Due to the high capacity and moderate volume expansion of silicon protoxide SiO_(x)(160%)compared with that of Si(300%),reducing silicon dioxide SiO_(2)into SiO_(x)while maintaining its special nano-morphology makes i...Due to the high capacity and moderate volume expansion of silicon protoxide SiO_(x)(160%)compared with that of Si(300%),reducing silicon dioxide SiO_(2)into SiO_(x)while maintaining its special nano-morphology makes it attractive as an anode of Li-ion batteries.Herein,through a one-pot facile high-temperature annealing route,using SBA15 as the silicon source,and embedding tin dioxide SnO_(2)particles into carbon coated SiO_(x),the mesoporous SiO_(x)-SnO_(2)@C rod composite was prepared and tested as the anode material.The results revealed that the SnO_(2)particles were distributed uniformly in the wall,which could further improve their volume energy densities.The coated carbon plays a role in maintaining structural integrality during lithiation,and the rich mesopores structure can release the expanded volume and enhance Li-ion transfer.At 0.1 A·g^(-1),the gravimetric and volumetric capacities of the composite were as high as 1271 mAh·g^(-1)and 1573 mAh·cm^(-3),respectively.After 200 cycles,the 95%capacity could be retained compared with that upon the 2nd cycle at 0.5 A·g^(-1).And the rod morphology was well kept,except that the diameter of the rod was 3 times larger than its original size after the cell was discharged into 0.01 V.展开更多
Mesoporous carbon supports mitigate platinum(Pt)sulfonic poisoning through nanopore-confined Pt deposition,yet their morphological impacts on oxygen transport remain unclear.This study integrates carbon support morpho...Mesoporous carbon supports mitigate platinum(Pt)sulfonic poisoning through nanopore-confined Pt deposition,yet their morphological impacts on oxygen transport remain unclear.This study integrates carbon support morphology simulation with an enhanced agglomerate model to establish a mathematical framework elucidating pore evolution,Pt utilization,and oxygen transport in catalyst layers.Results demonstrate dominant local mass transport resistance governed by three factors:(1)active site density dictating oxygen flux;(2)ionomer film thickness defining shortest transport path;(3)ionomer-to-Pt surface area ratio modulating practical pathway length.At low ionomer-to-carbon(I/C)ratios,limited active sites elevate resistance(Factor 1 dominant).Higher I/C ratios improve the ionomer coverage but eventually thicken ionomer films,degrading transport(Factors 2–3 dominant).The results indicate that larger carbon particles result in a net increase in local transport resistance by reducing external surface area and increasing ionomer thickness.As the proportion of Pt situated in nanopores or the Pt mass fraction increases,elevated Pt density inside the nanopores exacerbates pore blockage.This leads to the increased transport resistance by reducing active sites,and increasing ionomer thickness and surface area.Lower Pt loading linearly intensifies oxygen flux resistance.The model underscores the necessity to optimize support morphology,Pt distribution,and ionomer content to prevent pore blockage while balancing catalytic activity and transport efficiency.These insights provide a systematic approach for designing high-performance mesoporous carbon catalysts.展开更多
The pore structures and electrochemical performances of mesoporous carbons prepared by silica sol template method as electrode material for supercapacitor were investigated. The mean pore size and mass specific capaci...The pore structures and electrochemical performances of mesoporous carbons prepared by silica sol template method as electrode material for supercapacitor were investigated. The mean pore size and mass specific capacitance of the mesoporous carbons increase with the increase of mass ratio of silica sol to carbon source （glucose）. A modified template method, combining silica sol template method and ZnCl2 chemical activation method, was proposed to improve the mass specific capacitance of the mesoporous carbon with an improved BET surface area. The correlation of rate capability and pore structure was studied by constant current discharge and electrochemical impedance spectroscopy. A commercially available microporous carbon was used for comparison. The result shows that mesoporous carbon with a larger pore size displays a higher rate capability. Mesoporous carbon synthesized by modified template method has both high mass specific capacitance and good rate capability.展开更多
The toxic effects to microorganism induced by nanomaterials have received considerable attentions in the past decades [1]. Herein, two diverse nanomaterials i.e. multi-walled carbon nanotubes (MWCNTs) and mesoporous s...The toxic effects to microorganism induced by nanomaterials have received considerable attentions in the past decades [1]. Herein, two diverse nanomaterials i.e. multi-walled carbon nanotubes (MWCNTs) and mesoporous silica nanospheres (MSNs) were prepared to investigate their deleterious effects on Caenorhabditis. elegans (C. elegans)[2-3]. As shown in Figure 1A, histidine functionalized MWCNTs (his-MWCNTs) were in length of ~500 nm with outer diameter ~20 nm, while fluorescein isothiocyanate dyed MSNs (FITC-MSNs) were in an average diameter of ~70 nm (Figure 1B). Microscopic images display his-MWCNTs having been ingested into intestine of C. elegans after co-incubation for 2 h, as arrowed in Figure 1C and 1E. In contrast, no MSNs were observed to be ingested after co-incubating in the same liquid medium. However, fluorescence microscopic images (Figure 1D and 1F) demonstrate that FITC-MSNs could be ingested by C. elegans after co-incubation for 24 h or longer time via seeding Kingagar plates with FITC-MSNs.展开更多
The template carbonization method was utilized for the production of mesoporous carbons using attapulgite as a template and sucrose as carbon precursor. Sucrose was polymerized and carbonized in the tubes of natural a...The template carbonization method was utilized for the production of mesoporous carbons using attapulgite as a template and sucrose as carbon precursor. Sucrose was polymerized and carbonized in the tubes of natural attapulgite using a sulfuric acid catalyst. The structure of the template and carbons were investigated by powder X-ray diffraction, transmission electron microscopy, and Nitrogen adsorption analysis techniques. At the micrometer level, the carbon material templated with the natural attapulgite had the similar morphology. Nitrogen adsorption analysis showed that the obtained porous carbons possess a wide pore size distribution and a large pore volume, especially in the range of mesopores.展开更多
文摘Due to the high capacity and moderate volume expansion of silicon protoxide SiO_(x)(160%)compared with that of Si(300%),reducing silicon dioxide SiO_(2)into SiO_(x)while maintaining its special nano-morphology makes it attractive as an anode of Li-ion batteries.Herein,through a one-pot facile high-temperature annealing route,using SBA15 as the silicon source,and embedding tin dioxide SnO_(2)particles into carbon coated SiO_(x),the mesoporous SiO_(x)-SnO_(2)@C rod composite was prepared and tested as the anode material.The results revealed that the SnO_(2)particles were distributed uniformly in the wall,which could further improve their volume energy densities.The coated carbon plays a role in maintaining structural integrality during lithiation,and the rich mesopores structure can release the expanded volume and enhance Li-ion transfer.At 0.1 A·g^(-1),the gravimetric and volumetric capacities of the composite were as high as 1271 mAh·g^(-1)and 1573 mAh·cm^(-3),respectively.After 200 cycles,the 95%capacity could be retained compared with that upon the 2nd cycle at 0.5 A·g^(-1).And the rod morphology was well kept,except that the diameter of the rod was 3 times larger than its original size after the cell was discharged into 0.01 V.
