Search Results (197)

ZnO–ZnCr₂O₄ heterojunction nanocomposites were synthesized via co-precipitation with nominal spinel loadings of 10, 20, and 30 wt.% (denoted ZnCr-10, ZnCr-20, ZnCr-30) to evaluate structure–property–performance relationships in photocatalytic dye degradation. Rietveld refinement of XRD data revealed actual crystalline phase fractions of 12.1%, 32.4%, and 39.9% ZnCr₂O₄, respectively, with systematic morphological evolution from dispersed nanoparticles (ZnCr-10) to densely agglomerated structures (ZnCr-30) observed by SEM. Optical analysis demonstrated that ZnCr-10 (apparent band gap 3.09 eV) retains ZnO-dominated absorption with moderate interfacial electronic coupling, while ZnCr-20 shows enhanced visible response (2.89 eV) through interface-mediated transitions. ZnCr-30 exhibits strong sub-bandgap absorption (1.63 eV) originating from defect states rather than intrinsic band narrowing. Photoluminescence studies under UV excitation revealed optimal radiative recombination suppression in ZnCr-10, consistent with efficient interfacial charge separation, whereas excessive loading (ZnCr-30) introduced defect-mediated recombination centers. Photocatalytic degradation of Rhodamine B (5 mg/L, 0.5 g/L catalyst, solar irradiation) followed the order: ZnCr-10 (k = 0.0307 min⁻¹) > ZnO (0.0203 min⁻¹) > ZnCr-20 (0.0230 min⁻¹) > ZnCr₂O₄ (0.0166 min⁻¹) > ZnCr-30 (0.0113 min⁻¹). The optimal ZnCr-10 performance is attributed to balanced interfacial contact between phases enabling charge separation without excessive agglomeration or defect accumulation. Operational parameters (pH 7, 50 mg/100 mL, 100 µL H₂O₂) were optimized, achieving 98% degradation in 60 min. This study demonstrates that photocatalytic enhancement in ZnO–spinel heterojunctions is governed by interfacial architecture and defect management rather than optical absorption alone, providing design principles for efficient solar-driven environmental remediation. Full article

Hydrogen trapping at carbide/matrix interfaces is important for improving the resistance of steels to hydrogen embrittlement. In this work, the segregation behavior of hydrogen at the coherent α-Fe/V₄C₃ interface was investigated by first-principles calculations. Representative hydrogen sites were considered systematically, including interstitial sites in the near-interface region, interfacial sites, and carbon-vacancy sites in V₄C₃. All of the sites examined are energetically favorable for hydrogen trapping, but the carbon vacancy inside V₄C₃ exhibits the strongest trapping tendency. Charge density, Bader charge, and density-of-states analyses indicate that hydrogen at this site gains more electrons and forms stronger interactions with neighboring V atoms, leading to enhanced stability. The behavior of H₂ at the internal carbon vacancy was also evaluated. After structural relaxation, the H₂ molecule dissociated into two separate H atoms, indicating that hydrogen is more stably trapped in atomic rather than molecular form. These findings reveal the crucial role of carbon vacancies in regulating hydrogen trapping at the α-Fe/V₄C₃ interface and provide atomic-scale insight into the hydrogen trapping mechanism of vanadium carbide precipitates in steels. Full article

To solve the problems of high injection pressure and low water injection in an ultra-low-permeability reservoir, nanoemulsion was injected to reduce the surface interfacial tension, change the wettability, and achieve the purpose of depressurization. In this paper, the surface and interfacial tension, wettability properties, and particle size distribution characterization of nanoemulsion were determined, and the performance of nanoemulsion was evaluated by laboratory experiments such as core displacement. At the same time, the depressurize and augmented injection mechanism of the nanoemulsion was studied through a scanning electron microscope. The experiment shows that the nanoemulsion system has good compatibility with brine. With the increase in temperature, the surface and interfacial tension does not change, and there is no precipitation. And the system can reduce the oil–water interfacial tension to about 1 mN·m⁻¹ under the best conditions. By measuring the wettability angle of nanoemulsion at the concentration of 0.1% to 0.5%, which can adjust the wettability of the rock surface, the hydrophilicity is weakened. The depressurization performance of nanoemulsion under different injection rates, concentrations, and slug sizes was also compared through core displacement experiments, to provide reasonable experimental support for field operations. In the most reasonable case, the depressurization rate after using nanoemulsion can reach 16.78%. Full article

