New insight into the effect on the alkali cations of Liþ,Naþ,and Kþpre-intercalated between adjacent layers of Mn3(PO4)2$3H2O towards the charge storage mechanism and their electrochemical kinetics of i...New insight into the effect on the alkali cations of Liþ,Naþ,and Kþpre-intercalated between adjacent layers of Mn3(PO4)2$3H2O towards the charge storage mechanism and their electrochemical kinetics of intercalation/deintercalation in three alkali electrolytes is demonstrated.The electrochemical perfor-mance of the designed LieMn3(PO4)2$3H2O material outperforms that most of Mn-based pseudocapa-citive electrode materials.The designed unique stratified structure is attractive for quick charge migration,which confirms that the appropriate pre-intercalation of alkali cation between layers is an efficient strategy to improve kinetics for the high-power density pseudocapacitive supercapacitor energy storage application.展开更多
Metal-organic frameworks （MOFs） have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-I（also named Cu-BTC or MOF-199） was...Metal-organic frameworks （MOFs） have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-I（also named Cu-BTC or MOF-199） was chemically reduced by doping it with alkali metals （Li, Na and K） and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction （XRD）, thermo-gravimetric analysis （TGA） and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li＋, Na＋ and K＋, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64 mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST- 1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.展开更多
The electrocatalytic CO_(2)reduction reaction(CO_(2)RR)has attracted increasing attention in recentyears.Practical electrocatalysis of CO_(2)RR must be carried out in aqueous solutions containing electrolytesof alkali...The electrocatalytic CO_(2)reduction reaction(CO_(2)RR)has attracted increasing attention in recentyears.Practical electrocatalysis of CO_(2)RR must be carried out in aqueous solutions containing electrolytesof alkali metal cations such as sodium and potassium.Although considerable efforts havebeen made to design efficient electrocatalysts for CO_(2)RR and to investigate the structure–activityrelationships using molecular model complexes,only a few studies have been investigated the effectof alkali metal cations on electrocatalytic CO_(2)RR.In this study,we report the effect of alkali metalcations(Na^(+)and K^(+))on electrocatalytic CO_(2)RR with Fe porphyrins.By running CO_(2)RR electrocatalysisin dimethylformamide(DMF),we found that the addition of Na^(+)or K^(+)considerably improves thecatalytic activity of Fe chloride tetrakis(3,4,5‐trimethoxyphenyl)porphyrin(FeP).Based on thisresult,we synthesized an Fe porphyrin^(N)18C6‐FeP bearing a tethered 1‐aza‐18‐crown‐6‐ether(^(N)18C6)group at the second coordination sphere of the Fe site.We showed that with the tethered^(N)18C6 to bind Na^(+)or K^(+),^(N)18C6‐FeP is more active than FeP for electrocatalytic CO_(2)RR.This workdemonstrates the positive effect of alkali metal cations to improve CO_(2)RR electrocatalysis,which isvaluable for the rational design of new efficient catalysts.展开更多
Prussian blue analogue(PBA)material is a promising cathode for applications in Na-ion and K-ion batteries which can support high c-rates for charge and discharge.In this study,the material of composition[K2 CuIIFeII(C...Prussian blue analogue(PBA)material is a promising cathode for applications in Na-ion and K-ion batteries which can support high c-rates for charge and discharge.In this study,the material of composition[K2 CuIIFeII(CN)6]was synthesized and its structural and electrochemical redox behavior was investigated with 5 different alkali insertion cations(Li^+,Na^+,K^+,Rb^+,Cs^+).Galvanostatic measurements indicate that the redox potential strongly depends on the ionic radius of the inserted cation.The redox potential varies by 400 m V between using Li^+(0.79A)or Cs^+(1.73A)in the electrolyte.The underlying modification of the Fe2^+/Fe3^+redox potential in PBA is proposed to be due to the weakening of the Fe–C bond in the material.This hypothesis is supported by XRD measurements which reveal that the lattice parameter of the de-intercalated host structure follows the same trend of monotonic increase with the cation size.The relatively minor volume changes accompanying the redox(1.2%–2.4%)allow the PBA to accommodate differently sized cations,although the structural hindrances are quite pronounced at high c-rates for the larger ones(Rb^+and Cs^+).Cycle aging studies indicate that the minimum capacity fade rate is observed in case of K^+ and Rb^+ containing electrolyte.The peak intensity corresponding to the[220]crystallographic plane varies depending on the state of charge of PBA,since this plane contains the insertion cations.Owing to the sensitivity of the redox potential to the insertion cation coupled with the observed fast ion-exchange ability,the PBA material may find additional analytical applications such as ion sensing or filtration devices.展开更多
