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Iron or its oxides (FexOy) commonly exist in the ash of fossil fuel and biomass, and are used as oxygen carriers in chemical looping process, and Fe3O4 is a main occurrence. The NO reduction mechanisms by CO over Fe3O4 (111) surface was investigated via density functional theory (DFT) calculations. An optimized unit cell of Fe3O4 was constructed. The interaction between molecules and cell surface was described by the calculated adsorption properties and electronic structures. Results showed that the most stable adsorption of NO/CO belongs to chemisorption and NO has higher adsorption energy than CO. NO can be absorbed onto Fe3O4 surface to form (NO)2 dimer structure, which easily decomposes via a small energy barrier. (NO)2 dimer mechanism is a possible pathway for the reduction of NO by CO over Fe3O4, following three steps: 2NO → (NO)2*, (NO)2* → N2O + O*, O* + CO* → CO2. After the decomposition, the intermediate species N2O molecule and the remaining O atom adsorbed strongly on the Fe3O4 surface can be removed by CO. CO also promotes the gaseous decomposition of N2O. DFT results also showed O2 will prevent NO reduction reaction. The calculated reaction rate constants further verify the existence of (NO)2 dimer mechanism and the rate-limiting step is the removal of the surface O atom. [ABSTRACT FROM AUTHOR]

It has become increasingly popular in recent years to create improved functionalized nanomaterials in an effort to enhance their physicochemical, catalytic, and biological capabilities. In this study, eco-friendly, especially water dispersible metal ferrite (MFe2O4 (M: Cu, Ni, Cd, Mn, and Co)) supported bio-nanocomposites from hemp biomass were synthesized low-cost method by co-precipitation procedure. They were characterized by ATR-FTIR, XRD, SEM, TEM (STEM), EDX, VSM, Uv-Vis, and TG/DTG analyses. The variation of their ionic conductivity with temperature and concentration and also their catalytic effects against cationic dyes such as methylene blue (MB), crystal violet (CrV), and malachite green oxalate (MGO) were investigated. XRD patterns and FTIR spectra of the AHB-MFe2O4, especially the stretching of Fe-O and M-O, showed the formation of metal ferrite bio-nanocomposites. Also, interaction between the biomass and metal ferrite nanoparticles was obviously seen from XRD patterns and FTIR spectra of the AHB-MFe2O4. It was determined that AHB-MFe2O4 bio-nanocomposites have high thermal stability, high thermal stability, high ionic conductivity as 12–14 mS/cm (almost higher than that of the 0.1 M KCl) and negative surface charge. Moreover, they exhibited high catalytic performance against cationic dyes such as MB, CrV, and MGO in sun light by over 90%. [ABSTRACT FROM AUTHOR]

The present study imparts a quantitative kinetic assessment of the halogenations of thiazole and its two methyl derivatives namely 2-methylthiazole and 4-methylthiazole in aqueous medium. The kinetic study investigated the effect of bromide, chloride, and iodide ions on the bromination, chlorination, and iodination reactions respectively. Halogenated thiazole derivatives have substantial commercial importance in the medicinal and industrial fields due to their versatile reactivity linked to electronic distribution. Hence the kinetic study will assist in these applications. Halide ions have been found to exhibit a catalytic effect on the halogenation of thiazole and its methyl derivatives by respective molecular halogens. The catalytic effect has been determined based on rate constants and energy of activation for the halogenation reactions. The reaction mechanism is suggested owing to the catalytic effect of halide ions. [ABSTRACT FROM AUTHOR]

Solid‐state hydrogen storage using metal hydrides offers the potential for high energy storage capacities. However, the requirement for high‐temperature operations (above 400°C) and challenges with heat exchange are significant drawbacks. From this perspective, adsorption on porous materials presents a viable solution to these challenges. Carbon nanostructures, such as graphene and graphene oxide (GO) derivatives, are well‐suited for hydrogen storage because of their lightweight nature, low density, and large surface area. However, the primary obstacle for practical applications is the poor storage capacity of carbon nanostructures under ambient conditions. Utilizing a cost‐effective transition element such as nickel as a catalyst offers significant potential for storing hydrogen in atomic and molecular forms by invoking the spillover mechanism. Thermally reduced graphene oxide (TrGO) modifies the surface, providing abundant active sites that attract hydrogen effectively. Porous silicon (PS) enhances the surface properties of graphene sheets, attracting hydrogen to the surface. The current study assesses a synthesized TrGO, PS, and Ni composition to leverage their individual properties for hydrogen storage. Field‐emission scanning electron microscopy examines the sheet structure of TrGO (used as the host material) and the incorporation of PS and Ni on its surface. The calculated specific surface area of TrGO is ~450 m2 g−1. X‐ray diffraction is used to identify the various phases in the composition, while Raman spectroscopy measures the degree of disorder within the composition. The pressure‐composition isotherms reveal hydrogen storage capacities of ~6.53 wt% for the TrGO + PS composition and ~2.43 wt% for the TrGO + PS + Ni composition. Despite the decrease in weight percentage of TrGO + PS + Ni due to the higher Ni content, dissociation enhances the adsorption rate from 0.35 to 0.53 wt% h−1. [ABSTRACT FROM AUTHOR]

Pyroglutamate (pE)‐modified amyloid‐β (Aβ) peptides play a crucial role in the development of Alzheimer's disease. pEAβ3‐42 can rapidly form oligomers that gradually elongate hydrophobic segments to form β‐sheet‐rich amyloid intermediates, ultimately resulting in the formation of mature amyloid fibrils. pEAβ3‐42 can also catalyze the aggregation of Aβ species and subsequently accelerate the formation of amyloid senile plaques. Considering the recent clinical success of the pEAβ3‐42‐targeting antibody donanemab, molecules that strongly bind pEAβ3‐42 and prevent its aggregation and catalytic effect on Aβs may also provide potential therapeutic options for Alzheimer's disease. Here, we demonstrate that the natural antibiotic cyclopeptide tyrocidine A (TA) not only strongly inhibits the aggregation of Aβ1‐42 as previously reported, but also interacts with the hydrophobic C‐terminus and middle domain of pEAβ3‐42 to maintain an unordered conformation, effectively impeding the formation of initial oligomers and subsequently halting the aggregation of pEAβ3‐42. Furthermore, TA can disrupt the "catalytic effect" of pEAβ3‐42 on amyloid aggregates, effectively suppressing Aβ aggregation and ultimately preventing the pathological events induced by Aβs. [ABSTRACT FROM AUTHOR]

