Journal of Materials Science & Technology最新文献

Effective separation of bulk phase and surface charges is crucial for maximizing charge utilization in the process of photocatalytic energy conversion. In this study, SnS₂ nanoflowers and twinned Mn_0.5Cd_0.5S solid solution (T-MCS) nanoparticles were fabricated by a one-step solvothermal method respectively, followed by the formation of SnS₂/T-MCS nanohybrids through a facile physical solvent evaporation process for high-efficiency photocatalytic hydrogen (H₂) production. The T-MCS crystal structure consists of alternating wurtzite Mn_0.5Cd_0.5S (WZ-MCS) and zinc blende Mn_0.5Cd_0.5S (ZB-MCS), forming a twin structure within the semiconductor. The charge migration mechanism between WZ-MCS and ZB-MCS follows the S-scheme pathway owing to slight differences in energy levels within their respective crystal structures, resulting in exceptional bulk phase charge separation capacity of T-MCS. Additionally, SnS₂ enhances the electrochemical performance of the catalysts by providing more active sites, reducing charge transfer resistance and H₂ production overpotential, thereby facilitating faster reaction kinetics. The photoelectrochemical tests, radical trapping experiments, density functional theory (DFT), and electron paramagnetic resonance spectroscopy (EPR) confirm that the charge transfer path between SnS₂ and T-MCS follows an S-type route that accelerates interfacial photo-induced electrons and holes separation while preserving useful charges. The synergistic impact of twinned homojunction and S-type heterojunction in 10 wt.% SnS₂/T-MCS composite contributes to a remarkable H₂ production rate of 182.82 mmol h^–1 g^–1, which is 761.8 times higher than that achieved with SnS₂ alone (0.24 mmol h^–1 g^–1), as well as 5.8 times higher than that achieved with T-MCS alone (31.54 mmol h^–1 g^–1). This study offers novel insights into designing highly efficient sulfide photocatalysts specifically targeting solar-driven H₂ evolution through a dual S-scheme transfer pathway.

The application of silicon in lithium-ion batteries has been impaired by the low conductivity and large volume expansion. Herein, we develop a facile “surface amination” strategy to successfully encapsulate Si nanoparticles within the ZIF-8-derived N-doped carbon matrix. The amino group-containing organosilica serves as the linking agent between Si nanoparticles and Zn²⁺ and facilitates the coating of the ZIF-8 layer on the Si nanoparticles. This in turn induces the construction of N-doped carbon matrix encapsulated Si nanoparticles (NH₂-Si@C) during the subsequent carbonization. With buffered volume change and increased conductivity, the rationally designed NH₂-Si@C demonstrates a high reversible capacity (1494 mAh g^–1 at 1 A g^–1) and satisfactory rate performance (1062 mAh g^–1 at 5 A g^–1).

In this study, we demonstrate the direct in-situ synthesis of NiTi alloys with tunable chemical composition (Ni/Ti atomic ratio) and corresponding thermomechanical response. This synthesis is achieved by regulating the feeding speed ratio of pure Ni and Ti wires during the additive manufacturing process based on dual-wire-feed electron beam directed energy deposition (EB-DED) technology. Under appropriate process conditions, the resulting NiTi alloys exhibit a controllable evolution around the near-equiatomic composition and display a typical columnar grain morphology characteristic of additively manufactured NiTi alloys. With an increase in Ni content (shifting from Ti-rich to Ni-rich), the second phase particles present in the samples change from Ti-rich phase (Ti2Ni) to Ni-rich phases (such as Ni₄Ti₃ and Ni₃Ti₂). The phase transformation temperatures gradually decrease with increasing Ni content, and the predominant matrix phase transitions from martensite to austenite. The as-built NiTi alloy exhibits a typical tensile curve with a good tensile elongation of 11%, fabricated under suitable composition and microstructure conditions. This result surpasses values reported in current in-situ synthesized NiTi alloys through additive manufacturing methods. Moreover, it almost reaches the levels achieved by additively manufactured NiTi alloys using pre-alloyed raw materials. Furthermore, this study reports, for the first time in the field of in-situ synthesized NiTi alloys, a good tensile shape memory effect, achieving an impressive recovery rate of up to 70% under a tensile strain of 6%. This investigation provides a meaningful theoretical perspective and technical strategy for the integrated customization of NiTi alloy components in structure, composition, and function. This low-cost and high-efficiency approach is particularly attractive for the preparation of functional graded, large-scale and disposable NiTi components.

Spinal fusion is a commonly used technique to treat acute and chronic spinal diseases by fusion of the adjacent vertebrae, aiming at achieving stability and eliminating the mobility of the objective segment. While bone autografts and allografts have been conventionally used for spinal fusion, limitations persist in achieving optimization of both good osteoinductive capacity and mechanical stability. In this study, additively manufactured Zn-Li scaffolds were developed and evaluated for their potential in spinal fusion. First, three scaffold structures (BCC, Diamond, and Gyroid) were designed and verified in vitro. Due to the smooth transition surfaces and uniform degradation behavior, the Gyroid Zn-Li scaffold demonstrated mechanical integrity during degradation and enhanced cellular proliferation compared to the other two scaffolds. Subsequently, Zn-Li scaffolds (Gyroid) were selected for posterolateral lumbar fusion (L4/L5) in rabbits. Following 12 weeks of implantation, the Zn-Li scaffolds demonstrated a moderate biodegradation rate and satisfactory biocompatibility. Compared to bone allografts, the Zn-Li scaffolds significantly improved osseointegration adjacent to the transverse processes, which led to enhanced segmental stability of the fused vertebrae post posterolateral lumbar fusion. Overall, the results show that the biodegradable Zn-Li scaffold holds substantial potential as the next-generation graft for spinal fusion.