To enhance the engineering performance of fine-grained composite soils with unbalanced particle gradation, high plasticity, and poor water stability, a synergistic stabilization strategy combining particle structure regulation and microbially induced calcium carbonate precipitation (MICP) was proposed. The particle size distribution and fundamental engineering properties of a titanium gypsum–clay (TSC) composite soil were first optimized through systematic single-factor blending tests. The results indicate that a TS:C ratio of 60:40 significantly improved gradation characteristics, reduced plasticity, and enhanced both compaction behavior and load-bearing capacity. Based on the optimized gradation framework, MICP treatment was subsequently introduced to further enhance water stability. The effects of key parameters, particularly the type of calcium source, on the evolution of water stability were systematically investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to elucidate the underlying reinforcement mechanisms. The results demonstrate that the water stability coefficient increased markedly from 0.35 to 0.83 following MICP treatment, while strength degradation under water immersion was effectively mitigated. Microscopic observations reveal that microbially precipitated calcite fills pore spaces and forms a continuous cementation network via particle bridging and interfacial bonding, leading to an approximately 32% reduction in porosity. Overall, the proposed synergistic strategy offers an effective and sustainable approach for improving the water stability and structural integrity of complex fine-grained composite soils. Full article

The CO₂ storage–regeneration (CO₂-SR) process represents a promising strategy for integrating CO₂ capture and catalytic conversion within a single cyclic operation using multifunctional catalysts. In this concept, CO₂ is first stored on basic sites and subsequently converted through methane activation, enabling the coupling of CO₂ capture and reforming reactions in a single reactor. In this work, a series of unsupported Ni–Ba catalysts were investigated as model multifunctional materials for the CO₂-SR process. Catalysts with different Ni/Ba ratios were prepared to analyze how the distribution of storage and catalytic sites influences the cyclic CO₂ capture–conversion behavior. In addition, Rh was introduced as a promoter either during synthesis by co-precipitation or ex situ by impregnation, allowing to evaluate the influence of Rh location and surface enrichment on the catalytic properties. Rh incorporation in the NiBa catalyst (Ni/Ba = 10/1 and Ni/Rh = 100/1) increased the specific surface area (BET area 64 m²·g⁻¹ vs. 55 m²·g⁻¹ for NiBa) and reduced the NiO crystallite size from 250.4 Å to 231.5 Å, indicating improved dispersion of the metallic phase. XPS analysis revealed the coexistence of Rh⁰ and Rh³⁺ species, suggesting that Rh acts as a redox mediator that facilitates hydrogen activation and promotes hydrogen spillover to neighboring Ni sites. Raman and CO₂-TPD results show that Ba-derived domains stabilize carbonate species responsible for CO₂ storage, while Rh enhances catalyst reducibility and modifies the kinetics of carbonate decomposition during the regeneration stage. Transient CO₂–CH₄ pulse experiments demonstrate that the CO₂-SR process proceeds through a dynamic surface cycle involving reversible carbonate formation on Ba-derived basic sites coupled with methane activation on Ni-containing interfacial sites. The results indicate that catalyst performance is governed by a hierarchical surface architecture composed of Ni–O–Ba interfacial domains, reversible Ba–O–Ba carbonate storage sites, and more stable Ba-rich domains. The distribution of these domains, controlled by the Ni/Ba ratio and the dispersion of the metallic phase, determines the reversibility of carbonate formation and the efficiency of the cyclic CO₂ storage–regeneration process. Full article

