11 research outputs found
In Operando Monitoring of the Pore Dynamics in Ordered Mesoporous Electrode Materials by Small Angle X-ray Scattering
To monitor dynamic volume changes of electrode materials during electrochemical lithium storage and removal process is of utmost importance for developing high performance lithium storage materials. We herein report an in operando probing of mesoscopic structural changes in ordered mesoporous electrode materials during cycling with synchrotron-based small angel X-ray scattering (SAXS) technique. In operando SAXS studies combined with electrochemical and other physical characterizations straightforwardly show how porous electrode materials underwent volume changes during the whole process of charge and discharge, with respect to their own reaction mechanism with lithium. This comprehensive information on the pore dynamics as well as volume changes of the electrode materials will not only be critical in further understanding of lithium ion storage reaction mechanism of materials, but also enable the innovative design of high performance nanostructured materials for next generation batteriesclose0
Enzyme-Treated Caviar Prevents UVB Irradiation-Induced Skin Photoaging
For this research article, we investigated the protective effects of enzyme-treated caviar powder extract (CV) in ultraviolet B (UVB)-irradiated hairless mice and keratinocytes by confirming moisturizing-related factors and elasticity-related factors. UVB irradiation induced wrinkle formation, dehydration, oxidative stress, and inflammation in the dorsal skin of mice; however, these were suppressed in the CV-supplemented groups in UVB-irradiated hairless mice. Furthermore, in UVB-irradiated keratinocytes, CV treatment increased the antioxidant enzyme activities and the levels of sphingomyelin and hyaluronic acid and decreased the production of pro-inflammatory cytokines and the expression of IkB-α and p65 phosphorylation. These findings indicate that CV can directly protect keratinocytes against UVB irradiation-induced oxidative stress and inflammation. Therefore, we suggest that CV can protect against UVB-induced skin photoaging. Therefore, we suggest that caviar is effective for skin health by preventing UVB-induced skin photoaging
Discovery of abnormal lithium-storage sites in molybdenum dioxide electrodes.
Developing electrode materials with high-energy densities is important for the development of lithium-ion batteries. Here, we demonstrate a mesoporous molybdenum dioxide material with abnormal lithium-storage sites, which exhibits a discharge capacity of 1,814 mAh g(-1) for the first cycle, more than twice its theoretical value, and maintains its initial capacity after 50 cycles. Contrary to previous reports, we find that a mechanism for the high and reversible lithium-storage capacity of the mesoporous molybdenum dioxide electrode is not based on a conversion reaction. Insight into the electrochemical results, obtained by in situ X-ray absorption, scanning transmission electron microscopy analysis combined with electron energy loss spectroscopy and computational modelling indicates that the nanoscale pore engineering of this transition metal oxide enables an unexpected electrochemical mass storage reaction mechanism, and may provide a strategy for the design of cation storage materials for battery systems
New Insight into the Reaction Mechanism for Exceptional Capacity of Ordered Mesoporous SnO2 Electrodes via Synchrotron-Based X-ray Analysis
Tin oxide-based materials, operating via irreversible conversion and reversible alloying reaction, are promising lithium storage materials due to their higher capacity. Recent studies reported that nanostructured SnO2 anode provides higher capacity beyond theoretical capacity based on the alloying reaction mechanism; however, their exact mechanism remains still unclear. Here, we report the detailed lithium storage mechanism of an ordered mesoporous SnO2 electrode material. Synchrotron X-ray diffraction and absorption spectroscopy reveal that some portion of Li2O decomposes upon delithiation and the resulting oxygen reacts with Sn to form the SnOx phase along with dealloying of LixSn, which are the main reasons for unexpected high capacity of an ordered mesoporous SnO2 material. This finding will not only be helpful in a more complete understanding of the reaction mechanism of Sn-based oxide anode materials but also will offer valuable guidance for developing new anode materials with abnormal high capacity for next generation rechargeable batteries.
<i>In Operando</i> Monitoring of the Pore Dynamics in Ordered Mesoporous Electrode Materials by Small Angle X‑ray Scattering
To monitor dynamic volume changes of electrode materials during electrochemical lithium storage and removal process is of utmost importance for developing high performance lithium storage materials. We herein report an <i>in operando</i> probing of mesoscopic structural changes in ordered mesoporous electrode materials during cycling with synchrotron-based small angel X-ray scattering (SAXS) technique. <i>In operando</i> SAXS studies combined with electrochemical and other physical characterizations straightforwardly show how porous electrode materials underwent volume changes during the whole process of charge and discharge, with respect to their own reaction mechanism with lithium. This comprehensive information on the pore dynamics as well as volume changes of the electrode materials will not only be critical in further understanding of lithium ion storage reaction mechanism of materials, but also enable the innovative design of high performance nanostructured materials for next generation batteries
Visible-Light Driven Photocatalytic Degradation of Organic Dyes over Ordered Mesoporous Cd<sub><i>x</i></sub>Zn<sub>1–<i>x</i></sub>S Materials
Highly
ordered mesoporous Cd<sub><i>x</i></sub>Zn<sub>1–<i>x</i></sub>S materials were obtained via a
simple nanoreplication method using a mesoporous silica template with
a 3-D bicontinuous cubic Ia3d mesostructure. Combined analyses using
X-ray diffraction, N<sub>2</sub> sorption, electron microscopy, and
diffuse reflectance UV–visible spectroscopy revealed that the
ordered mesoporous ternary compound semiconductor materials exhibited
well-developed crystalline frameworks, high surface areas of 80–120
m<sup>2</sup>g<sup>–1</sup>, uniform mesopore sizes of about
20 nm, ordered arrangement of mesopores, and outstanding visible light
absorption properties. Photocatalytic activities were investigated
by degradation of methylene blue and rhodamine B under visible light
over the mesoporous Cd<sub><i>x</i></sub>Zn<sub>1–<i>x</i></sub>S materials. Due to the high surface area and outstanding
light absorption properties, the ordered mesoporous Cd<sub><i>x</i></sub>Zn<sub>1–<i>x</i></sub>S exhibited
excellent photocatalytic performances for the degradation of methylene
blue and rhodamine B. This study indicates a potential application
of the mesoporous compound semiconductors in the efficient visible-light-driven
photolysis of organics that may cause environmental pollution