For the heterogeneous alloy catalysts of water electrolysis, it has been reported that conductivity can be improved through structural modifications by introducing other elements like chalcogens. ...Transition metal sulfides can induce numerous lattice defects due to their unique interface formation, thereby promoting abundant active sites and facilitating electron/ion movement. In this study, we report the enhanced electrochemical activity of NiFeS formed on nickel foam (NiFeS@NF) for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) during the water electrolysis, especially, the seawater electrolysis. NiFeS@NF synthesized through a one-step electrochemical deposition had an amorphous-like highly porous structure with the aggregates of spherical nanoparticles attached to nickel foam. Compared to NiFe@NF, NiFeS@NF catalysts demonstrated a reduced overpotential by ~32 mV and ~96 mV for OER and HER, respectively, at 100 mA cm
−2
and secured electrochemical stability over 24 h. Moreover, bifunctional seawater electrolysis using NiFeS@NF as both electrodes demonstrated the reduced overpotential by ~80 mV with durability over time. This facile synthesis method for anion doping and the enhanced and selective electrolysis of seawater without producing Cl
2
gas holds promise for the creation of high-performance electrocatalysts applicable in a wide range of hydrogen energy-related fields.
Graphical Abstract
Reports of emergent conductivity, superconductivity and magnetism have helped to fuel intense interest in the rich physics and technological potential of complex-oxide interfaces. Here we employ ...magnetic force microscopy to search for room-temperature magnetism in the well-studied LaAlO3/SrTiO3 system. Using electrical top gating to control the electron density at the oxide interface, we directly observe the emergence of an in-plane ferromagnetic phase as electrons are depleted from the interface. Itinerant electrons that are reintroduced into the interface align antiferromagnetically with the magnetization at first screening and then destabilizing it as the conductive regime is approached. Repeated cycling of the gate voltage results in new, uncorrelated magnetic patterns. This newfound control over emergent magnetism at the interface between two non-magnetic oxides portends a number of important technological applications.
The accurate prediction of human pharmacokinetics is critically important in modern drug discovery since it drives both pharmacological and toxicological effects. Although significant progress has ...been made in predicting drug disposition by hepatic drug-metabolizing enzymes, predicting transporter-mediated clearance is still highly uncertain. Furthermore, different approaches are often used to predict clearance with and without transporter involvement, hence the major clearance pathway for a compound must first be determined to know which approach to use. As a result of these challenges, a novel unified method has been developed using cryopreserved suspended human hepatocytes to predict human hepatic clearance for both enzyme- and transporter-mediated mechanisms. This method hypothesizes that, once in vitro metabolic stability is scaled by partition coefficients between hepatocytes and buffer with 4% bovine serum albumin, in vivo clearance can be better predicted. With this method, good in vitro-in vivo correlation of human hepatic clearance has been obtained for a set of 32 structurally diverse compounds, including such transporters as organic anion-transporting polypeptide substrates. The clearance predictions for most compounds are within 3-fold of observed values. This is the first time that multiple compounds result in good in vitro-in vivo extrapolation using an entirely "bottom-up" approach without any empirical scaling factor when transporter-mediated clearance is involved. Potential exceptions are compounds with significant biliary and/or extra-hepatic clearance. The method offers an alternative approach to more accurately predict human hepatic clearance when multiple complex mechanisms are involved.
Complex-oxide interfaces host a diversity of phenomena not present in traditional semiconductor heterostructures. Despite intense interest, many basic questions remain about the mechanisms that give ...rise to interfacial conductivity and the role of surface chemistry in dictating these properties. Here we demonstrate a fully reversible >4 order of magnitude conductance change at LaAlO3/SrTiO3 (LAO/STO) interfaces, regulated by LAO surface protonation. Nominally conductive interfaces are rendered insulating by solvent immersion, which deprotonates the hydroxylated LAO surface; interface conductivity is restored by exposure to light, which induces reprotonation via photocatalytic oxidation of adsorbed water. The proposed mechanisms are supported by a coordinated series of electrical measurements, optical/solvent exposures, and X-ray photoelectron spectroscopy. This intimate connection between LAO surface chemistry and LAO/STO interface physics bears far-reaching implications for reconfigurable oxide nanoelectronics and raises the possibility of novel applications in which electronic properties of these materials can be locally tuned using synthetic chemistry.
The fabrication of porous metal structures usually involves complicated processes such as lithography or etching. In this study, a facile and clean method based on thermal evaporation at high ...pressure is introduced, by which a highly porous, black colored structure of Au can be formed through the control of homogeneous nucleation and growth during evaporation. The deposited films have different morphologies, from columnar to nanoporous structures, depending on the working pressure. These porous structures consist of Au nanoparticle aggregates, and a large number of nano-gaps are found among the nanoparticles. Thus, these structures indicate a much higher intensity of surface-enhanced Raman spectroscopy (SERS) when compared with commercial SERS substrates. The SERS intensity depends on the working pressure and thickness. Even circumstances that can induce agglomeration of nanoparticle aggregates do not deteriorate the sensitivity of SERS. These nanoporous structures based on high-pressure thermal evaporation are expected to provide a new platform for the development of low-cost and highly sensitive chemical sensors.