Cr–N coatings are promising for severe-service applications owing to their high corrosion and wear resistance, yet their performance is governed by phase constitution and multilayer architecture. In this study, a monolithic Cr coating and three Cr-based multilayer coatings, Cr/Cr(N), Cr/Cr₂N, and Cr/CrN, were synthesized by a hybrid DCMS/HiPIMS process and systematically compared with respect to structure, mechanical properties, and oxidation behavior at 900 °C. XRD and TEM showed that Cr/Cr(N) was primarily characterized by a bcc Cr-type structure, while the N-containing layers exhibited slightly expanded lattice spacings relative to pure Cr; no Cr₂N precipitates were detected within the resolution of the analyses. Among the multilayers, Cr/Cr(N) provided the most favorable combination of hardness, adhesion, and indentation damage tolerance, reaching 885 HV and a critical scratch load of 80 N while maintaining damage tolerance comparable to monolithic Cr. By contrast, Cr/Cr₂N and Cr/CrN displayed more pronounced brittle damage and lower interfacial reliability. Upon oxidation at 900 °C, Cr and Cr/Cr(N) formed relatively compact Cr₂O₃ scales, whereas Cr/Cr₂N, and particularly Cr/CrN, experienced stronger oxidation-induced phase decomposition, blistering, and local delamination. These findings identify Cr(N) solid-solution sublayers as an effective alternative to brittle ceramic nitride layers. Full article

Preparing a highly wear-resistant AlTiN coating on a powder metallurgy (PM) M42 high-speed steel substrate is a key strategy to enhance tool performance and meet the demands of efficient machining. This study adopted a process route comprising substrate preparation, heat treatment regulation, and arc-PVD deposition of AlTiN coatings to systematically investigate the influence of sintering temperature (1130, 1160, and 1190 °C) and austenitizing time (1150 °C for 0, 15, 60, and 120 min) on the microstructure and mechanical properties of the substrate, as well as on the tribological performance of the AlTiN coatings. The results indicate that elevating the sintering temperature promotes densification of the matrix, with Vickers hardness increasing from 366 HV to 462 HV and bending strength (σ) increasing from 1064 MPa to 1310 MPa. The predominant carbide phases identified are MC, M₂C, and M₆C. During austenitizing, microstructural changes consistent with a progressive transformation from M₂C to MC and M₆C carbides were indicated by SEM and XRD analyses. Precipitation strengthening was most evident after 60 min, with hardness reaching 868 HV. In contrast, bending strength (σ) exhibited a progressive decline with increasing austenitizing time, decreasing from 1310 MPa to 1015 MPa after 120 min, illustrating a clear trade-off between hardness and toughness. The wear behavior of the coating is governed synergistically by substrate hardness, bending strength (σ), coating–substrate interfacial adhesion strength (L_C), and carbide phase transformation. Elevated substrate hardness enhances anti-wear performance; bending strength influences crack propagation and spallation tendency; and L_C determines the efficiency of interfacial load transfer. The carbide phase evolution appears to modulate the coating’s wear behavior by regulating both the microstructure and mechanical properties of the substrate. Among the six sample conditions evaluated, the A3 sample (sintered at 1190 °C and austenitized for 120 min) exhibited the lowest wear rate (2.38 × 10⁻⁶ mm³·N⁻¹·m⁻¹), demonstrating superior wear resistance. These findings provide a reference for process optimization and rational design of M42/AlTiN composite coating systems. Full article

