To address the pollution from dyeing wastewater and the recycling challenges of powdered photocatalysts, this study aimed to develop an easily recoverable and efficient photocatalytic composite. Carbon dots (CDs) were synthesized using plant oil and rhodamine dye as precursors. Leveraging their unique amphiphilic nature and self-dispersing property, the carbon dots were uniformly loaded onto carbon fiber (CF) via a simple impregnation method to construct a carbon dots/carbon fiber composite (CDs/CF). The morphology and structure of the material were analyzed using various characterization techniques, and its photocatalytic performance was evaluated through dye degradation experiments. The intrinsic surface activity of the carbon dots enabled their stable dispersion in the aqueous phase and spontaneous, uniform loading onto the carbon fiber without requiring any dispersants or binders. Experiments demonstrated that the composite exhibits excellent and stable dye degradation performance under visible light. This is attributed to the synergistic effect of the good photocatalytic activity of the carbon dots, the tight interfacial contact and effective charge transfer between the components, and the macroscopic ease of recovery of the composite. This research provides a new strategy for developing highly efficient and easily recyclable photocatalytic materials for wastewater treatment.

To address the issues of renewable energy storage and the bottlenecks of volume expansion and slow kinetics in sodium-ion batteries, this study designs a "MOFs-derived-sulfidation-selenidation" stepwise strategy. MXene is prepared from Ti₃AlC₂, and a MXene/MIL-100 precursor is constructed through hydrothermal treatment. Subsequently, MXene/Fe₃S₄@FeSe₂ multi-heterojunctions are obtained through sulfidation and selenidation. The material exhibits a "hollow tubular flower cluster structure", with MXene ensuring structural stability and the Fe₃S₄/FeSe₂ heterointerface promoting electron transfer. Sodium storage performance tests show that at 0.1 A/g, its specific capacity is approximately 450 mAh/g, and it still reaches 400 mAh/g at 2 A/g with recoverable capacity. After 100 cycles, it maintains a high capacity retention rate and stable Coulombic efficiency, providing a new path and theoretical experimental support for the development of high-performance sodium-ion battery electrode materials.

In response to the increasingly severe energy shortage and environmental problems, the development of clean and sustainable energy technologies has become imperative. Hydrogen, with its high energy density and zero-emission characteristics, is regarded as a highly promising clean energy carrier. Among various hydrogen production technologies, solar-driven photocatalytic water splitting demonstrates broad application prospects due to its direct conversion of solar energy into chemical energy. This study employed photodeposition and deposition-precipitation methods to prepare Au nanoparticle-modified TiO₂ nanosheet composite photocatalytic materials, thoroughly investigating the influence of different preparation strategies on material microstructure and photocatalytic activity. The results show that the TiO₂-0.1Au-DP sample prepared by deposition-precipitation exhibits excellent photocatalytic hydrogen production performance, with a hydrogen production rate reaching 1 325.9 μmol/(g·h), significantly outperforming the photodeposition sample with the same Au loading by 1.88 times. This superior performance is mainly attributed to the smaller particle size and more uniform dispersion of Au nanoparticles prepared by this method, effectively constructing Schottky junctions and greatly enhancing the separation efficiency of photogenerated carriers. Time-resolved PL spectroscopy analysis confirms that the average carrier lifetime of the TiO₂-0.1Au-DP sample is 1.4888 ns, much higher than the 1.1438 ns of the TiO₂-0.1Au-PD sample. XPS characterization further reveals the existence of a special electronic interaction between small-sized Au particles and the TiO₂ matrix. This research provides new insights for the rational design of efficient photocatalysts.

In this study, the effects of rare earth Y on the microstructure, mechanical properties, and oxidation resistance of WC-Ni-Ni₃Al cemented carbide were investigated. Different alloys with varying Y contents were prepared using the powder metallurgy method. The results indicated that the addition of the rare earth element Y resulted in the refinement of WC grains. The amount of abnormally grown WC grains was reduced. With the increase of Y content, the average grain size and Vickers hardness of the alloy showed a trend of first increasing and then decreasing. The refining effect was most significant when the amount of yttrium nitrate added was 1.0 wt.%, under this condition, the average grain size of the alloy was 1.192 μm, and the hardness reached a maximum value of 977.75 kgf/mm². XRD phase analysis revealed that, the ordered γ’-Ni₃Al precipitated phase was in-situ formed in the binder phase of the cemented carbide via AlN addition. The addition of the rare earth element Y promoted the growth of the Ni₃Al precipitates along the <100> direction. This preferential orientation became more pronounced with increasing Y content. The orientation growth of Ni₃Al, induced by addition of Y, facilitated the formation of dense Al₂(WO₄)₃ at a lower temperature. A thinner oxide layer was consequently formed. The oxidation resistance of the cemented carbide was thus enhanced.

