Classical monocyte ontogeny dictates their functions and fates as tissue macrophages.

Classical monocytes (CMs) are ephemeral myeloid immune cells that circulate in the blood. Emerging evidence suggests that CMs can have distinct ontogeny and originate from either granulocyte-monocyte- or monocyte-dendritic-cell progenitors (GMPs or MDPs). Here, we report surface markers that allowed segregation of murine GMP- and MDP-derived CMs, i.e., GMP-Mo and MDP-Mo, as well as their functional characterization, including fate definition following adoptive cell transfer. GMP-Mo and MDP-Mo yielded an equal increase in homeostatic CM progeny, such as blood-resident non-classical monocytes and gut macrophages; however, these cells differentially seeded various other selected tissues, including the dura mater and lung. Specifically, GMP-Mo and MDP-Mo differentiated into distinct interstitial lung macrophages, linking CM dichotomy to previously reported pulmonary macrophage heterogeneity. Collectively, we provide evidence for the existence of two functionally distinct CM subsets in the mouse that differentially contribute to peripheral tissue macrophage populations in homeostasis and following challenge.

Tafenoquine-Atovaquone Combination Achieves Radical Cure and Confers Sterile Immunity in Experimental Models of Human Babesiosis.

Human babesiosis is a potentially fatal tick-borne disease caused by intraerythrocytic Babesia parasites. The emergence of resistance to recommended therapies highlights the need for new and more effective treatments. Here we demonstrate that the 8-aminoquinoline antimalarial drug tafenoquine inhibits the growth of different Babesia species in vitro, is highly effective against Babesia microti and Babesia duncani in mice and protects animals from lethal infection caused by atovaquone-sensitive and -resistant B. duncani strains. We further show that a combination of tafenoquine and atovaquone achieves cure with no recrudescence in both models of human babesiosis. Interestingly, elimination of B. duncani infection in animals following drug treatment also confers immunity to subsequent challenge. Altogether, the data demonstrate superior efficacy of tafenoquine plus atovaquone combination over current therapies for the treatment of human babesiosis and highlight its potential in providing protective immunity against Babesia following parasite clearance.

Microbe-disease associations prediction by graph regularized non-negative matrix factorization with L 2 , 1 $$ {L}_{2,1} $$ norm regularization terms.

Microbes are involved in a wide range of biological processes and are closely associated with disease. Inferring potential disease-associated microbes as the biomarkers or drug targets may help prevent, diagnose and treat complex human diseases. However, biological experiments are time-consuming and expensive. In this study, we introduced a new method called iPALM-GLMF, which modelled microbe-disease association prediction as a problem of non-negative matrix factorization with graph dual regularization terms and L 2 , 1 $$ {L}_{2,1} $$ norm regularization terms. The graph dual regularization terms were used to capture potential features in the microbe and disease space, and the L 2 , 1 $$ {L}_{2,1} $$ norm regularization terms were used to ensure the sparsity of the feature matrices obtained from the non-negative matrix factorization and to improve the interpretability. To solve the model, iPALM-GLMF used a non-negative double singular value decomposition to initialize the matrix factorization and adopted an inertial Proximal Alternating Linear Minimization iterative process to obtain the final matrix factorization results. As a result, iPALM-GLMF performed better than other existing methods in leave-one-out cross-validation and fivefold cross-validation. In addition, case studies of different diseases demonstrated that iPALM-GLMF could effectively predict potential microbial-disease associations. iPALM-GLMF is publicly available at https://github.com/LiangzheZhang/iPALM-GLMF.

Myoglobin deficiency impairs maximal oxygen uptake and exercise performance: a lesson from Mb-/- mice.

