Two homogeneous photoelectrocatalytic systems composed of simple polypyridyl Co complexes[Co(tpy)2](PF6)2and[Co(bpy)3](PF6)2as electrocatalysts and a Si wafer as the photoelectrode were used for combined photoelectroc...Two homogeneous photoelectrocatalytic systems composed of simple polypyridyl Co complexes[Co(tpy)2](PF6)2and[Co(bpy)3](PF6)2as electrocatalysts and a Si wafer as the photoelectrode were used for combined photoelectrochemical reduction of CO2to CO.A high photocurrent density of1.4mA/cm2was observed for the system with the[Co(tpy)2](PF6)2catalyst and a photovoltage of400mV was generated.Faradaic efficiencies of CO were optimized to83%and94%for the[Co(tpy)2](PF6)2and[Co(bpy)3](PF6)2complexes,respectively,in acetonitrile solution with10%methanol(volume fraction,same below)as a protic additive.Addition of2%water volume fraction induced a large amount of non‐specific H2evolution by the Si photoelectrode.展开更多
Nanostructured gold catalyst supported on metal oxide is highly active for the CO oxidation reac‐tion. In this work, a new type of oxide support, zinc tin oxide, has been used to deposit 0.7 wt%Au via a deposition‐p...Nanostructured gold catalyst supported on metal oxide is highly active for the CO oxidation reac‐tion. In this work, a new type of oxide support, zinc tin oxide, has been used to deposit 0.7 wt%Au via a deposition‐precipitation method. The textural properties of Zn2SnO4 support have been tuned by varying the molar ratio between base （N2H4＆#183;H2O） and metal ion （Zn2＋） to be 4/1, 8/1 and 16/1. The catalytic tests for CO oxidation reaction revealed that the reactivity on Au‐Zn2SnO4 with N2H4＆#183;H2O/Zn2＋ = 8/1 was the highest, while the reactivity on Au‐Zn2SnO4 with N2H4＆#183;H2O/Zn2＋ =16/1 was almost identical to that of the pure support. Both fresh and used catalysts have been characterized by multiple techniques including nitrogen adsorption‐desorption, X‐ray diffraction, transmission electron microscopy, high‐angle annular dark‐field scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, X‐ray adsorption fine structure, and tempera‐ture‐programmed reduction by hydrogen. These demonstrated that the textural properties, espe‐cially pore volume and pore size distribution, of Zn2SnO4 play crucial roles in the averaged size of gold nanoparticles, and thus determine the catalytic activity of Au‐Zn2SnO4 for CO oxidation.展开更多
Photorhabdus luminescens is a Gram-negative, bioluminescent, pigment producing enteric bacterium, which is pathogenic to insects and has the capability to undergo phase variation. The phase I variant of P. luminescens...Photorhabdus luminescens is a Gram-negative, bioluminescent, pigment producing enteric bacterium, which is pathogenic to insects and has the capability to undergo phase variation. The phase I variant of P. luminescens exists as a mutualistic symbiont where it plays a critical role in the life-cycle of the soil-dwelling nematode, Heterorhabditis bacteriophora. Both the bacterium and the nematode receive their nutritional requirements from the bioconversion of the insect host which is rich in many macromolecules such as the disaccharide, trehalose. Trehalose is a non-reducing disaccharide of glucose that is formed by an a-1,1-glycosidic bond and is associated with the physiology of many bacteria, insects and nematodes. Trehalose has been shown to be the most abundant storage sugar found within insect hemolymph （1%-2%）. The physicochemical properties of trehalose allow this carbohydrate to act as a stress protectant where it has been implicated with thermal stress, dehydration, and osmotic protection of many microorganisms. Due to these properties, trehalose may allow culture stability of the phase I variant in vitro and in vivo. Traits of the phase I variant that were studied in this work include bioluminescence and the production of the red anthroquinone-derived pigment. The carbohydrates that were utilized in this study were glucose and trehalose; where shake flask cultures of the phase I variant were cultured at room temperature for up to six days in carbohydrate supplemented basal media with increasing carbohydrate concentrations of 0. 1%, 0.5% and 1.0% （v/v）. Relative luminosity, pigmentation and pH were graphed as a function of time, carbohydrate used, and carbohydrate concentration. Data obtained from this study suggests that the supplementation of 1.0% trehalose, when culturing the phase I variant ofP. luminescens, can maintain bioluminosity and pigmentation over extended periods of time （five days） as compared to basal media and basal media supplemented with 1.0% glucose.展开更多
Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition‐precipitation followed by microwave irradiation as a drying method and then calcination.The drying method influenced the...Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition‐precipitation followed by microwave irradiation as a drying method and then calcination.The drying method influenced the size of the Au particles.Au(III)was partly reduced during conventional oven drying,resulting in Au aggregates.In contrast,Au(III)was preserved during microwave drying owing to rapid and uniform heating,and the Au diameter was minimized to1.4nm on Al2O3.This method can be applied to several metal oxide supports having different microwave absorption efficiencies,such as MnO2,Al2O3,and TiO2.These catalysts exhibited higher catalytic activities for CO oxidation at low temperature and for selective aerobic oxidation of sulfide than those prepared by conventional methods.展开更多
Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2.Our recent studies revealed that[(μ-bdt)Fe2(CO)6](1,bdt=benzene-1,2-dith...Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2.Our recent studies revealed that[(μ-bdt)Fe2(CO)6](1,bdt=benzene-1,2-dithiolato),a[FeFe]-hydrogenase model with a rigid and conjugate S-to-S bridge,was catalytically active for the selective photochemical reduction of CO2 to CO,while its analogous complex[(μ-edt)Fe2(CO)6](2,edt=ethane-1,2-dithiolato)was inactive.In this study,it was found that the turnover number of 1 for CO evolution reached 710 for the 1/[Ru(bpy)3]2+/BIH(BIH=1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]-imidazole)system under optimal conditions over 4.5 h of visible-light irradiation,with a turnover frequency of 7.12 min−1 in the first hour,a high selectivity of 97%for CO,and an internal quantum yield of 2.8%.Interestingly,the catalytic selectivity of 1 can be adjusted and even completely switched in a facile manner between the photochemical reductions of CO2 to CO and of protons to H2 simply by adding different amounts of triethanolamine to the catalytic system.The electron transfer in the photocatalytic system was studied by steady-state fluorescence and transient absorption spectroscopy,and a plausible mechanism for the photocatalytic reaction was proposed.展开更多
The aim of this research was to study the effect of spraying nutritional solution ＂PRO.SOL＂ and chelated iron on vegetative and floral growth characteristics on Gazania plant. Randomized Complete Block Design （R.C....The aim of this research was to study the effect of spraying nutritional solution ＂PRO.SOL＂ and chelated iron on vegetative and floral growth characteristics on Gazania plant. Randomized Complete Block Design （R.C.B.D） was adopted utilizing two applications in three replicates. Three concentration levels of nutritional solution PRO.SOL （10.00, 5.00 and 0.00 mg/L） and four concentration levels of chelated iron （90.00, 60.00, 30.00 and 0.00 mg/L） were applied in this experiment. The interaction between the two factors was also measured. The mean values were compared using L.S.D test at probability level 0.05. Spraying PRO.SOL at concentration 10.00 mg/L or chelated iron concentration level 90.00 mg/L improved growth parameters. There was significant increase in： number of total leaves per plant, shoot dry weight, leaves total chlorophyll content, number of off-shoots, number and length of primary roots, length of the peduncle, number of flowers, number of petals and flower dry weight. Meanwhile leaf carbohydrate contents, phosphorus percentage and leaf iron content were increased significantly compared with the （unsprayed plants）. The interaction treatment, spraying nutritional solution PRO.SOL at concentration level 10.00 mg/L with 90 mg Lt chelated iron had a significant increase in all studied growth parameters, i.e., the number of flowers and petals gave 8.33 flowers and 18.67 petals compared with the control treatment which gave 3.33 flowers and 13.00 petals. Meanwhile leaf carbohydrate contents, phosphorus percentage and leaf iron content increased significantly in comparison with the unsprayed plants which gave the least values.展开更多
基金supported by the National Key R&D Program of China (2016YFB0600901)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17030300)~~
文摘Two homogeneous photoelectrocatalytic systems composed of simple polypyridyl Co complexes[Co(tpy)2](PF6)2and[Co(bpy)3](PF6)2as electrocatalysts and a Si wafer as the photoelectrode were used for combined photoelectrochemical reduction of CO2to CO.A high photocurrent density of1.4mA/cm2was observed for the system with the[Co(tpy)2](PF6)2catalyst and a photovoltage of400mV was generated.Faradaic efficiencies of CO were optimized to83%and94%for the[Co(tpy)2](PF6)2and[Co(bpy)3](PF6)2complexes,respectively,in acetonitrile solution with10%methanol(volume fraction,same below)as a protic additive.Addition of2%water volume fraction induced a large amount of non‐specific H2evolution by the Si photoelectrode.