The current study focused on the design of an extremely sensitive electrochemical sensor of ascorbic acid based on a mixture of NiAl2O4-NiO nanoparticles that, produced in a single step using the sol–gel method, on an ITO electrode. This new sensing platform is useful for the detection of ascorbic acid with a wide range of concentrations extending from the attomolar to the molar. SEM micrographs show the porous structure of the NiAl2O4-NiO sample, with a high specific surface area, which is beneficial for the catalytic performance of the nanocomposite. An XRD diffractogram confirmed the existence of two phases, NiAl2O4 and NiO, both corresponding to the face-centred cubic crystal structure. The performances of the modified electrode, as a biomolecule, in the detection of ascorbic acid was evaluated electrochemically by cyclic voltammetry and chronoamperometry. The sensor exhibited a sensitive electrocatalytic response at a working potential of E = +0.3 V vs. Ag/Ag Cl, reaching a steady-state current within 30 s after each addition of ascorbic acid solution with a wide dynamic range of concentrations extending from attolevels (10−18 M) to molar (10 mM) and limits of detection and quantification of 1.2 × 10−18 M and 3.96 × 10−18 M, respectively. This detection device was tested for the quantification of ascorbic acid in a 500 mg vitamin C commercialized tablet that was not pre-treated. [ABSTRACT FROM AUTHOR]

[Display omitted] Sodium-selenium (Na-Se) batteries have gained attention due to their high energy density and power density, resulting from the liquid–liquid reaction at the interface in the dimethoxyethane electrolyte. Nevertheless, the pronounced shuttle effect of polyselenides causes low coulomb efficiency and inadequate cycling stability for Na-Se batteries. Herein, the iron nanoparticles surface modified accordion-like Ti 3 C 2 T x MXene (MXene/Fe) synthesized via the molten salt etching is utilized as the host of Se species for high-performance Na-Se battery cathode. Benefiting from the layered structure and chemical adsorption of accordion-like MXene, the shuttle effect of the cathode is effectively inhibited. Simultaneously, electrochemical kinetics is boosted due to the catalytic effect of Fe nanoparticles, which facilitate the transformation of polyselenide from long-chain to short-chain, contributing to pseudocapacitive capacity. Consequently, the Se-based cathode delivers a steady capacity of 575.0 mA h g−1 at 0.2 A/g, and even a high capacity of 500 mAh/g at 50 A/g based on the mass of Se@MXene/Fe electrode, indicating the ultrafast Na+ ion storage. Most notably, this structure demonstrated remarkable long-term cycling stability for 5000 cycles with a high capacity retention of 97.4 %. The electrochemical energy storage mechanism is further revealed by in situ Raman. Herein, the confinement-catalysis structure shines light on inhibiting shuttling and facilitating ultrafast ion storage. [ABSTRACT FROM AUTHOR]

The transition metal complexes of triaminoguanidine (TAGwhere M = Cobalt (Co) or Iron (Fe)) have been prepared. The catalytic effect of these complexes on the thermolysis of energetic composite based on nitrocellulose and diethylene glycol dinitrate? has been investigated. Extensive characterization of the resulting energetic composites was carried out sing scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Isoconversional kinetic analysis was performed to determine the Arrhenius parameters associated with the thermolysis of the elaborated energetic formulations. It is found that TAG-M complexes have strong catalytic effect on the thermokinetic decomposition of NC/DEGDN by decreasing the apparent activation energy and significantly increased the total heat release. The models that govern the decomposition processes are also studied, and it is revealed that different react io n processes are accomplished by introduction metal complexes of triaminoguanidine. Overall, this study serves as a valuable reference for future research focused on the investigation of catalytic combustion features of solid propellants. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries with advantages of high energy densities (2600 Wh·kg−1/2800 Wh·L−1) and sulfur abundance are regarded as promising candidates for next-generation high-energy batteries. However, the conventional carbon host used in sulfur cathodes suffers from poor chemical adsorption towards Li-polysulfides (LPS) in liquid electrolyte and sluggish redox kinetics, leading to low capacity and rate capability. Besides, carbon host used in Li metal anode with the intrinsic property of poor lithiophilicity and high Li-nucleation barrier gives rise to uncontrollable dendrite growth and further battery failure. Therefore, non-carbon hosts with chemical adsorption toward LPS and catalytic activity for accelerating LPS redox conversion as well as lithiophilic property for guiding uniform Li deposition are proposed and demonstrated a high efficiency in both sulfur cathodes and Li metal anodes. In this review, the principle and challenges of Li-S batteries are first presented, then recent work using non-carbon hosts in Li-S batteries is summarized comprehensively, and the mechanism of non-carbon host in improving sulfur utilization and stabilizing Li metal anode is discussed in detail. Furthermore, remaining challenges and outlook on the implementation of non-carbon host for practical carbon-free Li-S batteries are also provided. [ABSTRACT FROM AUTHOR]

Abstract For several laboratory experiments with microplastics, a simple and fast quantification method is advantageous. At the same time, the requirements are often lower compared to microplastic detection from environmental samples. We determined the concentration of non-purgable organic carbon of polystyrene (PS) particles (diameter 0.5, 1, 2, 6 μm) in suspension with known concentrations. Commercially available PS particles were used to test the Total Organic Carbon (TOC) analyzer method for quantifying microplastics in the lower micrometer range under absence of other organic compounds. Addition of iron or aluminum hydroxide to the samples prior to the measurement increased the recovery from 52.9 to 89.7% relative to measurements in the absence of metal hydroxides. With increasing particle size, the recovery in the presence of iron hydroxides decreased from 95.1% at 0.5 μm to 67.1% at 6 μm PS particles and in the presence of aluminum hydroxides from 92.6% at 0.5 μm to 88.9% at 6 μm PS particles. We conclude that metal hydroxides have a catalytic effect on the thermocatalytic oxidation of PS particles and allow a complete conversion to CO2 for a successful quantification of PS particles using a TOC analyzer. Especially for particles larger than 0.5 μm, in the absence of metal hydroxides, the TOC device is not able to fully oxidize the PS particle to CO2 and subsequently detect its concentration. Thus, TOC analysis of PS particles in the presence of metal hydroxides provides a cheap and simple alternative for quantifying microplastic particles in the lower micrometer range for laboratory experiments (e.g. sedimentation studies) where no other organic substances are present.

Aqueous zinc‐sulfur (Zn‐S) batteries show great potential for unlocking high energy and safety aqueous batteries. Yet, the sluggish kinetic and poor redox reversibility of the sulfur conversion reaction in aqueous solution challenge the development of Zn‐S batteries. Here, we fabricate a high‐performance Zn‐S battery using highly water‐soluble ZnI2 as an effective catalyst. In situ experimental characterizations and theoretical calculations reveal that the strong interaction between I− and the ZnS nanoparticles (discharge product) leads to the atomic rearrangement of ZnS, weakening the Zn‐S bonding, and thus facilitating the electrochemical oxidation reaction of ZnS to S. The aqueous Zn‐S battery exhibited a high energy density of 742 Wh kg(sulfur)−1 at the power density of 210.8 W kg(sulfur)−1 and good cycling stability over 550 cycles. Our findings provide new insights about the iodide catalytic effect for cathode conversion reaction in Zn‐S batteries, which is conducive to promoting the future development of high‐performance aqueous batteries. [ABSTRACT FROM AUTHOR]