Myoglobin (Mb) plays an important role at rest and during exercise as a reservoir of oxygen and has been suggested to regulate NO• bioavailability under hypoxic/acidic conditions. However, its ultimate role during exercise is still a subject of debate. We aimed to study the effect of Mb deficiency on maximal oxygen uptake ( V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_2}\max }}$ ) and exercise performance in myoglobin knockout mice (Mb-/- ) when compared to control mice (Mb+/+ ). Furthermore, we also studied NO• bioavailability, assessed as nitrite (NO2 - ) and nitrate (NO3 - ) in the heart, locomotory muscle and in plasma, at rest and during exercise at exhaustion both in Mb-/- and in Mb+/+ mice. The mice performed maximal running incremental exercise on a treadmill with whole-body gas exchange measurements. The Mb-/- mice had lower body mass, heart and hind limb muscle mass (P < 0.001). Mb-/- mice had significantly reduced maximal running performance (P < 0.001). V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_2}\max }}$ expressed in ml min-1 in Mb-/ - mice was 37% lower than in Mb+/+ mice (P < 0.001) and 13% lower when expressed in ml min-1  kg body mass-1 (P = 0.001). Additionally, Mb-/- mice had significantly lower plasma, heart and locomotory muscle NO2 - levels at rest. During exercise NO2 - increased significantly in the heart and locomotory muscles of Mb-/- and Mb+/+ mice, whereas no significant changes in NO2 - were found in plasma. Our study showed that, contrary to recent suggestions, Mb deficiency significantly impairs V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_2}\max }}$ and maximal running performance in mice. KEY POINTS: Myoglobin knockout mice (Mb-/- ) possess lower maximal oxygen uptake ( V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_2}\max }}$ ) and poorer maximal running performance than control mice (Mb+/+ ). Respiratory exchange ratio values at high running velocities in Mb-/- mice are higher than in control mice suggesting a shift in substrate utilization towards glucose metabolism in Mb-/- mice at the same running velocities. Lack of myoglobin lowers basal systemic and muscle NO• bioavailability, but does not affect exercise-induced NO2 - changes in plasma, heart and locomotory muscles. The present study demonstrates that myoglobin is of vital importance for V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_2}\max }}$ and maximal running performance as well as explains why previous studies have failed to prove such a role of myoglobin when using the Mb-/- mouse model.

OsMADS5 interacts with OsSPL14/17 to inhibit rice root elongation by restricting cell proliferation of root meristem under ammonium supply.

Nitrogen (N) is a vital major nutrient for rice (Oryza sativa). Rice responds to different applications of N by altering its root morphology, including root elongation. Although ammonium ( NH 4 + ) is the primary source of N for rice, NH 4 + is toxic to rice roots and inhibits root elongation. However, the precise molecular mechanism that NH 4 + -inhibited root elongation of rice is not well understood. Here, we identified a rice T-DNA insert mutant of OsMADS5 with a longer seminal root (SR) under sufficient N conditions. Reverse-transcription quantitative PCR analysis revealed that the expression level of OsMADS5 was increased under NH 4 + compared with NO 3 - supply. Under NH 4 + conditions, knocking out OsMADS5 (cas9) produced a longer SR, phenocopying osmads5, while there was no significant difference in SR length between wild-type and cas9 under NO 3 - supply. Moreover, OsMADS5-overexpression plants displayed the opposite SR phenotype. Further study demonstrated that enhancement of OsMADS5 by NH 4 + supply inhibited rice SR elongation, likely by reducing root meristem activity of root tip, with the involvement of OsCYCB1;1. We also found that OsMADS5 interacted with OsSPL14 and OsSPL17 (OsSPL14/17) to repress their transcriptional activation by attenuating DNA binding ability. Moreover, loss of OsSPL14/17 function in osmads5 eliminated its stimulative effect on SR elongation under NH 4 + conditions, implying OsSPL14/17 may function downstream of OsMADS5 to mediate rice SR elongation under NH 4 + supply. Overall, our results indicate the existence of a novel modulatory pathway in which enhancement of OsMADS5 by NH 4 + supply represses the transcriptional activities of OsSPL14/17 to restrict SR elongation of rice.

Refining flowering date enhances sesame yield independently of day-length.

