Atomically Dispersed Ru-doped Ti4O7 Electrocatalysts for Chlorine Evolution Reaction with a Universal Activity.

Chlorine has been supplied by the chlor-alkali process that deploys dimensionally stable anodes (DSAs) for the electrochemical chlorine evolution reaction (ClER). The paramount bottlenecks have been ascribed to an intensive usage of precious elements and inevitable competition with the oxygen evolution reaction. Herein, a unique case of Ru2+-O4 active motifs anchored on Magnéli Ti4O7 (Ru-Ti4O7) via a straightforward wet impregnation and mild annealing is reported. The Ru-Ti4O7 performs radically active ClER with minimal deployment of Ru (0.13 wt%), both in 5 m NaCl (pH 2.3) and 0.1 m NaCl (pH 6.5) electrolytes. Scanning electrochemical microscopy demonstrates superior ClER selectivity on Ru-Ti4O7 compared to the DSA. Operando X-ray absorption spectroscopy and density functional theory calculations reveal a universally active ClER (over a wide range of pH and [Cl-]), through a direct adsorption of Cl- on Ru2+-O4 sites as the most plausible pathway, together with stabilized ClO* at low [Cl-] and high pH.

Atomistic Scale Modeling of Anode/Electrolyte Interfaces in Li-Ion Batteries.

A key issue in lithium-ion batteries is understanding the solid electrolyte interphase (SEI) resulting from a reductive reaction on the anode/electrolyte interface. The presence of the SEI layer affects the transport behavior of the ions and electrons between the anode and electrolyte. Despite the influence on interfacial properties, the formation and evolution mechanism of the SEI layer are unclear owing to their complexity and dynamic nature. Atomistic-scale simulations have promoted the understanding of the reaction mechanism on the anode/electrolyte interface, the formation and evolution of the SEI layer, and their fundamental properties. This Perspective discusses the modeling and interpretations of anode/SEI/electrolyte interfaces through computational methods at the atomic-scale and highlights interfacial modeling techniques for a realistic interface design, which can overcome the limited time and length scale with high accuracy.

Regulating Electronic Structure of Iron Nitride by Tungsten Nitride Nanosheets for Accelerated Overall Water Splitting.

Two essential characteristics that are required for hybrid electrocatalysts to exhibit higher oxygen and hydrogen evolution reaction (OER and HER, respectively) activity are a favorable electronic configuration and a sufficient density of active sites at the interface between the two materials within the hybrid. In the present study, a hybrid electrocatalyst is introduced with a novel architecture consisting of coral-like iron nitride (Fe2 N) arrays and tungsten nitride (W2 N3 ) nanosheets that satisfies these requirements. The resulting W2 N3 /Fe2 N catalyst achieves high OER activity (268.5 mV at 50 mA cm-2 ) and HER activity (85.2 mV at 10 mA cm-2 ) with excellent long-term durability in an alkaline medium. In addition, density functional theory calculations reveal that the individual band centers experience an upshift in the hybrid W2 N3 /Fe2 N structure, thus improving the OER and HER activity. The strategy adopted here thus provides a valuable guide for the fabrication of cost-effective multi-metallic crystalline hybrids for use as multifunctional electrocatalysts.

Density-Dependence of Surface Transport in Tellurium-Enriched Nanograined Bulk Bi2 Te3.

Three-dimensional topological insulators (3D TI) exhibit conventional parabolic bulk bands and protected Dirac surface states. A thorough investigation of the different transport channels provided by the bulk and surface carriers using macroscopic samples may provide a path toward accessing superior surface transport properties. Bi2 Te3 materials make promising 3D TI models; however, due to their complicated defect chemistry, these materials have a high number of charge carriers in the bulk that dominate the transport, even as nanograined structures. To partially control the bulk charge carrier density, herein the synthesis of Te-enriched Bi2 Te3 nanoparticles is reported. The resulting nanoparticles are compacted into nanograined pellets of varying porosity to tailor the surface-to-volume ratio, thereby emphasizing the surface transport channels. The nanograined pellets are characterized by a combination of resistivity, Hall- and magneto-conductance measurements together with (THz) time-domain reflectivity measurements. Using the Hikami-Larkin-Nagaoka (HLN) model, a characteristic coherence length of ≈200 nm is reported that is considerably larger than the diameter of the nanograins. The different contributions from the bulk and surface carriers are disentangled by THz spectroscopy, thus emphasizing the dominant role of the surface carriers. The results strongly suggest that the surface transport carriers have overcome the hindrance imposed by nanoparticle boundaries.