C276 Hastelloy/Q235 Steel cladding plates were prepared by vacuum-sealed hot rolling (VSHR) with a small hole. The effects of different Ni interlayers on the macro-morphology, microstructure, mechanical properties and corrosion resistance of the cladding plates were systematically investigated. The results indicated that without an interlayer, a large number of Mo-rich white M₆C particles formed near the C276 Hastelloy side, along with the formation of black Cr-Mn oxides at the interface. The addition of the Ni interlayer suppressed the diffusion of the C element from the Q235 Steel toward the C276 Hastelloy, consequently reducing the precipitation of M₆C carbides and Cr-Mn oxides. When the Ni interlayer thickness was 0.5 mm, the M₆C carbides on the Hastelloy side disappeared completely. The incorporation of a Ni interlayer increased the hardness of the C276 Hastelloy side and the interface layer, as well as the shear strength of the cladding plate. This was mainly because the Ni interlayer acted as a barrier to suppress the development of a Mo/Cr-depleted zone adjacent to the C276 Hastelloy and decrease interfacial Cr-Mn oxides, thus enhancing interfacial bonding. Under all three conditions, the cladding plates were bent without cracking. Moreover, the addition of a Ni interlayer also improved the corrosion resistance of the cross-section of the C276 Hastelloy. XPS analysis of the passive film revealed that the corrosion resistance was primarily attributed to the formation of Mo- and Cr-containing oxides on the surface. The corrosion resistance reached the optimal with the Ni interlayer thickness of 0.5 mm, in which Mo and Cr played a crucial role. Full article

This study elucidates the mechanism enabling the low-voltage electrolysis of black liquor (BL) for integrated resource recovery. The process simultaneously generates protons at the anode via the oxidation of organics (OOR), which occurs at a lower potential than the oxygen evolution reaction (OER), and induces lignin precipitation. Concurrently, hydrogen and hydroxide ions are produced at the cathode through the hydrogen evolution reaction (HER). Driven by the electric field, sodium ions migrate from the anode to the cathode chamber, combining with hydroxide ions to form sodium hydroxide, thereby achieving the synchronous production of acid, alkali, hydrogen, and modified lignin in a single process. Using a platinum electrode, we conducted a mechanistic investigation through linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and detailed product analysis. The results show that overall efficiency is controlled by competition at the anode between OOR and OER, which directly determines proton yield. A critical trade-off exists between anodic proton generation and cathodic alkali recovery, driven by the competitive migration of protons and sodium ions across the cation-exchange membrane. The proton yield was highly dependent on the initial BL composition, with a characteristic peak observed under specific conditions. Conversely, the sodium hydroxide recovery rate was maximized when the anolyte pH remained high, minimizing competitive proton migration. This work provides fundamental insights into the interfacial mechanisms of BL electrocatalytic, establishing it as a versatile electrochemical biorefinery platform for simultaneous proton and alkali production from a renewable waste stream, beyond its role as a hydrogen source and lignin recovery. Full article

Urban underground construction in water-rich sandy strata produces large quantities of high-fluidity pipe-jacking spoil whose high water content, residual conditioning agents and heavy metal contaminants make conventional dewatering and landfilling increasingly unsustainable under carbon peaking and neutrality targets. This study explores a low-carbon route that converts such spoil into CO₂ foamed concrete through a coupled alkali activation–CO₂ foaming process. Ground granulated blast furnace slag and fly ash are used as geopolymer precursors, while a CO₂-based aqueous foam is introduced as both a pore-forming phase and carbon source. Single-factor tests and an L16(4⁴) orthogonal design are conducted to quantify the effects of CO₂ concentration, foam volume fraction, geopolymer dosage and alkali activator content on fluidity, setting time and compressive strength. Scanning electron microscopy (SEM) is employed to examine pore structure, gel morphology, carbonate precipitation and the interfacial transition zone around spoil particles. The results identify an optimum mix window (CO₂ 60–80%, foam 70–80%, geopolymer ≈ 20% and alkali activator ≈ 10% of solids) that delivers a fluidity above 210 mm, 28-day strength exceeding 3.0 MPa and a uniform closed-pore network. A multi-scale mechanism is proposed in which physical foaming, chemical carbonation and spoil particle immobilization act synergistically to form a dense gas–solid–soil composite suitable for in situ backfilling. Full article