BACKGROUND: The transition from vegetative to reproductive growth is a key factor in yield maximization. Sesame (Sesamum indicum), an indeterminate short-day oilseed crop, is rapidly being introduced into new cultivation areas. Thus, decoding its flowering mechanism is necessary to facilitate adaptation to environmental conditions. In the current study, we uncover the effect of day-length on flowering and yield components using F 2 populations segregating for previously identified quantitative trait loci (Si_DTF QTL) confirming these traits. RESULTS: Generally, day-length affected all phenotypic traits, with short-day preceding days to flowering and reducing yield components. Interestingly, the average days to flowering required for yield maximization was 50 to 55 days, regardless of day-length. In addition, we found that Si_DTF QTL is more associated with seed-yield and yield components than with days to flowering. A bulk-segregation analysis was applied to identify additional QTL differing in allele frequencies between early and late flowering under both day-length conditions. Candidate genes mining within the identified major QTL intervals revealed two flowering-related genes with different expression levels between the parental lines, indicating their contribution to sesame flowering regulation. CONCLUSIONS: Our findings demonstrate the essential role of flowering date on yield components and will serve as a basis for future sesame breeding.

MARVEL analysis of high-resolution rovibrational spectra of 13 C 16 O 2 .

A set of empirical rovibrational energy levels, obtained through the MARVEL (measured active rotational-vibrational energy levels) procedure, is presented for the 13 C 16 O 2 isotopologue of carbon dioxide. This procedure begins with the collection and analysis of experimental rovibrational transitions from the literature, allowing for a comprehensive review of the literature on the high-resolution spectroscopy of 13 C 16 O 2 , which is also presented. A total of 60 sources out of more than 750 checked provided 14,101 uniquely measured and assigned rovibrational transitions in the wavenumber range of 579-13,735 cm - 1 . This is followed by a weighted least-squares refinement yielding the energy levels of the states involved in the measured transitions. Altogether 6318 empirical rovibrational energies have been determined for 13 C 16 O 2 . Finally, estimates have been given for the uncertainties of the empirical energies, based on the experimental uncertainties of the transitions. The detailed analysis of the lines and the spectroscopic network built from them, as well as the uncertainty estimates, all serve to pinpoint possible errors in the experimental data, such as typos, misassignment of quantum numbers, and misidentifications. Errors found in the literature data were corrected before including them in the final MARVEL dataset and analysis.

Jahn-Teller distortion, octahedra rotations and orbital ordering in perovskites: KScF 3 as a model system.

The KScF 3 perovskite has been used as a model for investigating the relative importance of the Jahn-Teller (JT) lift of degeneracy, the ScF 6 octahedra rotation (OR), and the quadrupole-quadrupole interaction linked to different occupancy of the Sc t 2 g subshell in various sites of the unit cell (orbital ordering, OO). The group-subgroup sequence P m 3 ¯ m , P 4 m m m , P 4 m b m , and P n m a , supplemented by C m m m and I 4 m c m , has been explored by using an all electron Gaussian type basis set, hybrid functionals, and the CRYSTAL17 code. The JT lift of degeneracy provides a stabilization about 5 times larger than the sum of the OO and OR effects. The energy gained in the transition from P 4 m m m to P 4 m b m , consisting in a rotation of the octahedra around the c axis, is 1077 µ E h . From P 4 m b m to P n m a , additional rotations around the a and b axes are possible, and the d Sc electron can occupy a different t 2 g orbital, with a total energy reduction of 2318 µ E h . The rotation of the octahedra reduces the strength of superexchange: in going from P 4 m m m to P n m a the G-AFM stabilization with respect to FM shrinks by a factor 4.

Effect of Crystal Transformation on the Intrinsic Defects and the Microwave Absorption Performance of Mo2 TiC2 Tx /RGO Microspheres.

The nitrides and carbides of transition metals are highly favored due to their excellent physical and chemical properties, among which MXene is a hot research topic for microwave absorption. Herein, the controlled preparation of 3D Mo2 TiC2 Tx -based microspheres toward microwave absorption is reported for the first time. With the merits of the performances of both reduced graphite oxide (RGO) and MXene sufficiently considered, the influence of carbonization temperature on the internal crystal structure and the effective microwave-material interaction surface of the prepared Mo2 TiC2 Tx /RGO is systematically investigated. The structure-activity relationships relating the apparent morphology and crystal structure to the microwave absorption performance are deeply explored, and the wave absorption mechanism is put forward as well. The results show that the Mo2 TiC2 Tx /RGO-700 product obtained after heating treatment at 700 °C exhibits excellent microwave absorption performance, with the RLmin being up to -55.1 dB@2.1 mm@13.8 GHz, and the corresponding effective absorption bandwidth covering 5.7 GHz. The outstanding microwave absorption characteristics are attributed to the appropriate impedance matching, high specific surface area, rich intrinsic defects, desirable conductivity, and strong multipolarization capabilities. This work enriches the types of MXene-based composite absorbers and provides a new strategy for controlled preparation of high-performance 3D composite absorbers.

