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91.
Formation of a Surficial Bifunctional Nanolayer on Nb2O5 for Ultrastable Electrodes for Lithium‐Ion Battery
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Jun Young Cheong Chanhoon Kim Ji‐Won Jung Ki Ro Yoon Su‐Ho Cho Doo‐Young Youn Hye‐Yeon Jang Il‐Doo Kim 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(19)
Safe and long cycle life electrode materials for lithium‐ion batteries are significantly important to meet the increasing demands of rechargeable batteries. Niobium pentoxide (Nb2O5) is one of the highly promising candidates for stable electrodes due to its safety and minimal volume expansion. Nevertheless, pulverization and low conductivity of Nb2O5 have remained as inherent challenges for its practical use as viable electrodes. A highly facile method is proposed to improve the overall cycle retention of Nb2O5 microparticles by ammonia (NH3) gas‐driven nitridation. After nitridation, an ultrathin surficial layer (2 nm) is formed on the Nb2O5, acting as a bifunctional nanolayer that allows facile lithium (Li)‐ion transport (10–100 times higher Li diffusivity compared with pristine Nb2O5 microparticles) and further prevents the pulverization of Nb2O5. With the subsequent decoration of silver (Ag) nanoparticles (NPs), the low electric conductivity of nitridated Nb2O5 is also significantly improved. Cycle retention is greatly improved for nitridated Nb2O5 (96.7%) compared with Nb2O5 (64.7%) for 500 cycles. Ag‐decorated, nitridated Nb2O5 microparticles and nitridated Nb2O5 microparticles exhibit ultrastable cycling for 3000 cycles at high current density (3000 mA g?1), which highlights the importance of the surficial nanolayer in improving overall electrochemical performances, in addition to conductive NPs. 相似文献
92.
Dominance of Plasmonic Resonant Energy Transfer over Direct Electron Transfer in Substantially Enhanced Water Oxidation Activity of BiVO4 by Shape‐Controlled Au Nanoparticles
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Mi Gyoung Lee Cheon Woo Moon Hoonkee Park Woonbae Sohn Sung Bum Kang Sanghan Lee Kyoung Jin Choi Ho Won Jang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(37)
The performance of plasmonic Au nanostructure/metal oxide heterointerface shows great promise in enhancing photoactivity, due to its ability to confine light to the small volume inside the semiconductor and modify the interfacial electronic band structure. While the shape control of Au nanoparticles (NPs) is crucial for moderate bandgap semiconductors, because plasmonic resonance by interband excitations overlaps above the absorption edge of semiconductors, its critical role in water splitting is still not fully understood. Here, first, the plasmonic effects of shape‐controlled Au NPs on bismuth vanadate (BiVO4) are studied, and a largely enhanced photoactivity of BiVO4 is reported by introducing the octahedral Au NPs. The octahedral Au NP/BiVO4 achieves 2.4 mA cm?2 at the 1.23 V versus reversible hydrogen electrode, which is the threefold enhancement compared to BiVO4. It is the highest value among the previously reported plasmonic Au NPs/BiVO4. Improved photoactivity is attributed to the localized surface plasmon resonance; direct electron transfer (DET), plasmonic resonant energy transfer (PRET). The PRET can be stressed over DET when considering the moderate bandgap semiconductor. Enhanced water oxidation induced by the shape‐controlled Au NPs is applicable to moderate semiconductors, and shows a systematic study to explore new efficient plasmonic solar water splitting cells. 相似文献
93.
Na?Young?Kang Seong?Ihl?Woo Yu?Jin?Lee Jongyoon?Bae Won?Choon?Choi Yong-Ki?ParkEmail author 《Journal of Materials Science》2016,51(8):3735-3749
We successfully synthesized hydrothermally stable ZSM-5 with crystalline nano seeds. We employed a template-free method using ZSM-5 crystalline nano seeds and sodium silicate as a silica source. The prepared ZSM-5 exhibited uniform crystal size and relative crystallinity greater than 100 %. The size of the crystalline nano seed in the scale of 100 nm was found to be the optimum size for obtaining uniform, highly crystalline ZSM-5 with structural stability. After P-modification, the synthesized ZSM-5 with the optimally sized seed showed high hydrothermal stability and improved catalytic naphtha cracking activity compared to a commercial ZSM-5 catalyst. In order to find the elements for the increased hydrothermal stability, the samples were evaluated by studying crystallinity, aluminum spectrum, and acidity using XRD, solid-state NMR, and NH3-TPD, respectively after steaming at 800 °C for 24 h. It is speculated that the increased hydrothermal stability of the ZSM-5 resulted mainly from the increased aluminum structural stability. 相似文献
94.