Current challenges with the in vitro-in vivo extrapolation (IVIVE) of hepatic uptake clearance involving organic anion-transporting polypeptide (OATP) 1B1/1B3 hinder drug design strategies. Here we ...evaluated the effect of 100% human plasma on the uptake clearance using transfected human embryonic kidney (HEK) 293 cells and primary human hepatocytes and assessed IVIVE. Apparent unbound uptake clearance (PS
) increased significantly (
< 0.05) in the presence of plasma (vs. buffer incubations) for about 50% of compounds in both OATP1B1-transfected and wild-type HEK cells. Thus, plasma showed a minimal effect on the uptake ratios. With cultured human hepatocytes, plasma significantly (
< 0.05) increased PS
for 11 of 19 OATP1B substrates (median change of 2.1-fold). Cell accumulation in HEK cells and hepatocytes was also increased for tolbutamide, which is not an OATP substrate. Plasma-to-buffer ratio of PS
obtained in hepatocytes showed a good correlation with unbound fraction in plasma, and the relationship was best described by a "facilitated-dissociation" model. IVIVE was evaluated for the 19 OATP1B substrates using hepatocyte data in the presence of buffer and plasma. PS
from buffer incubations markedly underpredicted hepatic intrinsic clearance (calculated via well stirred and parallel tube models) with an estimated bias of 0.10-0.13. Predictions improved when using PS
from plasma incubations; however, considerable systemic underprediction was still apparent (0.19-0.26 bias). Plasma data with a global scaling factor of 3.8-5.3 showed good prediction accuracy (95% predictions within 3-fold; average fold error = 1.7, bias = 1). In summary, this study offers insight into the effect of plasma on the uptake clearance and its scope in improving IVIVE. SIGNIFICANCE STATEMENT: Our study using diverse anionic compounds shows that human plasma facilitates organic anion-transporting polypeptide 1B-mediated as well as passive uptake clearance, particularly for the highly bound compounds. Leveraging data from transfected human embryonic kidney 293 cells and primary human hepatocytes, we further evaluated mechanisms involved in the observed plasma-facilitated uptake transport. Enhanced hepatic uptake rate in the presence of plasma could be of relevance, as such mechanisms likely prevail in vivo and emphasize the need to maintain physiologically relevant assay conditions to achieve improved translation of transport data.
The breaking of symmetry across an oxide heterostructure causes the electronic orbitals to be reconstructed at the interface into energy states that are different from their bulk counterparts
. The ...detailed nature of the orbital reconstruction critically affects the spatial confinement and the physical properties of the electrons occupying the interfacial orbitals
. Using an example of two-dimensional electron liquids forming at LaAlO
/SrTiO
interfaces
with different crystal symmetry, we show that the selective orbital occupation and spatial quantum confinement of electrons can be resolved with subnanometre resolution using inline electron holography. For the standard (001) interface, the charge density map obtained by inline electron holography shows that the two-dimensional electron liquid is confined to the interface with narrow spatial extension (~1.0 ± 0.3 nm in the half width). On the other hand, the two-dimensional electron liquid formed at the (111) interface shows a much broader spatial extension (~3.3 ± 0.3 nm) with the maximum density located ~2.4 nm away from the interface, in excellent agreement with density functional theory calculations.
Electromechanical coupling in complex oxide heterostructures opens new possibilities for the development of a broad range of novel electronic devices with enhanced functionality. In this article, the ...switchable hysteretic electromechanical behavior of crystalline epitaxial LaAlO3 (LAO) thin films associated with polarization induced by electrical and mechanical stimuli is investigated. The field–time‐dependent testing of the induced polarization states along with transport measurements and theoretical modeling suggests that the ferroelectric‐like response of the LAO thin films is mediated by the field‐induced ion migration in the bulk of the film. Comparative analysis of the dynamics of polarization reversal under the electrical field and mechanical stress applied via a tip of a scanning probe microscope demonstrates that both electrical and mechanical stimulus can be used to effectively control polarization at least at the submillisecond timescale. However, the mechanical writing is more localized than the electrical one. A combined electrical/mechanical approach for tuning the physical properties of oxide heterostructures may potentially facilitate novel memory and logic devices, in which the data bits are written mechanically and read electrically.
Electrically and mechanically induced ferroelectric‐like polar states are investigatedIn the ultrathin LaAlO3 films, using a combination of scanning probe microscope techniques. The ferroelectric‐like behavior is associated with the reorganization of oxygen vacancies between the two stable states, which can be controlled at the submillisecond timescale using either the electrical or the mechanical stimulus.
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