The density functional theory based on hybrid-method B3LYP was used to investigate the interaction of the alkaline-earth cations or alkali cations with crown tetraalanylpeptide which was the coronary structures of hom...The density functional theory based on hybrid-method B3LYP was used to investigate the interaction of the alkaline-earth cations or alkali cations with crown tetraalanylpeptide which was the coronary structures of homothetic cyclotetraalapeptide and was represented as the model basic. Many properties including binding energy, optimum geometry structures and population analysis were calculated. It was shown that there was little change on the coronary structure before and after C4-AIa combination with small I A or ｜I A cations, and the electrons moved from C4-AIa to alkaline-earth cations or alkali cations during this process. Combination with C4-Ala, Be2~ was more predominant than Mg2~ and Ca2~ remarkably, but Li~ was not more predominant than Na＋ and K＋. The distances between alkaline-earth cations and the center of C4-Ala were 0.000 nm, 0.150 nm and 0.225 nm, respectively, when the binding energy at minimum, and that for alkali cations were 0.225 nm, 0.250 nm and 0.300 nm.展开更多
An inorganic cation exchanger, zeolitic material, was synthesized from dehydrated cake, which was discharged from recycling of construction waste soil, using the alkali fusion method. The waste clay was mixed with NaO...An inorganic cation exchanger, zeolitic material, was synthesized from dehydrated cake, which was discharged from recycling of construction waste soil, using the alkali fusion method. The waste clay was mixed with NaOH powder (the weight ratio of NaOH/waste clay = 1.0) and then heated at 300°C for 1 h to make a fused material. This fused material was then added to distilled water, and then heated at 90°C, 120°C, 150°C and 180°C for 12 h in reaction bombs under autogenous pressure in order to synthesize the cation exchanger. As a result, waste cake can be converted into fused material with high solubility, and zeolitic materials can be synthesized from the fused material. A mixture of zeolite-X and hydroxysodalite was synthesized at 90°C and 120°C, hydroxysodalite alone was synthesized at 150°C and 180°C. By increasing the synthesis temperature, the cation exchange capacity (CEC) of the product decreased, and the highest CEC of the product at 90°C, including zeolite-X, was 2.06 mmol/g, which is 64.3% of commercial zeolite-13X (3.2 mmol/g).展开更多
基金This research work was supported by the Sichuan Science and Technology Project(No.2020YJ0163)the Research Foundation for Teacher Development of Chengdu University of Technology(No.10912-2019KYQD-06847).
文摘New insight into the effect on the alkali cations of Liþ,Naþ,and Kþpre-intercalated between adjacent layers of Mn3(PO4)2$3H2O towards the charge storage mechanism and their electrochemical kinetics of intercalation/deintercalation in three alkali electrolytes is demonstrated.The electrochemical perfor-mance of the designed LieMn3(PO4)2$3H2O material outperforms that most of Mn-based pseudocapa-citive electrode materials.The designed unique stratified structure is attractive for quick charge migration,which confirms that the appropriate pre-intercalation of alkali cation between layers is an efficient strategy to improve kinetics for the high-power density pseudocapacitive supercapacitor energy storage application.
文摘Metal-organic frameworks （MOFs） have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-I（also named Cu-BTC or MOF-199） was chemically reduced by doping it with alkali metals （Li, Na and K） and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction （XRD）, thermo-gravimetric analysis （TGA） and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li＋, Na＋ and K＋, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64 mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST- 1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.
文摘The electrocatalytic CO_(2)reduction reaction(CO_(2)RR)has attracted increasing attention in recentyears.Practical electrocatalysis of CO_(2)RR must be carried out in aqueous solutions containing electrolytesof alkali metal cations such as sodium and potassium.Although considerable efforts havebeen made to design efficient electrocatalysts for CO_(2)RR and to investigate the structure–activityrelationships using molecular model complexes,only a few studies have been investigated the effectof alkali metal cations on electrocatalytic CO_(2)RR.In this study,we report the effect of alkali metalcations(Na^(+)and K^(+))on electrocatalytic CO_(2)RR with Fe porphyrins.By running CO_(2)RR electrocatalysisin dimethylformamide(DMF),we found that the addition of Na^(+)or K^(+)considerably improves thecatalytic activity of Fe chloride tetrakis(3,4,5‐trimethoxyphenyl)porphyrin(FeP).Based on thisresult,we synthesized an Fe porphyrin^(N)18C6‐FeP bearing a tethered 1‐aza‐18‐crown‐6‐ether(^(N)18C6)group at the second coordination sphere of the Fe site.We showed that with the tethered^(N)18C6 to bind Na^(+)or K^(+),^(N)18C6‐FeP is more active than FeP for electrocatalytic CO_(2)RR.This workdemonstrates the positive effect of alkali metal cations to improve CO_(2)RR electrocatalysis,which isvaluable for the rational design of new efficient catalysts.
