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Introduction: T cells play a critical role in inflammatory diseases. The aim of the present study was to investigate the effects of Majie cataplasm (MJC) on asthma and to propose a possible mechanism involved in this process. Methods: Airway inflammation, infiltration of inflammatory cells, levels of interleukin (IL)-4, IL-10, IL-17, and interferon (IFN)-γ, levels of Th2, Treg, Th17, and Th1 cells, and the expressions of IL-4, IL-10, IL-17, IFN-γ, GATA binding protein 3 (GATA-3), Foxp3, RAR-related orphan receptor gamma (RORγt), and T-bet were detected. Result: MJC treatment reduced lung airway resistance and inflammatory infiltration in lung tissues. MJC treatment also reduced the numbers of eosinophils and neutrophils in the blood and bronchoalveolar lavage fluid (BALF). The levels of IL-4 and IL-17 in the blood, BALF, and lungs were suppressed by MJC, and IFN-γ and IL-10 were increased. Furthermore, MJC suppressed the percentage of Th2 and Th17 and increased the percentage of Th1 and Treg in spleen cells. In addition, MJC can inhibit asthma by increasing expressions of IFN-γ, IL-10, T-bet, and Foxp3, as well as decreasing expressions of IL-4, IL-17, GATA-3, and RORγt. Conclusion: MJC may improve airway hyperresponsiveness and inflammation by regulating Th1/Th2/Treg/Th17 balance in ovalbumin-induced rats. And MJC may be a new source of anti-asthma drugs. [ABSTRACT FROM AUTHOR]

With the advent of the 5G era, electromagnetic pollution has become increasingly severe. Developing high-performance electromagnetic shielding materials that are flexible and possess excellent mechanical properties is an ideal choice for modern integrated electronic devices and microwave protection, particularly for low-frequency electromagnetic waves. Herein, single-layer and double-layer composite fabrics coated with Barium ferrite (BaFe 12 O 19) and Graphene oxide (GO) were prepared using a coating strategy to achieve high shielding and wave absorption capabilities in the low-frequency band. The layered structure of BaFe 12 O 19 and GO enhances interface loss for reflecting and absorbing microwaves. The double-layer coated composite fabric, with GO as the surface coating material and BaFe 12 O 19 as the bottom coating material, achieved a shielding efficiency (SE) of 66.57 dB with a thickness of only 1.1 mm. Additionally, the minimum reflection loss (RL) reached −11.41 dB at 1.33 GHz, demonstrating exceptional electromagnetic protection at low frequencies. Moreover, the GO-BaFe 12 O 19 coated composite fabric exhibited excellent UV resistance, mechanical stability, and infrared stealth protection. The material holds significant implications in the field of electromagnetic protection, especially for personal protective equipment and equipment protection. • Single-layer and double-layer composite fabrics coated with BaFe 12 O 19 and GO were prepared using a coating strategy to achieve high shielding and wave absorption capabilities in 0.01∼3 GHz. • The double-layer structure of BaFe 12 O 19 coating and GO coating enhances interface loss for reflecting and absorbing microwaves. • The uniform conductive network of the conductive fabric helps to reflect the waves. • The SE of the GO-BaFe 12 O 19 coated composite fabric can reach 66.57 dB at 2.9 GHz, and the RL can reach -11.41 dB at 1.33 GHz. • The composite fabric also has good mechanical firmness, flexibility, and anti-ultraviolet properties, which is of great significance in the field of electromagnetic protection. [ABSTRACT FROM AUTHOR]

The development of hydrogen–oxygen fuel cells with an alkaline electrolyte was highly limited by the sluggish kinetics of the hydrogen oxidation reaction (HOR). Here, with a pyrolysis-reduction route, a new RuNi-based electrocatalyst was prepared, which presents an ultrathin nanowire-like structure. In alkaline media, this catalyst shows an excellent catalytic performance with an exchange current density of 1.10 mA cm−2disk for hydrogen oxidation. The exchange current density and mass activity of this catalyst are much higher than those of its single-metal counterparts and even the commercial Pt/C catalyst containing 20% Pt. Such a remarkable catalytic activity can be explained by the interaction between Ru and Ni; the incorporation of Ni may induce an electronic effect on the optimization of the Ru–Had strength and provide a functional surface that can absorb OH species, thus boosting the catalytic activity. These findings may cast a new light on the exploration of low-cost but high-efficiency catalysts for fuel cells. [ABSTRACT FROM AUTHOR]

The effect of Water Mist System (WMS) settings on fire Heat Release Rate (HRR), smoke gas temperature, smoke blocking effectiveness and required critical velocity were investigated in a 3 m (width) × 2.2 m(height) × 30 m (length) tunnel model equipped with longitudinal ventilation (LV). A total of 60 tests were conducted in 12 configurations, varying the nozzles position, nozzle row number and nozzles pressure. Additionally, 5 bucket tests were also carried out to assess the influence of LV on water mist trajectories. The bucket test results revealed a strong correlation between fire HRRs and the "local" water quantity on the ground near the fire source, particularly for smaller fires. The WMS's effectiveness in reducing the maximum smoke gas temperature rise and critical velocity largely depends on the nozzles which are placed closest to the fire source to a great extent. Reducing the distance to the fire source or increasing water flow rates could both enhance the reduction effect. However, activating additional upstream nozzle rows provides minimal benefit, as the interaction between adjacent rows becomes negligible at higher LV velocities. In contrast, increasing the number of nozzle rows can enhance smoke blocking effectiveness, as measured by the confinement velocity reduction rate. The findings demonstrate that the entrainment and blockage effect of WMS are the primary determinants of the smoke back-layering (BL) degree under the confinement velocity conditions, rather than the smoke cooling effect. Furthermore, positioning the WMS upstream of the fire source and maintaining a certain distance can optimize the combined effects of WMS and LV on fire HRR and smoke back-layering control, which is partly due to the water mist deflection under ventilation flow. This preliminary study provides foundational data on fire and smoke control using water mist in longitudinally ventilated tunnels and offers insights for the optimal design of WMSs. [ABSTRACT FROM AUTHOR]

In this paper, a composite film with a thickness of 0.25 mm was prepared, which has the functions of infrared stealth, ultraviolet protection, sound absorption, and thermal insulation. Firstly, polyaniline was synthesized through chemical oxidative polymerization using aniline as a monomer, acetic acid as a dopant, and ammonium persulfate as an oxidant. Then, the synthesized polyaniline (PANI), hollow glass beads (HGB), and carbon fiber powder (CFP) were sequentially added to waterborne polyurethane, and a film coating machine was used to prepare a multifunctional composite film of PANI/HGB/CFP. Finally, the composite film's infrared properties, ultraviolet protection properties, sound absorption properties, thermal constants, resistance to water penetration properties, bending properties, tensile properties, chemical corrosion resistance, and aging resistance were tested. The results show that the prepared PANI/HGB/CFP composite film has an infrared emissivity of 0.668 and an ultraviolet protection factor (UPF) of 1072, indicating that it can block more than 99 % of ultraviolet rays. Additionally, it has an acoustic absorption coefficient of 0.386. At the same time, the thermal conductivity is 0.04629 W/mK, making it a highly efficient material for heat preservation and thermal insulation. The prepared PANI/HGB/CFP composite film is expected to be a new multifunctional military tarpaulin. [Display omitted] • PANI/HGB/CFP composite film was prepared by adding polyaniline, hollow glass beads, and carbon fiber powder into WPU. • PANI/HGB/CFP composite film has infrared stealth, ultraviolet protection, sound absorption, thermal insulation, and so on. • PANI/HGB/CFP composite film is applied to military tarpaulins, which can ensure the smooth operation of military equipment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chlorella pyrenoidosa could effectively remove dissolved organic phosphorus (DOP). • The absorption of DOP mechanisms included direct and post-hydrolysis absorption. • DOP showed higher growth-promoting effect and increased microalgal biomass yield. • G-6-P promoted central carbon metabolism and biosynthetic pathways. • ATP increased photosynthetic activity but inhibited TCA cycle and purine metabolism. Microalgae-based biotechnology holds significant potential for addressing dual challenges of phosphorus removal and recovery from wastewater; however, the removal mechanism and metabolic adaptation of microalgae to dissolved organic phosphorus (DOP) are still unclear. This study investigated the removal mechanisms and metabolomic responses of the Chlorella pyrenoidosa to different DOP forms, including adenosine triphosphate (ATP), glucose-6-phosphate (G-6-P), and β-glycerophosphate (β-GP). The results showed C. pyrenoidosa could efficiently take up above 96% DOP through direct transport and post-hydrolysis pathways. The uptake of inorganic phosphorus (IP) followed pseudo first order kinetic model, while DOP followed pseudo second order kinetic model. Metabolite profiling revealed substantial alterations in central carbon metabolism depending on the DOP source. G-6-P upregulated glycolytic and TCA cycle intermediates, reflecting enhanced carbohydrates, amino acids and nucleotides biosynthesis. In contrast, ATP down-regulated carbohydrate and purine metabolism, inhibiting sustainable growth of microalgae. This study offers theoretical support for phosphorus-containing wastewater treatment using microalgae. [ABSTRACT FROM AUTHOR]