The β-manganese-type crystal PbIn₆Te₁₀ is an excellent optical material in mid-far infrared nonlinear optics, capable of efficiently generating laser outputs above 8 μm. However, the growth of crack-free PbIn₆Te₁₀ crystals with high-quality is extremely challenging due to issues such as impurity phases in the polycrystalline raw materials and significant infrared residual absorption in the grown crystals. In this work, we investigated the effects of compositional conditions on intrinsic defects and transmittance in PbIn₆Te₁₀ crystals through first-principles calculations and crystal growth experiments. Analysis of the DFT calculation results revealed that under PbTe-rich conditions, In_Pb and V_In defects have lower defect formation energies and are the dominant defects in the grown crystals. In contrast, under In₂Te₃-rich conditions, In_Pb and V_Pb defects are more likely to form in the grown crystals. We grew PbIn₆Te₁₀ crystals under both PbTe-rich and In₂Te₃-rich conditions using an improved Bridgeman method and carried out the annealing treatments. The differences between the two sets of crystals were compared through infrared transmission tests, EDS, and XPS. The results indicated that crystals grown under In₂Te₃-rich conditions exhibited higher optical transmittance, which was 37% higher than that grown under PbTe-rich conditions and closer to the stoichiometric ratio relatively. XPS studies showed that the two different conditions led to variations in the chemical valence states of the elements. Finally, we demonstrated that PIT crystals with good optical quality can be grown under In₂Te₃-rich compositional conditions.

Ammonia serves as a critical industrial feedstock and a carbon-free hydrogen carrier. Its conventional production relies heavily on the Haber-Bosch process, which operates under high temperature and pressure, consuming substantial energy and generating significant greenhouse gas emissions, thereby posing substantial environmental challenges. The electrocatalytic nitrate reduction reaction (NO^-₃RR) for ammonia synthesis has attracted increasing attention due to its mild reaction conditions. This approach not only enables green ammonia production under ambient conditions but also offers a sustainable pathway for mitigating nitrate pollution. The development of high-performance electrocatalysts is central to enhancing NO^-₃RR efficiency, as they critically govern the reaction pathway selectivity and ammonia yield. This review systematically summarizes the reaction mechanisms of NO^-₃RR and recent advances in electrocatalyst design, with a focus on key strategies such as doping engineering, vacancy modulation, interface construction, and single-atom configurations to improve catalytic activity, selectivity, Faradaic efficiency, and stability. Furthermore, it outlines the current challenges and future directions in this field. This review aims to provide new perspectives for nitrate reduction research, accelerate the development of efficient ammonia-synthesis electrocatalysts, and contribute to the transition toward a sustainable energy system.

In high-end equipment manufacturing sectors such as aerospace, oil and gas extraction, petrochemicals, and nuclear power, the development of high-performance corrosion-resistant alloy materials represents both a critical scientific challenge requiring breakthroughs and a key engineering requirement for technological advancement. High-entropy alloys (HEA) transcend traditional alloy design paradigms by leveraging their unique multi-component solid solution microstructures and locally disordered chemical environments, demonstrating exceptional corrosion resistance. This paper systematically reviews the core factors influencing the corrosion resistance of HEA and their typical application scenarios, summarizes recent advancements in advanced design strategies and research progress of corrosion-resistant HEA, and outlines future prospects for engineering applications and key development directions.

Lithium-ion batteries have become a cornerstone of modern energy technologies owing to their high energy density and long cycle life. However, conventional approaches for fabricating electrode materials generally suffer from high energy consumption, complex multistep processes, and limited controllability over the microstructure and chemical composition of the final product. As an emerging ultra-rapid heating strategy, the Joule heating method offers an alternative pathway for structural engineering and performance enhancement of electrode materials, benefiting from its instantaneous heating/cooling capability, localized energy input, and strongly non-equilibrium reaction environments. In this review, the latest progress of Joule heating in synthesizing lithium-ion battery cathode materials (olivine-type, layered, and spinel structures) and anode materials (carbon-based, silicon-based, and other metal compounds), is comprehensively summarized. The mechanistic roles of Joule heating in defect induction, heterostructure formation, interfacial stabilization, and electrochemical performance enhancement are critically analyzed. Finally, future perspectives are provided regarding the development of Joule heating as an energy-efficient, high-throughput, and scalable strategy for the manufacturing of high-performance lithium-ion battery materials.