We study the effect of geopolitics on short-term financial market reactions to IMF program approvals. If IMF programs are influenced by geopolitics, they may be less successful in stabilizing the economy. This could lead financial market participants to sell the country's assets and thus reduce the catalytic effect of IMF programs. Using a monthly panel data set for about 100 IMF members covering 1993-2019, we find that if geopolitics are involved, the approval of a new IMF program increases risk aversion of financial market participants. To measure geopolitical interest, we focus on program approvals for temporary members of the United Nations Security Council (UNSC). We find that temporary UNSC members receiving an IMF program face higher bond and bill yields, depreciating exchange rates, and weaker stock market developments. This is consistent with investors reducing exposure to the country's financial assets. Such a negative investor reaction is not observed for IMF program approvals for non-UNSC temporary members. [ABSTRACT FROM AUTHOR]

For several laboratory experiments with microplastics, a simple and fast quantification method is advantageous. At the same time, the requirements are often lower compared to microplastic detection from environmental samples. We determined the concentration of non-purgable organic carbon of polystyrene (PS) particles (diameter 0.5, 1, 2, 6 μm) in suspension with known concentrations. Commercially available PS particles were used to test the Total Organic Carbon (TOC) analyzer method for quantifying microplastics in the lower micrometer range under absence of other organic compounds. Addition of iron or aluminum hydroxide to the samples prior to the measurement increased the recovery from 52.9 to 89.7% relative to measurements in the absence of metal hydroxides. With increasing particle size, the recovery in the presence of iron hydroxides decreased from 95.1% at 0.5 μm to 67.1% at 6 μm PS particles and in the presence of aluminum hydroxides from 92.6% at 0.5 μm to 88.9% at 6 μm PS particles. We conclude that metal hydroxides have a catalytic effect on the thermocatalytic oxidation of PS particles and allow a complete conversion to CO2 for a successful quantification of PS particles using a TOC analyzer. Especially for particles larger than 0.5 μm, in the absence of metal hydroxides, the TOC device is not able to fully oxidize the PS particle to CO2 and subsequently detect its concentration. Thus, TOC analysis of PS particles in the presence of metal hydroxides provides a cheap and simple alternative for quantifying microplastic particles in the lower micrometer range for laboratory experiments (e.g. sedimentation studies) where no other organic substances are present. [ABSTRACT FROM AUTHOR]

The high dehydrogenation temperature of α-AlH 3 has always been an important factor hindering its development. In order to solve this problem, we synthesize Bi-MOF by hydrothermal method and burn it under inert gas to obtain Bi@C, which is used as catalyst (x Bi@C, x = 3, 5 and 7 wt%) to improve the hydrogen desorption performance of α-AlH 3. The dehydrogenation onset temperature of α-AlH 3 +5 wt% Bi@C drop to 80.4 °C, which is reduced by 43.4% compared with pure α-AlH 3. At 120 °C, it can provide a stable hydrogen capacity of 7.45 wt%. In contrast, pure α-AlH 3 releases only 6.66 wt% hydrogen at the same time. The density functional theory calculations further indicate that the existence of Bi@C catalyst can make the Al–H bond length increase, more conducive to the release of hydrogen. The results show that the synergistic effect of Bi and porous carbon in Bi@C materials can improve the hydrogen desorption kinetics of α-AlH 3 , providing a good prospect for the application of α-AlH 3 in hydrogen storage. [Display omitted] • The dehydrogenation performance of the Bi@C doped α-AlH 3 is investigated. • The Bi@C can reduce the initial hydrogen release temperature of α-AlH 3 and accelerate the hydrogen release rate. • The catalytic principle relies on the synergistic effects of Bi and porous carbon. [ABSTRACT FROM AUTHOR]

The current study focused on the design of an extremely sensitive electrochemical sensor of ascorbic acid based on a mixture of NiAl2O4-NiO nanoparticles that, produced in a single step using the sol–gel method, on an ITO electrode. This new sensing platform is useful for the detection of ascorbic acid with a wide range of concentrations extending from the attomolar to the molar. SEM micrographs show the porous structure of the NiAl2O4-NiO sample, with a high specific surface area, which is beneficial for the catalytic performance of the nanocomposite. An XRD diffractogram confirmed the existence of two phases, NiAl2O4 and NiO, both corresponding to the face-centred cubic crystal structure. The performances of the modified electrode, as a biomolecule, in the detection of ascorbic acid was evaluated electrochemically by cyclic voltammetry and chronoamperometry. The sensor exhibited a sensitive electrocatalytic response at a working potential of E = +0.3 V vs. Ag/Ag Cl, reaching a steady-state current within 30 s after each addition of ascorbic acid solution with a wide dynamic range of concentrations extending from attolevels (10−18 M) to molar (10 mM) and limits of detection and quantification of 1.2 × 10−18 M and 3.96 × 10−18 M, respectively. This detection device was tested for the quantification of ascorbic acid in a 500 mg vitamin C commercialized tablet that was not pre-treated.

Hydrogen is a clean and carbon-free energy reliable carrier to fulfill the energy supply requirement for an energy-sustainable society. Among different hydrogen energy storage techniques, solid-state hydrogen storage demonstrates elevated bulk density and gravimetric capacity and addresses safety concerns. The work studies the synergetic effect of porous Silicon (PS) as the host storage material and Ni as the catalyst in the composite form. The PS fabricated by electrochemical anodization is ball-milled with Ni powder to prepare the composite. The composite shows an improved hydrogen storage capacity of 1.64 wt% at 40 bar and 120 °C. The capacity increases to 2.69 wt% with the increase in pressure to 60 bar at 60 °C, indicating the large active surface. The physical and chemical changes to the composite are analyzed using SEM, XRD, and Raman spectroscopy. The differential scanning calorimetry shows the catalytic effect of Ni by reducing the decomposition temperature of individual PS. The synergetic effect of PS and Ni produces a synergetic effect that leads to the dissociation of molecules, improves hydrogen storage capacity, and reduces the temperature required for desorption. • Planetary ball milling of PS and Ni forms Ni decorated PS or PS-Ni composite. • The composite shows a hydrogen storage capacity of 1.64 wt% at 40 bar and 120 °C. • The storage increases to 2.69 wt% at 60 bar and 60 °C, indicating a high active surface. • The decomposition temperature reduces due to the synergetic effect of PS and Ni. • Ni as a catalyst improves solid-state hydrogen adsorption and desorption in PS. [ABSTRACT FROM AUTHOR]

In the present paper, a scalable, economically feasible, and continuous process for making cellulose-based carbon fibers (CFs) is described encompassing precursor spinning, precursor additivation, thermal stabilization, and carbonization. By the use of boric acid (BA) as an additive, the main drawback of cellulose-based CFs, i.e., the low carbon yield, is overcome while maintaining a high level of mechanical properties. This is demonstrated by a systematic comparison between CFs obtained from a BA-doped and an un-doped cellulose precursor within a temperature range for carbonization between 1000 and 2000 °C. The changes in chemical composition (via elemental analysis) and physical structure (via X-ray scattering) as well as the mechanical and electrical properties of the resulting CFs were investigated. It turned out that, in contrast to current opinion, the catalytic effect of boron in the formation of graphite-like structures sets in already at 1000 °C. It becomes more and more effective with increasing temperature. The catalytic effect of boron significantly affects crystallite sizes (La, Lc), lattice plane spacings (d002), and orientation of the crystallites. Using BA, the carbon yield increased by 71%, Young's modulus by 27%, and conductivity by 168%, reaching 135,000 S/m. At the same time, a moderate decrease in tensile strength by 25% and an increase in density of 14% are observed. [ABSTRACT FROM AUTHOR]