基金“Le Studium Loire Valley Institute for Advanced Studies” for financial and logistical support to the researchers involved in this study“Region Centre” for financial support under the “Lavoisier” program
文摘Prussian blue analogue(PBA)material is a promising cathode for applications in Na-ion and K-ion batteries which can support high c-rates for charge and discharge.In this study,the material of composition[K2 CuIIFeII(CN)6]was synthesized and its structural and electrochemical redox behavior was investigated with 5 different alkali insertion cations(Li^+,Na^+,K^+,Rb^+,Cs^+).Galvanostatic measurements indicate that the redox potential strongly depends on the ionic radius of the inserted cation.The redox potential varies by 400 m V between using Li^+(0.79A)or Cs^+(1.73A)in the electrolyte.The underlying modification of the Fe2^+/Fe3^+redox potential in PBA is proposed to be due to the weakening of the Fe–C bond in the material.This hypothesis is supported by XRD measurements which reveal that the lattice parameter of the de-intercalated host structure follows the same trend of monotonic increase with the cation size.The relatively minor volume changes accompanying the redox(1.2%–2.4%)allow the PBA to accommodate differently sized cations,although the structural hindrances are quite pronounced at high c-rates for the larger ones(Rb^+and Cs^+).Cycle aging studies indicate that the minimum capacity fade rate is observed in case of K^+ and Rb^+ containing electrolyte.The peak intensity corresponding to the[220]crystallographic plane varies depending on the state of charge of PBA,since this plane contains the insertion cations.Owing to the sensitivity of the redox potential to the insertion cation coupled with the observed fast ion-exchange ability,the PBA material may find additional analytical applications such as ion sensing or filtration devices.
文摘The density functional theory based on hybrid-method B3LYP was used to investigate the interaction of the alkaline-earth cations or alkali cations with crown tetraalanylpeptide which was the coronary structures of homothetic cyclotetraalapeptide and was represented as the model basic. Many properties including binding energy, optimum geometry structures and population analysis were calculated. It was shown that there was little change on the coronary structure before and after C4-AIa combination with small I A or ｜I A cations, and the electrons moved from C4-AIa to alkaline-earth cations or alkali cations during this process. Combination with C4-Ala, Be2~ was more predominant than Mg2~ and Ca2~ remarkably, but Li~ was not more predominant than Na＋ and K＋. The distances between alkaline-earth cations and the center of C4-Ala were 0.000 nm, 0.150 nm and 0.225 nm, respectively, when the binding energy at minimum, and that for alkali cations were 0.225 nm, 0.250 nm and 0.300 nm.
文摘An inorganic cation exchanger, zeolitic material, was synthesized from dehydrated cake, which was discharged from recycling of construction waste soil, using the alkali fusion method. The waste clay was mixed with NaOH powder (the weight ratio of NaOH/waste clay = 1.0) and then heated at 300°C for 1 h to make a fused material. This fused material was then added to distilled water, and then heated at 90°C, 120°C, 150°C and 180°C for 12 h in reaction bombs under autogenous pressure in order to synthesize the cation exchanger. As a result, waste cake can be converted into fused material with high solubility, and zeolitic materials can be synthesized from the fused material. A mixture of zeolite-X and hydroxysodalite was synthesized at 90°C and 120°C, hydroxysodalite alone was synthesized at 150°C and 180°C. By increasing the synthesis temperature, the cation exchange capacity (CEC) of the product decreased, and the highest CEC of the product at 90°C, including zeolite-X, was 2.06 mmol/g, which is 64.3% of commercial zeolite-13X (3.2 mmol/g).
基金Project(2016CX019) supported by the Innovation-Driven Project of Central South University,ChinaProject(51674302) supported by the National Natural Science Foundation of China。