Zinc-iodine batteries (ZIBs) exhibit tremendous application potential in large-scale grid energy storage and flexible electronic devices owing to their high theoretical capacity, abundant resource availability, and excellent safety and stability. However, the cathode materials of ZIBs are highly susceptible to polyiodide dissolution and the shuttle effect during the cycling process. This inevitably leads to the irreversible loss of active materials, the corrosion of the zinc anode, and the decay of Coulombic efficiency. Moreover, the intrinsically poor electrical conductivity of elemental iodine and its sluggish solid-liquid phase conversion kinetics severely restrict the rate performance of the batteries, which significantly impedes their industrialization process. In view of this, starting from the fundamental electrochemical mechanisms of ZIBs, this thesis systematically reviews the recent research progress on cathode materials for these batteries. Furthermore, the strategies for enhancing their electrochemical performance are comprehensively analyzed and discussed, aiming to provide valuable references for the design and development of advanced ZIB cathode materials. Finally, the current limitations of ZIB cathode materials are summarized, and the prospective development directions in this field are outlined.

Under the dual carbon goals, this study utilizes industrial solid waste to prepare low-carbon cementitious materials for 3D printing using chromium iron slag. This study first determined the optimal dosage ranges of chromium iron slag micro powder and kaolinite through single-factor experiments. Subsequently, response surface methodology was employed to investigate their effects on flowability, slump, and compressive strength, identifying the optimal dosage of cementitious materials. At this dosage, the influence of varying chromium iron slag sand content on the cementitious materials was explored. Finally, the cementitious materials were printed, and their mechanical properties were evaluated. Results indicate that the regression models established via response surface methodology yielded correlation coefficients R² of 0.99, 0.9923, and 0.9893, demonstrating excellent predictive accuracy. The optimal admixture ratios were 15% chromium iron slag powder and 12% kaolinite. When chromium iron slag sand fully replaced river sand, the cementitious material exhibited good extrusion and constructability. Microstructural analysis revealed that variations in printing paths and durations led to incomplete interfacial hydration reactions, forming weak layers that caused anisotropic mechanical properties. This study provides theoretical foundations and practical pathways for the resource utilization of chromium iron slag in 3D printing.

Phase change microcapsules of TD-OC/MUF were prepared by in-situ polymerization method, where melamine-urea-formaldehyde (MUF) resin was used as shell material and tetradecanol-octadecane (TD-OC) as core material. The effects of emulsifier ratio, core-shell ratio, and pH value on microcapsule preparation were investigated to determine the optimal preparation conditions. The morphology, thermal conductivity, phase-change properties, chemical composition, leakage resistance, and thermal stability of the microcapsules were characterized using an optical microscope, scanning electron microscope (SEM), thermal conductivity analyzer, differential scanning calorimeter (DSC), Fourier-transform infrared spectrometer (FT-IR), and thermogravimetric analyzer (TG). The prepared microcapsules were incorporated into cement mortar to prepare wallboard, and their temperature-response characteristics were evaluated. The thermal conductivity and temperature-delay performance of the wallboard were measured using a thermal conductivity analyzer and a high-low temperature air bath. The experimental results showed that TD-OC/MUF microcapsules prepared using a mixed emulsifier of styrene-maleic anhydride copolymer and sodium dodecylbenzenesulfonate (SMA-SDBS, m_SMA∶m_SDBS=2∶1), a core-shell ratio of 2.4∶1, and pH value of 4.7-5.0 exhibited good morphology, with an average particle size of 11.9 μm. The phase change temperature and latent heat were 23.75 °C and 174.3 J/g, respectively. The thermal conductivity of the microcapsules was 0.197 W/(m·K). No leakage occurred after 400 freezing/melting cycles, and the microcapsules maintained favorable phase change performance. Thermogravimetric analysis indicated the good thermal resistance and stability of the microcapsules, which could be applied for wallboard. When the microcapsules were incorporated into cement mortar to prepare wallboard, both the interior and exterior surface temperature of wallboard decreased. The peak temperature reduced, and the time required to reach the peak temperature significantly extended. As the content of microcapsules increased, the extent of the decrease in the surface temperature of the wallboard enlarged, and the delay time of the peak temperature increased. The thermal conductivity values of the common wallboard and wallboard containing 5%, 10%, and 15% microcapsules were 1.072, 0.898, 0.714, and 0.520 W/(m·K), respectively. The incorporation of microcapsules effectively reduced the thermal conductivity of the wallboard.

