SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4277-1
Two-dimensional (2D) magnetic materials hold promise for next-generation spintronics, yet most exhibit Curie temperatures (Tc) far below room temperature, limiting practical applications. Here, we report the realization of room-temperature ferromagnetism in CuCrSe2 nanosheets via controlled anion removal achieved by post-synthetic vacuum annealing. Raw CuCrSe2 shows a low Tc of ~120 K, whereas annealed CuCrSe2 (A-CuCrSe2) nanosheets exhibit robust ferromagnetic ordering above 300 K. Structural and compositional analyses, including transmission electron microscopy, Raman spectroscopy, and X-ray absorption spectroscopy, confirm that A-CuCrSe2 retains the original layered crystal structure with an estimated Se vacancy concentration of approximately 10%. Magnetic measurements reveal room-temperature ferromagnetism in exfoliated nanosheets, corroborated by magnetic imaging and electric transport measurements. Anomalous Hall effect (AHE) measurements uncover the coexistence of two ferromagnetic phases within the same sample: one with low Tc (~120 K) and another with high Tc (>300 K), indicating spatially heterogeneous magnetic ordering driven by anion removal distribution. Density functional theory (DFT) calculations elucidate the microscopic mechanism, suggesting that Se vacancies modulate the magnetic exchange interactions, enhancing Tc. This work demonstrates that anion modulation is an effective intrinsic strategy to achieve room-temperature ferromagnetism in 2D materials, potentially advancing spintronic applications.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025091203
The persistence of tetracycline (TC) in aquatic environments poses significant ecological risks. This study developed a homogeneous reaction system based on carboxylated Fe2+ enhanced peroxymonosulfate (PMS) activation, using citric acid (CA) as a ligand. Carboxylation improved Fe2+ stability and catalytic activity, while solid PMS served as the oxidant, circumventing issues of traditional Fenton processes such as H2O2 instability, complex heterogeneous catalyst preparation, high disposal costs, and toxic metal leaching. The acidic pretreatment enabled by CA inhibited Fe2+ oxidation and promoted sustained PMS activation without external energy input. Under optimized conditions (TC 5 mg·L−1, Fe2+ 0.02 mmol·L−1, CA 0.001 mmol·L−1, PMS 2 mmol·L−1), 88.80% TC degradation was achieved within 60 min. Mechanistic studies revealed that CA protected Fe2+ active sites via carboxyl coordination, facilitating continuous generation of reactive species, including singlet oxygen (1O2) and sulfate radicals (SO4•−). 1O2 was the dominant species (50.5% contribution), followed by SO4•− (35.7%), synergistically driving efficient TC degradation while significantly reducing iron sludge production. Phytotoxicity assays confirmed that treated water exhibited no significant toxicity to wheat seedlings (P > 0.05), indicating effective ecological risk elimination. This work provides a low-energy, operationally simple, and environmentally friendly technology for antibiotic-contaminated water treatment, with promising practical application potential.
New Carbon Materials•2026•DOI: 10.1016/S1872-5805(26)61093-1
Advanced catalyst structures with good active site accessibility and strong metal-support interactions are crucial for oxygen reduction reaction (ORR) catalysis. A hierarchically porous Pt catalyst supported on honeycomb-like nitrogen-doped carbon (Pt/HNC-400, where 400 denotes the optimal dosage (mg) of the sacrificial SiO2 hard template used during synthesis) was fabricated by combining template-assisted pyrolysis and alcohol reduction. The fabrication involves the template-assisted pyrolysis of ZIF-67 (which provides the N-dopant through its 2-methylimidazole ligand) followed by HF etching to completely remove the SiO2, yielding a 3D interconnected porous carbon support. Compared to a commercial Pt/C, it had an exceptional ORR performance with a half-wave potential of 0.901 V (41 mV higher), a mass activity at 0.9 V that was 15.3 times higher, and significantly improved durability (a half-wave potential decay of 25 mV vs. 80 mV after 10,000 accelerated durability tests (ADTs)). Mechanistic investigations showed that this superior performance is due to the combined effects of the 3D porous structure, ultrafine Pt nanoparticles with strong metal-support interactions, and in-situ formed Co-Nx moieties from the pyrolysis of precursor ZIF-67. After 10,000 ADTs it was shown to have excellent structural integrity, retaining 87.4% of its initial electrochemically active surface area (102.7 m2 g−1). This study may assist the development of new high-performance ORR catalysts.