To solve the problem of electromagnetic radiation pollution, it is especially important to develop electromagnetic wave-absorbing materials with excellent performance. The preparation of composite multifunctional textile materials with excellent wave-absorbing properties is one of the research hotspots for practical personal protection applications. In this work, PPy/Fe 3 O 4 /rGO polyester/cotton composite fabrics were prepared by impregnation, chemical reduction, chemical co-precipitation and in situ polymerization. When the thickness is 0.97 mm, the minimum reflection loss (RL min) of PPy/Fe 3 O 4 /rGO polyester/cotton composite fabric is −12.12 dB, and the effective absorption bandwidth (EAB) is 4.7 GHz, which is excellent in wave absorption. Meanwhile, the PPy/Fe 3 O 4 /rGO polyester/cotton composite fabrics have excellent UV resistance (UV transmittance ratio of UVA and UVB bands as low as 0.02 %, UPF value of 100+), antistatic properties (static voltage half-life of 0.2 s), and excellent thermal management properties (thermal conductivity as low as 0.05796 W/(m·K)), and so on. The PPy/Fe 3 O 4 /rGO polyester/cotton composite fabrics prepared in this study are suitable for a variety of application scenarios, such as individual electromagnetic protection, individual protection in extremely cold environments, and individual heating physiotherapy, which is of great reference significance for the research of wearable individual protective textile materials. • PPy/Fe 3 O 4 /rGO polyester/cotton composite fabrics were prepared by impregnation, chemical reduction, chemical co-precipitation and in situ polymerization. • The RL min of PPy/Fe 3 O 4 /rGO polyester/cotton composite fabric was -12.12 dB and the EAB was 4.7 GHz when the thickness was 0.97 mm. • The ultraviolet transmittance ratio in both UVA and UVB bands is 0.02%, and the UPF value is 100+; the static voltage half-life is 0.2 s; and the low thermal conductivity is 0.05796 W/(m·K). [ABSTRACT FROM AUTHOR]

We have previously shown that circRNAs in host cells are involved in the process of Chlamydia trachomatis infection. In this study we aimed to identify significantly altered circRNAs/lncRNAs/mRNAs in Chlamydia muridarum infected cells and investigate their biological functions in the interaction between Chlamydia muridarum and host cells. For this purpose, circRNA, lncRNA and mRNA expression profiles were screened and identified in HeLa cells with or without Chlamydia muridarum infection by microarray. Bioinformatics analyses including Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and Gene Ontology (GO) analysis were then carried out and the circRNA-miRNA ceRNA network was constructed. The differentially expressed circRNAs and lncRNAs were selected for validation by RT-qPCR. The results shown that a total of 834 circRNAs, 2149 lncRNAs and 1283 mRNAs were found to be differentially expressed. Enrichment analysis of GO and KEGG showed that the dysregulated genes involved nuclear-transcribed mRNA catabolic process, protein binding, RNA catabolic process and translation, the MAPK signaling pathway, apoptosis, Toll-like receptor signaling pathway, cAMP signaling pathway and Notch signaling pathway may play important roles in Chlamydia infection. Our study provides a systematic outlook on the potential function of non-coding RNAs in the molecular basis of Chlamydia infection. [ABSTRACT FROM AUTHOR]

[Display omitted] • A composite electrocatalyst of Au/Co-FeOOH was shown. • The electrocatalyst presents enhanced catalytic activity under photo-irradiation. • With photo-irradiation, the overpotential at 10 mA cm−2 for oxygen evolution decreased of 77 mV. • Hot electron excitation and charge transfer are proposed to induce the catalytic activity enhancement. As one of the most important reactions involved in water splitting, oxygen evolution reaction (OER) suffers from a slow kinetic. Herein, with a composite catalyst of Au/Co-FeOOH, it was shown that the photo-irradiation could greatly activate the catalytic performance for OER due to the plasmon effect of Au nanoparticles. With 532 nm of photo-irradiation, the overpotential at 10 mA cm−2 for OER decreased from 386 to 309 mV with the optimized composite. It is believed that the two factors, hot electron excitation promoting the formation of active species and the charge transfer modulating the electronic structure of active sites, are responsible for the enhancement of catalytic activity. These findings highlighted the possibility of activation of OER catalysis by photo-irradiation and would open up a new route for the design of advanced electrocatalysts. [ABSTRACT FROM AUTHOR]

Compared with other crops, peanut planting costs are lower, and it is very drought-tolerant, and can obtain better benefits. In this paper, 16 peanut varieties were selected, and drought resistance tests were carried out at the flowering and cutting stage under water stress conditions. The root characteristics related to drought resistance of peanuts and the physiological mechanism of drought resistance of different varieties were studied to screen peanut varieties with better drought resistance. According to the relative value (RV) of each trait, the drought resistance coefficient (DC) and drought resistance are calculated. The results show that A596, NC6, Shanhua11 and shanhua7 have strong drought resistance, Shanhua12, Nongda 818, Shanhua 8, Huayu 20, Haihua 1, 79266, Shanhua 9, Hua 17 have moderate drought resistance, while Jihua 4, Guihua 836 , ICG6848 and Baisha1016 have weaker drought resistance. [ABSTRACT FROM AUTHOR]

In this study, the typical wet impregnation method was employed to prepare advanced electrocatalysts for oxygen evolution reaction (OER). The preparation process is easy‐operation and doesn't require any complex synthesis steps. This strategy was demonstrated with Fe3+/Ni2+ loaded on porous carbon as an example. The thus formed pre‐catalyst was in situ activated in the electrochemical test process, during which the electrochemically active species for OER are achieved. With the optimized catalyst, a current density of 10 mA.cm−2 can be obtained at an overpotential of 275 mV. This catalytic performance is close to or even better than the benchmarked RuO2 and IrO2 catalysts. Especially, the catalyst also exhibits good catalytic stability. This study presents a new non‐chemical synthesis route for advanced oxygen evolution catalysts. [ABSTRACT FROM AUTHOR]