Lithium-sulfur batteries have garnered widespread attention due to their high theoretical specific capacity, abundant raw materials, and low cost. However, the insulating nature of sulfur and lithium sulfide (Li₂S), significant volume expansion during cycling, the shuttle effect of lithium polysulfides (LiPSs), and sluggish LiPSs conversion kinetics pose substantial obstacles to the practical application of Li-S batteries. To address these challenges, composite materials have emerged as a promising strategy, leveraging synergistic effects among multiple components and tailorable structural architectures. In this study, a binary sulfur-affinic ZrB₂/MXene composite was fabricated via a one-step borothermal method and employed as a sulfur host in the cathode. Both B and Zr atoms can form bonds with polysulfide anions, and the dual sulfur-affinity of metal borides facilitates electron transfer to sulfur species, enriching catalytically active sites. The incorporation of MXene mitigates agglomeration of the metal boride, further increasing active catalytic sites and accelerating lithium polysulfide conversion. Electrochemical evaluations demonstrate that the ZrB₂/MXene composite electrocatalyst exhibits excellent LiPSs conversion capability and significantly enhances catalytic efficiency. Under rate performance tests, the S/ZrB₂/MXene electrode delivers an initial discharge specific capacity of 1395.9 mA·h/g at 0.1 C, and 801.6 mA·h/g at 1 C. After 500 cycles, it retains a discharge capacity of 512.3 mA·h/g with a low capacity decay rate of 0.072% per cycle. This work provides valuable insights for designing advanced boride-based electrocatalysts for high-performance Li-S batteries.

Against the backdrop of global energy structure transformation driven by the "dual carbon" goals, adsorption heat transformation technology directly addresses the core contradiction between "idle low-grade thermal energy" and "high-grade energy consumption", playing a crucial role in achieving the "dual carbon" goals within the field of cooling and heating supply. However, the adsorbent currently used in adsorption heat transformation are exhibiting drawbacks such as low utilization efficiency of low-grade thermal energy, high driving temperature, and insufficient performance. In this study, by optimizing the dosage of the structure-directing agent (SDA), a synthesis route for high-stability SAO-type aluminophosphate crystals was developed, and their adsorption performance was systematically evaluated. The results show that the material exhibits excellent ultra-low temperature driving characteristics. In the refrigeration mode, a maximum coefficient of performance (COP) of 0.78 can be achieved with a regeneration temperature of only 63 ℃, under the harsh operating conditions of 30 ℃ condensation temperature and 5 ℃ evaporation temperature. Under the heat pump mode, a maximum COP of 1.80 can be reached when driving temperature is 80 ℃. In the heat storage mode (T_ev=10 ℃,T_con=30 ℃,T_des=77 ℃), the heat storage density of the material can reach 1 067 kJ/kg. This study provides a new strategy for the material design of high-efficiency adsorption heat transformation systems and exhibits promising energy-saving potential and application prospects.

In this study, ferrous ions confined on the hematite nanoparticles with different morphology (HNPs_x, where x denotes the ethanol/water volume ratio, 9∶1, 5∶5, and 1∶9) were prepared and utilized as catalysts for peracetic acid (PAA) activation. Compared to HNPs_5∶5 and HNPs_1∶9, HNPs_9∶1 exhibited superior Fe(Ⅱ) confinement capability and catalytic performance, achieving 95.7% degradation of Rhodamine B (RhB, 25 mg/L) within 5 min. Quenching experiments revealed that the primary active species in the HNPs_9∶1/Fe(Ⅱ)/PAA system were ·OH, Fe(Ⅳ), and R-O·. Among these, ·OH exhibited the highest contribution to RhB degradation (45.9%). Compared to HNPs_5∶5 and HNPs_1∶9, HNPs_9∶1 possessed a higher (001) facet exposure ratio, which is more favorable for confining Fe(Ⅱ) and enhancing its activation for PAA-mediated pollutant degradation. This study provides a theoretical basis for designing highly efficient catalysts via surface confinement effects and further elucidates the mechanism of hematite catalysts in advanced oxidation processes under crystal-facet effects.