High-Rate Nonaqueous Mg-CO2 Batteries Enabled by Mo2 C-Nanodot-Embedded Carbon Nanofibers.

The widespread acceptance of nonaqueous rechargeable metal-gas batteries, known for their remarkably high theoretical energy density, faces obstacles such as poor reversibility and low energy efficiency under high charge-discharge current densities. To tackle these challenges, a novel catalytic cathode architecture for Mg-CO2 batteries, fabricated using a one-pot electrospinning method followed by heat treatment, is presented. The resulting structure features well-dispersed molybdenum carbide nanodots embedded within interconnected carbon nanofibers, forming a 3D macroporous conducting network. This cathode design enhances the volumetric efficiency, enabling effective discharge product deposition, while also improving electrical properties and boosting catalytic activity. This enhancement results in high discharge capacities and excellent rate capabilities, while simultaneously minimizing voltage hysteresis and maximizing energy efficiency. The battery exhibits a stable cycle life of over 250 h at a current density of 200 mA g-1 with a low initial charge-discharge voltage gap of 0.72 V. Even at incredibly high current densities, reaching 1600 mA g-1 , the battery maintains exceptional performance. These findings highlight the crucial role of cathode architecture design in enhancing the performance of Mg-CO2 batteries and hold promise for improving other metal-gas batteries that involve deposition-decomposition reactions.

Current Progress of Mo-Based Metal Organic Frameworks Derived Electrocatalysts for Hydrogen Evolution Reaction.

As an important half-reaction for electrochemical water splitting, electrocatalytic hydrogen evolution reaction suffers from sluggish kinetics, and it is still urgent to search high efficiency non-platinum-based electrocatalysts. Mo-based catalysts such as Mo2 C, MoO2 , MoP, MoS2 , and MoNx have emerged as promising alternatives to Pt/C owing to their similar electronic structure with Pt and abundant reserve of Mo. On the other hand, due to the adjustable topology, porosity, and nanostructure of metal organic frameworks (MOFs), MOFs are extensively used as precursors to prepare nano-electrocatalysts. In this review, for the first time, the progress of Mo-MOFs-derived electrocatalysts for hydrogen evolution reaction is summarized. The preparation method, structures, and catalytic performance of the catalysts are illustrated based on the types of the derived electrocatalysts including Mo2 C, MoO2 , MoP, MoS2 , and MoNx . Especially, the commonly used strategies to improve catalytic performance such as heteroatoms doping, constructing heterogeneous structure, and composited with noble metal are discussed. Moreover, the opportunities and challenges in this area are proposed to guide the designment and development of Mo-based MOF derived electrocatalysts.

Phase-Transition of Mo2C Induced by Tungsten Doping as Heterointerface-Rich Electrocatalyst for Optimizing Hydrogen Evolution Activity.

Electrochemical hydrogen evolution reaction (HER) from water splitting driven by renewable energy is considered a promising method for large-scale hydrogen production, and as an alternative to noble-metal electrocatalysts, molybdenum carbide (Mo2C) has exhibited effective HER performance. However, the strong bonding strength of intermediate adsorbed H (Hads) with Mo active site slows down the HER kinetics of Mo2C. Herein, using phase-transition strategy, hexagonal ß-Mo2C could be easily transferred to cubic δ-Mo2C through electron injection triggered by tungsten (W) doping, and heterointerface-rich Mo2C-based composites, including ß-Mo2C, δ-Mo2C, and MoO2, are presented. Experimental results and density functional theory calculations reveal that W doping mainly contributes to the phase-transition process, and the generated heterointerfaces are the dominant factor in inducing remarkable electron accumulation around Mo active sites, thus weakening the Mo─H coupling. Wherein, the ß-Mo2C/MoO2 interface plays an important role in optimizing the electronic structure of Mo 3d orbital and hydrogen adsorption Gibbs free energy (ΔGH*), enabling these Mo2C-based composites to have excellent intrinsic catalytic activity like low overpotential (η10 = 99.8 mV), small Tafel slope (60.16 dec-1), and good stability in 1 m KOH. This work sheds light on phase-transition engineering and offers a convenient route to construct heterointerfaces for large-scale HER production.