Exploring a low-cost and high-performance oxygen evolution catalyst for water splitting to produce clean energy hydrogen is a hot topic. In this study, a simple physical adsorption strategy was used to prepare pre-catalysts of Fe3+–Co2+ species on carbon for the oxygen evolution reaction (OER). The optimized precatalyst shows an excellent electrocatalytic performance, delivering a current density of 10 mA cm−2 at a low overpotential of 295 mV with a small Tafel slope of 61.3 mV dec−1 in 1 M KOH. This study proposes the design of efficient oxygen evolution catalysts by a typical physical adsorption route. [ABSTRACT FROM AUTHOR]

• Simple aromatic proteins, soluble microbial matters and VFAs were prior utilized. • The distribution of VFAs determines the composition of PHA. • Acetic acid played a more important role than other acids. • Even-number acids were easier to be used than odd-number acids in PHA synthesis. • The variation of PHB was consistent with that of PHA, while PHV has a lag. The organic acid rich acidogenic liquid produced from waste sludge anaerobic fermentation was used as a potential feedstock for polyhydroxyalkanoates (PHA) production, which is a cost-effective and environmentally sustainable PHA production system. To analyze the effect of substrate on monomer composition of PHA, different acidogenic liquid generated from waste sludge fermentation in varied initial pH were used as external carbon source. The maximal PHA content accounted for 60.3 % of the dry cell with initial fermentation pH 10.0 sludge acidogenic liquid and the recovered polymer composition was 98.3 % polyhydroxybutyrate (PHB) and 1.7 % polyhydroxyvalerate (PHV) by mass. The utilization efficiency of soluble chemical oxygen demand (SCOD), protein, NH 4 +-N and volatile fatty acids (VFAs) was 95.4 %, 90.5 %, 98.0 %, 99.3 %, respectively. The tyrosine-like protein, tryptophan-like protein, fulvic acid-like organics and soluble microbial by-products were primary used for PHA production, while the humic acid-like organics used little. Furthermore, mass balance analysis was introduced to further illustrate the technology reliability. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have been regarded as promising catalyst materials due to the richness of coordinately unsaturated metal sites on the surface, which can act as catalytic active centres. In this study, a hybrid MOF material composed of Fe-based MOF and Co-based MOF was prepared with the involvement of graphene oxide nanosheets as additive. It was demonstrated that the hybrid MOF materials showed much higher electro-catalytic activity towards oxygen evolution than the single-phase counterparts. To drive current density of 10 mA cm-2, the hybrid CoFe-based MOF only needed an over potential of 290 mV in 1 M KOH. The catalytic activity could sustain for a longer time with only slight current density decrease. During oxygen evolution operation, the MOF catalyst evolved into catalytic active species but kept well the microscale sheet-like structure. It is thus believed that this study will provide an avenue for the development of advanced electrocatalysts. Image 1 • Easy and cost-effective preparation of FeCo-based MOF nanosheets. • The MOF hybrid shows excellent catalytic activity toward oxygen evolution. • The MOF hybrid shows an overpotential of 290 mV at 10 mA cm-2 for oxygen evolution. • Long term catalytic performance stability was confirmed. • The MOF hybrid evolves into catalytic active species but keeps sheet-like structures. [ABSTRACT FROM AUTHOR]

Hydrogen oxidation reaction (HOR) with alkaline solution is an important process for anion exchange membrane hydrogen-oxygen fuel cells, while it presents slow kinetics because it contains the coupling of adsorbed hydrogen (H ad) and hydroxyl (OH ad) species. Herein, PtRu alloy network-like structure with small size was prepared by a solution phase reduction route, which acts as an electrocatalyst for HOR. The presence of Ru changed the d -band center of Pt and so optimized the hydrogen bonding energy on Pt sites. At the same time, Ru species provides functional surface for the adsorption of OH species. The ultrathin size of the alloy units provides richness of exposed active sites for HOR. Benefited from the above factors, the obtained PtRu alloy with Pt:Ru ratio of 1:1 shows the optimized catalytic activity, providing an exchange current density of 1.93 mA cm−2, which is 2.7-fold and 1.5-fold of those for commercial Pt/C and pristine Pt catalyst, respectively. This work provides a new advanced electrocatalyst for alkaline HOR. • An new PtRu-based electrocatalyst was prepared for hydrogen oxidation. • The PtRu-based electrocatalyst presents network like microstructure with small size. • The optimized PtRu catalyst shows enhanced catalytic activity compared to Pt. • Ru modulates the d -band center and optimizes the hydrogen bonding energy on Pt sites. • The presence of Ru provides functional surface for adsorbing of OH species. [ABSTRACT FROM AUTHOR]

Rational reconstruction of oxygen evolution reaction (OER) pre-catalysts and the performance index is crucial but still challenging. Herein, a coordination compound composed by ferrocenedicarboxylic acid and Co2+ was prepared, which was then treated by NaBH 4 solution for the rational reconstruction. The electrochemical activation of the treated product results in the generation of oxyhydroxides with unique microstructure acting as the catalytic active phase, which exhibits excellent electrocatalytic activity with a low overpotential of 256 mV for 10 mA cm−2 towards OER and a half-wave potential of 0.69 V (vs RHE) for oxygen reduction (ORR). Ru species was then loaded on the treated product to further improve the catalytic activity for oxygen reduction. The annealed product (Ru-CoFe/C) presents a core-shell structure with carbon layer on the surface. The product presents an increased half-wave potential of 0.744 V (vs RHE) for ORR with the OER/ORR overpotential gap of 0.776 V for 10 and 1 mA cm−2, respectively, showing the bifunctional catalytic activity. Ru species with small size improves the catalytic activity for ORR; the carbon shell provides the high stability. A Zn-air battery was then fabricated with the Ru-CoFe/C catalyst, which delivers a high power density of 88 mW cm−2 and a large specific capacity of 709 mAh g−1, as well as an excellent cycling stability over 65 h, surpassing commercial Pt/C + RuO 2 based counterpart, demonstrating its feasibility in the field of renewable electronic devices. This work affords valuable guidelines for the application of ferrocene-based materials in OER and for the exploring of advanced bifunctional ORR/OER catalysts in rational construction of high-quality Zn-air batteries. • A pre-catalyst composed by ferrocenedicarboxylic acid and Co2+ was obtained. • Treating of the pre-catalyst by NaBH4 solution induces the rational reconstruction. • The treated catalyst shows excellent electrocatalytic activity for oxygen evolution. • A bifunctional catalyst for oxygen evolution and oxygen reduction was also prepared by loading of Ru species. • A Zn-air battery was then fabricated with the Ru-loaded catalyst, which presents a high energy density. [ABSTRACT FROM AUTHOR]

In this study, Ag nanoparticles loaded CoFe 2 O 4 /Fe 2 O 3 nanorod arrays on carbon fiber cloth have been successfully fabricated by a hydrothermal route followed by a calcination treatment and photochemical reduction process. The as-prepared composite has been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The obtained Ag@CoFe 2 O 4 /Fe 2 O 3 nanorod arrays show excellent SERS performance, which provides enhancement factors (EF) as high as about 1.2 × 10 8 for Rhodamine 6G (R6G). The SERS signals collected over a 20 µm × 20 µm area show relative standard deviation lower than 12%, suggesting good SERS signal uniformity. In addition, the Ag@CoFe 2 O 4 /Fe 2 O 3 nanorod arrays can be used as an effective photo-Fenton catalyst photocatalytical degradation of R6G. It was found that 99.15% of R6G can be degraded in an hour. This bifunctional composite that can act both as SERS substrates and as photo-Fenton catalyst would facilitate the cleaning and recycling of SERS substrates for reusing through a photocatalytic process, as well as facilitate the integration of rapid detection and effective degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