As a representative neonicotinoid pesticide, imidacloprid has raised extensive ecological and health concerns due to its widespread use, environmental persistence, and toxicity to non-target organisms. The peroxymonosulfate (PMS) based advanced oxidation process, capable of generating highly reactive radicals (^·OH and SO^·-₄), is regarded as an effective method for degrading such structurally stable pesticide pollutants. In this study, a carbon-based Co₃O₄ catalyst derived from two-dimensional ZIF-67 was prepared. The effects of PMS concentration, catalyst dosage, and pH on its performance in activating PMS to degrade imidacloprid were systematically investigated. The results show that the derived catalyst ZDCO-2, prepared with a Co/2-methylimidazole ratio of 2:1, achieved efficient PMS activation. Within 15 min, it reached a degradation efficiency of 96.04% for 10 mg/L imidacloprid (IMI) and maintained high degradation performance within a pH range of 7-11. Quenching experiments confirmed that SO^·-₄ and ¹O₂ are the primary reactive species in the process. This study provides a sustainable and efficient catalyst for the treatment of wastewater containing neonicotinoid pesticides.

With the urgent global demand for clean energy and environmental pollution control, the development of efficient, stable, and low-cost functional materials has become increasingly critical. Ti₄O₇, a type of titanium suboxide, has garnered attention in various fields such as photocatalysis and batteries due to its excellent catalytic performance and electrical conductivity. In this study, Ti₄O₇ powders were prepared using titanium dioxide (TiO₂) powder as the titanium source, with carbon black and glucose serving as the carbon sources, respectively. The preparation process was optimized by adjusting key process parameters, including reaction temperature, holding time, and ingredient ratios. The phase composition, micro-morphology, and optical properties of the prepared Ti₄O₇ powders were systematically characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible-near-infrared spectrophotometry (UV-VIS-NIR), and fluorescence spectrophotometry (SPF). Additionally, the visible-light photocatalytic activity of Ti₄O₇ powder was evaluated by investigating its degradation efficiency towards methylene blue. The results indicate that both carbon sources can produce single-phase Ti₄O₇ powders with uniform particle sizes, which are approximately 1–2 μm. Under visible light irradiation, the photodegradation efficiencies of methylene blue by Ti₄O₇ powders prepared with carbon black and glucose as carbon sources reach 92.1% and 95.15%, respectively, both of which are significantly higher than that of pure TiO₂. This study demonstrates that the Ti₄O₇ powder prepared by glucose reduction not only uses more environmentally friendly raw materials but also exhibits superior photocatalytic performance compared to that of carbon black.

As a major metallurgical country, China faces the challenges of low resource utilization rates of steel slag and red mud (RM) which seriously threaten the ecological environment. In this study, to achieve the goal of collaborative utilization of steel slag and RM, steel slag-red mud based foamed ceramics (S-R/FC) were prepared by using steel slag, nepheline syenite, white clay, red mud (RM), quartz sand (QS), silicon carbide (SiC) as raw materials with process of mixing, molding and high-temperature foaming. The effect of phase composition, SiC content, RM and QS addition amount on the properties of the S-R/FC were investigated. Results showed that the RS-1-1 group with the mass content of 10% RM and 10% QS has an ideal foaming effect. In this group, with SiC content increasing, the volume expansion rate and porosity firstly increase and then decrease, while the bulk density has a reverse trend. When the SiC content is 1%, the S-R/FC obtains the optimal performance, and the volume expansion rate, bulk density, porosity and flexural strength are 173.70%, 1.66 g/cm³, 52.52% and 15.94 MPa, respectively. It’s expected to provide an effective approach for the collaborative and comprehensive utilization of steel slag and RM.

During the operation of water treatment systems, the structural stability of ultrafiltration membranes is critical to maintaining the system’s continuous, efficient, and reliable operation. To systematically investigate the mechanical behavior of polyvinylidene fluoride (PVDF) tubular ultrafiltration membranes and quantify their burst pressure, this study obtained material constitutive parameters via quasi-static tensile tests. The material parameters are obtained through inversion methods. Combined with finite element analysis, the study analyzed stress distribution and deformation characteristics under varying permeation pressures, quantitatively elucidating the influence of membrane thickness on burst pressure. The results showed that the PVDF membrane exhibited significant nonlinear viscoelastic behavior, with a measured tensile strength of 88.1 MPa and a fracture strain of 0.36. Under osmotic pressure, maximum stress concentrated in the geometric center, rising significantly with increased pressure. Increasing membrane thickness from 0.05 mm to 0.5 mm caused the burst pressure to increase from 0.49 MPa to 1.88 MPa. Although a thicker membrane increases the effective load-bearing area and reduces internal stress under a given pressure, it correspondingly leads to a higher burst pressure. This study can provide technical support for the structural optimization design, the determination of service safety thresholds, and the stable engineering operation of tubular ultrafiltration membranes.