Synergistic Contribution of Oligo(ethylene glycol) and Fluorine Substitution of Conjugated Polymer Photocatalysts toward Solar Driven Sacrificial Hydrogen Evolution.

To separately explore the importance of hydrophilicity and backbone planarity of polymer photocatalyst, a series of benzothiadiazole-based donor-acceptor alternating copolymers incorporating alkoxy, linear oligo(ethylene glycol) (OEG) side chain, and backbone fluorine substituents is presented. The OEG side chains in the polymer backbone increase the surface energy of the polymer nanoparticles, thereby improving the interaction with water and facilitating electron transfer to water. Moreover, the OEG-attached copolymers exhibit enhanced intermolecular packing compared to polymers with alkoxy side chains, which is possibly attributed to the self-assembly properties of the side chains. Fluorine substituents on the polymer backbone produce highly ordered lamellar stacks with distinct π-π stacking features; subsequently, the long-lived polarons toward hydrogen evolution are observed by transient absorption spectroscopy. In addition, a new nanoparticle synthesis strategy using a methanol/water mixed solvent is first adopted, thereby avoiding the screening effect of surfactants between the nanoparticles and water. Finally, hydrogen evolution rate of 26 000 µmol g-1  h-1 is obtained for the copolymer incorporated with both OEG side chains and fluorine substituents under visible-light irradiation (λ > 420 nm). This study demonstrates how the glycol side chain strategy can be further optimized for polymer photocatalysts by controlling the backbone planarity.

Artificial intelligence-assisted ultrasound-guided focused ultrasound therapy: a feasibility study.

OBJECTIVES: Focused ultrasound (FUS) therapy has emerged as a promising noninvasive solution for tumor ablation. Accurate monitoring and guidance of ultrasound energy is crucial for effective FUS treatment. Although ultrasound (US) imaging is a well-suited modality for FUS monitoring, US-guided FUS (USgFUS) faces challenges in achieving precise monitoring, leading to unpredictable ablation shapes and a lack of quantitative monitoring. The demand for precise FUS monitoring heightens when complete tumor ablation involves controlling multiple sonication procedures. METHODS: To address these challenges, we propose an artificial intelligence (AI)-assisted USgFUS framework, incorporating an AI segmentation model with B-mode ultrasound imaging. This method labels the ablated regions distinguished by the hyperechogenicity effect, potentially bolstering FUS guidance. We evaluated our proposed method using the Swin-Unet AI architecture, conducting experiments with a USgFUS setup on chicken breast tissue. RESULTS: Our results showed a 93% accuracy in identifying ablated areas marked by the hyperechogenicity effect in B-mode imaging. CONCLUSION: Our findings suggest that AI-assisted ultrasound monitoring can significantly improve the precision and control of FUS treatments, suggesting a crucial advancement toward the development of more effective FUS treatment strategies.

Tuning Local Coordination Environments of Manganese Single-Atom Nanozymes with Multi-Enzyme Properties for Selective Colorimetric Biosensing.

Single-atom nanozymes (SAzymes) are promising in next-generation nanozymes, nevertheless, how to rationally modulate the microenvironment of SAzymes with controllable multi-enzyme properties is still challenging. Herein, we systematically investigate the relationship between atomic configuration and multi-enzymatic performances. The constructed MnSA -N3 -coordinated SAzymes (MnSA -N3 -C) exhibits much more remarkable oxidase-, peroxidase-, and glutathione oxidase-like activities than that of MnSA -N4 -C. Based on experimental and theoretical results, these multi-enzyme-like behaviors are highly dependent on the coordination number of single atomic Mn sites by local charge polarization. As a consequence, a series of colorimetric biosensing platforms based on MnSA -N3 -C SAzymes is successfully built for specific recognition of biological molecules. These findings provide atomic-level insight into the microenvironment of nanozymes, promoting rational design of other demanding biocatalysts.