基金supported by the Program of Ministry of Science and Technology of China(No.2023YFB2504200)support of Shanghai Rising-Star Program(Grant No.24QB2703200)the Major Science and Technology Projects of Yunnan Province(No.202302AH360001).
文摘Mesoporous carbon supports mitigate platinum(Pt)sulfonic poisoning through nanopore-confined Pt deposition,yet their morphological impacts on oxygen transport remain unclear.This study integrates carbon support morphology simulation with an enhanced agglomerate model to establish a mathematical framework elucidating pore evolution,Pt utilization,and oxygen transport in catalyst layers.Results demonstrate dominant local mass transport resistance governed by three factors:(1)active site density dictating oxygen flux;(2)ionomer film thickness defining shortest transport path;(3)ionomer-to-Pt surface area ratio modulating practical pathway length.At low ionomer-to-carbon(I/C)ratios,limited active sites elevate resistance(Factor 1 dominant).Higher I/C ratios improve the ionomer coverage but eventually thicken ionomer films,degrading transport(Factors 2–3 dominant).The results indicate that larger carbon particles result in a net increase in local transport resistance by reducing external surface area and increasing ionomer thickness.As the proportion of Pt situated in nanopores or the Pt mass fraction increases,elevated Pt density inside the nanopores exacerbates pore blockage.This leads to the increased transport resistance by reducing active sites,and increasing ionomer thickness and surface area.Lower Pt loading linearly intensifies oxygen flux resistance.The model underscores the necessity to optimize support morphology,Pt distribution,and ionomer content to prevent pore blockage while balancing catalytic activity and transport efficiency.These insights provide a systematic approach for designing high-performance mesoporous carbon catalysts.
文摘The pore structures and electrochemical performances of mesoporous carbons prepared by silica sol template method as electrode material for supercapacitor were investigated. The mean pore size and mass specific capacitance of the mesoporous carbons increase with the increase of mass ratio of silica sol to carbon source （glucose）. A modified template method, combining silica sol template method and ZnCl2 chemical activation method, was proposed to improve the mass specific capacitance of the mesoporous carbon with an improved BET surface area. The correlation of rate capability and pore structure was studied by constant current discharge and electrochemical impedance spectroscopy. A commercially available microporous carbon was used for comparison. The result shows that mesoporous carbon with a larger pore size displays a higher rate capability. Mesoporous carbon synthesized by modified template method has both high mass specific capacitance and good rate capability.
文摘The toxic effects to microorganism induced by nanomaterials have received considerable attentions in the past decades [1]. Herein, two diverse nanomaterials i.e. multi-walled carbon nanotubes (MWCNTs) and mesoporous silica nanospheres (MSNs) were prepared to investigate their deleterious effects on Caenorhabditis. elegans (C. elegans)[2-3]. As shown in Figure 1A, histidine functionalized MWCNTs (his-MWCNTs) were in length of ~500 nm with outer diameter ~20 nm, while fluorescein isothiocyanate dyed MSNs (FITC-MSNs) were in an average diameter of ~70 nm (Figure 1B). Microscopic images display his-MWCNTs having been ingested into intestine of C. elegans after co-incubation for 2 h, as arrowed in Figure 1C and 1E. In contrast, no MSNs were observed to be ingested after co-incubating in the same liquid medium. However, fluorescence microscopic images (Figure 1D and 1F) demonstrate that FITC-MSNs could be ingested by C. elegans after co-incubation for 24 h or longer time via seeding Kingagar plates with FITC-MSNs.
文摘The template carbonization method was utilized for the production of mesoporous carbons using attapulgite as a template and sucrose as carbon precursor. Sucrose was polymerized and carbonized in the tubes of natural attapulgite using a sulfuric acid catalyst. The structure of the template and carbons were investigated by powder X-ray diffraction, transmission electron microscopy, and Nitrogen adsorption analysis techniques. At the micrometer level, the carbon material templated with the natural attapulgite had the similar morphology. Nitrogen adsorption analysis showed that the obtained porous carbons possess a wide pore size distribution and a large pore volume, especially in the range of mesopores.