To investigate the differences in electronic structure between shallow-level and deep-level dopants in crystalline silicon, this study systematically examines the defect structures, band characteristics, density of states, and charge transition levels of three representative dopants—B, P, and Se—based on first-principles calculations within the framework of density functional theory (DFT). A Si (2×2×2) supercell model was constructed, and substitutional doping configurations (Si₆₃B, Si₆₃P, and Si₆₃Se) were established, followed by structural optimization and electronic structure calculations. The results indicate that, after B and P doping, the overall band structures remain similar to that of intrinsic silicon. The impurity levels are located near the valence band maximum and conduction band minimum, respectively, with the Fermi level shifting toward the valence band and conduction band, exhibiting typical shallow acceptor and shallow donor characteristics. In contrast, Se doping introduces localized impurity states in the middle of the band gap, which appears as pronounced peaks within the gap in both the total and projected density of states, indicating deep-level defect behavior. Further analysis of defect formation energies and charge transition levels reveals that the transition levels of B-and P-doped systems are distributed near the band edges, corresponding to low ionization energies. By comparison, the transition energy level of the Se-doped system is located in the middle region of the bandgap, and the ionization energy is significantly increased. This work provides insight into the fundamental differences between shallow and deep-level impurities in crystalline silicon from an electronic structure perspective and offers theoretical guidance for semiconductor doping engineering.

To achieve high-density and low-resistivity indium tin oxide (ITO) targets, this study employs CeO₂-Ga₂O₃ co-doping to regulate the composition of ITO targets while optimizing sintering temperature and holding time. A target with a relative density of 99.88% and a resistivity of 2.4×10^-4 Ω·cm was obtained by doping 0.25 wt%CeO₂-0.75 wt%Ga₂O₃ at a sintering temperature of 1 450 ℃ and a holding time of 6 h,with a resistivity of 2.4×10^-4 Ω·cm. Targets doped with CeO₂-Ga₂O₃ exhibited relatively low and stable resistivity across the 1 350-1 550 ℃ range. Experimental results demonstrate that introducing Ga₂O₃ promotes grain boundary diffusion, significantly enhancing ITO sintering activity and lowering the sintering temperature. The incorporation of CeO₂ provides additional free electrons, reducing resistivity. The resistivity of CeO₂-Ga₂O₃ co-doped ITO targets was successfully stabilized at a low level of 2.4-2.6×10^-4 Ω·cm while achieving higher relative density.

Aiming at the problem of poor performance of total coal gangue coarse aggregate concrete cause by high water absorption and high mud content of aggregate, according to the chemical compensation mechanism, the performance regulation and synergistic effect of polycarboxylate superplasticizer (PCE) combined with sodium gluconate (SG), sodium tripolyphosphate (ST) and sodium lignosulfonate (SL) on the performance of coal gangue coarse aggregate concrete were studied. The optimal dosage of PCE was determined to be 1.0% (mass ratio of cementitious material) by single factor test. On this basis, the compounding effect of retarding components was analyzed by gradient dosage (0.05%-0.2%) test. The synergistic compensation mechanism of the compound system was revealed by macroscopic tests such as slump, expansion and compressive strength, as well as microscopic characterization such as nuclear magnetic resonance pore structure analysis and X-ray diffraction phase analysis. The results show that the introduction of suitable retarding components constructs a time-structure dual compensation mechanism, which delays early hydration in the time dimension and improves the loss of working performance. The 60 min mortar fluidity loss rate of 0.15% SG is only 2.1%. In the structural dimension, the hydration process is regulated by different mechanisms, the pore structure is optimized, and the mechanical properties are improved. Microscopic tests show that the SG compound system can significantly increase the proportion of gelled pores, reduce the content of harmful pores, and form a dense microstructure. The combination of PCE and three retarding components can improve the performance, and the order of effect is SG > ST > SL, and there is an optimal dosage of 0.15%. Among them, SG achieves the best compensation effect by accurately regulating the hydration kinetics, and the dosage effect achieves the best compensation effect. ST provides good initial workability through excellent dispersion performance, and SL limits the compensation efficiency due to competitive adsorption and air entraining effect. The compounding synergy greatly improves the performance of the whole coal gangue coarse aggregate concrete, making it more widely used in various engineering constructions.

