Progress in Natural Science: Materials International最新文献

Equal channel angle pressing is recognized for its ability to refine alloy grains and alter grain orientation, thereby achieve better mechanical performance of the magnesium alloy. This study investigates the microstructures, dynamic recrystallization mechanism, texture development, and mechanical performance of GW94K (Mg–8.7Gd–4.18Y–0.42Zr wt. %) Mg alloy following ECAP-4 passes at 400 ​°C and 3 ​mm/min. Results show that when high-temperature deformation is undertaken, twin formation is suppressed while dislocation slip is facilitated, increasing dislocation density during deformation. Following ECAP deformation, the sample displayed higher fracture elongation, TYS, and UTS than the as-solutioned GW94K alloy. In particular, the GW94K alloy performed well mechanically after ECAP-4 passes, with an ultimate TYS of 231 ​MPa, an UTS of 290 ​MPa, and an elongation of 14.8 ​%. DDRX and shear bands induce CDRX, both of which are important in plastic deformation. as well as in modifying microstructure and grain orientation during ECAP deformation.

As a H₂O₂ electrochemical biomimetic enzyme sensor, the stability, repeatability and sensitivity of hemin-based composites are closely connected with the loading of hemin on high-performance matrix. Herein, polypyrrole/paper-derived carbon (PPy/PC) nanocomposite was used for the construction of a hemin-based non-enzymatic sensor to detect H₂O₂. Where the poplar wood is used to obtain crude cellulose through a straightforward paper-making process. This crude cellulose is then subjected to pyrolysis to yield the desired paper-based carbon material. The hemin-decorated PPy/PC was demonstrated possessing remarkable electrocatalytic activity for H₂O₂ reduction, and the possible mechanism of the reactions was discussed. The electrochemical sensor, utilizing the H-PPy/PC composite, achieved a low detection limit of 30 ​nM, along with enhanced selectivity and stability under optimized conditions. The favorable results observed can primarily be attributed to the superior electrochemical performance of PPy/PC, as well as its unique 3D interconnected structure. This structure effectively impedes the self-dimerization of hemin, thereby ensuring the generation of active catalytic species.

Controlled fabrication of materials by surface modification techniques has been a hot research topic. In this paper, one-dimensional (1D) core-shell structure Fe@Co nanowires (NWs) were successfully prepared by anchoring 0-dimensional (0D) Co nanoparticles on 1D Fe NWs based on the in situ reduction method. The electromagnetic parameters of the specimens at a filler mass fraction of 25 ​wt% were tested and the microwave loss mechanism was deeply analyzed. Binary magnetic metals in a core-shell structure have excellent multi-band microwave absorption capability (S-band, X-band and Ku-band). This is due to the heterogeneous interface and magnetic coupling effects tuning the dielectric and magnetic loss. This study offers a workable plan for creating effective multi-band magnetic metal-based microwave absorbers.

Defective NH₂-UiO-66 adsorbent (named as NH₂-UiO-66-SD) was successfully fabricated via post-synthesis method with the aid of both sodium carbonate anhydrous (Na₂CO₃) and diethylenetriaminepentaacetic acid (DTPA), in which the defective structure was confirmed by various characterizations. The as-obtained defective NH₂-UiO-66-SD exhibited outstanding Pb(II) sorption capacity (172.21 ​mg ​g⁻¹) and rapid diffusion rate (29.87 ​mg ​g⁻¹ min^−0.5) at room temperature with optimal pH being 5.47. The Pb(II) sorption behavior was conformed to pseudo-second-order kinetics and Langmuir model, demonstrating that the chemical sorption of the monolayer played a dominant model. As well, the thermodynamic parameters like standard Gibbs free energy change ΔG^o (−31.21 ​kJ ​mol⁻¹), standard enthalpy change ΔH^o (12.79 ​kJ⁻¹ ​mol⁻¹) and standard entropy change ΔS^o (146.73 ​J ​mol⁻¹ ​K⁻¹) revealed that the Pb(II) sorption process of NH₂-UiO-66-SD was spontaneous, endothermic and disordered. Furthermore, the NH₂-UiO-66-SD exhibited desirable desorption and recirculation performances (removal efficiencies >85 ​% in 5 runs) with ideal stability. Moreover, the Pb(II) sorption mechanism of NH₂-UiO-66-SD mainly included the electrostatic attractions and coordinative interactions. Overall, this work offered an intriguing method of fabricating defective NH₂-UiO-66 adsorbent, which vastly enhanced adsorption efficiency for toxic metal ions elimination from wastewater.