Considering sub-micron potassium titanate whiskers (BX-101), nanoscale potassium titanate whiskers (AX-301), sub-micron potassium titanate whiskers (AX-316) and high strength potassium titanate crystal (AX-319) as functional fillers, heat resistant ablative coated fabrics which have high radiant heat reflectivity were prepared. The effect of the type of functional filler on the thermal protection performance of heat resistant ablative coated fabrics was mainly discussed. Research showed that the microstructure of potassium titanate functional filler had a significant impact on the radiant heat reflectivity and thermal insulation performance of the prepared coated fabric. The coated fabric which took nanoscale potassium titanate whiskers (AX-301) with a minimum diameter and greater length-diameter ratio as functional filler has the highest thermal reflectivity and the best insulation property. Heat ray reflectivity of potassium titanate coated fabrics had positive correlation with their crystallinities. The higher the coated fabric crystallinity was, the greater the heat ray reflectivity. Thermogravimetric analysis results showed that after adding four kinds of potassium titanate fillers, the thermal stability of the prepared coated fabrics was enhanced, and the nanoscale potassium titanate whiskers (AX-301) coated fabrics had the best thermal stability. The microstructure of potassium titanate had a significant impact on the thermal protective performance of the prepared coated fabric. Nanoscale potassium titanate whiskers (AX-301) coated fabric has the highest thermal reflectivity, the best insulation property and thermal stability [ABSTRACT FROM AUTHOR]

In the high temperatures experienced in fire, radiant heat accounts for 80% of the total heat flow; therefore, improving the radiation protection is the best way to enhance the thermal protective performance of thermal insulation ablation resistant coated fabrics. To achieve this goal, the coating process and the ingredients used were optimized, spherical nano-SiO2 and other particles were added, and thermal insulation ablation resistant coated fabrics with high radiant heat reflectivity were prepared. The influence of the spherical nano-SiO2 content on the thermal protection performance of the prepared coated fabrics was investigated. Research showed that (1) the radiant heat reflectivity of the prepared coated fabrics improves significantly with increasing content of spherical nano-SiO2; when the mass fraction of spherical nano-SiO2 is 15%, the reflectivity of coated fabrics is at its largest, and its average value was 74.30%. At present, the average size of grains in samples increased 1.9 times; (2) after adding the spherical nano-SiO2, the thermal stability of the thermal insulation ablation resistant coated fabrics is significantly improved; the residual mass is as high as 88.49% at 1200°C, which is 18.77% higher than the residual mass of the coated fabrics with no spherical nano-SiO2 added at the same temperature. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks represent an emerging class of effective pre-electrocatalysts with low cost and high activity for oxygen evolution, which is a critical process involved in water splitting and metal-air batteries. In this study, a new electrode with ferrocene-based coordination compounds supported by nickel foam was designed and prepared, in which the coordination compounds are assembled by cobalt chloride and 1, 1'-ferrocenedicarboxylic acid. The as-obtained pre-catalytic electrode shows remarkable electrocatalytic activity and stability towards oxygen evolution. In 1 M KOH, the electrode can provide a current density of 50 mA cm−2 at an overpotential of 268 mV with Tafel slope of 109 mV dec−1. During the catalytic process, the metal-organic framework surface shows an obvious phase evolution behavior. The synergetic effect between Co and Fe sites, and the unique microstructure of the in situ derived active species are believed to be responsible for the excellent electrocatalytic performance. The catalytic electrode was also investigated as a cathode in a Zn-air battery, which presents an energy density of 572 mW h g Zn −1, a peak power density of 60 mW cm−2, and an excellent cyclability of over 50 h. This work presents a new type pre-catalytic electrode for oxygen evolution and would provide some hints for the development of advanced catalytic electrodes. [Display omitted] • An new MOF-based pre-catalytic electrode was prepared for water oxidation. • Cobalt chloride and ferrocenedicarboxylic acid were selected to fabricate the MOF materials. • The electrode show unique sheet-like structure and high catalytic activity for water oxidation. • The application of the electrode in Zn-air battery was demonstrated. [ABSTRACT FROM AUTHOR]

Nearly monodispersed Ag3PO4 nanocrystals with size of 10 nm were prepared through a colloidal chemical route. It was proven that the synthesized Ag3PO4 nanoparticles have intrinsic peroxidase-like catalytic activity. They can quickly catalyze oxidation of the peroxidase substrate 3, 3, 5, 5-tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue color. The catalysis reaction follows Michaelis-Menten kinetics. The calculated kinetic parameters indicate a high catalytic activity and the strong affinity of Ag3PO4 nanocrystals to the substrate (TMB). These results suggest the potential applications of Ag3PO4 nanocrystals in fields such as biotechnology, environmental chemistry, and medicine. [ABSTRACT FROM AUTHOR]

With a facile solvothermal method, Ag@Fe3O4 nanowire was successfully prepared and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The obtained Ag@Fe3O4 nanowire posses enhanced peroxidase-like activity with good stability and high absorbance. The optimization of pH, H2O2 concentration and loading capacity were carried out. The result of kinetic analysis indicates that the catalyzed reaction followed a Michaelis-Menten behavior. The good peroxidase-like activity makes Ag@Fe3O4 nanowire be promising for real application in biomedicine. [ABSTRACT FROM AUTHOR]

Porous CuO micro-/nanostructures with clean surface, prepared through Cu2(OH)2CO3 precursor followed by calcination in air, were proven to be an effective peroxidase mimic. They can quickly catalyze oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue color. The obtained porous CuO micro-/nanostructure have potential application in wastewater treatment. The apparent steady-state kinetic parameter was studied with TMB as the substrate. In addition, the potential application of the porous CuO in wastewater treatment was demonstrated with phenol-containing water as an example. Such investigation not only confirms the intrinsic peroxidase-like activity of micro-/nanostructured CuO, but also suggests its potential application in wastewater treatment. [ABSTRACT FROM AUTHOR]

Hierarchical Ni(OH)2 microstructures with sizes of several micrometers have been synthesized through a polymer mediated self-assembly route. The hierarchical Ni(OH)2 microstructures are built of sheet-like building blocks, which are further composed of “side to side” stacking of tiny sheet-like units. The influence of various experimental parameters on the microstructure was investigated. It is believed that the polymer, poly(sodium-4-styrene sulfonate), selectively bonded on the surface of Ni(OH)2 clusters mediates the formation of hierarchical Ni(OH)2 microstructures. In addition, through the chemical conversion of Ni(OH)2 to NiO, an oxide sensor was fabricated, which exhibits excellent gas sensing performances to ethanol and propanol, suggesting the potential applications. It is also anticipated that these Ni(OH)2 microstructures will have successful applications in Ni-based batteries, electrodes, and so on. [ABSTRACT FROM AUTHOR]

Abstract: Co3O4/ZnO nanocomposites were prepared by an easy wet-chemistry route without any organic additive or surfactant used. The nanocomposites were systematically characterized by X-ray powder diffraction, scanning electron microscopy, (high-resolution) transmission electron microscopy, selected area electron diffraction, and energy-dispersive X-ray spectroscopy. The results show that ZnO is loaded on the surface of Co3O4 nanoparticles with a compact and clean hetero-interface. The obtained nanocomposites were tested for gas-sensing applications with ethanol and formaldehyde as model gases. It was revealed that the nanocomposites exhibit enhanced gas-sensing performance such as high stability and high sensing response. The sensing responses to 100ppm ethanol or formaldehyde (46 to ethanol and 20 to formaldehyde) are much higher than those of pristine Co3O4 nanoparticles (6.2 to ethanol and 4.4 to formaldehyde), commercial Co3O4 powder (1.6 to ethanol and 1.5 to formaldehyde), and pure ZnO sample (7.5 to ethanol and 4.1 to formaldehyde). These results suggest that the integration of Co3O4 with ZnO is a promising route to the development of effective sensing materials. The excellent gas-sensing properties and the easily up-scalable preparation route make the prepared nanocomposites be promising for real applications. [Copyright &y& Elsevier]