Oxygen reduction reaction (ORR) is the core cathodic reaction in advanced energy conversion devices such as proton exchange membrane fuel cells (PEMFCs) and metal-air batteries, but its intrinsic characteristic of slow kinetic rate, as well as the high cost problem caused by the scarcity of existing commercial catalysts (such as platinum-based catalysts), severely restricts the large-scale application and industrialization process of such energy devices. To break through the above bottleneck, this paper adopts a simple and controllable synthesis method to prepare boron (B) doped carbon supported nickel (Ni/B-C) catalysts and systematically studies their ORR catalytic performance. Electrochemical test results show that the prepared Ni/B-C catalyst exhibits excellent ORR activity, and its electrocatalytic performance is comparable to that of commercial Pt/C catalysts. This research provides a feasible idea for the development of low-cost, high-performance non-precious metal ORR catalysts and offers important reference for promoting the low-cost development of energy conversion devices such as PEMFCs and metal-air batteries.

To investigate the influence of temperature on the structure and properties of CrAlN coatings, the coatings were fabricated by multi-arc ion plating and subsequently subjected to vacuum annealing at 800, 900, 1 000, and 1 100 ℃ for 2 h. The microstructure, mechanical and tribological properties of the coatings were characterized and analyzed using XRD, SEM-EDS, a micro-Vickers hardness tester, an acoustic emission automatic scratch tester, and a tribological wear tester. The results showed that the hardness and bonding strength of the coating generally exhibit a decreasing trend with increasing temperature. However, a transient increase in both hardness (1 852 HV) and bonding strength (57.6 N) was observed at 900 ℃, which is attributed to the precipitation of h-Cr₂N and w-AlN phases. The friction coefficient of the coatings demonstrates a stable and gradually decreasing trend with increasing heat treatment temperature up to 900 ℃, indicating good tribological performance. However, when the temperature reaches or exceeds 1 000 ℃, a sharp increase in wear depth is observed, and the protective capability of the coating for the substrate is significantly deteriorated. It is concluded that the service temperature of CrAlN coatings should be maintained at or below 900 ℃ to ensure their stable performance and long-term protective function in cutting tool applications.

This study investigated the effects of calcium formate (CF) on the physical-mechanical properties of ferroaluminate cement (FAC)-based grouting materials, including fluidity, setting time, compressive strength, drying shrinkage, mass loss, and electric resistivity, and analyzed its hydration characteristics using XRD and SEM. Results indicated that at low admixture levels (0.3%), calcium formate improved the initial fluidity of FAC pastes. The 30 min fluidity, setting time, initial electrical resistivity, and 24 h electrical resistivity decreased with increasing calcium formate content. The addition of CF effectively enhanced the compressive strength within 28 d, with the 6 h compressive strength increasing by up to 50.3% and the 28 d by up to 11.7% within 0.3%-1.2% CF content. The drying shrinkage and mass loss at 0.3% CF content were comparable to the control, but both increased significantly with further increments in CF content. Microscopic analysis revealed that CF enhanced both the formation quantity and rate of calcium aluminate hydrate, with its promoting effect positively correlated with CF dosage at 6 h of hydration, whilst the most pronounced hydration promotion at 28 d was observed at a 0.3% dosage.

In this study, La₂O₃-C composite catalysts were successfully synthesized by the chemical blowing carbonization method. Meanwhile, the defect level, pore distribution and specific surface area were characterized. Additionally, Mg₉₆La₄ + 5.0 wt% La₂O₃-C composite materials were synthesized by mechanical ball milling. The effects of La₂O₃-C content on the microstructure and hydrogen storage kinetics of Mg-La alloys were characterized by XRD, TEM, PCT, etc. The results show that the presence of La₂O₃-C improves the dehydrogenation/hydrogenation kinetics. Magnesium based alloys with La₂O₃-C exhibit superior hydrogen absorption and desorption kinetics compared to alloys without La₂O₃-C addition. Among them, LaH₃ produced after hydrogenation is nanoparticles. At 340 ℃, the hydrogen absorption of La₂O₃-C composite alloy within 5 min is 3.9 wt%, and the release of 3.0 wt% H₂ takes the same time. The activation energy for hydrogen desorption is reduced to 100.3 kJ/mol. The excellent performance of the composites is mainly attributed to the co-catalytic effect between carbon and rare earth oxides in the composite catalyst.

