SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3771-9
High-entropy carbonitride ultra-high temperature ceramics (HECN-UHTCs) typically require high densification temperatures, leading to grain coarsening and degraded mechanical properties. This study introduces CrSi2 as a sintering additive for (Ti, Zr, Hf, Nb, Ta)(C, N), effectively reducing the densification temperature by 200 °C. During sintering, interdiffusion and cation exchange result in the formation of an orthorhombic (Ti, Zr, Nb)2Cr4Si5 phase within the ceramic matrix. The resulting dual-phase ceramic exhibits a hardness of 24.65 ± 0.23 GPa and a fracture toughness of 6.03 ± 0.48 MPa m1/2, significantly surpassing most reported HECN-UHTCs. Enhanced mechanical properties are attributed to crack deflection, increased localized lattice strain, and Cr grain boundary segregation. This liquid phase-assisted low-temperature sintering strategy offers a promising pathway for densifying other ultra-high temperature ceramics.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3857-1
High-Be Cu-Be alloys exhibit dendritic segregation and brittle β/γ phases, complicating processing and applications. This study investigates the influence of cooling path on eutectoid transformation, microstructure, and mechanical properties in Cu-2.8Be and Cu-3.8Be alloys. A two-step homogenization treatment effectively eliminates segregation and suppresses the formation of harmful acicular phases. Diffusion-kinetic and thermodynamic analyses demonstrate that both the initial temperature and cooling rate determine eutectoid morphology and extent. Crystallographic and Eshelby-based analyses reveal that the β → γ transformation involves an isotropic contraction of ~3.9%, producing much lower strain energy than the anisotropic β → α transformation (~28.5% expansion and ~9.2% contraction), thus explaining the preferential nucleation of γ. Rapid cooling promotes incomplete eutectoid decomposition along grain boundaries, forming fine α/γ lamellae with interlamellar spacing down to ~7 nm. Lattice strain analysis confirms considerable distortions at α/γ interfaces (ε_xx = 0.0167, ε_yy = 0.0095). The mechanical incompatibility and high internal strain at these interfaces cause stress concentration and crack initiation. This work establishes a process-microstructure-property-mechanism framework essential for controlling the performance of high-Be Cu-Be alloys.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3993-y
Conventional liquid-phase in-situ synthesis of Cu-TiB2 composites often suffers from coarse and non-uniformly distributed reinforcements, stemming from insufficient understanding and control over the in-situ nucleation and growth mechanisms of TiB2 particles. This study introduces a novel melt dispersion-turbulent mixing (MDTM) in-situ reaction technology to fabricate high-performance Cu-TiB2 composites. The MDTM strategy synergistically refines reaction micro-regions by reducing the initial melt droplet size via melt dispersion while enhancing solute convection via turbulence, promoting high-density nucleation and refinement of TiB2 particles. Based on turbulence characteristics and in-situ reaction kinetics, we optimized the melt disperser parameters and established a quantitative model linking particle size to disperser rotation speed and reactant solute concentration. It was found that disperser rotation speed governs three distinct nucleation and growth mechanisms for TiB2 particles. Low-density nucleation at low disperser rotation speeds (0–50 r/min) leads to coarse TiB2 particles. At medium rotation speeds (100–150 r/min), the refinement of micro-regions in the dual-melt reaction achieves high-density TiB2 nucleation. Conversely, at high rotation speeds (150–200 r/min), intense turbulence weakens the nucleation driving force and induces TiB2 particle coarsening. This work provides new insights into liquid-phase in-situ reaction mechanisms and offers a novel, controllable route for fabricating high-performance micro/nano particle-reinforced metal matrix composites.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3892-2
Single-atom co-catalysts on semiconductor substrates offer a cost-efficient route to enhance photocatalytic performance with minimal precious metal loading. However, precise tuning of local coordination environments and construction of efficient single-atom co-catalysts remain challenging for overall water splitting. Here, we employ an icing-assisted photochemical reduction strategy to anchor atomically dispersed Pt species as hydrogen evolution co-catalysts on Al3+-doped SrTiO3 (Pt SA-STO). The optimized Pt SA-STO exhibits remarkable activity, with hydrogen and oxygen evolution rates of 13.62 and 6.71 mmol h−1 g−1, respectively, and a turnover frequency (TOF) of 2114.5 h−1. We pioneer the use of nuclear magnetic resonance (NMR) spectroscopy to quantitatively track the temporal evolution of Pt4+ to Pt2+ under continuous irradiation during the icing-assisted photoreduction. Advanced characterizations and theoretical calculations confirm that single-atom Pt co-catalysts facilitate directional transfer and extraction of photogenerated charge carriers, effectively suppressing surface recombination. This work provides insights into designing novel single-atom co-catalysts by deepening understanding of electronic configurations and active sites in photocatalytic overall water splitting.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025042502
Rice husk biochar (BC) was modified with boron (B) and nitrogen (N) doping and loaded with Fe3S4 to fabricate B-BC@Fe3S4 and N-BC@Fe3S4 catalysts for peroxydisulfate (PDS) activation and enrofloxacin (ENR) degradation. Characterization via SEM, BET, XRD, Raman, and XPS confirmed successful heteroatom incorporation and uniform Fe3S4 dispersion, enhancing specific surface area and defect sites. Degradation experiments showed that B-BC@Fe3S4 and N-BC@Fe3S4 achieved ENR removal efficiencies of 90.72% and 91.89%, respectively, significantly outperforming unmodified BC@Fe3S4 (82.21%). Mechanistic studies revealed that PDS activation proceeded via Fe3S4-mediated electron transfer generating radical species (SO4•−, •OH, O2•−) and via B/N functional groups promoting non-radical singlet oxygen (1O2) formation. Notably, N-BC@Fe3S4 exhibited superior resistance to Fe3+ leaching and greater environmental adaptability under varying pH, anion, and humic acid conditions. These findings demonstrate that B/N-doped biochar-supported Fe3S4 are effective catalysts for PDS activation, offering promising potential for antibiotic removal from real wastewater matrices.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2026050701
Azo food colorants are persistent aquatic pollutants posing risks to ecosystems and human health. Utilizing biomass waste to produce low-cost activated carbon offers a sustainable strategy for their removal. In this study, activated carbon (HPR-AC) was synthesized from Haematococcus pluvialis residue via phosphoric acid activation, and its adsorption performance was evaluated using Sunset Yellow (SY), Ponceau 4R (P4R), and Tartrazine (TY) as model pollutants. The effects of solution pH, adsorbent dosage, initial dye concentration, and temperature on adsorption efficiency were systematically examined. Characterization by BET, FTIR, XRD, and XPS revealed that HPR-AC possesses a high specific surface area and an abundant mesoporous structure. The adsorption process was well described by the Langmuir isotherm and pseudo-second-order kinetic models, indicating monolayer chemisorption and an endothermic nature. At pH 5 and 55 °C, the maximum adsorption capacities reached 67.12, 79.72, and 72.75 mg·g−1 for SY, P4R, and TY, respectively. Statistical physics modeling further suggested a multilayer physical adsorption mechanism, primarily governed by pore filling, electrostatic interactions, hydrogen bonding, π-π stacking, and charge transfer. These findings provide both theoretical insights and empirical data for the valorization of H. pluvialis residue and the development of efficient, sustainable adsorbents for azo dye removal from water.