通过强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)技术研究在光电分解水制氢体系中碳点光阳极与KOH电解液界面的动力学行为。结果表明,光强在30–90 m W·cm^(-2)范围内,界面的电子传输时间(τ_d)、电子寿命(τ_n)、电子扩散系...通过强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)技术研究在光电分解水制氢体系中碳点光阳极与KOH电解液界面的动力学行为。结果表明,光强在30–90 m W·cm^(-2)范围内,界面的电子传输时间(τ_d)、电子寿命(τ_n)、电子扩散系数(D_n)、电子扩散长度(L_n)均没有变化;当光强增加到110和130 m W·cm^(-2)时,τ_d和τ_n延长,而D_n减小。实验表明,不同于Ti O_2/电解液等界面,碳点光电极/电解液界面中碳点电极存在的缺陷少,因此电子主要以无陷阱限制扩散方式传输为主。且在30–130 m W·cm^(-2)的光强范围内,与τ_d和τ_n相关的载流子收集效率(η_(cc))相近。展开更多
设计、构建了用于扫描电化学显微镜原位检测Li^+/Na^+电池及室温液态金属电池反应过程的电解池,成功用于电池正极界面反应动力学检测。测得氧化还原电介质二茂铁在LiFePO4、Li Co O2和Na3V2(PO4)3三种不同正极界面反应电子转移速率常数(...设计、构建了用于扫描电化学显微镜原位检测Li^+/Na^+电池及室温液态金属电池反应过程的电解池,成功用于电池正极界面反应动力学检测。测得氧化还原电介质二茂铁在LiFePO4、Li Co O2和Na3V2(PO4)3三种不同正极界面反应电子转移速率常数(kf)分别为1.06×10^-3cm/s、1.47×10^-3cm/s和9.09×10^-4cm/s。实时监测了三种不同碳含量Na3V2(PO4)3正极界面微区(80×80μm2)储钠活性位点分布,探索了室温Li||Ga电池液态金属正极界面锂化反应过程。表明基于扫描电化学显微镜技术的原位电池分析方法具有极高的分辨率和灵敏度,且对不同电池体系均可实现实时原位高分辨动力学检测。为研究Li^+/Na^+电池及液态金属电池等极具应用潜力的电化学储能技术提供了一种原位无损检测方法。展开更多
The interface properties between hydrated cement paste(hcp)and aggregates largely determine the various performances of concrete.In this work,molecular dynamics simulations were employed to explore the atomistic inter...The interface properties between hydrated cement paste(hcp)and aggregates largely determine the various performances of concrete.In this work,molecular dynamics simulations were employed to explore the atomistic interaction mechanisms between the commonly used aggregate phase calcite/silica and calcium silicate hydrates(C-S-H),as well as the effect of moisture.The results suggest that the C-S-H/calcite interface is relatively strong and stable under both dry and moist conditions,which is caused by the high-strength interfacial connections formed between calcium ions from calcite and high-polarity non-bridging oxygen atoms from the C-S-H surface.Silica can be also adsorbed on the dry C-S-H surface by the H-bonds;however,the presence of water molecules on the interface may substantially decrease the affinities.Furthermore,the dynamics interface separation tests of C-S-H/aggregates were also implemented by molecular dynamics.The shape of the calculated stress-separation distance curves obeys the quasi-static cohesive law obtained experimentally.The moisture conditions and strain rates were found to affect the separation process of C-S-H/silica.A wetter interface and smaller loading rate may lead to a lower adhesion strength.The mechanisms interpreted here may shed new lights on the understandings of hcp/aggregate interactions at a nano-length scale and creation of high performance cementitious materials.展开更多
文摘通过强度调制光电流谱(IMPS)和强度调制光电压谱(IMVS)技术研究在光电分解水制氢体系中碳点光阳极与KOH电解液界面的动力学行为。结果表明,光强在30–90 m W·cm^(-2)范围内,界面的电子传输时间(τ_d)、电子寿命(τ_n)、电子扩散系数(D_n)、电子扩散长度(L_n)均没有变化;当光强增加到110和130 m W·cm^(-2)时,τ_d和τ_n延长,而D_n减小。实验表明,不同于Ti O_2/电解液等界面,碳点光电极/电解液界面中碳点电极存在的缺陷少,因此电子主要以无陷阱限制扩散方式传输为主。且在30–130 m W·cm^(-2)的光强范围内,与τ_d和τ_n相关的载流子收集效率(η_(cc))相近。
文摘设计、构建了用于扫描电化学显微镜原位检测Li^+/Na^+电池及室温液态金属电池反应过程的电解池,成功用于电池正极界面反应动力学检测。测得氧化还原电介质二茂铁在LiFePO4、Li Co O2和Na3V2(PO4)3三种不同正极界面反应电子转移速率常数(kf)分别为1.06×10^-3cm/s、1.47×10^-3cm/s和9.09×10^-4cm/s。实时监测了三种不同碳含量Na3V2(PO4)3正极界面微区(80×80μm2)储钠活性位点分布,探索了室温Li||Ga电池液态金属正极界面锂化反应过程。表明基于扫描电化学显微镜技术的原位电池分析方法具有极高的分辨率和灵敏度,且对不同电池体系均可实现实时原位高分辨动力学检测。为研究Li^+/Na^+电池及液态金属电池等极具应用潜力的电化学储能技术提供了一种原位无损检测方法。
基金Projects(6512009004A,51908119,U1706222)supported by the National Natural Science Foundation of ChinaProject(BK20190367)supported by the Natural Science Foundation of Jiangsu Province,China。
文摘The interface properties between hydrated cement paste(hcp)and aggregates largely determine the various performances of concrete.In this work,molecular dynamics simulations were employed to explore the atomistic interaction mechanisms between the commonly used aggregate phase calcite/silica and calcium silicate hydrates(C-S-H),as well as the effect of moisture.The results suggest that the C-S-H/calcite interface is relatively strong and stable under both dry and moist conditions,which is caused by the high-strength interfacial connections formed between calcium ions from calcite and high-polarity non-bridging oxygen atoms from the C-S-H surface.Silica can be also adsorbed on the dry C-S-H surface by the H-bonds;however,the presence of water molecules on the interface may substantially decrease the affinities.Furthermore,the dynamics interface separation tests of C-S-H/aggregates were also implemented by molecular dynamics.The shape of the calculated stress-separation distance curves obeys the quasi-static cohesive law obtained experimentally.The moisture conditions and strain rates were found to affect the separation process of C-S-H/silica.A wetter interface and smaller loading rate may lead to a lower adhesion strength.The mechanisms interpreted here may shed new lights on the understandings of hcp/aggregate interactions at a nano-length scale and creation of high performance cementitious materials.