Abstract: Large-scale novel hierarchical ZnO microspheres were fabricated by a facile precursor procedure in the absence of self-assembled templates, organic additives, or matrices. A field emission scanning electron microscopy (FESEM) image reveals that the ZnO microspheres with diameter of 5–18μm are built by sheet-like ZnO networks with average thickness of 40nm and length of several microns. High resolution transmission electron microscopy (HRTEM) image indicates that the building blocks, sheet-like ZnO networks, are porous mesocrystal terminated with {01−10} crystal planes. A potential application of the ZnO microspheres as a catalyst in the synthesis of 5-substituted 1H-tetrazoles was investigated. It was found that the hierarchical ZnO microsphere catalyst exhibits structure-induced enhancement of catalytic performance and a strong durability. [Copyright &y& Elsevier]

In order to improve the electromagnetic wave absorbing performance of carbon fiber cloth at low frequency and reduce the secondary pollution caused by the shielding mechanism, a flexible sandwich composite was designed by a physical mixing coating process. This was composed of a graphene layer that absorbed waves, a carbon fiber cloth layer that reflected waves, and a graphite layer that absorbed transmitted waves. The influence of the content of graphene was studied by a control variable method on the electromatic and mechanical properties. The structures of defect polarization relaxation and dipole polarization relaxation of graphene, the interfacial polarization and electron polarization of graphite, the conductive network formed in the carbon fiber cloth, and the interfacial polarization of each part, combined together to improve the impedance matching and wave multiple reflections of the material. The study found that the sample with 40% graphene had the most outstanding absorbing performance. The minimum reflection loss value was −18.62 dB, while the frequency was 2.15 GHz and the minimum reflection loss value compared to the sample with no graphene increased 76%. The composites can be mainly applied in the field of flexible electromagnetic protection, such as the preparation of stealth tent, protective covers of electronic boxes, helmet materials for high-speed train drivers, etc. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive set of numerical simulations for the characterization of a water mist spray emerging from a nozzle positioned at 2.2 m from floor level and operating at a pressure of 1.0 MPa. The droplet volume-median diameter is about 90 μm and the spray half-angle is around 42 °. The spray shape is visualized using a laser sheet and the water flux density distribution on the ground is measured with a 'bucket' test. An initial comprehensive numerical study using the Fire Dynamics Simulator (FDS) has been carried out by varying several numerical and physical models and parameters (e.g., cell size and turbulence modelling). The simulated sprays were very narrow (in comparison to the actual spray), yielding overestimations of the peak water flux density at floor level by about 430% (on average). Subsequently, it was found that there is a significant impact of the drag force modelling because the spray at hand is dense (near the nozzle). An ad-hoc reduction of the drag coefficient to a constant value leads to better results. The current study calls upon new developments for droplet aerodynamic modelling in dense sprays. [ABSTRACT FROM AUTHOR]

Directly applying metal-organic frameworks (MOFs) as electrocatalysts or pre-catalysts for the oxygen evolution reaction (OER) faces significant challenges, due to the lack of exposed active sites, low electronic conductivity, and poor structure stability. Herein, a novel alkaline leaching-solvothermal strategy is proposed to synthesize seaweed-like Co-MOF/Cu(OH) 2 on copper foam (CF), which is applied as self-supporting pre-catalyst for OER. After electrochemical activation, Co-MOF/Cu(OH) 2 /CF only requires an overpotential of 279 mV at 50 mA cm−2 and operates steadily for 72 h with negligible activity deterioration. The high activity and stability mainly benefit from the unique structural arrangement, in which Cu(OH) 2 nanoneedles serve as firm substrates to grow and stabilize Co-MOFs. The two-dimensional Co-MOFs with nanometer thickness and high accessible surfaces could expose sufficient metal coordination sites, which are ready for reconstruction and electrocatalysis. Additionally, CF framework helps to maintain the self-supporting structure and acts as current collector to enhance the charge/electron transfer efficiency during OER. [Display omitted] • Alkaline leaching-solvothermal method to prepare self-supporting Co-MOF/Cu(OH) 2 /CF. • The seaweed-like structure to stabilize Co-MOF and expose sufficient active sites. • High activity and stability for OER catalysis after electrochemical activation. [ABSTRACT FROM AUTHOR]

Sb nanoparticles (∼50 nm) are embedded uniformly on the surface of carbon fibers (Sb NPs–SCFs) without scattered Sb NPs. The Sb NPs–CNFs anode exhibits excellent sodium storage, delivering a second cycle discharge capacity of 455.7 mA h g−1 at 1.0 A g−1 and a stable capacity of 381.9 mA h g−1 after 200 cycles, achieving a notable retention of 83.8%. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Facile mass transport channel and accessible active sites are crucial for binder‐free air electrode catalysts in rechargeable flexible zinc‐air battery (ZAB). Herein, a ZnS/NH3 dual‐assisted pyrolysis strategy is proposed to prepare N/S‐doped hierarchical porous bamboo carbon cloth (HP‐NS‐BCC) as binder‐free air electrode catalyst for ZAB. BCC fabric with abundant micropores is firstly used as flexible carbon support to facilitate the heteroatom‐doping and construct the hierarchical porous structure. ZnS nanospheres and NH3 activization together facilitate the electronic modulation of carbon matrix by N/S‐doping and optimize the macro/meso/micropores structure of carbon fibers. Benefiting from the highly‐exposed N/S‐induced sites with enhanced intrinsic activity, the optimized mass transport of biocarbon fibers, as well as the ultra‐large specific surface area of 2436.1 m2·g–1, the resultant HP‐NS‐BCC catalyst exhibits improved kinetics for oxygen reduction/evolution reaction. When applied to rechargeable aqueous ZABs, it achieves a significant peak power density of 249.1 mW·cm−2. As binder‐free air electrode catalyst, the flexible ZAB also displays stable cycling over 500 cycles with a minimal voltage gap of 0.42 V, showcasing promising applications in flexible electronic devices. [ABSTRACT FROM AUTHOR]

Background: Thyroid dysfunction plays an important role in the pathology of diabetes-associated cognitive dysfunction (DACD). However, thyroid hormone (TH) signaling and action changes in DACD brains remain unknown. This study evaluated the alternations in TH signaling and action in the brains of DACD mice and explored the beneficial effects of levothyroxine (L-T4) treatment. Methods: KK-Ay mice, serving as a spontaneous type 2 diabetes mellitus model, underwent intragastric administration of 10 ng/g and 20 ng/g of L-T4 solution or normal saline for 8 weeks. Age-matched C57BL/6J mice were used as normal controls. Cognitive and memory functions were examined through the open field and Morris water maze tests. Hippocampal TH signaling and pathogenic status were evaluated. The potential signaling pathways involved in the neuroprotective action of L-T4 were investigated through RNA sequencing and further verified through quantitative real-time PCR (qPCR), Western blotting (WB), immunofluorescence (IF), and fluorescent multiplex immunohistochemistry (mIHC) in vivo and vitro. Results: The expressions of hippocampal TH transporters (Mct8 and Oatp1c1), Dio2, and TH receptor were upregulated, whereas Dio3 as well as the TH-positive regulated genes MBP, Enpp2, and Klf9 were downregulated in DACD mice. Exogenous L-T4 partially alleviated cognitive and memory dysfunction and restored hippocampal neuronal activity by optimizing TH signaling. RNA sequencing provided insights into the role of type I interferon (IFN-I) signaling and necroptosis on the amelioration of hippocampal damage after L-T4 treatment. WB and qPCR further confirmed that the levels of key proteins for IFN-I signaling and necroptosis (p-STAT1, p-STAT2, IRF9, ZBP1, p-RIP3, and p-MLKL) were increased, but largely returned after L-T4 administration in vivo and T3 treatment in vitro. IF and mIHC revealed that IRF9 and p-MLKL colocalized in neurons, but not in astrocytes or microglia, of the hippocampus in DACD mice. The diabetes mellitus group had an increased number of IRF9+ p-MLKL+ NeuN+ cells, which decreased after L-T4 treatment. The elevated IFN-I signaling-mediated necroptosis in HT22 cells was also decreased by T3. Conclusion: We demonstrated abnormal hippocampal TH signaling and action in DACD. Promoting TH action with exogenous L-T4 ameliorated hippocampal impairment through inhibiting IFN-I signaling-induced necroptosis. [ABSTRACT FROM AUTHOR]

