Bimetallic CoCu nanocomposites were synthesized in polyol by using Ru as heterogeneous nucleation agent and stearic acid as surfactant, and their catalytic properties were investi- gated by hydrogenolysis of glycerol ...Bimetallic CoCu nanocomposites were synthesized in polyol by using Ru as heterogeneous nucleation agent and stearic acid as surfactant, and their catalytic properties were investi- gated by hydrogenolysis of glycerol to propanediols. It was found that the surfactant could induce Co nanocrystals to form nanowires as structure-directing agent, while it＇s ineffective for Cu because only spherical Cu particles were produced under the same condition. When Co2＋ and Cu2＋ coexist in polyol, Cu2＋ is firstly reduced and forms the spherical particles, and then the Cu particles afford surface for the subsequential reduction of Co2＋ and growth of Co nanocrystals to form the nanorods, obtaining the urchin-like CoCu nanocomposites. The catalytic performance in selective hydrogenolysis of glycerol to propanediols proposed that the CoCu urchin-like nanocomposites was superior to the Co nanowires possibly due to that the synergistic effect between Co and Cu component promoted conversion of glyc- erol and obtained the higher propanediol yields based on the specific surface areas of the catalysts.展开更多
Surface segregation is ubiquitous in multi-component materials and is of great important for catalysis but little is known on the surface structure under graphene encapsulation.Here,we show that the graphene encapsula...Surface segregation is ubiquitous in multi-component materials and is of great important for catalysis but little is known on the surface structure under graphene encapsulation.Here,we show that the graphene encapsulated CoCu performs well for the electrocatalytic oxidation of 5-hydroxymethylfurfural(HMF)to2,5-furandicarboxylic acid(FDCA)with the onset potential before 1.23 VRHEand a nearly 100%selectivity of FDCA under 1.4 VRHE.From the experimental results,the unprecedented catalytic performance was attributed to local structural distortion and sub-nanometer lattice composition of the CoCu surface.We accurately show the dispersed Cu doped Co_(3)O_(4) nano-islands with a lot of edge sites on the bimetallic Co-Cu surface.While,the gradient components effectively facilitate the establishment of built-in electric field and accelerate the charge transfer.Theoretical and experimental results reveal that the surface Co and neighbouring Cu atoms in sub-nanometer lattice synergistically promote the catalysis of HMF.This work offers new insights into surface segregation in tuning the element spatial distribution for catalysis.展开更多
AIM: To evaluate the effect of Cocus nucifera L. flowers in reducing the major multiple symptoms of letrozole-induced polycystic ovarian disease(PCOD) in female rats. METHOD: Female, virgin Wistar rats were treated wi...AIM: To evaluate the effect of Cocus nucifera L. flowers in reducing the major multiple symptoms of letrozole-induced polycystic ovarian disease(PCOD) in female rats. METHOD: Female, virgin Wistar rats were treated with letrozole(1 mg/kg body wt) to induce PCOD, and after 21 days of induction rats were administered orally with 100 and 200 mg·kg-1 of Cocus nucifera flower aqueous extract, respectively. Estrus cycle and blood sugar were monitored once a week throughout the study. After scarification, various biochemical parameters, such as antioxidant status(superoxide dismutase(SOD) and glutathione reductase(GSH)) of the uterus homogenate, lipid profile(total cholesterol(TC), high density lipoprotein(HDL), low density lipoprotein(LDL), and triglycerides(TG)) of the serum were determined. Weights of the uterus and ovaries were separately monitored. The characteristics of changes in the ovary were evaluated by histopathological studies. RESULTS: GC-MS analysis of the aqueous extract showed the presence of volatile and pharmacologically active phytoconstituents. C. nucifera flower extract-treated groups showed estrus cyclicity and increased uterus weight which indicates the estrogenic effect. The improved blood sugar level, ideal lipid profile, good antioxidant status, and histopathology results revealed the recovery from poly cystic ovaries. CONCLUSION: The results indicate that C. nucifera flower is a potential medicine for the treatment of PCOD and this study supports the traditional uses of C. nucifera flower.展开更多
基金This work was supported by the National Ba- sic Research Program of China （No.2012CB215304）, tile Science Foundation of Guangdong Province （No.$2012040006992）, and the International Co- operation Project of Ministry of Science and Technology of China （No.2012DFA61080）.
