Villadsenbroe7036

We observed that the oxide/hydroxide crystals in HQ-Cu and AN-Cu were fragmented into nanosized irregular Cu grains under the applied negative potentials. Such a fragmentation process, which is the consequence of an oxidation-reduction cycle and does not occur in electropolished Cu, not only built an intricate network of grain boundaries but also exposed a variety of high-index facets. These two features greatly facilitated the C-C coupling, thus accounting for the enhanced C2+ selectivity. Our work demonstrates that the use of advanced characterization techniques enables investigating the structural and chemical states of electrodes in unprecedented detail to gain new insights into a widely studied system.The development of color-tunable white-light-emitting systems is significant for artificial smart materials. Recently, a set of conformational dependent fluorophores N,N'-diaryl-dihydrodibenzo[a,c]phenazines (DPACs) have been developed with unique photoluminescence mechanism vibration-induced emission (VIE). DPACs can emit intrinsical blue emission at a bent excited state and abnormal orange-red emission at a planar excited state, which are due to the varied π-conjugation via excited-state configuration transformation along the N-N' axis from bent to planar form. Herein, a novel VIE-active compound DPAC-[B15C5]2 is designed and synthesized with two wings of benzo-15-crown-5. The excited-state vibration of the DPAC moiety can be modulated by tuning the supramolecular assembly and disassembly via chelation competition of K+ between 15-crown-5 and 18-crown-6, and hence, a wide-color-tuning emission is achieved from blue to orange-red including white. Dynamic light scattering and transmission electron microscopy experiments were conducted to exhibit the supramolecular assembling process. Additionally, the moisture detection in organic solvents is realized since the water could dissociate the supramolecular assembly.An electrochemical sensor that contains patterned regions of sp2-carbon in a boron-doped diamond (BDD) matrix is presented for the quantitative detection of hypochlorite (OCl-) at high concentrations in the alkaline, chemically oxidizing environment associated with bleach. As BDD itself is unresponsive to OCl- reduction within the solvent window, by using a laser micromachining process, it is possible to write robust electrochemically active regions of sp2-carbon into the electrochemically inert sp3-BDD electrode. In this work, four different laser patterned BDD electrodes are examined, and their response compared across a range of OCl- concentrations (0.02-1.50 M). A single macrospot (0.37 mm diameter disk) electrode and a closely spaced microspot (46 μm diameter disk) hexagonal array electrode, containing the same surface area of sp2-carbon, are shown to provide the most linear response toward OCl- reduction. Finite element modeling (FEM) is employed to better understand the electrochemical system, due to the complexity of the electrode geometry, as well as the need to include contributions from migration and Ohmic drop at these high concentrations. FEM data suggest that only a small percentage (∼1 × 10-3%) of the total laser-machined sp2 area is active toward the OCl- reduction process and that this process is kinetically very sluggish (∼keff = 1 × 10-12 cm s-1). The sensitivity at the array electrode (-0.127 ± 0.004 mA M-1; R2 = 0.992) is higher than that at the single-spot electrode (-0.075 ± 0.002 mA M-1; R2 = 0.996) due to the enhanced effect of transport to the edges of the microspots, shown via simulation. The electrodes returned a relatively stable response over a greater than 3 month period of use in the OCl- solutions, demonstrating these hybrid sp2-BDD electrodes show promise for long-term monitoring applications in the harsh environments associated with bleaching applications.The impact of phase transformation from spinel-structured Li4Ti5O12 to rocksalt-type Li7Ti5O12 on the electrochromic properties of the material is studied. Thin films of Li4Ti5O12 are deposited on platinum-coated substrates using radio-frequency-ion beam sputtering. In situ and ex situ optical spectroscopy (in reflectance geometry) is performed along with electrochemical characterization. In situ measurements demonstrate the reversible electrochromic behavior of the deposited thin films and the effect of the change of lithium content on the reflectance spectrum. Ex situ measurements quantify the optical constants of thin films for different charge states by modeling the reflectance spectrum with a Clausius-Mossotti relation. The model reveals the presence of one or two dominant resonant frequencies in the case of Li4Ti5O12 or Li7Ti5O12, respectively, in the UV/visible/NIR region of light. The single strong resonance in the case of Li4Ti5O12 is assigned to transition from O 2p to Ti t2g, that is, across the band gap, whereas for the Li7Ti5O12 phase, the two resonances correspond to the electronic transitions from O 2p to empty Ti t2g and from filled Ti t2g to empty Ti eg. Selleckchem Tanespimycin The concentration dependence of the derived dielectric constants points out a fast lithium ion transport through the grain boundaries, thereby segregating a conductive lithium-rich phase at the grain boundaries. This increases the electronic conductivity of the thin films in the initial stages of intercalation and explains the debated mechanism of the fast discharge/charge capability of Li4Ti5O12 electrodes.Recent research endeavors have established metal-organic frameworks (MOFs) as suitable platforms for the adsorptive removal of various environmental pollutants. In this regard, the sorptive performances of four MOFs (MOF-199, UiO-66, UiO-66-NH2, and Co-CUK-1) were investigated against two gaseous aliphatic ketones (methyl ethyl ketone (MEK) and methyl isobutyl ketone (MiBK)) at a low partial pressure (0.1 Pa). Activated carbon was utilized as a reference commercial sorbent. The 10% breakthrough volume (BTV10) values for MEK decreased in the following order MOF-199 (4772 L atm g-1) > activated carbon (224 L atm g-1) > UiO-66-NH2 (106 L atm g-1) > UiO-66 (53 L atm g-1) > Co-CUK-1 (16 L atm g-1). In case of MiBK, the relative ordering in BTV10 was consistently maintained while showing noticeable increases in its magnitude MOF-199 (7659 L atm g-1) > activated carbon (816 L atm g-1) > UiO-66-NH2 (304 L atm g-1) > UiO-66 (150 L atm g-1) > Co-CUK-1 (31 L atm g-1). The superiority of MOF-199 was confirmed toward the adsorptive removal of gaseous aliphatic ketones.