New Carbon Materials•2026•DOI: 10.1016/S1872-5805(26)61113-4
Porous pyrolytic carbon (PPyC) serves as the buffer layer in TRi-structural ISOtropic (TRISO) fuel particles, providing storage for fission gases, preventing damage to outer layers, and absorbing stresses caused by fuel-kernel swelling. However, the changes of PPyC micro- and meso-structure at high temperatures remain insufficiently understood. In this study, PPyC fabricated by chemical vapor deposition was heat-treated from 1200 to 1600 °C and characterized across atomic-to-mesoscopic scales. Results show that the structure changes with temperature with a transition at approximately 1400 °C. Below 1400 °C, a decrease in Raman ID/IG ratio, narrowing of the graphite diffraction peak, and increased sp2 hybridization indicate progressive ordering associated with defect redistribution. Concurrent decreases in true density and mesopore volume, together with increased closed porosity, are consistent with partial conversion of open pores into closed pores. Above 1400 °C, increased ID/IG ratio, broadening of the diffraction peak near the rhombohedral graphite (101) reflection, and transition regions between crystalline and amorphous material observed by TEM indicate increasing structural disorder. Meanwhile, initially distinct PPyC particle boundaries blur and merge into broad, plate-like domains. Subsequent decrease in closed porosity and increase in mesopore surface area are consistent with partial connection of closed pores to the open-pore network. This work shows that intrinsic coupling between atomic-scale structural change and mesoscale pore connectivity provides a basis for assessing high-temperature structural stability of PPyC in TRISO fuel particles.
New Carbon Materials•2026•DOI: 10.1016/S1872-5805(26)61108-0
Adipic acid is a key monomer for nylon-6,6 and nylon-6, yet its industrial production via nitric acid oxidation of KA oil suffers from high energy consumption and N2O emissions. This study reports a green catalytic system for one-pot oxidation of cyclohexane to adipic acid using a Cu/Cu2O@C composite catalyst derived from wood chips. During pyrolysis, wood chips serve as both carbon support precursor and in-situ reducing agent, converting Cu2+ into Cu/Cu2O active species. The abundant defects in biomass carbon form strong coordination interactions with copper, regulating the electronic distribution of active sites and enhancing catalytic performance. Under optimized conditions (100 °C, 12 h), the Cu/[email protected] catalyst achieves a cyclohexane conversion of 19.36% and an adipic acid selectivity of 73.28%. Mechanistic studies reveal that the electronic interaction between the carbon support and copper species strengthens adsorption of cyclohexanone, promoting selective formation of adipic acid. The reaction follows a free radical chain mechanism involving hydroxyl and alkyl radicals. This work provides a viable strategy for developing eco-friendly, low-cost, and high-efficiency catalytic materials for industrial adipic acid synthesis.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3830-6
Controlled fabrication of artificial multiple-stranded helices is central to deciphering chirality complexity and hierarchical self-assembly processes. Inspired by biological helical nanostructures, we designed a twisted figure-of-eight chiral macrocycle (M1) from pyrene and benzene diimide subcomponents to direct hierarchical assembly of double- and quadruple-stranded superhelices. Single-crystal X-ray diffraction reveals that M1 undergoes charge-transfer and CH···π interactions-driven helical wrapping, forming right-handed (P) single strands that intertwine into quadruple π-helical superstructures. Crucially, the macrocycle's adaptive cavity and interstitial voids could bind electron-deficient naphthalene diimide (NDI) guests through charge transfer interactions, triggering transformation to left-handed (M) double helices. This structural shift induces helicity inversion and optical anisotropy changes, demonstrating a rare case of crystalline-state multiple-helix conversion with supramolecular chirality inversion. This work establishes a template-free methodology for synthesizing multiple-stranded π-helices and controlling their transformations through supramolecular engineering.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3897-6