基金supported by the National Natural Science Foundation of China (21373259, 21301107)the Hundred Talents Project of the Chinese Academy of Sciences, the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA09030102)+2 种基金the Open Funding from Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciencesthe Fundamental Research Fund-ing of Shandong University (2014JC005)the Taishan Scholar Project of Shandong Province (China)~~
文摘Nanostructured gold catalyst supported on metal oxide is highly active for the CO oxidation reac‐tion. In this work, a new type of oxide support, zinc tin oxide, has been used to deposit 0.7 wt%Au via a deposition‐precipitation method. The textural properties of Zn2SnO4 support have been tuned by varying the molar ratio between base （N2H4＆#183;H2O） and metal ion （Zn2＋） to be 4/1, 8/1 and 16/1. The catalytic tests for CO oxidation reaction revealed that the reactivity on Au‐Zn2SnO4 with N2H4＆#183;H2O/Zn2＋ = 8/1 was the highest, while the reactivity on Au‐Zn2SnO4 with N2H4＆#183;H2O/Zn2＋ =16/1 was almost identical to that of the pure support. Both fresh and used catalysts have been characterized by multiple techniques including nitrogen adsorption‐desorption, X‐ray diffraction, transmission electron microscopy, high‐angle annular dark‐field scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, X‐ray adsorption fine structure, and tempera‐ture‐programmed reduction by hydrogen. These demonstrated that the textural properties, espe‐cially pore volume and pore size distribution, of Zn2SnO4 play crucial roles in the averaged size of gold nanoparticles, and thus determine the catalytic activity of Au‐Zn2SnO4 for CO oxidation.
文摘Photorhabdus luminescens is a Gram-negative, bioluminescent, pigment producing enteric bacterium, which is pathogenic to insects and has the capability to undergo phase variation. The phase I variant of P. luminescens exists as a mutualistic symbiont where it plays a critical role in the life-cycle of the soil-dwelling nematode, Heterorhabditis bacteriophora. Both the bacterium and the nematode receive their nutritional requirements from the bioconversion of the insect host which is rich in many macromolecules such as the disaccharide, trehalose. Trehalose is a non-reducing disaccharide of glucose that is formed by an a-1,1-glycosidic bond and is associated with the physiology of many bacteria, insects and nematodes. Trehalose has been shown to be the most abundant storage sugar found within insect hemolymph （1%-2%）. The physicochemical properties of trehalose allow this carbohydrate to act as a stress protectant where it has been implicated with thermal stress, dehydration, and osmotic protection of many microorganisms. Due to these properties, trehalose may allow culture stability of the phase I variant in vitro and in vivo. Traits of the phase I variant that were studied in this work include bioluminescence and the production of the red anthroquinone-derived pigment. The carbohydrates that were utilized in this study were glucose and trehalose; where shake flask cultures of the phase I variant were cultured at room temperature for up to six days in carbohydrate supplemented basal media with increasing carbohydrate concentrations of 0. 1%, 0.5% and 1.0% （v/v）. Relative luminosity, pigmentation and pH were graphed as a function of time, carbohydrate used, and carbohydrate concentration. Data obtained from this study suggests that the supplementation of 1.0% trehalose, when culturing the phase I variant ofP. luminescens, can maintain bioluminosity and pigmentation over extended periods of time （five days） as compared to basal media and basal media supplemented with 1.0% glucose.
