Yiyao Ge

This work demonstrates a cation-exchange strategy to construct Zn _x Cd _{1− x} S-MoS ₂ epitaxial heterostructures with precisely tuned band structures and atomically coherent interfaces, achieving a hydrogen evolution rate of 60.88 mmol·g ⁻¹ h ⁻¹ .

Silicon carbide (SiC) ceramics normally exhibit high hardness but suffer from inherent brittleness, limiting their applications in extreme environments. Traditional strengthening strategies that enhance mechanical strength generally result in the sacrifice of fracture toughness, leading to the typical “strength‐toughness trade‐off”. Here, we report a dual‐strengthening strategy that simultaneously boosts hardness, compressive strength, and fracture toughness of SiC ceramic through the synergistic nanocrystallization and coherent interface effects. Using a polycarbosilane precursor‐derived approach, a HfC‐reinforced SiC ceramic has been fabricated via the in situ crystallization of amorphous SiC intermediate during fast hot‐pressing sintering. The rapid heating enables the direct transformation from amorphous to nanocrystalline SiC matrix, which inhibits the over growth of SiC grain while simultaneously forming coherent HfC/SiC interfaces characterized by aligned crystallographic orientations. Such coherent interfacing between HfC and SiC phases contributes to their strong atomic‐level bonding and thus facilitates effective fracture energy transfer during loading. The resulting SiC ceramic composite containing 20 wt% HfC shows significant mechanical property improvements with Vickers hardness increasing by 20%, compressive strength increasing by 53% and fracture toughness enhancing by 36% compared to pure nanocrystalline SiC ceramic. The simultaneous enhancement of mechanical strength and fracture toughness, together with the improved hardness, demonstrates the synergistic effect of nanocrystallization strengthening and coherent interface reinforcement. This precursor‐derived in situ crystallization strategy provides a promising route for designing advanced composite ceramics with superior mechanical performances.

Prismatic SiC fibers with periodic serrated structure, mostly reaching millimeter‐sized lengths, were synthesized by a simple catalyst‐free method. The process involved heating SiC nanopowder in a graphite crucible at 1700°C under 0.1‐MPa argon atmosphere. The synthesized SiC products consist of SiC fibers several millimeters in length and mostly 0.5–3 µm in diameter. Further, the vapor‐solid growth mechanism and detailed growth process of SiC fibers are discussed. The millimeter‐sized prismatic SiC fibers have the potential to be applied in fields such as electromagnetic wave absorption.

Amorphous PdAg alloy nanoparticles with tunable composition have been prepared for a highly efficient electrochemical CO ₂ reduction reaction.

Si ₃ N ₄ –BN composites were fabricated by spark plasma sintering, and the effects of starting BN particle sizes on microstructure, mechanical properties, and thermal shock resistance of the composites were systematically investigated. The samples with submicron BN effectively refined β ‐Si ₃ N ₄ grains, resulting in enhanced mechanical properties, including flexural strength and hardness. Among all samples, the 800‐S7B2 sample exhibited the optimal combination of properties, with a flexural strength of 1008 ± 49 MPa, fracture toughness of 6.8 ± 0.1 MPa·m ^1/2 , and hardness of 8.1 ± 0.1 GPa. Thermal shock tests indicated that both the samples with submicron BN and the samples with microscale BN retained approximately 90% of their residual flexural strength after thermal shock at 1200°C. Notably, the samples with microscale BN exhibited higher R ^IV and α _cr values due to their greater fracture toughness‐to‐strength ratio, enhancing resistance to crack propagation and resulting in superior thermal shock performance, with residual flexural strength exceeding 90% after thermal shock at 1200°C. These results demonstrate that controlling the BN particle size is an effective strategy to optimize the microstructure, mechanical performance, and thermal shock resistance of Si ₃ N ₄ –BN composites.