Hydrogen is now being used as a renewable clean energy carrier. One of the main issues with the application of hydrogen energy is a shortage of security and efficient hydrogen storage technology. TiMn-based alloys are considered promising hydrogen storage materials, but their comprehensive hydrogen storage properties and cyclic stable performance limit their further practical application. The hydrogen storage properties of alloys can be enhanced by substituting transition metal elements. Therefore, the comprehensive hydrogen storage performance of the Ti_0·9Zr_0·1Mn_0·95Cr_0·7V_0.2M_0.15 (M ​= ​Fe, Co, Ni, Cu, Mo) alloys was systematically investigated according to the Mn element on the B side is partially replaced by variety of transition metal elements. The M ​= ​Ni alloy, which showed the highest hydrogen storage capacity among the group of alloys, was used to explore cycle stability. The plateau pressures of the series alloys decreased in order, Fe ​> ​Co ​> ​Ni ​> ​Cu ​> ​Mo. Aspects of hydrogen absorption kinetics, all of the alloys can reach full hydrogen absorption saturation within 400 ​s at 303 ​K. The Ti_0·9Zr_0·1Mn_0·95Cr_0·7V_0·2Mo_0.15 alloy possessed the fastest hydrogen absorption kinetic rate (t_0.9 ​= ​65 ​s) and the smallest hysteresis factor. This suggests that the substitution of Mo elements is effective in improving the hysteresis of the Laves phase alloys. Among the series of alloys, the M ​= ​Ni alloy exhibited the best overall hydrogen storage performance, which hydrogen storage capacity can reach 1.81 ​wt% and 97% of its capacity is kept after 100 cycles.

This paper explores the potential of Longan peel waste (LPw) as a sustainable and cost-effective matrix for selenium-based cathodes in Li-Se and Na-Se batteries. Following activation, we created LP₂—a designation for the carbon precursor derived from LPw, activated at a 1:2 ratio of carbonized LPw to KOH. This nomenclature, where ‘LP' stands for ‘Longan peel' and ‘2′ reflects the optimization of this ratio, led to a hierarchical porous structure with an average pore size of 3.0307 ​nm and a significant BET surface area of 111.9386 ​m² ​g^-1. Selenium was incorporated into the LP₂ matrix using a simple melt diffusion technique, yielding the composite Se@LP₂. In Li-Se batteries, Se@LP₂ exhibited an initial discharge capacity of 1033.75 mAh g⁻¹ ​at 0.1C. At a 1C rate, the composite demonstrated a capacity retention of 301.14 mAh g⁻¹ after 550 cycles and 380.91 mAh g⁻¹ after 100 cycles. Moreover, for Na-Se batteries, the composite showcased a capacity retention of 347.18 mAh g⁻¹ after 100 cycles at 0.1C. These findings underscore LP₂'s potential as a viable and efficient matrix for selenium-based cathodes, revealing promising prospects for the advancement of highly efficient Li-Se and Na-Se batteries.