Low-salinity water flooding (LSWF) has been widely investigated as an enhanced oil recovery (EOR) method for carbonate reservoirs; however, the relative contributions of wettability alteration and oil–brine interfacial tension (IFT) reduction remain poorly understood, particularly under strongly oil-wet conditions. This study systematically investigates the physicochemical mechanisms governing oil recovery during hybrid LSWF–surfactant flooding in oil-wet carbonate systems. Oil-wet Indiana limestone cores were used as representative carbonate reservoir rocks. Seawater and its diluted analogs were employed as base brines and combined with anionic and cationic surfactants at varying concentrations. Zeta potential and pH measurements were conducted to characterize electrostatic interactions at the rock–brine and oil–brine interfaces, while dynamic contact angle and pendant-drop IFT measurements were used to quantify wettability evolution and fluid–fluid interactions. Core flooding experiments were subsequently performed to link interfacial phenomena to macroscopic oil recovery behavior. The results demonstrate that brine dilution induces more negative surface charges at both interfaces, promoting double-layer expansion and electrostatic repulsion, which stabilizes the aqueous film and drives wettability alteration toward a water-wet state. The addition of anionic surfactants further amplifies this effect by increasing surface charge negativity, whereas cationic surfactants preferentially adsorb onto the negatively charged rock surface, limiting wettability alteration despite producing greater IFT reduction. Sulfate ions enhance wettability alteration by facilitating divalent cation interactions with adsorbed oil components; however, excessive sulfate concentrations lead to precipitation-induced flow impairment. Core flooding results reveal that diluted seawater combined with an anionic surfactant yields the highest incremental oil recovery. Our findings conclusively demonstrate that wettability alteration—rather than IFT reduction—is the more dominant recovery mechanism in oil-wet carbonate reservoirs under the investigated conditions. These results provide mechanistic guidance for optimized brine and surfactant design in hybrid LSWF–chemical EOR applications. Full article

The growing consumer trend toward plant-based diets is prompting the food industry to seek alternatives to animal protein. Chickpea protein (CPP) stands out for its high protein content (14.9–24.6%) and represents a sustainable alternative. Therefore, this study evaluated and compared the techno-functional performance of CPP and whey protein isolate (WPI), with a focus on their emulsifying capabilities for plant-based food development. CPP was extracted via alkaline extraction and isoelectric precipitation. The techno-functional properties were evaluated, including solubility index (%), foaming capacity (%), emulsion activity index (EAI), gelling, and interfacial properties. Additionally, CPP was used as an emulsifier in plant-based emulsions, and the emulsion stability was compared with WPI for two months. Although CPP exhibited a lower solubility index (60 ± 1.0%) than WPI (95 ± 0.3%), its foaming capacity was identical (CPP: 57 ± 6%; WPI: 58 ± 4%) and exhibited a significantly higher emulsion activity index (22 ± 0.3 m²/g) than WPI (15 ± 0.8 m²/g). In terms of gelation, WPI formed stronger gels (1.2–2.1 N) than CPP (0.05–0.06 N), at the same concentrations. Interfacial tension measurements showed that, while CPP exhibited a higher interfacial saturation concentration (0.055 g/L vs. 0.023 g/L), it was more effective at reducing equilibrium interfacial tension than WPI. Finally, emulsion stability over two months was similar when using CPP or WPI as emulsifiers. CPP demonstrates a competitive functional profile; however, its implementation as a sustainable ingredient will require physical or chemical modifications to improve its functional properties for complex food matrices. Full article