Crystal Facet-Manipulated 2D Pt Nanodendrites to Achieve an Intimate Heterointerface for Hydrogen Evolution Reactions.

Despite the Pt-catalyzed alkaline hydrogen evolution reaction (HER) progressing via oxophilic metal-hydroxide surface hybridization, maximizing Pt reactivity alongside operational stability is still unsatisfactory due to the lack of well-designed and optimized interface structures. Producing atomically flat two-dimensional Pt nanodendrites (2D-PtNDs) through our 2D nanospace-confined synthesis strategy, this study tackles the insufficient interfacial contact effect during HER catalysis by realizing an area-maximized and firmly bound lateral heterointerface with NiFe-layered double hydroxide (LDH). The well-oriented {110} crystal surface exposure of Pt promotes electronic interplay that bestows strong LDH binding. The charge-relocated interfacial bond in 2D-PtND/LDH accelerates the hydrogen generation steps and achieves nearly the highest reported Pt mass activity enhancement (∼11.2 times greater than 20 wt % Pt/C) and significantly improved long-term operational stability. This work uncovers the importance of the shape and facet of Pt to create heterointerfaces that provide catalytic synergy for efficient hydrogen production.

A Versatile Strategy for Achieving Fast-Charging Batteries via Interfacial Engineering: Pseudocapacitive Potassium Storage without Nanostructuring.

The rapid transport of alkali ions in electrodes is a long-time dream for fast-charging batteries. Though electrode nanostructuring has increased the rate-capability, its practical use is limited because of the low tap density and severe irreversible reactions. Therefore, development of a strategy to design fast-charging micron-sized electrodes without nanostructuring is of significant importance. Herein, a simple and versatile strategy to accelerate the alkali ion diffusion behavior in micron-sized electrode is reported. It is demonstrated that the diffusion rate of K+ ions is significantly improved at the hetero-interface between orthorhombic Nb2 O5 (001) and monoclinic MoO2 (110) planes. Lattice distortion at the hetero-interface generates an inner space large enough for the facile transport of K+ ions, and electron localization near oxygen-vacant sites further enhances the ion diffusion behavior. As a result, the interfacial-engineered micron-sized anode material achieves an outstanding rate capability in potassium-ion batteries (KIBs), even higher than nanostructured orthorhombic Nb2 O5  which is famous for fast-charging electrodes. This is the first study to develop an intercalation pseudocapacitive micron-sized anode without nanostructuring for fast-charging and high volumetric energy density KIBs. More interestingly, this strategy is not limited to K+ ion, but also applicable to Li+ ion, implying the versatility of interfacial engineering for alkali ion batteries.

Disordered-Layer-Mediated Reverse Metal-Oxide Interactions for Enhanced Photocatalytic Water Splitting.

In heterogeneous catalysts, metal-oxide interactions occur spontaneously but often in an undesired way leading to the oxidation of metal nanoparticles. Manipulating such interactions to produce highly active surface of metal nanoparticles can warrant the optimal catalytic activity but has not been established to date. Here we report that a prior reduced TiO2 support can reverse the interaction with Pt nanoparticles and augment the metallic state of Pt, exhibiting a 3-fold increase in hydrogen production rate compared to that of conventional Pt/TiO2. Spatially resolved electron energy loss spectroscopy of the Ti valence state and the electron density distribution within Pt nanoparticles provide direct evidence supporting that the Pt/TiO2/H2O triple junctions are the most active catalytic sites for water reduction. Our reverse metal-oxide interaction scheme provides a breakthrough in the stagnated hydrogen production efficiency and can be applied to other heterogeneous catalyst systems composed of metal nanoparticles with reducible oxide supports.

Precise Modulation of Triple-Phase Boundaries towards a Highly Functional Exsolved Catalyst for Dry Reforming of Methane under a Dilution-Free System.

