence environment controlled by tectonics.The high-quality source rocks in Member 1 of Shahejie Formation developed in the saline environment account for 81.9%of total subsag area,and are distributed widely and extensively.The high-quality source rocks in Member 3 of Shahejie Formation and Member 3 of Dongying Formation is developed in the tectonic subsidence environment,and horizontally,the subsag subsidence rates has a positive correlation with the area proportion of the high-quality source rocks in the sag;vertically,the reduction-oxidation interface of the lake controls the enrichment of highquality source rocks.Controlled by the saline environment and rapid subsidence environment,the highquality source rocks in the Bozhong sag and adjacent areas have three types of development condition:the saline water,the tectonic subsidence,and joint control of the saline water and the tectonic subsidence.The humid climate and low subsidence rate are not favorable for development of high-quality source rocks.
基金supported by the National Natural Science Foundation of China(No.22008135)China Postdoctoral Science Foundation(No.2020M670345)National Natural Science Foundation(No.EEC-1647722),Beijing Municipal Science&Technology Commission(No.Z191100007219003).
文摘Surface characterization of metal nanoparticles is a critical need in nanocatalysis for in-depth understanding of the structure-function relationships.The surface structure of nanoparticles is often different from the subsurface,and it is challenging to separately characterize the surface and the subsurface.In this work,theoretical calculations and extended X-ray absorption fine structure(EXAFS)analysis illustrate that the surface atoms of noble metals(Pt and Pd)are oxidized in the air,while the subsurface atoms are not easily oxidized.Taking advantage of the oxidation properties,we suggest a stepwise reduction-oxidation approach to determine the surface atomic arrangement of noble metal nanoparticles,and confirm the rationality of this approach by identifying the surface structure of typical 2-3 nm Pt and Pd nanoparticles.The reduction-oxidation approach is applied to characterize the surface structure of model Pd-Sb bimetallic catalyst,which illustrates that the surface Pd is well isolated by Sb atoms with short bond distance at 2.70Å,while there are still Pd-Pd bonds in the subsurface.Density functional theory(DFT)calculations and Pd L edge X-ray absorption near edge structure(XANES)indicate that the isolation of surface Pd significantly decreases the adsorption energies of Pd-hydrocarbon,which leads to the high propylene selectivity and turnover frequency Pd-Sb bimetallic catalyst for propane dehydrogenation.
文摘One hind leg(about 7% TBSA)of a rat was scalded and the changes of thereduction-oxidation state and protein degradation in the soleus muscle were observed inthe 72nd h after scalding both in vitro and in vivo.It was found that the lactate/pyruvate(L/P)and malate/pyruvate(M/P)ratios in the soleus muscle were significantly lower andthe protein degradation rate significantly higher in the scalded rats than those in the controland in the unscalded legs.After the addition of insulin to the medium,significant eleva-tion of L/P and M/P ratios and reduction of the protein degradation rate were observedin the soleus muscle.These findings suggest that there is a good correlation between thechanges of the reduction-oxidation and the protein degradation rate in the cytosol of thesoleus muscle after scalding in rats.
基金financially supported by the National Basic Research Program of China(Nos.2013CB632601 and 2013CB632604)the National Science Foundation for Distinguished Young Scholars of China(Nos.51125018 and 51504230)+3 种基金the Key Research Program of the Chinese Academy of Sciences(No.KGZD-EW-201-2)the National Natural Science Foundation of China(Nos.51374191,21106167,2160624,and 51104139)the Financial Grant from the China Postdoctoral Science Foundation(Nos.2012M510552 and 2013T60175)the Nonprofit Industry Research Subject of Environmental Projection(No.201509053)
文摘An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures： low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70 wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.
基金supported by the National Natural Science Foundation of China(40930210,40921062 and 41130207)the National Basic Research Program of China(2011CB808800)the 111 Program(B08030)
文摘Microbes are well-known for their great diversity and abundance in modern natural environments.They also are believed to pro-vide critical links among higher organisms and their associated environments.However,the low diversity of morphological fea-tures and structures of ancient microbes preserved in sediments and rocks make them difficult to identify and classify.This diffi-culty greatly hinders the investigation of geomicrobes throughout Earth history.Thus,most previous paleontological studies have focused on faunal and floral fossils.Here,geomicrobial functional groups(GFGs),or a collection of microbes featured in specific ecological,physiological or biogeochemical functions,are suggested to provide a way to overcome the difficulties of ancient mi-crobe investigations.GFGs are known for their great diversity in ecological,physiological and biogeochemical functions.In addi-tion,GFGs may be preserved as the biogeochemical,mineralogical and sedimentological records in sediments and rocks.We reviewed the functions,origins and identification diagnostics of some important GFGs involved in the elemental cycles of carbon,sulfur,nitrogen and iron.GFGs were further discussed with respect to their significant impacts on paleoclimate,sulfur chemistry of ancient seawater,nutritional status of geological environments,and the deposition of Precambrian banded iron formations.