Synergetic Effect of Mo-Doped and Oxygen Vacancies Endows Vanadium Oxide with High-Rate and Long-Life for Aqueous Zinc Ion Battery.

Vanadium (V)-based oxides have garnered significant attention as cathode materials for aqueous zinc-ion batteries (AZIBs) due to their multiple valences and high theoretical capacity. However, their sluggish kinetics and low conductivity remain major obstacles to practical applications. In this study, Mo-doped V2O3 with oxygen vacancies (OVs, Mo-V2O3-x@NC) is prepared from a Mo-doped V-metal organic framework. Ex situ characterizations reveal that the cathode undergoes an irreversible phase transformation from Mo-V2O3-x to Mo-V2O5-x·nH2O and serves as an active material exhibiting excellent Zn2+ storage in subsequent charge-discharge cycles. Mo-doped helps to further improve cycling stability and increases with increasing content. More importantly, the synergistic effect of Mo-doped and OVs not only effectively reduces the Zn2+ migration energy barrier, but also enhances reaction kinetics, and electrochemical performance. Consequently, the cathode demonstrates ultrafast electrochemical kinetics, showing a superior rate performance (190.9 mAh g-1 at 20 A g-1) and excellent long-term cycling stability (147.9 mAh g-1 at 20 A g-1 after 10000 cycles). Furthermore, the assembled pouch cell exhibits excellent cycling stability (313.6 mAh g-1 at 1 A g-1 after 1000 cycles), indicating promising application prospects. This work presents an effective strategy for designing and fabricating metal and OVs co-doped cathodes for high-performance AZIBs.

Releasing Au Electrons to Mo Site for Weakened Mo─H Bond of Mo2C MXene Cocatalyst Toward Improved Photocatalytic H2 Production.

Mo2C MXene (Mo2CTx) is one of the most promising noble-metal-free cocatalysts for photocatalytic H2 production because of its excellent electron transport capacity and abundant Mo sites. However, Mo2CTx typically exhibits a strong Mo─Hads bond, resulting in that the produced H2 difficultly desorbs from the Mo surface for the limited activity. To effectively weaken the Mo─Hads bond, in this paper, a regulation strategy of electron donor Au releasing electrons to the d-orbitals of Mo sites in Mo2CTx is proposed. Herein, the Mo2CTx-Au/CdS photocatalysts are prepared through a two-step process, including the initial loading of Au nanoparticles on the Mo2CTx surface and the subsequent in situ growth of CdS onto the Mo2CTx-Au surface. Photocatalytic measurements indicate that the maximal H2-production rate of Mo2CTx-Au/CdS reaches up to 2799.44 µmol g-1 h-1, which is 30.99 and 3.60 times higher than that of CdS and Mo2CTx/CdS, respectively. Experimental and theoretical data corroborate that metallic Au can transfer free electrons to Mo2CTx to generate electron-enriched Moδ- sites, thus causing the increased antibonding-orbital occupancy state and the weakened Mo─Hads bond for the boosted H2-production efficiency. This research provides a promising approach for designing Mo2CTx-based cocatalysts by regulating the antibonding-orbital occupancy of Mo sites for improved photocatalytic performance.

Amorphous Ni-Fe-Mo Oxides Coupled with Crystalline Metallic Domains for Enhanced Electrocatalytic Oxygen Evolution by Promoted Lattice-Oxygen Participation.