The blend of hydroxylammonium nitrate (HAN) and imidazole-based ionic liquid has shown good feasibility in chemical and electric dual-mode green space propulsion. As conventional catalyst-driven ignition faces challenges arising from long preheat delay and catalyst failure, this work designs a novel ignition actuator using a microwave plasma torch. The precise tuning of the ¼-λ resonant cavity and improvement in the quality factor (QF) of the microwave igniter make the device efficient and thus allow the propellant to be ignited at a power of approximately 100 W. In the present reduced test rig, the maximum fuel flow rate corresponds to 0.1 N chemical thrusters, and the plasma-assisted ignition is mainly attributed to thermal and kinetic effects. The temperature of the actuator and the plasma torch is investigated by infrared thermometry and spectral fitting of excited molecule nitrogen, respectively. First, the hot electrode tube helps evaporate water molecules and accelerate the liquid jet through rapid gas expansion. Then, the ionic liquid quickly decomposes to small species when the flow reaches the torch with a nitrogen vibrational temperature above 4000 K and rotational temperature above 2000 K. Meanwhile, the nonequilibrium plasma-excited species enhance the combustion of gaseous intermediates by direct impact dissociation, where the OH radical profile is visualized using the planar laser-induced fluorescence technique. In addition, the copper atoms released by plasma erosion are expected to exhibit a significant catalytic effect on ionic liquid decomposition, which is a critical step in controlling the overall reaction rate. It is also noted that such mild erosion does not affect the multi-start operations during the firing test that lasts for at least 30 min. [ABSTRACT FROM AUTHOR]

Hazardous emissions majorly NOx and the poor performance of alternative fuels (biodiesel/its blends) are global concerns, as fossil fuel depletion and rising energy prices encourage researchers to rely on alternative energy sources with the addition of nano additives in the recent decade. The current experimental study investigates the performance, combustion, and emission characteristics of biodiesel-diesel mixtures dispersed with titanium dioxide (TiO2) as a fuel additive on a 1-cylinder diesel engine. TiO2 was dispersed in a Tamarind Oil Methyl Ester (TOME)-diesel blend (B20) in three concentrations of 40, 80, and 120 ppm via ultrasonication in the presence of QPAN80 surfactant to enhance the stability of the prepared fuel sample. A ratio of 1:4 TiO2:QPAN80 was found to produce the highest stability and homogeneity which is evidenced by the characterization of TiO2. The engine tests revealed that the greatest decrement in BSFC, CO, HC, and NOx was observed as 15.2%, 15.2%, 11.10%, and 9.06%, and the maximum BTE, HRR, and CP were improved by 9.76%, 50.32 J/degree, and 50.32 bar for the B20T80 blend correlated with B20 blend. Thus, the inclusion of TiO2 nano additives improved overall engine performance and decreased emissions of CI engines significantly. [ABSTRACT FROM AUTHOR]

Hydrothermal dechlorination of polyvinyl chloride (PVC) is primarily performed in stainless-steel reactors prone to chlorine-induced pitting corrosion, contaminating the reaction media with Fe2+, Ni2+, and Cr2+ possibly triggering shifts in the degradation chemistry. This study investigated the single and synergistic effects of Fe2+ and Ni2+ on urea-assisted hydrothermal dechlorination of PVC under mild conditions. Significant improvement in dechlorination degree was observed at 210 °C when 5 mmol/L Fe2+ or 10 mmol/L Ni2+ was added. Furthermore, positive interaction between the cations was confirmed when the simultaneous use of 1 mmol/L Fe2+ and 0.25 mmol/L Ni2+ achieved the same catalytic performance. The presence of these ions prevented adhesive contact of PVC particles, thus limiting the mass-transfer resistance and autocatalytic effect. The experimental design revealed that dechlorination and its improvement were temperature-dependent (p < 0.0001). Ni2+ and Fe2+ exerted quadratic and linear effects, respectively, on dechlorination. The highest catalytic activity occurred in the temperature range of 217.5–222.5 °C. The results show that total concentrations of as low as 1.08 mmol/L accelerated dechlorination, indicating the inappropriateness of using steel reactors for determining intrinsic PVC degradation chemistry. However, Fe–Ni composites have the potential to be used as catalysts. [ABSTRACT FROM AUTHOR]

Ni and carbon materials exhibit remarkable catalysis for the hydriding reaction of Mg. But the underlying mechanism of Ni/C hybrid catalysis is still unclear. In this work, density functional theory (DFT) calculation is applied to investigate the effect of Ni/C co-incorporation on the hydriding reaction of Mg crystal. The morphology and crystal structure of the Ni/C co-incorporated Mg sample show that the co-incorporated structure is credible. The transition state searching calculation suggests that both the incorporations of Ni and C are beneficial for the H2 dissociation. But Ni atom has a dramatic improvement for H2 dissociation and makes the H diffusion become limiting step of the hyriding reaction. The Ni dz2 orbit and H s orbit accept the electrons and combine together compactly, while the Ni dxy orbit is half-occupied. The catalytic effect of Ni on H2 dissociation can be ascribed to the bridging effect of Ni dxy orbit. The incorporation of C can weaken the over-strong interaction between Ni and H which hindered the H diffusion on Mg(0001). The Ni/C co-incorporated Mg(0001) shows the best performance during hyriding reaction compared with the clean and single incorporated Mg(0001).

Lithium-sulfur (Li-S) batteries are the potential alternative for the lithium-ion batteries, owing to their remarkable energy density and specific capacity. Nevertheless, the lower utilization of active materials and the “shuttle effect” have impeded their widespread commercialization. To address these hurdles, a pioneering method has been proposed, involving a lithium phosphate-incorporated multi-walled carbon nanotube (Li3PO4@MWCNT) interlayer. The Li3PO4@MWCNT interlayer primarily serves as a physical barrier against polysulfide shuttling. Its highly conductive cross-link structure enables it to adsorb chemically derived lithium polysulfides (LiPS) and catalyze their conversion by incorporating Li3PO4 into the MWCNT matrix. This synergistic effect of immobilizing and converting LiPS results in a significant reduction in the “shuttle effect,” leading to enhanced sulfur utilization. The experimental results evidence the enhanced performance of the Li-S cells, with a capacity of 381 mAh g−1 at 0.1C and high C-rate performance of 393 mAh g−1 at 1C.

