Hoyletobiasen2075

Nonaqueous rechargeable lithium-oxygen batteries (LOBs) are one of the most promising candidates for future electric vehicles and wearable/flexible electronics. However, their development is severely hindered by the sluggish kinetics of the ORR and OER during the discharge and charge processes. Here, we employ MOF-assisted spatial confinement and ionic substitution strategies to synthesize Ru single atoms riveted with nitrogen-doped porous carbon (Ru SAs-NC) as the electrocatalytic material. By using the optimized Ru0.3 SAs-NC as electrocatalyst in the oxygen-breathing electrodes, the developed LOB can deliver the lowest overpotential of only 0.55 V at 0.02 mA cm-2. Moreover, in-situ DEMS results quantify that the e-/O2 ratio of LOBs in a full cycle is only 2.14, indicating a superior electrocatalytic performance in LOB applications. Theoretical calculations reveal that the Ru-N4 serves as the driving force center, and the amount of this configuration can significantly affect the internal affinity of intermediate species. The rate-limiting step of the ORR on the catalyst surface is the occurrence of 2e- reactions to generate Li2O2, while that of the OER pathway is the oxidation of Li2O2. This work broadens the field of vision for the design of single-site high-efficiency catalysts with maximum atomic utilization efficiency for LOBs.An aggregation-induced emission enhancement (AIEE) effect in fluorescent lipophilic 2,1,3-benzothiadiazole (BTD) derivatives and their organic nanoaggregates were studied. A set of techniques such as single-crystal X-ray, dynamic light scattering (DLS), electron paramagnetic resonance (EPR), UV-vis, fluorescence, and density functional theory (DFT) calculations have been used to decipher the formation/break (kinetics), properties, and dynamics of the organic nanoaggregates of three BTD small organic molecules. An in-depth study of the excited-state also revealed the preferential relaxation emissive pathways for the BTD derivatives and the dynamics associated with it. The results described herein, for the first time, explain the formation of fluorescent BTD nanoaggregate derivatives and allow for the understanding of their dynamics in solution as well as the ruling forces of both aggregation and break processes along with the involved equilibrium. One of the developed dyes could be used at a nanomolar concentration to selectively stain lipid droplets emitting an intense and bright fluorescence at the red channel. The other two BTDs could also stain lipid droplets at very low concentrations and were visualized preferentially at the blue channel.Mn11Ta4O21 is presented as the first hexagonal A-site manganite. Based on simple rules, the structure is compatible with a 14H-layer (cchchch)2 stacking sequence that is related to BaVO3 and BaCrO3 high-pressure polymorphs. The A-site overstoichiometry is explained through difference in ionic radii sizes between Ba and Mn. Magnetic properties show two transitions at TN1 = 88 K and TN2 = 56 K. Neutron powder diffraction evidence two magnetic structures with purely antiferromagnetic and ferrimagnetic orders below TN1 and TN2, respectively. A complementary description with 14H-(hhccccc)2 sequence of only Mn octahedra provides a direct comparison with BaMnO3-δ hexagonal perovskites and naturally explains the AFM order. Below TN2 a magneto-elastic coupling along with uniaxial negative thermal expansion are observed.Neutral loss of water and ammonia are often significant fragmentation channels upon collisional activation of protonated peptides. Here, we deploy infrared ion spectroscopy to investigate the dehydration reactions of protonated AlaSer, AlaThr, GlySer, GlyThr, PheSer, PheThr, ProSer, ProThr, AsnSer, and AsnThr, focusing on the question of the structure of the resulting [M + H - H2O]+ fragment ion and the site from which H2O is expelled. In all cases, the second residue of the selected peptides contains a hydroxyl moiety, so that H2O loss can potentially occur from this side-chain, as an alternative to loss from the C-terminal free acid of the dipeptide. Infrared action spectra of the product ions along with quantum-chemical calculations unambiguously show that dehydration consistently produces fragment ions containing an oxazoline moiety. This contrasts with the common oxazolone structure that would result from dehydration at the C-terminus analogous to the common b/y dissociation forming regular b2-type sequence ions. The oxazoline product structure suggests a reaction mechanism involving water loss from the Ser/Thr side-chain with concomitant nucleophilic attack of the amide carbonyl oxygen at its β-carbon, forming an oxazoline ring. However, an extensive quantum-chemical investigation comparing the potential energy surfaces for three entirely different dehydration reaction pathways indicates that it is actually the backbone amide oxygen atom that leaves as the water molecule.Charge transport in deoxyribonucleic acid (DNA) is of immense interest in biology and molecular electronics. Electronic coupling between the DNA bases is an important parameter describing the efficiency of charge transport in DNA. A reasonable estimation of this electronic coupling requires many expensive first principle calculations. In this article, we present a machine learning (ML) based model to calculate the electronic coupling between the guanine bases of the DNA (in the same strand) of any length, thus avoiding expensive first-principle calculations. The electronic coupling between the bases are evaluated using density functional theory (DFT) calculations with the morphologies derived from fully atomistic molecular dynamics (MD) simulations. A new and simple protocol based on the coarse-grained model of the DNA has been used to extract the feature vectors for the DNA bases. A deep neural network (NN) is trained with the feature vector as input and the DFT-calculated electronic coupling as output. Once well trained, the NN can predict the DFT-calculated electronic coupling of new structures with a mean absolute error (MAE) of 0.02 eV.The chemical looping process is promising for CO2 conversion because of the much higher CO2 conversion efficiency than the photocatalytic and electrocatalytic processes. Conventional oxygen carriers have to include a high content of inert support, typically Al2O3, to avoid sintering, thus leading to a trade-off between reactivity and stability. Here, we propose the use of ion-conductive Gd x Ce2-xO2-δ (GDC) to prepare the supported oxygen carriers. The resulting Fe2O3/GDC materials achieve both high reactivity and stability. Fe2O3/Gd0.3Ce1.7O2-δ shows high CO productivity (∼10.79 mmol·g-1) and CO production rate (∼0.77 mmol·g-1·min-1), which are twofold higher than that of Fe2O3/Al2O3. The performance remains stable even after 30 cycles. ML364 order The mechanism study confirmed the rate-limiting role of the oxygen-ion conductivity, and the GDC support enhanced the oxygen-ion conductivity of oxygen carriers during the redox reactions, thus leading to improved CO2 splitting performance. A roughly linear relationship between the oxygen-ion conductivity and CO2 yield is also obtained and verified in our testing conditions.