Dry reforming of methane (DRM) has been emerging as a viable solution to achieving carbon neutrality enhanced by the Paris Agreement as it converts the greenhouse gases of CO2 and CH4 into industrially useful syngas. However, there have been limited studies on the DRM catalyst under mild operating conditions with a high dilution gas ratio due to their deactivation from carbon coking and metal sintering. Herein, we apply the triple-phase boundary (TPB) concept to DRM catalyst via exsolution phenomenon that can secure elongated TPB by controlling the Fe-doping ratio in perovskite oxide. Remarkably, the exsolved catalyst with prolongated TPB shows exceptional CO2 and CH4 conversion rates of 95.9 % and 91.6 %, respectively, stable for 1000 hours under a dilution-free system. DFT calculations confirm that the Lewis acid of support and Lewis base of metal at the TPB promote the adsorption of reactants, resulting in lowering the overall CO2 dissociation and CH4 dehydrogenation energy.

Polymer Interface-Dependent Morphological Transition toward Two-Dimensional Porous Inorganic Nanocoins as an Ultrathin Multifunctional Layer for Stable Lithium-Sulfur Batteries.

Two-dimensional (2D) porous inorganic nanomaterials have intriguing properties as a result of dimensional features and high porosity, but controlled production of circular 2D shapes is still challenging. Here, we designed a simple approach to produce 2D porous inorganic nanocoins (NCs) by integrating block copolymer (BCP) self-assembly and orientation control of microdomains at polymer-polymer interfaces. Multicomponent blends containing BCP and homopoly(methyl methacrylate) (hPMMA) are designed to undergo macrophase separation followed by microphase separation. The balanced interfacial compatibility of BCP allows perpendicularly oriented lamellar-assembly at the interfaces between BCP-rich phase and hPMMA matrix. Disassembly of lamellar structures and calcination yield ultrathin 2D inorganic NCs that are perforated by micropores. This approach enables control of the thickness, size, and chemical composition of the NCs. 2D porous and acidic aluminosilicate NC (AS-NC) is used to fabricate an ultrathin and lightweight functional separator for lithium-sulfur batteries. The AS-NC layer acts as an ionic sieve to selectively block lithium polysulfides. Abundant acid sites chemically capture polysulfides, and micropores physically exclude them, so sulfur utilization and cycle stability are increased.

Tailoring Binding Abilities by Incorporating Oxophilic Transition Metals on 3D Nanostructured Ni Arrays for Accelerated Alkaline Hydrogen Evolution Reaction.

Developing efficient and inexpensive electrocatalysts for the hydrogen evolution reaction (HER) in alkaline water electrolysis plays a key role for renewable hydrogen energy technology. The slow reaction kinetics of HER in alkaline solutions, however, has hampered advances in high-performance hydrogen production. Herein, we investigated the trends in HER activity with respect to the binding energies of Ni-based thin film catalysts by incorporating a series of oxophilic transition metal atoms. It was found that the doping of oxophilic atoms enables the modulation of binding abilities of hydrogen and hydroxyl ions on the Ni surfaces, leading to the first establishment of a volcano relation between OH-binding energies and alkaline HER activities. In particular, Cr-incorporated Ni catalyst shows optimized OH-binding as well as H-binding energies for facilitating water dissociation and improving HER activity in alkaline media. Further enhancement of catalytic performance was achieved by introducing an array of three-dimensional (3D) Ni nanohelixes (NHs) that provide abundant surface active sites and effective channels for charge transfer and mass transport. The Cr dopants incorporated into the Ni NHs accelerate the dissociative adsorption process of water, resulting in remarkably enhanced catalytic activities in alkaline medium. Our approach can provide a rational design strategy and experimental methodology toward efficient bimetallic electrocatalysts for alkaline HER using earth-abundant elements.

Progress of Exsolved Metal Nanoparticles on Oxides as High Performance (Electro)Catalysts for the Conversion of Small Molecules.