Extensive researches are being conducted to improve the high dehydrogenation temperature and sluggish hydrogen release rate of magnesium hydride (MgH 2) for better industrial application. In this study, LiNbO 3 , a catalyst composed of alkali metal Li and transition metal Nb, was prepared through a direct one-step hydrothermal synthesis, which remarkably improved the hydrogen storage performance of MgH 2. With the addition of 6 wt% LiNbO 3 in MgH 2 , the initial dehydrogenation temperature decreases from 300 °C to 228 °C, representing a drop of almost 72 °C compared to milled MgH 2. Additionally, the MgH 2 -6 wt.% LiNbO 3 composite can quickly release 5.45 wt% of H 2 within 13 min at 250 °C, and absorbed about 3.5 wt% of H 2 within 30 min at 100 °C. It is also note that LiNbO 3 shows better catalytic effect compared to solely adding Li 2 O or Nb 2 O 5. Furthermore, the activation energy of MgH 2 -6 wt.% LiNbO 3 decreased by 44.37% compared to milled MgH 2. The enhanced hydrogen storage performance of MgH 2 is attributed to the in situ formation of Nb-based oxides in the presence of LiNbO 3 , which creates a multielement and multivalent chemical environment. [Display omitted] • LiNbO 3 is used as catalyst to improve the hydrogen storage performance of MgH 2. • The doping of LiNbO 3 reduces the onset dehydrogenation temperature of MgH 2. • The kinetic properties of MgH 2 -6 wt.% LiNbO 3 system are significantly improved. • Bimetallic synergy boosts LiNbO 3 catalytic activity for MgH 2 over Li 2 O and Nb 2 O 5. [ABSTRACT FROM AUTHOR]

The current research of Li–S batteries primarily focuses on increasing the catalytic activity of electrocatalysts to inhibit the polysulfide shuttling and enhance the redox kinetics. However, the stability of electrocatalysts is largely neglected, given the premise that they are stable over extended cycles. Notably, the reconstruction of electrocatalysts during the electrochemical reaction process has recently been proposed. Such in situ reconstruction process inevitably leads to varied electrocatalytic behaviors, such as catalytic sites, selectivity, activity, and amounts of catalytic sites. Therefore, a crucial prerequisite for the design of highly effective electrocatalysts for Li–S batteries is an in‐depth understanding of the variation of active sites and the influence factors for the in situ reconstruction behaviors, which has not achieved a fundamental understanding and summary. This review comprehensively summarizes the recent advances in understanding the reconstruction behaviors of different electrocatalysts for Li–S batteries during the electrochemical reaction process, mainly including metal nitrides, metal oxides, metal selenides, metal fluorides, metals/alloys, and metal sulfides. Moreover, the unexplored issues and major challenges of understanding the reconstruction chemistry are summarized and prospected. Based on this review, new perspectives are offered into the reconstruction and true active sites of electrocatalysts for Li–S batteries. [ABSTRACT FROM AUTHOR]

The development of cost‐effective and efficient catalysts for the hydrogen evolution reaction (HER) has been a subject of intense research for sustainable and clean energy in recent decades. For this purpose, CuO‐modified stainless steel (CuO‐SS) electrode was fabricated to attain HER in acidic media. Here in, CuO film was fabricated on a stainless steel (SS) surface following successive ionic layer adsorption and reaction (SILAR) method. A 60‐cycle CuO modification resulted in enhanced HER activity compared to the bare SS or CuO electrode with an average 99 % Faradic efficiency. Based on the Electrochemical Impedance Spectroscopy (EIS), at an HER potential, the bare SS electrode exhibited charge transfer resistance of 24.7 Ω whereas CuO‐SS electrode exhibited 6.47 Ω only. The overpotential was calculated to be 154 mV at the CuO‐SS electrode regarding HER. The results have significant implications for the development of cost‐effective and efficient electrocatalysts for hydrogen production. [ABSTRACT FROM AUTHOR]

Mg2FeH6- and Mg2CoH5-based composites with in situ formed YH3 and Mg2NiH4 nanoparticles were synthesized by ball milling of Mg10YNi + 4Fe (in mole ratio) and Mg10YNi + 4Co powders, respectively, at 4 MPa H2 followed by hydrogenation at 673 K for 60 h under a hydrogen pressure of 7 MPa. It is found that the nanocrystalline YH3 and Mg2NiH4 particles are indeed embedded in Mg2FeH6 and Mg2CoH5 matrixes. The hydrogen desorption rates of Mg2FeH6- and Mg2CoH5-based composites are enhanced compared to those undoped Mg2FeH6 and Mg2CoH5 hydrides, respectively, due to the synergetic catalysis of nanosized YH3 and Mg2NiH4 particles. This finding provides us with an efficient and simple approach for the improvement in hydrogen desorption kinetics of Mg-based hydrogen storage materials. [ABSTRACT FROM AUTHOR]

• Ag-D201 nanocomposites have been synthesized through in situ reduction method. • Ag-D201 exhibited great adsorption capacity and high selectivity for I− removal. • Adsorption by Ag-D201 was boosted in acidic solution under the catalysis of AgNPs. • The maximum adsorption capacity of Ag-D201 was 802 mg/g for I− at pH 2. • The adsorption mechanism was a synergistic effect of physical and chemical process. The removal of iodide (I−) from source waters is an effective strategy to minimize the formation of iodinated disinfection by-products (DBPs), which are more toxic than their brominated and chlorinated analogues. In this work, a nanocomposite Ag-D201 was synthesized by multiple in situ reduction of Ag-complex in D201 polymer matrix, to achieve highly efficient removal of iodide from water. Scanning electron microscope /energy dispersive spectrometer characterization showed that uniform cubic silver nanoparticles (AgNPs) evenly dispersed in the D201 pores. The equilibrium isotherms data for iodide adsorption onto Ag-D201 was well fitted with Langmuir isotherm with the adsorption capacity of 533 mg/g at neutral pH. The adsorption capacity of Ag-D201 increased with the decrease of pH in acidic aqueous solution, and reached the maximum value of 802 mg/g at pH 2. This was attributed to the oxidization of I−, by dissolved oxygen under the catalysis of AgNPs, to I 2 which was finally adsorbed as AgI 3. However, the aqueous solutions at pH 7 – 11 could hardly affect the iodide adsorption. The adsorption of I− was barely affected by real water matrixes such as competitive anions (SO 4 2−, NO 3 −, HCO 3 −, Cl−) and natural organic matter, of which interference of NOM was offset by the presence of Ca2+. The proposed synergistic mechanism for the excellent performance of iodide adsorption by the absorbent was ascribed to the Donnan membrane effect caused by the D201 resin, the chemisorption of I− by AgNPs, and the catalytic effect of AgNPs. Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]

Carbon materials have excellent catalytic effects on the hydrogen storage performance of MgH2. Here, carbon-supported Ni3S2 (denoted as Ni3S2@C) was synthesized by a facile chemical route using ion exchange resin and nickel acetate tetrahydrate as raw materials and then introduced to improve the hydrogen storage properties of MgH2. The results indicated the addition of 10 wt.% Ni3S2@C prepared by macroporous ion exchange resin can effectively improve the hydrogenation/dehydrogenation kinetic properties of MgH2. At 100 °C, the dehydrogenated MgH2-Ni3S2@C-4 composite could absorb 5.68 wt.% H2. Additionally, the rehydrogenated MgH2-Ni3S2@C-4 sample could release 6.35 wt.% H2 at 275 °C. The dehydrogenation/hydrogenation enthalpy changes of MgH2-Ni3S2@C-4 were calculated to be 78.5 kJ mol−1/−74.7 kJ mol−1, i.e., 11.0 kJ mol−1/7.3 kJ mol−1 lower than those of MgH2. The improvement in the kinetic properties of MgH2 was ascribed to the multi-phase catalytic action of C, Mg2Ni, and MgS, which were formed by the reaction between Ni3S2 contained in the Ni3S2@C catalyst and Mg during the first hydrogen absorption–desorption process.