The crystalline/amorphous heterophase nanostructures are promising functional materials for biomedicals, catalysis, energy conversion, and storage. Despite great progress is achieved, facile synthesis of crystalline metal/amorphous multinary metal oxides nanohybrids remains challenging, and their electrocatalytic oxygen evolution reaction (OER) performance along with the catalytic mechanism are not systematically investigated. Herein, two kinds of ultrafine crystalline metal domains coupled with amorphous Ni-Fe-Mo oxides heterophase nanohybrids, including Ni/Ni0.5-a Fe0.5 Mo1.5 Ox and Ni-FeNi3 /Ni0.5-b Fe0.5-y Mo1.5 Ox , are fabricated through controllable reduction of amorphous Ni0.5 Fe0.5 Mo1.5 Ox precursors by simply tuning the amount of used reductant. Due to the suited component in metal domains, the special structure with dense crystalline/amorphous interfaces, and strong electronic coupling of their components, the resultant Ni-FeNi3 /Ni0.5-b Fe0.5-y Mo1.5 Ox nanohybrids show greatly enhanced OER activity with a low overpotential (278 mV) to reach 10 mA cm-2 current density and ultrahigh turnover frequency (38160 h-1 ), outperforming Ni/Ni0.5-a Fe0.5 Mo1.5 Ox , Ni0.5 Fe0.5 Mo1.5 Ox precursors, commercial IrO2 , and most of recently reported OER catalysts. Also, such Ni-FeNi3 /Ni0.5-b Fe0.5-y Mo1.5 Ox nanohybrids manifest good catalytic stability. As revealed by a series of spectroscopy and electrochemical analyses, their OER mechanism follows the lattice-oxygen-mediated (LOM) pathway. This work may shed light on the design of advanced heterophase nanohybrids, and promote their applications in water splitting, metal-air batteries, or other clean energy fields.

Regulating the Oxygen Vacancy and Electronic Structure of NiCo Layered Double Hydroxides by Molybdenum Doping for High-Power Hybrid Supercapacitors.

Amelioration of nickel-cobalt layered double hydroxides (NiCo-LDH) with a high specific theoretical capacitance is of great desire for high-power supercapacitors. Herein, a molybdenum (Mo) doping strategy is proposed to improve the charge-storage performance of NiCo-LDH nanosheets growing on carbon cloth (CC) via a rapid microwave process. The regulation of the electronic structure and oxygen vacancy of the LDH is consolidated by the density functional theory (DFT) calculation, which demonstrates that Mo doping narrows the band gap, reduces the formation energy of hydroxyl vacancies, and promotes ionic and charge transfer as well as electrolyte adsorption on the electrode surface. The optimal Mo-doped NiCo-LDH electrode (MoNiCo-LDH-0.05/CC) has an amazing specific capacity of 471.1 mA h g-1 at 1 A g-1 , and excellent capacity retention of 84.8% at 32 A g-1 , far superior to NiCo-LDH/CC (258.3 mA h g-1 and 76.4%). The constructed hybrid supercapacitor delivers an energy density of 103.3 W h kg-1 at a power density of 750 W kg-1 and retains the cycle retention of 85.2% after 5000 cycles. Two assembled devices in series can drive thirty LED lamps, revealing a potential application prospect of the rationally synthesized MoNiCo-LDH/CC as an energy-storage electrode material.

Atomically-Thin Holey 2D Nanosheets of Defect-Engineered MoN-Mo5 N6 Composites as Effective Hybridization Matrices.

The defect engineering of inorganic solids has received significant attention because of its high efficacy in optimizing energy-related functionalities. Consequently, this approach is effectively leveraged in the present study to synthesize atomically-thin holey 2D nanosheets of a MoN-Mo5 N6 composite. This is achieved by controlled nitridation of assembled MoS2 monolayers, which induced sequential cation/anion migration and a gradual decrease in the Mo valency. Precise control of the interlayer distance of the MoS2 monolayers via assembly with various tetraalkylammonium ions is found to be crucial for synthesizing sub-nanometer-thick holey MoN-Mo5 N6 nanosheets with a tunable anion/cation vacancy content. The holey MoN-Mo5 N6 nanosheets are employed as efficient immobilization matrices for Pt single atoms to achieve high electrocatalytic mass activity, decent durability, and low overpotential for the hydrogen evolution reaction (HER). In situ/ex situ spectroscopy and density functional theory (DFT) calculations reveal that the presence of cation-deficient Mo5 N6 domain is crucial for enhancing the interfacial interactions between the conductive molybdenum nitride substrate and Pt single atoms, leading to enhanced electron injection efficiency and electrochemical stability. The beneficial effects of the Pt-immobilizing holey MoN-Mo5 N6 nanosheets are associated with enhanced electronic coupling, resulting in improvements in HER kinetics and interfacial charge transfer.