Utilizing electricity and heat from renewable energy to convert small molecules into value-added chemicals through electro/thermal catalytic processes has enormous socioeconomic and environmental benefits. However, the lack of catalysts with high activity, good long-term stability, and low cost strongly inhibits the practical implementation of these processes. Oxides with exsolved metal nanoparticles have recently been emerging as promising catalysts with outstanding activity and stability for the conversion of small molecules, which provides new possibilities for application of the processes. In this review, it starts with an introduction on the mechanism of exsolution, discussing representative exsolution materials, the impacts of intrinsic material properties and external environmental conditions on the exsolution behavior, and the driving forces for exsolution. The performances of exsolution materials in various reactions, such as alkane reforming reaction, carbon monoxide oxidation, carbon dioxide utilization, high temperature steam electrolysis, and low temperature electrocatalysis, are then summarized. Finally, the challenges and future perspectives for the development of exsolution materials as high-performance catalysts are discussed.

Effective Screening Route for Highly Active and Selective Metal-Nitrogen-Doped Carbon Catalysts in CO2 Electrochemical Reduction.

To identify high-efficiency metal-nitrogen-doped (M-N-C) electrocatalysts for the electrochemical CO2 -to-CO reduction reaction (CO2 RR), a method that uses density functional theory calculation is presented to evaluate their selectivity, activity, and structural stability. Twenty-three M-N4 -C catalysts are evaluated, and three of them (M = Fe, Co, or Ni) are identified as promising candidates. They are synthesized and tested as proof-of-concept catalysts for CO2 -to-CO conversion. Different key descriptors, including the maximum reaction energy, differences of the *H and *CO binding energy (ΔG*H -ΔG*CO ), and *CO desorption energy (ΔG*CO→CO( g ) ), are used to clarify the reaction mechanism. These computational descriptors effectively predict the experimental observations in the entire range of electrochemical potential. The findings provide a guideline for rational design of heterogeneous CO2 RR electrocatalysts.

High-Efficiency Anion-Exchange Membrane Water Electrolyzer Enabled by Ternary Layered Double Hydroxide Anode.

Developing high-efficiency and low-cost oxygen-evolving electrodes in anion exchange membrane (AEM) water electrolysis technology is one of the major challenges. Herein, it is demonstrated that the surface corrosion of a conventional Ni foam electrode in the presence of Fe3+ and V3+ cations can transform it into an electrode with a high catalytic performance for oxygen evolution reaction (OER). The corroded electrode consists of a ternary NiFeV layered double hydroxide (LDH) nanosheet array supported on the Ni foam surface. This NiFeV LDH electrode achieves an OER current density of 100 mA cm-2 at an overpotential of 272 mV in 1 m KOH, outperforming the IrO2 catalyst by 180 mV. Density functional theory calculations reveal that the unique structure and the presence of vanadium in NiFeV LDH play a key role in achieving improved OER activity. When coupled with a commercial Pt/C cathode catalyst, the resulting AEM water electrolyzer achieves a cell current density as high as 2.1 A cm-2 at a voltage of only 1.8 Vcell in 1 m KOH, which is similar to the performance of the proton exchange membrane water electrolyzer obtained from the IrO2 and Pt/C catalysts pair.

Interface-Dominated Topological Transport in Nanograined Bulk Bi2 Te3.

3D topological insulators (TI) host surface carriers with extremely high mobility. However, their transport properties are typically dominated by bulk carriers that outnumber the surface carriers by orders of magnitude. A strategy is herein presented to overcome the problem of bulk carrier domination by using 3D TI nanoparticles, which are compacted by hot pressing to macroscopic nanograined bulk samples. Bi2 Te3 nanoparticles well known for their excellent thermoelectric and 3D TI properties serve as the model system. As key enabler for this approach, a specific synthesis is applied that creates nanoparticles with a low level of impurities and surface contamination. The compacted nanograined bulk contains a high number of interfaces and grain boundaries. Here it is shown that these samples exhibit metallic-like electrical transport properties and a distinct weak antilocalization. A downward trend in the electrical resistivity at temperatures below 5 K is attributed to an increase in the coherence length by applying the Hikami-Larkin-Nagaoka model. THz time-domain spectroscopy reveals a dominance of the surface transport at low frequencies with a mobility of above 103 cm2 V-1 s-1 even at room temperature. These findings clearly demonstrate that nanograined bulk Bi2 Te3 features surface carrier properties that are of importance for technical applications.