CaCO₃/BiO_2−x/CdS (CCO/BO/CS) ternary composite photocatalyst was synthesized via a hydrothermal method combined with chemical precipitation, and its performance in the photocatalytic reduction of hexavalent chromium (Cr(VI)) under visible light was systematically investigated. Compared with pure BiO_2−x, CdS, and binary BiO_2−x/CdS composites, the CCO/BO/CS system exhibited significantly enhanced Cr(VI) reduction activity. Specifically, the CCO/BO/CS (0.75:1:2 wt) composite achieved a Cr(VI) reduction efficiency of 94.53% within 30 min of visible light irradiation—approximately 94.6 times and 6.1 times higher than those of BiO_2−x (1.0%) and CdS (15.52%). Photoelectrochemical and trapping experiments revealed that the enhanced performance stems from improved charge separation, accelerated interfacial electron transfer, and the promotional role of CaCO₃—likely through lattice distortion—rather than direct photocatalytic participation. This study highlights the innovation of incorporating low-cost, eco-friendly calcium carbonate into semiconductor-based photocatalysts to induce lattice distortion for enhanced charge separation, as an effective strategy for improving the reduction efficiency of Cr(VI). Full article

Lignin nanoparticles (LNPs) offer sustainable alternatives to petroleum-derived nanofillers, yet their industrial application remains limited by poor dispersion control and trade-offs between loading, optical clarity, and mechanical performance. Here, we present a molecular architecture-driven design framework that systematically decouples polymer network physics from nanoparticle dispersion in poly(vinyl alcohol)/LNP nanocomposites. Through eco-friendly self-precipitation, we synthesize uniform LNPs with size tunability, overcoming persistent reproducibility challenges. Systematic investigation across PVA molecular weights and LNP loadings reveals entanglement-controlled dispersion behavior. Combined rheological and small-angle X-ray scattering analyses demonstrate that macroscopic suspension rheology is governed exclusively by polymer chain overlap, remaining invariant across LNP loadings. Conversely, the nanoscale LNP microstructural organization—ranging from depletion-driven clustering in weakly entangled networks to network-confinement stabilization in densely entangled systems—fundamentally dictates the film’s optical clarity and mechanical toughness. This rheology-microstructure decoupling establishes critical processing windows for industrial formulations, where polymer entanglement ensures suspension processability while the LNP dispersion state enables optical–mechanical tunability. The entangled network’s structure-filtering effect provides robust protocols for fabricating sustainable, transparent bio-composites suitable for packaging, optics, and functional films. Our quantitative composition–structure–performance framework advances fundamental understanding of entanglement-mediated interfacial phenomena while delivering practical design rules for next-generation sustainable bio-composites. Full article

With the increasing number of failures in high-voltage cross-linked polyethylene cables caused by buffer layer ablation, it is of great significance to investigate the electro–thermal coupling characteristics and ablation driving mechanisms under different defect conditions. Based on a multiphysics coupling model, an electro–thermal coupled simulation of the cable buffer layer and corrugated aluminum sheath was carried out, considering three typical defect types: air-gap barrier, moisture ingress, and white-powder barrier. The distributions of air-gap electric field, interfacial current density, temperature, and heat source were systematically analyzed. From the perspective of ablation mechanisms, the maximum air-gap electric field and its spatial location, as well as the maximum temperature of the buffer layer and its corresponding region, were investigated under different defect conditions. Meanwhile, the probabilities of electrical ablation and thermal ablation, together with their corresponding threshold parameters, were quantitatively evaluated. The results show that when an air-gap barrier exists between the buffer layer and the aluminum sheath, air breakdown may occur when the air-gap thickness is approximately 0.01–0.05 mm. When the buffer layer is moisture-contaminated and the defect length exceeds approximately 2 m, the buffer layer temperature may exceed 165 °C. When white-powder precipitates in the buffer layer, partial discharge may be initiated at the early stage. With the increase in powder barrier proportion, the buffer layer temperature may exceed approximately 220 °C. It should be noted that these critical characteristics are obtained under the simulation conditions of this study. The specific values depend on material parameters and operating conditions and can provide theoretical support for cable operation condition assessment. Full article