Operando Spectroscopy Observation of Mo Clusters-Ti3 C2 TX Catalyst/Support Interface's Dynamic Evolution in Hydrogen Evolution Reaction.

The interaction between catalyst and support plays an important role in electrocatalytic hydrogen evolution (HER), which may explain the improvement in performance by phase transition or structural remodeling. However, the intrinsic behavior of these catalysts (dynamic evolution of the interface under bias, structural/morphological transformation, stability) has not been clearly monitored, while the operando technology does well in capturing the dynamic changes in the reaction process in real time to determine the actual active site. In this paper, nitrogen-doped molybdenum atom-clusters on Ti3 C2 TX (MoACs /N-Ti3 C2 TX ) is used as a model catalyst to reveal the dynamic evolution of MoAcs on Ti3 C2 TX during the HER process. Operando X-ray absorption structure (XAS) theoretical calculation and in situ Raman spectroscopy showed that the Mo cluster structure evolves to a 6-coordinated monatomic Mo structure under working conditions, exposing more active sites and thus improving the catalytic performance. It shows excellent HER performance comparable to that of commercial Pt/C, including an overpotential of 60 mV at 10 mA cm-2 , a small Tafel slope (56 mV dec-1 ), and high activity and durability. This study provides a unique perspective for investigating the evolution of species, interfacial migration mechanisms, and sources of activity-enhancing compounds in the process of electroreduction.

Decoding Upconversion-Emitting Phase in Complex Composites Through Single-Particle-Level Upconversion Imaging and Density Functional Theory Calculations.

The crystal structure and phase stability of a host lattice plays an important role in efficient upconversion phenomena. In stable hosts, lanthanides doping should not generally change the crystal structure of the host itself. But when phase of a system drastically changes after lanthanide doping resulting in multiple phases, accurate identification of upconverting phase remains a challenge. Herein, an attempt to synthesize lanthanide-doped NiMoO4 by microwave hydrothermal method produced MoO3/Yb2Mo4O15/NiMoO4 micro-nano composite upconversion phosphor. A combined approach of density functional theory (DFT) calculations and single-particle-level upconversion imaging has been employed to elucidate the phase stability of different phases and upconversion properties within the composite. Through single-particle-level imaging under 980 nm excitation, an unprecedented resolution in visualizing individual emitting and non-emitting regions within the composite has been achieved, thereby allowing to accurately assign the Yb2Mo4O15 as a sole upconversion emitting phase in the composite. Result of the DFT calculation further shows that the Yb2Mo4O15 phase is the most thermodynamically preferred over other lanthanide-doped phases in the composite. This comprehensive understanding not only advances the knowledge of upconversion emission from composite materials but also holds promise for tailoring optical properties of materials for various applications, including bioimaging, sensing, and photonics, where controlled light emission is crucial.

Transfer of High-Temperature-Sputtered BiFeO3 Thin Films onto Flexible Substrates Using α-MoO3 Layers.

Inducing external strains on highly oriented thin films transferred onto mechanically deformable substrates enables a drastic enhancement of their ferroelectric, magnetic, and electronic performances, which cannot be achieved in films on rigid single crystals. Herein, the growth and diffusion behaviors of BiFeO3 thin films grown at various temperatures is reported on α-MoO3 layers of different thicknesses using sputtering. When the BiFeO3 thin films are deposited at a high temperature, significant diffusion of Fe into α-MoO3 occurs, producing the Fe1.89Mo4.11O7 phase and suppressing the maintenance of the 2D structure of the α-MoO3 layers. Although lowering the deposition temperature alleviates the diffusion yielding the survival of the α-MoO3 layer, enabling exfoliation, the BiFeO3 is amorphous and the formation of the Fe1.89Mo4.11O7 phase cannot be suppressed at the crystallization temperature. High-temperature-grown BiFeO3 thin films are successfully transferred onto flexible substrates via mechanical exfoliation by introducing a blocking layer of Au and measured the ferroelectric properties of the transferred films.