SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3697-8
Multi-site coupling is a promising strategy for developing highly efficient and CO-resistant hydrogen oxidation reaction (HOR) catalysts for proton exchange membrane fuel cells (PEMFCs). However, designing multifunctional synergistic schemes for single-atom sites remains a significant challenge. Herein, we propose a dual-template-confined oxophilic engineering strategy to construct well-dispersed iridium-nickel (IrNi) atomic dimers adjacent to IrNi nanoclusters on porous nitrogen-doped carbon (IrNi Dimer/NC1.8-PNC). The paired IrNi dimer features an asymmetric Ir-N3 configuration coordinated with heteroatomic Ni-N3O via an N-bridge. Remarkably, IrNi Dimer/NC1.8-PNC exhibits a ~23-fold enhancement in mass activity (4.36 A mg−1 Ir at 20 mV) and 5-fold longer stability compared to benchmarking Pt/C toward HOR, while achieving a high rated power density of 1.18 W cm−2 in PEMFC anode applications. Furthermore, IrNi Dimer/NC1.8-PNC demonstrates superior CO tolerance over monometallic Ir and Pt/C in both half-cell and full-cell devices. Combined experimental and density functional theory studies reveal that oxophilic Ni modulates the electronic environment of Ir through alloying and dimer interactions, thereby enhancing HOR activity. Importantly, the asymmetric IrNi dimer enables efficient CO* and OH* co-adsorption while facilitating CO2* desorption, synergistically mitigating CO poisoning and improving atom utilization efficiency. This work provides a design strategy and fundamental insights for multi-site synergistic catalysts in PEMFC anodes.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025010302
Cadmium (Cd) contamination of agricultural soils poses significant economic and health risks. While extensive research has focused on Cd accumulation in staple crops like rice, data on oilseed crops remain scarce, hindering safety assessments of edible oils and oilseed meals. This study investigated Cd accumulation and translocation in rapeseed (Brassica napus) grown in You County, Hunan Province, a region severely contaminated with Cd. Rhizosphere soil and plant tissues (roots, stems, seeds) were collected and analyzed for Cd concentrations. Results showed that approximately 71% of rhizosphere soil samples exceeded the agricultural soil pollution risk screening value for Cd, indicating high ecological risk. Cd concentrations in roots and stems were (0.49 ± 0.39) mg·kg⁻¹ and (0.54 ± 0.31) mg·kg⁻¹, respectively, comparable to or higher than soil Cd levels (0.51 ± 0.31) mg·kg⁻¹, with elevated bioaccumulation and translocation factors. This suggests that improper disposal of rapeseed roots and stems, such as returning them to fields or burning, could lead to secondary Cd pollution. In contrast, Cd bioaccumulation and translocation factors in seeds were less than 1, and Cd concentrations in seeds, oil, and oilseed meals were relatively low. Comparative analysis with sesame, camellia oleifera, and peanut indicated that rapeseed-derived oil and meal contain lower Cd levels, positioning rapeseed as a promising low-Cd-accumulating edible oil crop for cultivation in Cd-contaminated areas.
Journal of Fuel Chemistry and Technology•2026•DOI: 10.3724/2097-213X.2025.JFCT.0031
The high-temperature behavior of biomass ash critically influences gasifier operational efficiency. This study investigates the differential high-temperature behaviors of corn straw ash (CSA) and wheat straw ash (WSA) using an intelligent ash fusion analyzer, high-temperature rotating viscometer, X-ray diffraction (XRD), SEM-EDS, and FactSage thermodynamic simulations. Both ashes contain high K2O (>30%) and exhibit flow temperatures below 1300 °C. Despite higher K2O and lower SiO2, CSA exhibits a higher flow temperature (1241 °C) than WSA, attributed to elevated CaO (10.39%) and MgO (7.33%) that promote formation of high-melting silicates (K2MgSiO4, K2Ca2Si2O7, CaSiO3). In contrast, WSA with lower CaO (4.92%) and MgO (2.82%) tends to form low-melting potassium silicates. At high temperatures, both slags are typical crystalline slags, with viscosity rising sharply below a critical temperature. For CSA, rapid nucleation and coarsening of silicate crystals (e.g., KAlSiO4 grain size increases from 20.5 nm at 1350 °C to 192.9 nm at 1050 °C) cause abrupt viscosity increase. For WSA, a high P2O5 content (10.05%) induces a 'chemical dilution effect', leading to persistent KAlSiO4 during cooling and elevated viscosity, especially at the final cooling stage. This study elucidates how ash chemical composition governs high-temperature phase equilibrium and non-equilibrium kinetics, thereby macroscopically affecting ash fusion and rheological behavior, providing a theoretical basis for deeper understanding of biomass ash high-temperature characteristics.