The association between L1 skeletal muscle index derived from routine CT and in-hospital mortality in CAP patients in the ED.

INTRODUCTION: Low muscle mass is associated with an increased mortality risk due to medical comorbidities such as chronic obstructive pulmonary disease, cardiovascular disease, and cerebrovascular disease. Computed tomography (CT) has been identified as the gold standard for measuring body composition. We evaluated the relationship between the L1 SMI measured from CT and in-hospital mortality in patients with community-acquired pneumonia (CAP). METHODS: From January 2015 to June 2015, 311 patients who were diagnosed with CAP and underwent CT in the ED were retrospectively analyzed. Multivariate binary logistic regression analysis was used to assess independent predictors of in-hospital mortality. All variables with a significance level < 0.1 by univariate analysis were included in a multivariate logistic regression model. The primary outcome was all-cause in-hospital mortality. RESULTS: Among the 311 patients, 33 (10.6%) died. We divided the patients into two groups based on the optimal sex-specific cut-off value of the L1 SMI (45 cm2/m2 in males and 40 cm2/m2 in females). A low L1 SMI was present in 90 (28.9%) of the 311 patients. In multivariate analysis, low L1 SMI, diabetes mellitus, albumin and APACHE II score were significantly associated with in-hospital mortality (aOR 3.39, 3.73, 0.09 and 1.10, respectively). CONCLUSION: SMI assessment at L1 is achievable in patients with CAP receiving routine chest CT, and the L1 SMI is associated with high in-hospital mortality, more hospitalizations and ventilator application in patients with CAP in the ED. This could help establish an early strategy for critical care of patients with L1 SMI obtained by chest CT for diagnosis in CAP patients in the ED.

Probing One-Dimensional Oxygen Vacancy Channels Driven by Cation-Anion Double Ordering in Perovskites.

Visualizing the oxygen vacancy distributions is highly desirable for understanding the atomistic oxygen diffusion mechanisms in perovskites. In particular, the direct observation of the one-dimensional oxygen vacancy channels has not yet been achieved in perovskites with dual ion (i.e., cation and anion) ordering. Here, we perform atomic-resolution imaging of the one-dimensional oxygen vacancy channels and their structural dynamics in a NdBaCo2O5.5 double perovskite oxide. An in situ heating transmission electron microscopy investigation reveals the disordering of oxygen vacancy channels by local rearrangement of oxygen vacancies at the specific temperature. A density functional theory calculation suggests that the possible pathway of oxygen vacancy migration is a multistep route via Co-O and Nd-Ov (oxygen vacancy) sites. These findings could provide robust guidance for understanding the static and dynamic behaviors of oxygen vacancies in perovskite oxides.

Enhancing Thermocatalytic Activities by Upshifting the d-Band Center of Exsolved Co-Ni-Fe Ternary Alloy Nanoparticles for the Dry Reforming of Methane.

Dry reforming of methane (DRM) is a feasible solution to address the reduction of greenhouse gases stipulated by the Paris Climate Agreement, given that it adds value by converting trivial gases, CO2 and CH4 , simultaneously into useful syngas. However, the conventional Ni catalyst undergoes deactivation due to carbon coking and particle agglomeration. Here we demonstrate a highly efficient and durable DRM catalyst: exsolved Co-Ni-Fe ternary alloy nanoparticles on the layered perovskite PrBaMn1.7 Co0.1 Ni0.2 O5+δ produced by topotactic exsolution. This method readily allows the generation of a larger number of exsolved nanoparticles with enhanced catalytic activity above that of Ni monometallic and Co-Ni bimetallic particles. The enhancement is achieved by the upshift of the d-band center of Co-Ni-Fe relative to those of Co-Ni and Ni, meaning easier charge donation to the adsorbate. Furthermore, the exsolved catalyst shows exceptional stability, with continuous DRM operation for about 350 hours.