Decoding the nature of catalytically active sites is an essential prerequisite for the rational design of catalysts for electrochemical H2O2 synthesis, but faces significant challenges, particularly for controversial cobalt single-atom catalysts (Co SACs). Herein, we report trace Co single-atom sites embedded within pyridinic N-rich carbon nanospheres (Co1-NNH3-C), synthesized via a self-assembly coupled surface-coating strategy. The Co1-NNH3-C catalyst demonstrates remarkable H2O2 selectivity (99%) and activity at current density of −3.5 mA cm−2 in 0.1 M H2SO4. Through a combined approach of molecular probe experiments, surface modification, and density functional theory (DFT) calculations, we disclose that pyridinic N, rather than Co single atoms, serves as the direct active site for 2e− oxygen reduction reaction (ORR). The trace Co (0.05 wt%) indirectly facilitated pyridinic N formation during pyrolysis but exhibits negligible direct catalytic involvement. DFT reveals pyridinic N sites optimize OOH intermediate adsorption (ΔG*OOH = 4.0 eV) and minimize reaction overpotential of 0.20 V, enabling scalable H2O2 production (907.5 mmol gcat−1 h−1). This work redefines the role of trace metal in SACs, providing a paradigm for designing metal-induced carbon catalysts for sustainable electrosynthesis for H2O2.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3833-1
Developing plasmonic nanomaterials with compositions beyond noble metals is crucial for expanding their applications. Transition metal nitrides, such as titanium nitride (TiN), exhibit excellent plasmonic optical properties and photothermal conversion efficiency, showing promise in catalysis, photothermal therapy, and seawater desalination. However, the structure-property relationship governing their plasmonic optical properties remains unclear. Here, we constructed Au@TiN core-shell nanostructures and systematically investigated the tunability of their geometry, composition, and optical properties. By varying the Au core size and TiN shell thickness, we achieved precise control over the localized surface plasmon resonance (LSPR) from visible to near-infrared wavelengths. Single-particle scattering spectroscopy revealed distinct plasmon hybridization modes, with experimental spectra matching theoretical simulations. The Au@TiN nanostructures exhibited enhanced photothermal conversion efficiency (η = 78.5%) under 808 nm laser irradiation, significantly outperforming pure TiN nanoparticles (η = 45.2%). This work demonstrates multi-factor control over plasmonic effects in TiN, providing insights for designing TiN-based plasmonic nanomaterials for catalysis and sensing.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202511047
Ultra-high voltage (UHV) transmission lines are critical infrastructure for China's energy strategy. Compared with conventional voltage lines, UHV lines exhibit nonlinear growth in resource and capital consumption, complex supply chains, and strong spatiotemporal heterogeneity in carbon emission factors, resulting in substantial and uncertain construction-phase emissions. Accurate accounting is essential for achieving carbon peaking and carbon neutrality goals in the power sector. To address issues of ambiguous system boundaries, weak characterization of input parameter uncertainty, and poor cross-year applicability of input-output carbon intensities, this study defines the accounting boundary using budget quotas and develops a hybrid life cycle assessment (HLCA) model. For easily traceable emission sources, process-based LCA (PLCA) is applied, with uncertainty analysis via distribution fitting and Monte Carlo simulation. For difficult-to-trace sources, input-output LCA (IO-LCA) is used with carbon intensity correction. A case study of a ±800 kV transmission line yields a construction-phase carbon emission intensity of 1,858.91 t·km⁻¹ (CO₂ equivalent), with a 95% confidence interval of [1,379.73, 2,486.45] t·km⁻¹. Sobol global sensitivity analysis identifies key emission reduction pathways. The method's validity is confirmed by comparison with existing studies, providing quantitative support for low-carbon design, construction optimization, and carbon auditing of UHV projects.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3984-5
Rechargeable aluminum batteries (RABs) are promising for large-scale energy storage due to high theoretical capacity, inherent safety, and abundant aluminum reserves. However, conventional AlCl3-based ionic liquid electrolytes suffer from high cost, uncontrolled dendrite growth, and severe anode corrosion. Here, a molecular-level ligand engineering strategy is proposed, employing nitrogen-containing cyclic amides with tunable N–H functionalities to modulate the coordination environment of deep eutectic electrolytes (DEEs). Combined experimental and theoretical investigations reveal that the α-pyrrolidone-based DEE (PDEE) possesses a wider electrochemical window, higher ionic conductivity, and lower polarization. Precise N–H regulation optimizes cationic ligand and chloroaluminate anion interactions, accelerating ion transport to facilitate uniform Al deposition without dendrites. The amine functionalities enable in situ construction of a uniform inorganic-organic bilayer solid electrolyte interphase, mitigating anode corrosion and enhancing long-term interfacial stability. As a result, Al//Al symmetric batteries with PDEE achieve stable cycling for over 2000 hours, while Al-graphite full batteries demonstrate negligible capacity decay after 6000 cycles. This study establishes that ligand molecular engineering offers an effective strategy for optimizing DEEs, enabling durable and high-performance RABs.