What is known and objective: Pain is the main symptom of herpes zoster (HZ), whilst postherpetic neuralgia (PHN) is a long‐term unbearable pain, which seriously affects the quality of life of patients and is also the most intractable problem for clinicians. Early antiviral treatment is considered as a key measure to reduce acute pain and PHN. Nevertheless, most patients still have long‐term pain after 7 days of antiviral treatment, and some patients will develop PHN. This study aimed to investigate whether prolonged duration of antiviral therapy could reduce HZ acute pain and the occurrence of PHN. Methods: The outpatient data of HZ patients over 50 years old who visited the Dermatology Department from January 2016 to May 2018 were retrospectively analysed. According to the different courses of treatment of famciclovir (FCV), the patients were divided into 7‐day FCV group and 14‐day FCV group. The numerical rating scale (NRS) score at the first visit and on the 7th, 14th and 21st days after the start of treatment, the adverse drug reactions and the incidence of PHN were compared between the two groups. Results: A total of 219 patients were involved in the analysis. For acute pain control, the 14‐day FCV group was better than the 7‐day FCV group. For patients with mild initial pain, there was no significant difference in NRS between the two treatments. For patients with moderate‐to‐severe initial pain, the NRS in the 14‐day FCV group was significantly lower than that of the 7‐day FCV group on the 14th and 21st days after starting treatment. PHN occurred in patients with moderate‐to‐severe initial pain, and the incidence was significantly lower in the 14‐day FCV group than in the 7‐day FCV group. There was no significant difference in the number of adverse reactions between the two groups. What is new and conclusion: Compared with the traditional 7‐day antiviral therapy, the 14‐day course of FCV can reduce the acute pain and the incidence of PHN in elderly patients with HZ, especially in patients with moderate to severe initial pain. Prolonging the course of medication did not increase the side effects. [ABSTRACT FROM AUTHOR]

The individual and combined effect of a water mist system (WMS) and longitudinal ventilation (LV) on the fire HRR, smoke temperature and back-layering (BL) degree were explored in a 3 m (width) × 2.2 m(height) × 30 m (length) tunnel model. A series of 39 tests has been conducted in 6 configurations, varying the velocity, water volume flow rate and nozzles arrangement. When the WMS or LV is imposed individually, the reduction effect on the HRR gets stronger with larger water volume flow rates or higher velocities. Yet, under the combined effect, the effect of the LV velocity on the HRR is non-monotonic: the HRR first reduces more, and then rises again with higher LV velocities for given WMS settings. The reduction in temperature monotonically increases with higher LV velocities, in contrast to the HRR behavior. The above phenomenon is explained to be due to the relatively 'low' flame height in the present paper, as a consequence of which the interaction between the flame and the water droplets mainly occurs in the lower part of the tunnel, while the interaction between the hot smoke and the water droplets mainly happens in the upper part. The fire HRR behavior mainly relates to the interaction in the lower part, while the temperature depends on both regions. Besides, for a certain BL distance, the required ventilation velocities reduce by 13%–55% with activated WMS, compared to the same conditions without WMS. The effect of covering the fire with a shield is also discussed. For relatively small velocities, the fire HRR, smoke temperature and BL distance are larger with the shield in place. [ABSTRACT FROM AUTHOR]

[Display omitted] Simultaneously dispersing phosphide crystallites and multiple heteroatoms in hollow carbon is a significant yet challenging task for achieving high-performance oxygen electrocatalysts of zinc-air batteries. Herein, a simple wrapping-pyrolysis strategy is proposed to prepare Co 2 P/CoP embedded in N, P, S triply-doped hollow carbon (Co 2 P/CoP@NPS-HC). Co 2 P/CoP@NPS-HC composite features hollow polyhedral structure populated with numerous catalytically active Co 2 P/CoP nanoparticles and N, P, S heteroatoms. This optimized catalyst exhibits excellent activity for oxygen reduction reaction, with a half-wave potential of 0.82 V vs. RHE, and impressive enhancement for oxygen evolution reaction, indicated by an overpotential of 400 mV at 10 mA cm−2. Moreover, Co 2 P/CoP@NPS-HC catalyst exhibits greater durability and superior methanol tolerance compared to commercial Pt/C. The excellent bifunctional electrocatalytic performance of Co 2 P/CoP@NPS-HC catalyst is attributed to the synergistic effect of uniformly dispersed Co 2 P/CoP nanoparticles and N, P, S triply-doped hollow carbon structure. The former provides abundant catalytically active sites, while the latter offers a high accessible specific surface area, as well as enhances catalytic activity and electronic conductivity due to its altered charge distribution. [ABSTRACT FROM AUTHOR]

• Nickel based materials catalyze hydrogen oxidation reaction. • Ni-NiO materials present improved catalytic activity than pristine Ni for hydrogen oxidation. • Doped carbon substrate can improve the catalytic performance of Ni-based catalysts. With the rapid development of anion exchange membranes, researchers began to shift their attention from proton exchange membrane fuel cells (PEMFCs) with acid electrolytes to anion exchange membrane fuel cells (AEMFCs) with alkaline electrolytes. Non-precious metal catalysts such as Fe-N-C catalysts are available for ORR at the cathode in alkaline electrolytes. But at the anode, the catalytic reaction kinetics of Pt catalysts in alkaline media is two orders of magnitude slower than that in acid media, which prompts researchers to develop new low-cost and high-efficient non-precious metal catalysts for HOR. Up to date, the typical non-precious metal catalysts for HOR are Ni-based materials. In this minireview, we firstly introduced the elementary steps of HOR and the important activity parameters for a HOR catalyst. Secondly, we briefly describe the performance of various Ni-based HOR catalysts reported in recent years. [ABSTRACT FROM AUTHOR]

A 1/3 scaled tunnel model was built to explore the effect of fire source elevation on fire and smoke behavior, and especially the critical velocity, in a tunnel with longitudinal ventilation. An experimental campaign has been carried out with a series of tests in 9 configurations, varying the fire size, ventilation velocity and fire elevation. Results in terms of combustion rate, ceiling temperature and critical velocity are discussed. If the flame reaches the ceiling when the fire source is elevated, the fuel burning rate increases by 15% due to increased heat feedback created by the part of the flame below the ceiling. The location of the maximum ceiling temperature can move towards the downstream region in such conditions. A variable named as the height of the effective tunnel, H ' , was proposed to substitute the tunnel height, H , in the Li et al. model [1] to consider the effect of fire elevation in predicting critical velocity. The accuracy was illustrated by means of the results of the present tests and those of other research studies. Based on a dimensional analysis, three conditions are identified on the basis of the ratio of the flame height to the height difference between fire surface and the tunnel ceiling, L f l H ' . This allows to demonstrate the variation of the critical velocity with changing fire elevations. The accuracy was illustrated by means of the results of the present tests and those of other research studies. The increase of fire elevation leads to the increase of the dimensionless variables Q ∗ (W H ' ) − 1 4 , L f l H ' and V ∗ (although this remains sometimes unchanged), rather than only a rise or diminution of critical velocity. [ABSTRACT FROM AUTHOR]