In recent years, molybdenum disulfide (MoS₂) has gained significant attention in the scientific community. Few-layered MoS₂ demonstrates unique properties and potential applications. However, the synthesis of few-layered and high-purity 1T-MoS₂ is still a challenge. In this study, we successfully employed a hydrothermal method to synthesize few-layered and high-purity 1T-MoS₂. The purity of the material is controlled by a combination of sodium borohydride and ethanol. Notably, the few-layered 1T-MoS₂ exhibits exceptional performance as a supercapacitor, including the high specific capacitance (250.3 ​F ​g⁻¹ at a current density of 1 ​A ​g⁻¹) and excellent long-trem cycling stability (90.7 ​% after 5000 cycles). Meanwhile, the asymmetric device assembled by 6-FL-1T-MoS₂ and active carbon on carbon cloths exhibits excellent flexibility and high energy and power density (23.1 ​μWh cm⁻² at 600 ​μW ​cm⁻², 55 ​μWh cm⁻² at 12000 ​μW ​cm⁻²). This work provides valuable insights into the synthesis of few-layered and high-purity 1T-MoS₂, opening up new avenues for further research and applications.

Electrochemical urea oxidation reaction (UOR) is a promising alternative to oxygen evolution reaction (OER) for realizing energy-saving hydrogen production. Developing efficient electrocatalysts for UOR becomes a central challenge. Recently, amorphous materials have been extensively used as UOR catalysts because of their numerous defective sites and flexible electronic properties. In this review, recent advancements in the development of amorphous UOR electrocatalysts are analyzed. The UOR mechanism is discussed, and the design of amorphous catalysts is then analyzed. The main catalyst design strategies are illustrated, including nanostructure control, heteroatom doping, composition regulation, and heterostructure construction. Also, electrocatalysts’ structure-performance correlation is interpreted. Perspectives in this field are proposed for guiding future studies on the development of high-performance amorphous catalysts towards energy sustainability.

The conversion of chalcogen atoms into other types of chalcogen atoms in transition metal dichalcogenides exhibits significant advantages in tuning the bandgaps and constructing lateral heterojunctions. However, despite atomic defects at the atomic scale were inevitably formed during conversion process, the construction of dislocations remains difficult. Here, we conducted in-situ sulfurization to achieve structural transformation from monolayer WSe₂ to WS₂ successfully. We probe these transformations at atomic scale using high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and study structural defects of sulfurized-WS₂ by strain and displacement fields. We discovered that high-quality WSe₂ flakes were completely sulfurized while dislocations were successfully constructed, manifesting atomic surface roughness and structural disorders. Our work provides insights into designing and optimizing customized Transition metal dichalcogenides (TMDs) materials in controlled synthesis and defect engineering.

With the growing problem of water pollution caused by antibiotics, the development of photocatalysts with high photogenerated carrier separation efficiency is crucial. A high-efficiency microsphere Fe/BiOCl/BiVO₄ with S-scheme heterojunction was synthesized by solvothermal method and its ciprofloxacin (CIP) degradation performance were investigated under visible light. XRD, FT-IR, SEM, EDS, HRTEM and XPS results show that the photocatalytic have good crystallization, morphology and the formed a microsphere. The photocatalytic performance of Fe/BiOCl/BiVO₄ for CIP was superior to pure BiOCl and BiVO₄ due to the microsphere and formed heterostructure between BiOCl and BiVO₄. The influencing factors of CIP degradation by Fe/BiOCl/BiVO₄ were investigated, and the results showed that Fe/BiOCl/BiVO₄ had high degradation efficiency not only at pH 5–9, but also in the presence of inorganic Cl⁻, NO₃⁻ and metal ions. Under the optimal conditions, the degradation rate of CIP was up to 100% in 75 ​min. In addition to CIP, the Fe/BiOCl/BiVO₄ photocatalysts degraded other organic pollutants, such as tetracycline, oxytetracycline, chlortetracycline, ofloxacin, levofloxacin, and rhodamine B, by more than 92%. The main active species were photogenerated holes (h⁺) and superoxide radicals (·O₂⁻). In addition, possible intermediates and toxicity of intermediates were analyzed and five potential pathways for CIP degradation were proposed.