2,4-Dihydroxybenzoic acid lead (β-Pb) was synthesized and its single crystal structure was reported firstly. β-Pb crystallizes in monoclinic system with space group of C2/m and crystal parameters of a=17.888(3) Å, b=4.8790(8) Å, c=21.408(4) Å, β=100.258(5) °, Z=2, V=1838.5(5) Å3, μ=12.213 mm−1, F(000) = 1000.0 and Dcalc = 1.920 g/cm3. 2,4-Dihydroxybenzoic acid presents a monoacid form only, two different coordination forms of Pb2+ exist in crystal structure of β-Pb, and the two phenolic hydroxyl groups all do not involved in coordination with lead ions. The thermal decomposition of β-Pb and its catalytic effect on thermal decomposition of AP and RDX were explored. For AP, the low-temperature decomposition temperature (LTT) and high-temperature decomposition temperature (HTT) decrease by 30.4 °C and 31.3 ℃ with the addition of β-Pb, and their apparent activation energies (Ea) decrease by 44.4 kJ/mol and 31.6 kJ/mol, respectively. For RDX, the thermal decomposition temperature and Ea decrease by 11 °C and 110.7 kJ/mol respectively, after the addition of β-Pb. β-Pb shows excellent catalytic decomposition effect on AP and RDX.

Ni and carbon materials exhibit remarkable catalysis for the hydriding reaction of Mg. But the underlying mechanism of Ni/C hybrid catalysis is still unclear. In this work, density functional theory (DFT) calculation is applied to investigate the effect of Ni/C co-incorporation on the hydriding reaction of Mg crystal. The morphology and crystal structure of the Ni/C co-incorporated Mg sample show that the co-incorporated structure is credible. The transition state searching calculation suggests that both the incorporations of Ni and C are beneficial for the H 2 dissociation. But Ni atom has a dramatic improvement for H 2 dissociation and makes the H diffusion become limiting step of the hyriding reaction. The Ni d z 2 orbit and H s orbit accept the electrons and combine together compactly, while the Ni d xy orbit is half-occupied. The catalytic effect of Ni on H 2 dissociation can be ascribed to the bridging effect of Ni d xy orbit. The incorporation of C can weaken the over-strong interaction between Ni and H which hindered the H diffusion on Mg(0001). The Ni/C co-incorporated Mg(0001) shows the best performance during hyriding reaction compared with the clean and single incorporated Mg(0001). [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium–sulfur batteries have great potential for next-generation electrochemical storage systems owing to their high theoretical specific energy and cost-effectiveness. However, the shuttle effect of soluble polysulfides and sluggish multi-electron sulfur redox reactions has severely impeded the implementation of lithium–sulfur batteries. Herein, we prepared a new type of Ti 3 C 2 -TiO 2 heterostructure sandwich nanosheet confined within polydopamine derived N -doped porous carbon. The highly polar heterostructures sandwich nanosheet with a high specific surface area can strongly absorb polysulfides, restraining their outward diffusion into the electrolyte. Abundant boundary defects constructed by new types of heterostructures reduce the overpotential of nucleation and improve the nucleation/conversion redox kinetics of Li 2 S. The Ti 3 C 2 –TiO 2 @NC/S cathode exhibited discharge capacities of 1363, and 801 mAh g−1 at the first and 100th cycles at 0.5C, respectively, and retained an ultralow capacity fade rate of 0.076% per cycle over 500cycles at 1.0C. This study provides a potential avenue for constructing heterostructure materials for electrochemical energy storage and catalysis. [ABSTRACT FROM AUTHOR]

SnO2 nanospheres with diameters of 30∼50 nm and PtxCu1-x bimetallic nanoparticles with sizes of approximately 10 nm were synthesized via hydrothermal and solvothermal methods, respectively. The PtxCu1-x bimetallic nanoparticles were impregnated on the surface of the SnO2 spheres to form PtxCu1-x-SnO2 nanocomposites. By varying the atomic ratios between platinum (Pt) and copper (Cu), we found that Pt0.75Cu0.25-SnO2, with a large specific surface area of 89.21 m2/g, enabled the selective and accurate detection of low-concentration formaldehyde compared to other metal-deposited samples and pure SnO2. The response value of Pt0.75Cu0.25-SnO2 to 500 × 10−9 formaldehyde was approximately 20 at an operating temperature of 160 ℃ with an extremely high-speed response (15 s). The porous structures with large specific surface areas, as well as the improved catalytic effects of Pt0.75Cu0.25, comprehensively contributed to the enhanced sensing performance towards formaldehyde.

Methane (CH4), as the main component of natural gas and coal mine gas, is widely used in daily life and industrial processes and its leakage always causes undesirable misadventures. Thus, the rapid detection of low concentration methane is quite necessary. However, due to its robust chemical stability resulting from the strong tetrahedral-symmetry structure, the methane molecules are usually chemically inert to the sensing layers in detectors, making the rapid and efficient alert a big challenge. In this work, palladium nanoparticles (Pd NPs) embedded indium oxide porous hollow tubes (In2O3 PHTs) were successfully synthesized using Pd@MIL-68 (In) MOFs as precursors. All In2O3-based samples derived from Pd@MIL-68 (In) MOFs inherited the morphology of the precursors and exhibited the feature of hexagonal hollow tubes with porous architecture. The gas-sensing performances to 5000 ppm CH4 were evaluated and it was found that Pd@In2O3-2 gave the best response (Ra/Rg = 23.2) at 370 °C, which was 15.5 times higher than that of pristine-In2O3 sensors. In addition, the sensing materials also showed superior selectivity against interfering gases and a rather short response/recovery time of 7 s/5 s. The enhancement in sensing performances of Pd@In2O3-2 could be attributed to the large surface area, rich porosity, abundant oxygen vacancies and the catalytic function of Pd NPs. [ABSTRACT FROM AUTHOR]