This study focuses on the high-temperature bulk properties of three binary alloys (La-Al, Ni-Al, La-Ni) and their extended Al-Ni-La ternary alloy system. For the binary alloys, molecular dynamics simulations combined with a subregular solid solution model were used to introduce temperature-dependent fitting parameters aV(T), bV(T), cV(T), and dV(T). These parameters follow quadratic law variations, enabling the successful extrapolation of low-temperature volume properties from high-temperature data. For ternary alloys, while the mixing volume of Al-Ni-La alloys can be predicted by summing the mixing volumes of binary alloys, this study introduces an extended Redlich-Kister-Muggianu (RKM) model with a ternary interaction term to enhance prediction accuracy. Results show that the RKM model effectively reduces errors, particularly under strong ternary interactions. Though a simple summation approach suffices for practical industrial applications, avoiding complex procedures, this study offers a crucial theoretical foundation for designing and optimizing high-temperature alloy materials. By providing reliable volume property predictions across temperature ranges, it serves as a valuable guide for experimental research and advances materials science by facilitating the development of more efficient and stable high-temperature alloys.

Based on first principles calculations, this paper constructs 6 La/Mo doping configurations for layered bismuth tungstate Bi₂WO₆. By regulating the spatial position of doping elements and their relationship with reaction sites, the influence of these configurations on the oxygen reduction reaction (ORR) performance is evaluated. The structural relaxation, formation energy, and electronic structure of different structures are analyzed. The free energy step diagram for redox reactions is established under the framework of the hydrogen electrode to compare the reaction driving forces of different configurations. The results indicate that doping sites and configurations simultaneously affect the formation energy, electronic structure characteristics, and key steps of oxygen reduction in materials. La doping is more conducive to stable formation, neighboring control of Mo helps to reduce theoretical overpotential, and La/Mo co-doping can present a more balanced trend between oxygen molecule adsorption and subsequent transformation. This study provides a theoretical basis for site engineering and doping strategy design of Bi₂WO₆ based non precious metal cathode catalysts.

Aiming at the problems of low initial Coulombic efficiency (ICE) and poor rate capability of sucrose-based hard carbon anodes for sodium-ion batteries, this work proposes a synergistic modification strategy of nitrogen doping and carbon coating. Using sucrose as the carbon source and L-lysine as the nitrogen source, a nitrogen-doped precursor was prepared via a hydrothermal method, which was then compounded with polyvinyl alcohol (PVA). Through high-temperature carbonization, a nitrogen-doped and carbon-coated sucrose-based hard carbon material (SC@NHC) was successfully fabricated. Structural characterizations reveal that the interlayer spacing of SC@NHC is expanded to 0.400 nm, and the introduction of pyridinic N and pyrrolic N provides more active sites for sodium storage. Meanwhile, the surface defects of SC@NHC are reduced and its specific surface area is decreased to 101.7 m²/g, which is conducive to reducing side reactions and thus improving the initial Coulombic efficiency. In addition, the material possesses more microporous structures that are suitable for sodium storage. Electrochemical test results demonstrate that SC@NHC exhibits excellent comprehensive electrochemical performance. It delivers a reversible specific capacity of 319.6 mAh/g at a current density of 0.1 A/g with a high initial Coulombic efficiency of 88%, and can still stably provide an effective specific capacity of 127.8 mA·h/g even at a high charge-discharge rate of 5 A/g, accompanied by superior cycling stability. Kinetic analyses confirm that the sodium storage mechanism of SC@NHC is governed by the hybrid control of capacitive behavior and diffusion process, where the capacitive contribution increases significantly with the rise of scan rate. The reduced charge transfer resistance and greatly improved sodium ion diffusion coefficient collectively account for its outstanding rate capability. Moreover, the full cell assembled with SC@NHC as the anode and sodium vanadium fluorophosphate (Na₃V₂(PO₄)₂F₃) as the cathode exhibits favorable rate capability and cycling stability during the charge-discharge process. This study provides crucial new insights for the design and modification of hard carbon materials.