• The TiO 2 , acetylene black and persulfate were combined in the degradation of TH. • The adsorption and activation efficiency of TiO 2 was improve by acetylene black. • The TH degradation was increased by 38.5% when persulfate was involved. The photocatalysis and advanced oxidation processes were combined in the degradation of tetracycline hydrochloride (TH). The TiO 2 doped with acetylene black (TiO 2 /AB) was employed with persulfate (PS) to generate reactive radicals. The TiO 2 /AB-2.5 wt% exhibited the best removal efficiency of TH, compared with TiO 2 /AB-1.25 wt%, TiO 2 /AB-5 wt% and TiO 2 /AB-10 wt%. The TiO 2 /AB/PS can significantly improve the TH degradation rate by 38.5% compared with the TiO 2 /AB. The operating conditions such as the PS dosage, TiO 2 /AB dosage, pH, and initial concentration of TH on the degradation of TH were investigated, and the optimal removal efficiency of TH was obtained when the concentration of PS was 3 mmol/L, TiO 2 /AB dosage was 0.5 g/L, pH = 4.1 and initial concentration of TH was 10 mg/L. The ethanol and tertiary butanol were used as the radical scavengers to identify the dominant reactive radical species in the TiO 2 / AB/PS system. The SO 4 − was demonstrated more important than OH in the degradation of TH. Then the intermediates and possible degradation pathways of TH were discussed. Finally, the stability of TiO 2 /AB and toxicity of TH were studied. The degradation efficiency was still above 85% after 5 cycles. The toxicity assessment results suggest that the aquatic toxicity of TH was effectively diminished. [ABSTRACT FROM AUTHOR]

• In situ formation of electrocatalytic species is shown with commercially products. • The formed species can drive 10 mA cm−2 at 330 mV, comparable to reported catalysts. • Bimetallic catalyst ink shows much higher activity than monometallic catalyst inks. • No energy-intensive preparation steps or noble metals are involved for the strategy. Scaling up new transition metal-based oxygen evolution catalysts for practical applications is still hindered by the complex synthesis route. In this study, in situ formation of electrocatalytic active species is simply achieved with a mixture ink composed of Nafion binder, commercially available acetylene black, and Fe3+/Co2+ ions. In this route, energy-intensive material preparation steps or noble metals are not required. The thus formed electrochemical active species can afford current density of 10 mA cm−2 at a lower overpotential of 330 mV and showing a small Tafel slope of 55 mV dec−1 in 1 M KOH, which is comparable to amounts of reported catalysts. It is proposed that the involved Fe3+/Co2+ ions are in situ transformed into hydroxides that further evolves into catalytic active species for oxygen evolution. The concept presented here is one of the simplest strategies to prepare highly active electrocatalysts for potential commercial application. [ABSTRACT FROM AUTHOR]

A bidirectional CLLC resonant converter (CLLC-BRC) based on GaN transistors is analyzed and designed in this paper. Similar resonant topologies are listed and commented on, with the CLLC topology showing competitiveness in bidirectional energy transmission. The analysis of the aforementioned converter has been provided, including the reveal of resonant frequencies of the CLLC topology and an improved zero-voltage switching (ZVS) condition with operation principles of the reverse mode and relevant parasitic parameters taken into account. The design methodology of the aforementioned converter based on pulse frequency modulation (PFM) is further discussed in detail. A prototype with a rated power of 400 W and a maximal operating frequency that is larger than 0.5 MHz was built to verify the proposed design methodology. The highest conversion efficiency of the prototype was 97.02% in the forward mode, and it was 95.96% in the reverse mode. [ABSTRACT FROM AUTHOR]

[Display omitted] • The current progress of Ir-based catalysts for hydrogen oxidation reaction. • The mechanism of hydrogen oxidation in alkaline solution. • Strategies for the catalytic activity improving. • Challenges and prospects of Ir-based catalysts. The utilization of renewable energy conversion devices is regarded as a viable approach to mitigate both the scarcity of energy resources and their detrimental impact on the environment. Consequently, the investigation of clean and sustainable energy sources possessing a high gravimetric energy density has served as a significant impetus for exploring hydrogen energy as a cost-effective substitute for fossil energy. Accelerating the reaction process and applying it on a larger scale both stand to benefit from the development of electrocatalysts that offer high levels of performance at reasonable prices. The development of efficient and cost-effective electrocatalysts for hydrogen oxidation reaction (HOR) is crucial for advancing the field of hydrogen fuel cells. Compared to commercial platinum catalyst (Pt/C), iridium-based (Ir-based) nanomaterials have demonstrated catalytic performance that is on par with Pt/C. This review firstly summarizes the recent progress of Ir-based catalysts and the electrocatalytic performance towards HOR. Then, the challenges and prospects are highlighted, which lie ahead for the future development and practical application of Ir-based nanomaterials. Further research to optimize the catalytic performance, reduce the catalyst loading, and cost, and understand the mechanism is emphasized. The findings could pave the way for developing advanced HOR electrocatalysts, accelerating the realization of efficient and sustainable hydrogen-based energy systems. [ABSTRACT FROM AUTHOR]

The hydrogen oxidation reaction is an important process in anion exchange membrane fuel cells with alkaline solutions. The pursuit of efficient catalysts for alkaline hydrogen oxidation has attracted considerable attention. In this study, we present a precursor route for the synthesis of a new Ir-based catalyst (Ir–Ni/NiO/C), in which Ir nanoclusters were immobilized on the generated Ni/NiO/C support derived from a metal–organic framework. The small size of Ir clusters facilitates the exposure of catalytically active sites. The electronic interplay between the Ir nanoclusters and the Ni/NiO/C support optimized the hydrogen binding energy (HBE) and hydroxide binding energy (OHBE) on the surface, which is unattainable on the contrasting Ir–C, Ir–Ni/C, and Ir–NiO/C products. The optimized catalyst shows excellent mass activity for alkaline hydrogen oxidation, which is 3.1 times that of the Pt/C catalyst. This study presents a promising pathway for the development of advanced HOR catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co/CoO heterogeneous nanoparticles with different size are uniformly dispersed in mesoporous N-doped carbon (NC). • The smallest Co/CoO/NC-S shows excellent catalytic activity for oxygen reduction reaction in zinc-air batteries. • The performance of Co/CoO/NC-S is attributed to the ultra-small nanoparticle size and heterogeneous interface. The size of metal compound particles and interface electronic structure of heterojunctions in a matrix greatly affect oxygen reduction performance in zinc-air batteries. However, it is still a big challenge to precisely control or regulate the size of these metal compound particles and the heterojunction structure. Herein, cobalt complexes with different-sized ligands are chosen as cobalt resources and adsorbed onto a mesoporous carbon, after which they are coated with polydopamine and calcined. Under the confinement effect of mesopores and the isolation effect of ligands and dopamine, the as-obtained Co/CoO heterogeneous nanoparticles are restricted to nano-size and uniformly dispersed in N-doped carbon (NC). The sizes of Co/CoO are estimated to be 39.7, 24.9 and 15.6 nm with increased CoO contents, corresponding to the adopted cobalt precursors of Co(OAc) 2 , Co(acac) 2 and Co(acac) 3 , respectively. The smallest Co/CoO/NC-S shows excellent catalytic activity for oxygen reduction reaction, with a half-wave potential of 0.82 V vs. RHE and a limiting current density of 4.59 mA cm−2. When applied to the cathode of zinc-air battery, a high peak power density of 131.9 mW cm−2 is achieved, which surpasses that of the battery powered by Pt/C. The excellent performance can be attributed to the formation of heterogeneous structures between Co and CoO, the smaller Co/CoO nanoparticles, and N -doped mesoporous carbon with effective charge/mass transport. This work provides an effective way to regulate the size and phase contents of heterogeneous particles in mesoporous carbon, which is highly valuable in electrocatalytic systems. [ABSTRACT FROM AUTHOR]