The fabrication of efficient, low‐cost, and stable bifunctional oxygen catalysts is crucial for zinc–air batteries (ZABs). High‐entropy materials have emerged to possess great potential as oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) bifunctional catalysts for ZABs, but its efficient synthesis with superior activity remains challenging. Herein, a rapid and facile microwave‐induced carbon thermal shock technique was developed to efficiently synthesize high‐entropy oxide (HEO) nanoparticles, i.e., (FeCoNiCrMn) ₃ O ₄ , that are uniformly anchored onto carbon nanotubes (CNT), denoted as (FeCoNiCrMn) ₃ O ₄ /CNT. The obtained (FeCoNiCrMn) ₃ O ₄ /CNT can work as a bifunctional catalyst, exhibiting excellent performance with the OER overpotential of 273 mV at 10 mA cm ⁻² and the ORR half‐wave potential of 0.771 V. Moreover, the ZAB assembled with (FeCoNiCrMn) ₃ O ₄ /CNT as the cathode demonstrates superior performance, with high specific capacity (828.8 mAh g _Zn ⁻¹ ), energy density (986.3 Wh kg _Zn ⁻¹ ), and outstanding long‐term durability exceeding 500 h. This work offers a scalable strategy in efficient construction of CNT‐supported HEO nanomaterials, thus facilitating the development of high‐efficiency electrocatalysts for practical ZAB applications.

Self‐supporting catalysts have attracted massive research interest in electrocatalysis because of their excellent conductivity and high utilization of active sites. However, traditional substrates, e.g., metal foams and carbon paper, suffer from structural instability and slow mass transfer due to their irregular pore structure, leading to reduced catalytic activity. Herein, we employ selective laser melting technology to construct a three‐dimensional (3D) CuNi self‐supporting electrocatalyst with a microchannel array (CuNi‐P). The ordered and interconnected porous structure efficiently facilitates mass transfer, and the decorated nanoparticles provide additional active sites. The obtained CuNi‐P also exhibits outstanding mechanical properties, ensuring long‐term durability. Moreover, the surface of CuNi‐P exhibits superhydrophilic and superaerophobic properties, enabling efficient mass transfer across the solid‐liquid‐gas three‐phase interfaces. Cu and Ni act synergistically to enhance NO ₃ ⁻ reduction to ammonia (NH ₃ ), delivering the lowest charge‐transfer resistance and a high NH ₃ yield rate of 10.6 mg h ⁻¹ cm ⁻² at −0.55 V. Additionally, CuNi‐P exhibits excellent electrocatalytic performance for glycerol oxidation reaction, enabling a bifunctional electrocatalytic system that couples NH ₃ and formate production. The system can achieve a high NH ₃ Faradaic efficiency of 95.5% at 1.6 V and a current density of 100 mA cm ⁻² at only 1.4 V, while maintaining stable performance for 500 h.

High-entropy alloy (HEA) nanomaterials are promising catalysts for proton exchange membrane water electrolysers (PEMWE), yet their crystalline structures have typically been restricted to thermodynamically stable phases. Here, using Au nanomaterials with distinct crystal phases as templates, we synthesize and stabilize Au@HEA core-shell nanostructures through a general and robust wet-chemical method in which the HEA is composed of up to ten metallic elements (Ir, Pt, Ni, Fe, Co, Rh, Pd, Ru, Cu and Mn). Phase-dependent water electrolysis is demonstrated as a proof-of-concept application. The hexagonal close-packed 4H-Au@4H-IrPtNiFeCo catalyst exhibits superior activity and stability for the acidic hydrogen evolution reaction, oxygen evolution reaction and overall water electrolysis compared with the conventional face-centred cubic IrPtNiFeCo catalyst. In a PEMWE at 60 °C, the 4H-Au@4H-IrPtNiFeCo catalyst achieves 3,000 mA cm^-2 at only 1.90 V and maintains stable operation for over 1,200 h at 1,000 and 2,000 mA cm^-2, with degradation rates of ~6.3 and ~15.7 µV h^-1, respectively. This work offers a strategy for designing highly efficient and stable HEA catalysts with tailored phases for future practical water electrolysis.