• Ni 3 S 2 @C composites were prepared using cheap cation exchange resins and Ni(CH 3 COO) 2 4H 2 O. • The comprehensive hydrogen storage performance of MgH 2 was significantly improved by the addition of Ni 3 S 2 @C. • The hydrogenation apparent activation energy of MgH 2 -Ni 3 S 2 @C-4 was 39.6 kJ mol−1. • The multi-phase (Mg/Mg 2 Ni, Mg/MgS, and Mg/C) interface provided more active sites to improve the hydrogen storage performance of MgH 2. Carbon materials have excellent catalytic effects on the hydrogen storage performance of MgH 2. Here, carbon-supported Ni 3 S 2 (denoted as Ni 3 S 2 @C) was synthesized by a facile chemical route using ion exchange resin and nickel acetate tetrahydrate as raw materials and then introduced to improve the hydrogen storage properties of MgH 2. The results indicated the addition of 10 wt.% Ni 3 S 2 @C prepared by macroporous ion exchange resin can effectively improve the hydrogenation/dehydrogenation kinetic properties of MgH 2. At 100 °C, the dehydrogenated MgH 2 -Ni 3 S 2 @C-4 composite could absorb 5.68 wt.% H 2. Additionally, the rehydrogenated MgH 2 -Ni 3 S 2 @C-4 sample could release 6.35 wt.% H 2 at 275 °C. The dehydrogenation/hydrogenation enthalpy changes of MgH 2 -Ni 3 S 2 @C-4 were calculated to be 78.5 kJ mol−1/−74.7 kJ mol−1, i.e., 11.0 kJ mol−1/7.3 kJ mol−1 lower than those of MgH 2. The improvement in the kinetic properties of MgH 2 was ascribed to the multi-phase catalytic action of C, Mg 2 Ni, and MgS, which were formed by the reaction between Ni 3 S 2 contained in the Ni 3 S 2 @C catalyst and Mg during the first hydrogen absorption–desorption process. [ABSTRACT FROM AUTHOR]

Magnesium-based hydrogen storage materials are considered as one of the most promising candidates for solid state hydrogen storage due to their advantages of high hydrogen capacity, excellent reversibility and low cost. In this paper, Mg91.4Ni7Y1.6 and Mg92.8Ni2.4Y4.8 alloys were prepared by melting and ball milling. Their microstructures and phases were characterized by X-ray diffraction, scanning electron microscope and transmission electron microscope, and hydrogen absorbing and desorbing properties were tested by the high pressure gas adsorption apparatus and differential scanning calorimetry (DSC). In order to estimate the activation energy and growth mechanism of alloy hydride, the JMAK, Arrhenius and Kissinger methods were applied for calculation. The hydrogen absorption content of Mg92.8Ni2.4Y4.8 alloy reaches 3.84 wt.% within 5 min under 350 ℃, 3 MPa, and the maximum hydrogen capacity of the alloy is 4.89 wt.% in same condition. However, the hydrogen absorption of Mg91.4Ni7Y1.6 alloy reaches 5.78 wt.% within 5 min, and the maximum hydrogen absorption of the alloy is 6.44 wt.% at 350 ℃ and 3 MPa. The hydrogenation activation energy of Mg91.4Ni7Y1.6 alloy is 25.4 kJ/mol H2, and the enthalpy and entropy of hydrogen absorption are -60.6 kJ/mol H2 and 105.5 J/K/mol H2, separately. The alloy begins to dehydrogenate at 210 ℃, with the dehydrogenation activation energy of 87.7 kJ/mol H2. By altering the addition amount of Ni and Y elements, the 14H-LPSO phase with smaller size and ternary eutectic areas with high volume fraction are obtained, which provides more phase boundaries and catalysts with better dispersion, and there are a lot of fine particles in the alloy, these structures are beneficial to enhance the hydrogen storage performance of the alloys.

In this paper, Au nanoparticles (AuNPs) loaded ZrO 2 /ZnSnO 3 nanocubes are prepared through hydrothermal route and chemical reduction method. The crystal structure, morphology, element distribution, chemical composition, specific surface area and pore size of ZrO 2 /ZnSnO 3 nanocubes are described with XRD, TEM, XPS and BET. Interestingly, the incorporation of Zr ions induces the fragmentation of the edge of ZnSnO 3 nanocubes, which enhance specific surface area of ZrO 2 /ZnSnO 3 nanocubes. The response of ZnSnO 3 materials for isopropanol is increased through doping ZrO 2 and modifying AuNPs. The 1.5 at% AuNPs-loaded 5 at% ZrO 2 /ZnSnO 3 nanocubes presents a higher response to 100 ppm isopropanol with a fast response/recovery time (3/4 s) at the operating temperature of 260℃. And the generation of ZnSnO 3 , ZrO 2 and AuNPs heterojunctions contributes to raise the isopropanol response. In addition, the catalysis of ZrO 2 and AuNPs also can increase their reaction speed between absorbed oxygen and isopropanol molecules. This research results provide a new scheme for the development of isopropanol sensor. • AuNPs-ZrO 2 /ZnSnO 3 nanocubes are prepared by one-step hydrothermal method and chemical reduction method. • The catalytic effect of AuNPs and ZrO 2 enhances the response and reduce the response/recovery time of the sensor. • The detection limit is up to 410 ppb. [ABSTRACT FROM AUTHOR]

[Display omitted] • Introducing the energetic compound NHA into solid propellants has improved their combustion performance. • NHA's catalysis of the propellant's condensed phase improves aluminum agglomeration. • Exploring NHA's catalytic mechanism on AP and describes the in situ modification effects of NHA on AP. Introducing energetic metal complexes into solid propellants is an effective strategy for enhancing their energy release and improving the agglomeration of their catalysts. In this study, the metal complex [Ni(N 2 H 4) 2 ](N 3) 2 (NHA) was incorporated into hydroxyl terminated polybutadiene-based composite solid propellants, and its optimal catalytic ratio and catalytic mechanism for ammonium perchlorate (AP) were investigated through performance characterization. The optimal catalyst content was determined to be 1 %, whereby the exothermic peak temperature advanced by 26 ℃ compared to the blank control group, as examined by differential scanning calorimetry. The heat of explosion was 5744.98 J·g−1. An increase in the burning rate while ensuring a pressure exponent below 0.5 (specifically, 0.399) was achieved simultaneously. The characterization of the flame structure demonstrated that the catalytic effect of NHA was concentrated in the condensed phase reaction zone of the propellant, which decreased in the Al agglomeration from 111.41 μm to 59.42 μm. Its catalytic effect is attributed to the rapid release of NiO particles during the decomposition of NHA, which formed a microchemical reaction zone on the AP surface, resulting in its increased porosity. The porous AP structure exposed more catalytically active sites, synergistically enhancing the catalytic efficacy. [ABSTRACT FROM AUTHOR]

Pristine SnO2, Fe-doped SnO2 and Ni-doped SnO2 were synthesized using facile hydrothermal method. Analysis based on XRD, TEM and UV–Vis DRS measurements demonstrated the successful insertion of Fe and Ni dopants into SnO2 crystal. Formaldehyde-detection measurements revealed that transition metal-doped SnO2 exhibited improved formaldehyde-sensing properties compared with that of pristine SnO2. When the amount of incorporated dopant (Fe or Ni) was 4 at.%, the most effective enhancement on sensing performance of SnO2 was obtained. At 160 °C, the 4 at.% Fe–SnO2 and 4 at.% Ni–SnO2 exhibited higher response values of 7.52 and 4.37 with exposure to low-concentration formaldehyde, respectively, which were 2.4 and 1.4 times higher than that of pristine SnO2. The change of electronic structure and crystal structure as well as catalytic effect of transition metals are chiefly responsible for the enhanced sensing properties.