95.
Guided Evolution of Bulk Metallic Glass Nanostructures: A Platform for Designing 3D Electrocatalytic Surfaces
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96.
97.
Electrocatalysts: Guided Evolution of Bulk Metallic Glass Nanostructures: A Platform for Designing 3D Electrocatalytic Surfaces (Adv. Mater. 10/2016)
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Gustavo Doubek Ryan C. Sekol Jinyang Li Won‐Hee Ryu Forrest S. Gittleson Siamak Nejati Eric Moy Candy Reid Marcelo Carmo Marcelo Linardi Punnathat Bordeenithikasem Emily Kinser Yanhui Liu Xiao Tong Chinedum O. Osuji Jan Schroers Sundeep Mukherjee André D. Taylor 《Advanced materials (Deerfield Beach, Fla.)》2016,28(10):1902-1902
98.
Reproducible Enhancement of Fluorescence by Bimetal Mediated Surface Plasmon Coupled Emission for Highly Sensitive Quantitative Diagnosis of Double‐Stranded DNA
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Nhu Hoa Thi Tran Kieu The Loan Trinh Jun‐Ho Lee Won Jung Yoon Heongkyu Ju 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(32)
Plasmonic enhancement of fluorescence from SYBR Green I conjugated with a double‐stranded DNA (dsDNA) amplicon is demonstrated on polymerase chain reaction (PCR) products. Theoretical computation leads to use of the bimetallic (Au 2 nm–Ag 50 nm) surface plasmons due to larger local fields (higher quality factors) than monometallic (Ag or Au) ones at both dye excitation and emission wavelengths simultaneously, optimizing fluorescence enhancement with surface plasmon coupled emission (SPCE). Two kinds of reverse Kretschmann configurations are used, which favor, in signal‐to‐noise ratio, a fluorescence assay that uses optically dense buffer such as blood plasma. The fluorescence enhancement (12.9 fold at maximum) with remarkably high reproducibility (coefficient of variation (CV) < 1%) is experimentally demonstrated. This facilitates credible quantitation of enhanced fluorescence, however unlikely to obtain by localized surface plasmons. The plasmon‐induced optical gain of 46 dB due to SPCE‐active dye molecules is also estimated. The fluorescence enhancement technologies with PCR enables LOD of the dsDNA template concentration of ≈400 fg µL?1 (CV < 1%), the lowest ever reported in DNA fluorescence assay to date. SPCE also reduces photobleaching significantly. These technologies can be extended for a highly reproducible and sufficiently sensitive fluorescence assay with small volumes of analytes in multiplexed diagnostics. 相似文献
99.
100.
The use a stabilized lithium structure as cathode material for batteries could be a fundamental alternative in the development of next-generation energy storage devices. However, the lithium structure severely limits battery life causes safety concerns due to the growth of lithium (Li) dendrites during rapid charge/discharge cycles. Solid electrolytes, which are used in high-density energy storage devices and avoid the instability of liquid electrolytes, can be a promising alternative for next-generation batteries. Nevertheless, poor lithium ion conductivity and structural defects at room temperature have been pointed out as limitations. In this study, through the application of a low-dimensional graphene quantum dot (GQD) layer structure, stable operation characteristics were demonstrated based on Li+ ion conductivity and excellent electrochemical performance. Moreover, the device based on the modified graphene quantum dots (GQDs) in solid state exhibited retention properties of 95.3% for 100 cycles at 0.5 C and room temperature (RT). Transmission electron microscopy analysis was performed to elucidate the Li+ ion action mechanism in the modified GQD/electrolyte heterostructure. The low-dimensional structure of the GQD-based solid electrolyte has provided an important strategy for stably-scalable solid-state lithium battery applications at room temperature. It was demonstrated that lithiated graphene quantum dots (Li-GQDs) inhibit the growth of Li dendrites by regulating the modified Li+ ion flux during charge/discharge cycling at current densities of 2.2–5.5 mA cm, acting as a modified Li diffusion heterointerface. A full Li GQD-based device was fabricated to demonstrate the practicality of the modified Li structure using the Li–GQD hetero-interface. This study indicates that the low-dimensional carbon structure in Li–GQDs can be an effective approach for stabilization of solid-state Li matrix architecture. 相似文献