Browsing by Subject "Nucleation and growth"

Now showing 1 - 4 of 4

Open Access
Guided lithium nucleation and growth on lithiophilic tin-decorated copper substrate
(Elsevier Inc., 2022-08-04) Ye, L.; Zhang, C.; Zhou, Y.; Ülgüt, Burak; Zhao, Y.; Qian, J.
Lithium metal is the ultimate anode choice for high energy rechargeable lithium batteries owing to its ultra-high theoretical capacity, however, Li dendrites and low Coulombic efficiency (CE) caused by disordered Li plating restrict its practical application. Herein, we develop an ultrathin Sn-decorated Cu substrate (Sn@Cu) fabricated by an electroless plating method to induce ordered Li nucleation and growth behavior. The lithiophilic Sn interfacial layer is found to play a critical role to lower the Li nucleation over-potential and promote fast Li-migration kinetics, and the underlying mechanism is revealed using the first principle calculations. Accordingly, a dense dendrite-free and Li deposition with large granular morphology is obtained, which significantly improved the CE and cycling performance of Li||Sn@Cu half cells symmetric cells. Symmetric cells using the Li-Sn@Cu electrode display a much-prolonged life span (>1200 h) with low overpotential (∼18 mV) at a high current density of 1 mA cm−2. Moreover, full cells paired with commercial LiFePO4 cathode (1.8 mAh cm−2) deliver enhanced cycling stability (0.5 C, 300 cycles) and excellent rate performance. This work provides a simple and effective way to bring about high efficiency and long lifespan substrates for practical applications.
Open Access
Multi-temperature zone droplet-based microreactor for increased temperature control in nanoparticle synthesis
(Wiley-VCH Verlag, 2014) Erdem, E. Y.; Cheng, J. C.; Doyle, F. M.; Pisano, A. P.
Microreactors are an emerging technology for the controlled synthesis of nanoparticles. The Multi-Temperature zone Microreactor (MTM) described in this work utilizes thermally isolated heated and cooled regions for the purpose of separating nucleation and growth processes as well as to provide a platform for a systematic study on the effect of reaction conditions on nanoparticle synthesis.
Open Access
Multifunctional electrospun polymeric nanofibrous mats for catalytic reduction, photocatalysis and sensing
(Royal Society of Chemistry, 2017) Arslan, O.; Uyar, Tamer
Fabrication and decoration of flexible Nylon 6,6 polymeric nanofibrous mats for production of multifunctional electrospun material was accomplished via visible light-emitting surface-protected silicon quantum dots (Si QD), ZnO nanoparticles (ZnO NP) and Pd nanocubes (Pd NC). UV-range light was utilized for Si QD production and, after hydrolysis/condensation together with nucleation and growth reactions, amine-modified, fluorescent Si QD were obtained. Additionally, available molecular groups on the Si QD coated onto the polymeric nanofibrous mats provided further attachment of metal oxide and metal NP for various catalytic purposes. Analytical investigations showed that visible-light emission could be maintained on the Nylon 6,6 mats for trinitrotoluene (TNT) sensing. Also, due to consecutive NP decoration, multifunctional, polymeric, flexible nanofibrous mats were obtained. Experiments revealed that fabricated multifunctional mats could reduce molecules such as paranitrophenol effectively or decompose waste dyes such as methylene blue via photocatalytic experiments, and sense the pollutant TNT in aqueous solutions as an all-in-one concept.
Open Access
Preparation of Au and Au-Pt nanoparticles within PMMA matrix using UV and X-ray irradiation
(2009) Ozkaraoglu, E.; Tunc, I.; Süzer, Şefik
Au and Au-Pt alloy nanoparticles are prepared and patterned at room temperature within the PMMA polymer matrix by the action of 254 nm UV light or X-rays. The polymer matrix enables us to entangle the kinetics of the photochemical reduction from the nucleation and growth processes, when monitored by UV-vis spectroscopy. Accordingly, increase of the temperature to 50 °C of the reaction medium increases the nucleation and growth rates of the nanoparticle formation by more than one order of magnitude, due to enhanced diffusion and nucleation at the higher temperature, but has no effect on the photochemical reduction process. Presence of Pt ions also increases the same rate, but by a factor two only. Similar photochemical reduction and particle growth take also place within the PMMA matrix, when these metal ions are subjected to prolonged exposure to X-rays, as evidenced by XPS analysis. Both angle-resolved and charge-contrast measurements using XPS reveal that the resultant Au and Pt species are in close proximity to each other, indicating the Au-Pt alloy formation to be the most likely case.