Lysozymes are hydrolytic enzymes characterized by their ability to cleave the β-(1,4)-glycosidic bonds in peptidoglycan, a major structural component of the bacterial cell wall. This hydrolysis action compromises the integrity of the cell wall, causing the lysis of bacteria. For more than 80 years, its role of antibacterial defense in animals has been renowned, and it is also used as a preservative in foods and pharmaceuticals. In order to improve the antimicrobial efficacy of lysozyme, extensive research has been intended for its modifications. This manuscript reviews the natural antibiotic compound lysozyme with reference to its catalytic and non-catalytic mode of antibacterial action, lysozyme types, susceptibility and resistance of bacteria, modification of lysozyme molecules, and its applications in the food industry. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting represents a promising alternative to conventional carbon-based energy sources. The hydrogen evolution reaction (HER) is a key process, still if conducted in alkaline media, its kinetics is slow thus requiring high amount of Pt based catalysts. Extensive research has been focused on reducing Pt utilization by pursuing careful electrode investigation. Here, a low-cost chemical methodology is reported to obtain large amount of microflowers made of interconnected NiO nanowalls (20 nm thick) wisely decorated with ultralow amounts of Pt nanoparticles. These decorated microflowers, dispersed onto graphene paper by drop casting, build a high performance HER electrode exhibiting an overpotential of only 66 mV at current density of 10 mA cm−2 under alkaline conditions. Intrinsic activity of catalyst was evaluated by measuring the Tafel plot (as low as 82 mV/dec) and turnover frequencies (2.07 s−1 for a Pt loading of 11.2 μg cm−2). The effect of Pt decoration has been modelled through energy band bending supported by electrochemical analyses. A full cell for alkaline electrochemical water splitting has been built, composed of Pt decorated NiO microflowers as cathode and bare NiO microflowers as anode, showing a low potential of 1.57 V to afford a current density of 10 mA cm−2 and a good long-term stability. The reported results pave the way towards an extensive utilization of Ni based nanostructures with ultralow Pt content for efficient electrochemical water splitting. • Pt nanoparticles decoration of NiO microflowers. • Effect of decoration on Hydrogen Evolution Reaction mechanism and on energy band modification of NiO. • Overall water splitting with NiO and Pt–NiO electrodes in alkaline conditions. [ABSTRACT FROM AUTHOR]

Normally, it is hard to regulate thermal defects precisely in their host lattice due to the stochastic nature of thermal activation. Here, we demonstrate a thermal annealing way to create patterned single sulfur vacancy (V S ) defects in monolayer molybdenum disulfide (MoS 2 ) with about 2 nm separations at subnanometer accuracy. Theoretically, we reveal that the S-Au interface coupling reduces the energy barriers in forming V S defects and that explains the overwhelming formation of interface V S defects. We also discover a phonon regulation mechanism by the moiré interface that effectively condenses the Γ-point out-of-plane acoustic phonons of monolayer MoS 2 to its TOP moiré sites, which has been proposed to trigger moiré-patterned thermal V S formation. The high-throughput nanoscale patterned defects presented here may contribute to building scalable defect-based quantum systems.

Lithium metal is considered as the most prospective electrode for next‐generation energy storage systems due to high capacity and the lowest potential. However, uncontrollable spatial growth of lithium dendrites and the crack of solid electrolyte interphase still hinder its application. Herein, Schottky defects are motivated to tune the 4f‐center electronic structures of catalysts to provide active sites to accelerate Li transport kinetics. As experimentally and theoretically confirmed, the electronic density is redistributed and affected by the Schottky defects, offering numerous active catalytic centers with stronger ion diffusion capability to guide the horizontal lithium deposition against dendrite growth. Consequently, the Li electrode with artificial electronic‐modulation layer remarkably decreases the barriers of desolvation, nucleation, and diffusion, extends the dendrite‐free plating lifespan up to 1200 h, and improves reversible Coulombic efficiency. With a simultaneous catalytic effect on the conversions of sulfur species at the cathodic side, the integrated Li–S full battery exhibits superior rate performance of 653 mA h g−1 at 5 C, high long‐life capacity retention of 81.4% at 3 C, and a high energy density of 2264 W h kg−1 based on sulfur in a pouch cell, showing the promising potential toward high‐safety and long‐cycling lithium metal batteries. [ABSTRACT FROM AUTHOR]

To overcome the gelation of gelatin at low temperatures, solve the brittleness of gelatin-based films and improve the reaction efficiency between the components, a facile design strategy is proposed for preparing gelatin/polyvinyl alcohol composite films (Gel-PVAs) with excellent flexibility. During the preparation process, sodium acetate trihydrate/urea deep eutectic solvent (SAT/U-DES) was introduced to dissolve the gelatin, which not only exhibited the higher crosslinking efficiency but also induced the plasticizing effect to the composite film. When the DES mass fraction was 60%, the solubility of the gelatin was up to 25%, and gelation did not occur at room temperature. In addition, the elongation at break of the Gel-PVA60 film reached up to 654%, which was a 631% increase when compared with that of the Gel-PVA0 film. These remarkable properties were due to the formation of new H-bonds with the groups in gelatin molecules induced by SAT/U-DES, which limited the reformation of the gelatin structures after cooling and improved the flexibility and ductility of the film. Moreover, the destruction of interchain interactions between the gelatin molecules allowed more carboxyl groups to react with PVA in the crosslinking modification system, which resulted in an improvement of the reaction efficiency without external catalysts. The schematic illustration for the preparation process of gelatin/PVA composite films are presented in the Figure. SAT/U-DES dissolved gelatin by breaking the intermolecular hydrogen bonds, and then —COOH of gelatin reacted with —OH of PVA to form ester bonds under the activation of EDC, and finally the solution was dried into a film with excellent flexibility. [Display omitted] • SAT/U-DES overcame the gelation behavior of gelatin at low temperatures. • Excellent-flexibility gelatin/PVA composite film was successfully prepared. • The crosslinking efficiency between components was improved without external catalysts. [ABSTRACT FROM AUTHOR]

How do investors respond when a country participates in an International Monetary Fund (IMF) programme? While there exists some optimism in and around the IMF on the catalytic effect of a Fund programme, empirical research on the catalytic finance reports rather diverse findings; contrary to most theoretical research, empirical studies report both positive and negative effects as well as null effects. This paper revisits the question of whether and how an IMF programme catalyses other finances, focusing on the catalytic effect on foreign direct investment (FDI). We modify the core theoretical logic behind the catalytic finance to identify conditions under which an IMF programme is more likely to catalyse FDI: we highlight the credibility of an IMF programme as a key determinant of any positive catalytic effect it may have and reason that politically motivated lending by the IMF can attenuate a programme's credibility, depressing the catalytic effect. We empirically capture politically motivated lending by looking at the relationship between a borrowing country and the United States and demonstrate that IMF loans to countries closely aligned with the United States are less likely to catalyse FDI than loans to countries that are not aligned with the United States. [ABSTRACT FROM AUTHOR]