Carbon fiber/phenolic resin composites have great potential application in the field of electronic information, where excellent structural-functional integration is required. In this work, the establishment of interfacial structures consisting of carbon nanotubes with different morphologies at the fiber/matrix interface is conducive to the further modulation of the mechanical, tribological, electromagnetic interference (EMI) shielding and thermal conductivity properties of carbon fiber/phenolic resin composites. Specially, array carbon nanotubes can deep into the resin matrix, effectively hindering crack extension, and constructing an electrically and thermally conductive network. Compared with the carbon fiber/phenolic composites, the tensile strength and modulus of elasticity (163.86 ± 9.60 MPa, 5.06 ± 0.25 GPa) of the array carbon nanotubes reinforced carbon fiber/phenolic composites were enhanced by 57.09% and 22.22%. The average friction coefficient and wear rate (0.20 ± 0.02, 1.11 × 10⁻¹³ ± 0.13 × 10⁻¹³ m³ N⁻¹ m⁻¹) were reduced by 39.39% and 74.31%. EMI shielding effectiveness up to 40 dB in the X-band at 0.4 mm sample thickness, diffusion coefficient (0.39 ± 0.003 mm²/s) and thermal conductivity (0.54 ± 0.004 W/(m K)) were enhanced by up to 14.37% and 50.42%. This study reveals the beneficial effects of morphological changes of carbon nanotubes on the design of interfacial structure, proposes the reinforcement mechanism of array carbon nanotubes, and opens up the prospect of carbon fiber/phenolic composites for electronic applications.

Perovskite solar cells (PSCs) exhibit significant development potential in the last decade due to their high efficiency and low manufacturing cost, with power conversion efficiencies (PCE) as high as 26.1%. However, several problems still limit PSCs' performance and industrialization, including layer defects, energy level mismatch, and chemical instability. MXenes are a promising class of two-dimensional (2D) transition metal carbides and nitrides with excellent hydrophilicity, the tunable figure of merit, desirable electrical conductivity, abundant surface chemical end groups, and low-temperature solution processability. These properties make MXenes easy to combine with other materials and enrich their composites' physical and chemical properties, making them more useful in PSCs. This review systematically summarizes the relationship and development of PSCs and MXenes. Several strategies for combining MXenes with various layer components in PSCs were introduced. Further, we discussed the advantages of MXenes as the hole-transporting layer, electron-transporting layer, perovskite active layer, and electrodes. Finally, we look forward to future research on MXene-based materials in the field of PSC and the next step of commercialization.

Hydrogen evolution reaction (HER) from water electrolysis is an ideal alternative solution to address the energy crisis and develop clean energy. However, the construction of an efficient electrocatalyst with multiple active sites that can ensure high metal utilization and promote reaction kinetics simultaneously still leaves a major challenge. Herein, we present a facile strategy to synthesize a HER catalyst comprising Pt single atoms (Pt_SA) anchored in Fe vacancies and Pt quantum dots (Pt_QD) on the surface of NiFe LDH. Benefitting from the hierarchical and ultrathin nanosheet arrays and strong electronic interaction between Pt_SA/Pt_QD and NiFe LDH matrix, the optimized sample (Pt_SA/QD-NiFe_V9 LDH) exhibits outstanding HER performance in 1 M KOH with ultra-low overpotentials of 20 and 67 mV at 10 and 100 mA cm^-2, respectively, outperforming the benchmark Pt/C electrocatalyst. In addition, the electrolyzer using Pt_SA/QD-NiFe_V9 LDH as a cathode requires voltages of only 1.48 and 1.73 V to yield current densities of 10 and 1000 mA cm^-2, respectively. The combination of in situ tests and density functional theory (DFT) calculations reveal that the synergy of Pt_SA and Pt_QD can optimize the kinetics of water dissociation and hydrogen desorption, thus the Volmer-Tafel pathway prevailing the HER process. This work provides a promising surface engineering strategy to develop catalysts for efficient and robust hydrogen evolution.

This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composite featuring particle-rare coarse grain (CG) and particle-rich fine grain (FG) zones was successfully fabricated. Experimental results demonstrated that compared with the homogeneous structure, the dual-heterostructure composite achieved a significant increase in elongation by 116% and a remarkable 165% improvement in the strength-ductility product (SDP), while maintaining a high ultimate tensile strength (UTS) of 417±4 MPa. This substantial performance enhancement is primarily attributed to the additional strain hardening induced by hetero-deformation-induced (HDI) strain hardening and crack-blunting capabilities, as elucidated by microstructural characterization and crystal plasticity finite element modeling (CPFEM). Notably, the strain hardening contribution from the CG zones at the early stage of deformation (≤ 45% of total plastic deformation amount) is minimal but increases significantly during the subsequent deformation stages. The dislocation increment rate in CG zones (219%) is observed to be more than double that in FG zones (95%), attributed to the large grain size and low dislocation density in CG zones, which provide more space for dislocation storage. In addition, the aggravated deformation inhomogeneity as deformation progresses leads to an increase in geometrically necessary dislocations (GNDs) generation near the heterogeneous interface, thereby enhancing HDI hardening. Fracture mechanism analysis indicated that the cracks mainly initiate in the FG region and are effectively blunted upon their propagation to the CG region, necessitating increased energy consumption and indicating higher fracture toughness for the dual-heterostructure composites. This study validates the effectiveness of the dual-heterostructure design in magnesium-based composites, providing a novel understanding of the deformation mechanism through both experimental analysis and CPFEM, paving the way for the development of high-performance, lightweight structural materials.