文摘Bimetallic CoCu nanocomposites were synthesized in polyol by using Ru as heterogeneous nucleation agent and stearic acid as surfactant, and their catalytic properties were investi- gated by hydrogenolysis of glycerol to propanediols. It was found that the surfactant could induce Co nanocrystals to form nanowires as structure-directing agent, while it＇s ineffective for Cu because only spherical Cu particles were produced under the same condition. When Co2＋ and Cu2＋ coexist in polyol, Cu2＋ is firstly reduced and forms the spherical particles, and then the Cu particles afford surface for the subsequential reduction of Co2＋ and growth of Co nanocrystals to form the nanorods, obtaining the urchin-like CoCu nanocomposites. The catalytic performance in selective hydrogenolysis of glycerol to propanediols proposed that the CoCu urchin-like nanocomposites was superior to the Co nanowires possibly due to that the synergistic effect between Co and Cu component promoted conversion of glyc- erol and obtained the higher propanediol yields based on the specific surface areas of the catalysts.
基金supported by the National Key R&D Program of China(2020YFA0710000)the National Natural Science Foundation of China(Grant No.:22122901,21902047)the Provincial Natural Science Foundation of Hunan(2020JJ5045,2021JJ20024,2021RC3054)。
文摘Surface segregation is ubiquitous in multi-component materials and is of great important for catalysis but little is known on the surface structure under graphene encapsulation.Here,we show that the graphene encapsulated CoCu performs well for the electrocatalytic oxidation of 5-hydroxymethylfurfural(HMF)to2,5-furandicarboxylic acid(FDCA)with the onset potential before 1.23 VRHEand a nearly 100%selectivity of FDCA under 1.4 VRHE.From the experimental results,the unprecedented catalytic performance was attributed to local structural distortion and sub-nanometer lattice composition of the CoCu surface.We accurately show the dispersed Cu doped Co_(3)O_(4) nano-islands with a lot of edge sites on the bimetallic Co-Cu surface.While,the gradient components effectively facilitate the establishment of built-in electric field and accelerate the charge transfer.Theoretical and experimental results reveal that the surface Co and neighbouring Cu atoms in sub-nanometer lattice synergistically promote the catalysis of HMF.This work offers new insights into surface segregation in tuning the element spatial distribution for catalysis.
文摘AIM: To evaluate the effect of Cocus nucifera L. flowers in reducing the major multiple symptoms of letrozole-induced polycystic ovarian disease(PCOD) in female rats. METHOD: Female, virgin Wistar rats were treated with letrozole(1 mg/kg body wt) to induce PCOD, and after 21 days of induction rats were administered orally with 100 and 200 mg·kg-1 of Cocus nucifera flower aqueous extract, respectively. Estrus cycle and blood sugar were monitored once a week throughout the study. After scarification, various biochemical parameters, such as antioxidant status(superoxide dismutase(SOD) and glutathione reductase(GSH)) of the uterus homogenate, lipid profile(total cholesterol(TC), high density lipoprotein(HDL), low density lipoprotein(LDL), and triglycerides(TG)) of the serum were determined. Weights of the uterus and ovaries were separately monitored. The characteristics of changes in the ovary were evaluated by histopathological studies. RESULTS: GC-MS analysis of the aqueous extract showed the presence of volatile and pharmacologically active phytoconstituents. C. nucifera flower extract-treated groups showed estrus cyclicity and increased uterus weight which indicates the estrogenic effect. The improved blood sugar level, ideal lipid profile, good antioxidant status, and histopathology results revealed the recovery from poly cystic ovaries. CONCLUSION: The results indicate that C. nucifera flower is a potential medicine for the treatment of PCOD and this study supports the traditional uses of C. nucifera flower.