Abstract Development of effective electrocatalysts for oxygen evolution reaction (OER) is critically important, which is believed as the bottleneck process in overall water splitting and chargeable metal-air battery. In this study, we fulfill an OER improvement by introducing of trace Au on CoFe 2 O 4 surface by electrochemical method. The loading of trace Au highly improves the OER activity, decreasing the overpotential of 374 mV at 10 mA cm−2 to 312 mV and showing a small Tafel slope of 35 mV dec−1 in 1 M KOH. The loaded trace Au largely increases the electrochemical active specific area. The electronic interactions between Au and the adjacent CoFe 2 O 4 modulate the electron structure of metal sites, which further optimize the binding strength between the involved intermediates and catalysts, facilitating the transform of rate-limiting step. Importantly, such enhanced electrocatalytic performance can be largely maintained after a long-time stability test. Graphical abstract Trace Au can highly improve the oxygen evolution of CoFe 2 O 4 catalyst. The loaded trace Au not only largely increases the electrochemical active specific area, but also optimizes the binding strength between the involved intermediates and the catalytic sites, significantly boosting the catalytic activity. Unlabelled Image Highlights • Trace Au can highly improve the catalytic oxygen evolution activity of CoFe 2 O 4. • The overpotential of CoFe 2 O 4 catalyst decreases from 374 mV at 10 mA cm−2 to 312 mV after the loading of trace Au species. • Trace Au increases the electrochemical active specific area of CoFe 2 O 4. • The electronic interactions between Au and the adjacent CoFe 2 O 4 modulate the electron structure of metal sites. [ABSTRACT FROM AUTHOR]

Constructing atom‐clusters (ACs) with in situ modulation of coordination environment and simultaneously hollowing carbon support are critical yet challenging for improving electrocatalytic efficiency of atomically dispersed catalysts (ADCs). Herein, a general diffusion‐controlled strategy based on spatial confining and Kirkendall effect is proposed to construct metallic ACs in N,P,S triply‐doped hollow carbon matrix (MACs/NPS−HC, M=Mn, Fe, Co, Ni, Cu). Thereinto, FeACs/NPS−HC with the best catalytic activity for oxygen reduction reaction (ORR) is thoroughly investigated. Unlike the benchmark sample of symmetrical N‐surrounded iron single‐atoms in N‐doped carbon (FeSAs/N−C), FeACs/NPS−HC comprises bi‐/tri‐atomic Fe centers with engineered S/N coordination. Theoretical calculation reveals that proper Fe gathering and coordination modulation could mildly delocalize the electron distribution and optimize the free energy pathways of ORR. In addition, the triple doping and hollow structure of carbon matrix could further regulate the local environment and allow sufficient exposure of active sites, resulting in more enhanced ORR kinetics on FeACs/NPS−HC. The zinc‐air battery assembled with FeACs/NPS−HC as cathodic catalyst exhibits all‐round superiority to Pt/C and most Fe‐based ADCs. This work provides an exemplary method for establishing atomic‐cluster catalysts with engineered S‐dominated coordination and hollowed carbon matrix, which paves a new avenue for the fabrication and optimization of advanced ADCs. [ABSTRACT FROM AUTHOR]

Constructing atom‐clusters (ACs) with in situ modulation of coordination environment and simultaneously hollowing carbon support are critical yet challenging for improving electrocatalytic efficiency of atomically dispersed catalysts (ADCs). Herein, a general diffusion‐controlled strategy based on spatial confining and Kirkendall effect is proposed to construct metallic ACs in N,P,S triply‐doped hollow carbon matrix (MACs/NPS−HC, M=Mn, Fe, Co, Ni, Cu). Thereinto, FeACs/NPS−HC with the best catalytic activity for oxygen reduction reaction (ORR) is thoroughly investigated. Unlike the benchmark sample of symmetrical N‐surrounded iron single‐atoms in N‐doped carbon (FeSAs/N−C), FeACs/NPS−HC comprises bi‐/tri‐atomic Fe centers with engineered S/N coordination. Theoretical calculation reveals that proper Fe gathering and coordination modulation could mildly delocalize the electron distribution and optimize the free energy pathways of ORR. In addition, the triple doping and hollow structure of carbon matrix could further regulate the local environment and allow sufficient exposure of active sites, resulting in more enhanced ORR kinetics on FeACs/NPS−HC. The zinc‐air battery assembled with FeACs/NPS−HC as cathodic catalyst exhibits all‐round superiority to Pt/C and most Fe‐based ADCs. This work provides an exemplary method for establishing atomic‐cluster catalysts with engineered S‐dominated coordination and hollowed carbon matrix, which paves a new avenue for the fabrication and optimization of advanced ADCs. [ABSTRACT FROM AUTHOR]

The sluggish oxygen evolution kinetics involved in water splitting and various metal-air batteries makes the effective and inexpensive electrocatalysts be highly desirable for oxygen evolution reaction (OER). Herein, an effective and facile two-step route is developed to construct Fe 3 O 4 @NiS x composite loaded on reduced graphene oxide (rGO). The morphology and microstructure of the composites were characterized by different characterization techniques. The obtained composites show amounts of heterointerfaces. The shift of binding energy in X-ray photoelectron spectrum demonstrates the existence of interfacial charge transfer effect between Fe 3 O 4 and NiS x . The optimized Fe 3 O 4 @NiS x /rGO sample exhibits excellent electrocatalytic performance toward OER in alkaline media, showing 10 mA·cm −2 at η = 330 mV, lower Tafel slope (35.5 mV·dec −1 ), and good durability, demonstrating a great perspective. The excellent OER performance can be ascribed to the synergetic effect between Fe and Ni species. It is believed that the heterointerfaces between Fe 3 O 4 and NiS x perform as active centers for OER. [ABSTRACT FROM AUTHOR]

Supercapacitors with superior performance and long cycling ability are attractive for the next-generation energy storage devices. Herein, an unique hybrid of nickel hydroxide carbonate nanobelts densely and strongly anchored on reduced graphene oxide nanosheets (HC/RGO) has been designed and synthesized through a facile hydrothermal approach. The as-prepared HC/RGO composites display a nearly two-dimensional architecture. Electrochemical investigation shows that the HC/RGO composite electrode has a maximum specific capacitance of 1662.4 F/g (3.5 F/cm 2 ) at 1.0 A/g with excellent rate capability (64.7% capacitance retention when increasing the current density from 1.0 to 10.0 A/g) and good cyclic stability. The outstanding electrochemical property of HC/RGO composite electrode is possibly attributed to the intrinsic nature of Ni 2 (OH) 2 (CO 3 ), the conductive RGO support, and the ultrathin thickness of Ni 2 (OH) 2 (CO 3 ) nanounits which can accelerate the electron transport and facilitate the redox reactions. This hydroxycarbonate-based hybrids with excellent electrochemical performance provide an new avenue for designing high-performance supercapacitor electrodes. [ABSTRACT FROM AUTHOR]