基金supported by JSPS KAKENHI Grant Numbers JP26810098 and JP16K17943~~
文摘Gold clusters and small nanoparticles supported on metal oxides could be prepared by deposition‐precipitation followed by microwave irradiation as a drying method and then calcination.The drying method influenced the size of the Au particles.Au(III)was partly reduced during conventional oven drying,resulting in Au aggregates.In contrast,Au(III)was preserved during microwave drying owing to rapid and uniform heating,and the Au diameter was minimized to1.4nm on Al2O3.This method can be applied to several metal oxide supports having different microwave absorption efficiencies,such as MnO2,Al2O3,and TiO2.These catalysts exhibited higher catalytic activities for CO oxidation at low temperature and for selective aerobic oxidation of sulfide than those prepared by conventional methods.
文摘Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2.Our recent studies revealed that[(μ-bdt)Fe2(CO)6](1,bdt=benzene-1,2-dithiolato),a[FeFe]-hydrogenase model with a rigid and conjugate S-to-S bridge,was catalytically active for the selective photochemical reduction of CO2 to CO,while its analogous complex[(μ-edt)Fe2(CO)6](2,edt=ethane-1,2-dithiolato)was inactive.In this study,it was found that the turnover number of 1 for CO evolution reached 710 for the 1/[Ru(bpy)3]2+/BIH(BIH=1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]-imidazole)system under optimal conditions over 4.5 h of visible-light irradiation,with a turnover frequency of 7.12 min−1 in the first hour,a high selectivity of 97%for CO,and an internal quantum yield of 2.8%.Interestingly,the catalytic selectivity of 1 can be adjusted and even completely switched in a facile manner between the photochemical reductions of CO2 to CO and of protons to H2 simply by adding different amounts of triethanolamine to the catalytic system.The electron transfer in the photocatalytic system was studied by steady-state fluorescence and transient absorption spectroscopy,and a plausible mechanism for the photocatalytic reaction was proposed.
文摘The aim of this research was to study the effect of spraying nutritional solution ＂PRO.SOL＂ and chelated iron on vegetative and floral growth characteristics on Gazania plant. Randomized Complete Block Design （R.C.B.D） was adopted utilizing two applications in three replicates. Three concentration levels of nutritional solution PRO.SOL （10.00, 5.00 and 0.00 mg/L） and four concentration levels of chelated iron （90.00, 60.00, 30.00 and 0.00 mg/L） were applied in this experiment. The interaction between the two factors was also measured. The mean values were compared using L.S.D test at probability level 0.05. Spraying PRO.SOL at concentration 10.00 mg/L or chelated iron concentration level 90.00 mg/L improved growth parameters. There was significant increase in： number of total leaves per plant, shoot dry weight, leaves total chlorophyll content, number of off-shoots, number and length of primary roots, length of the peduncle, number of flowers, number of petals and flower dry weight. Meanwhile leaf carbohydrate contents, phosphorus percentage and leaf iron content were increased significantly compared with the （unsprayed plants）. The interaction treatment, spraying nutritional solution PRO.SOL at concentration level 10.00 mg/L with 90 mg Lt chelated iron had a significant increase in all studied growth parameters, i.e., the number of flowers and petals gave 8.33 flowers and 18.67 petals compared with the control treatment which gave 3.33 flowers and 13.00 petals. Meanwhile leaf carbohydrate contents, phosphorus percentage and leaf iron content increased significantly in comparison with the unsprayed plants which gave the least values.
