SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3610-7
Electrochemical CO2 reduction reaction (CO2RR) offers an attractive route to produce value-added multicarbon (C2+) products, yet suffers from competing hydrogen evolution and monocarbon production. Here, we propose a dual-confinement effect on CO2 reactant and *CO intermediate, induced by tuning the pore configuration of reconstructed covalent organic frameworks (RC-COFs). The highly crystalline microporous RC-COF-1, when coated on a Cu electrode, enhances local CO2 concentration and restricts CO diffusion, thereby promoting C-C coupling. In acidic electrolyte, the RC-COF-1@Cu electrode achieves a maximum C2+ Faradaic efficiency (FE) of 67.0% at 500 mA cm−2, while maintaining a total carbon product FE above 90% across a broad current density range (100–500 mA cm−2). Experimental and theoretical analyses confirm that the ordered micropores of RC-COF-1 modulate reactant adsorption and intermediate diffusion, leading to improved C2+ selectivity. This work underscores the critical role of COF pore architecture in microenvironment engineering for heterogeneous catalysis.
The Chinese Journal of Process Engineering•2026•DOI: 10.12034/j.issn.1009-606X.225185
Sulfur hexafluoride (SF6), widely used as an insulating gas in high-voltage electrical equipment, possesses a global warming potential (GWP) 25,200 times that of CO2, necessitating efficient degradation technologies. This study employed computational fluid dynamics (CFD) to simulate the thermal catalytic degradation of SF6 in a fixed-bed reactor, integrating models for porous media, heat transfer, turbulence, and chemical kinetics. The simulations revealed significant radial non-uniformities in pressure, velocity, temperature, and species concentration distributions, with temperature identified as the dominant factor influencing degradation efficiency. Radial temperature gradients caused uneven reaction rates, with degradation rates near the wall substantially exceeding those at the central axis, thereby reducing overall SF6 conversion. To address this, structural optimizations were implemented, including reducing the reactor tube diameter and incorporating inert porous media with high thermal conductivity at both ends of the catalytic section. These modifications enhanced radial heat transfer, homogenized the temperature field, and improved the uniformity of reaction rates and species concentrations. Parametric studies on inlet gas velocity showed that both excessively low and high flow rates were detrimental: low velocities led to underutilization of the downstream catalyst and increased energy consumption, while high velocities deteriorated heat transfer and exacerbated radial temperature gradients. The optimal inlet velocity range was determined to be 0.4–0.8 m/s for a reactor tube inner diameter of 10 mm, balancing catalyst utilization, energy consumption, and degradation efficiency. This research provides data-driven guidance for the design and scale-up of SF6 catalytic degradation reactors.
New Carbon Materials•2026•DOI: 10.1016/S1872-5805(26)61106-7
Hard carbon anodes for sodium-ion batteries suffer from limited capacity, low initial Coulombic efficiency, and poor long-term cycling stability. To address these issues, we report a dual-stabilization strategy that combines micropore confinement and chemical bonding to control sulfur species in coal-derived hard carbon. Bituminous coal, with its naturally condensed aromatic framework, serves as the carbon precursor. A two-step thermal process first constructs a microporous carbon framework, followed by gas-phase sulfidation to introduce sulfur. The sulfur is confined within micropores and forms stable covalent C–S bonds with the carbon matrix, providing synergistic physical–chemical stabilization. This suppresses sulfur migration, prevents interfacial side reactions, and introduces additional redox-active sites. The optimized sample (HC-10) delivers a high reversible capacity of 450 mAh/g after 800 cycles at a current density of 1 A/g, with excellent rate capability and cycling stability. Mechanistic analysis reveals that the stabilized sulfur species reversibly participate in sodium-ion storage and improve interfacial kinetics. This work provides an effective strategy for stabilizing sulfur in coal-derived carbon materials and offers insights into the design of high-performance anodes for sodium-ion batteries.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202508050
This study investigated the spatial distribution and ecological risk of heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn) in soil beneath an informal waste dump in a pastoral area of Baingoin County, Nagqu City, Tibet, a high-altitude cold region with frequent freeze-thaw cycles. A total of 55 soil samples were collected from surface (0 cm), middle (10-30 cm), and deep (50 cm) layers. Single-factor index (Pi), geo-accumulation index (Igeo), Nemerow index (PN), and risk assessment code (RAC) were employed to evaluate contamination levels and potential ecological risks, while Kriging interpolation was used to map spatial distribution. Results showed that average concentrations of all seven heavy metals exceeded local background values. Horizontally, high-concentration zones were mainly located at five points within the dump. Vertically, Cd, Cu, Pb, and Zn were significantly enriched in the surface layer, whereas Ni exhibited higher concentrations in deeper layers, indicating downward migration driven by freeze-thaw processes. All evaluation methods identified Cd as the primary pollutant. Speciation analysis revealed that heavy metals were predominantly in the residual fraction, with Ni having the highest weak-acid-extractable fraction (5.55%), indicating strong mobility and potential biological toxicity. This study fills a gap in systematic research on informal waste dumps in high-altitude ecologically fragile areas and provides a case reference for environmental management and remediation of such sites in cold regions.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202507094
To address land waste and poor bearing capacity from sludge landfill, this study developed a composite solidifying agent using loess, fly ash, desulfurized gypsum, and cement. Orthogonal experiments combined strength testing, SEM/XRD microanalysis, permeability and heavy metal leaching tests, and cost accounting. Results show that cement significantly enhances early and mid-term strength, while loess dominates later strength development. Optimal fly ash and desulfurized gypsum content is 12% each. The optimal mix ratio (loess:fly ash:desulfurized gypsum:cement:sludge) is 0.1:0.12:0.12:0.08:1. The solidified matrix forms dense structures via C-S-H gel and ettringite (Aft), effectively controlling heavy metal leaching at low cost. This work enables solid waste resource utilization and provides robust support for sludge solidification engineering.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202605014
Chlorinated aliphatic hydrocarbons (CAHs) are prevalent groundwater contaminants at industrial sites in China. This pilot-scale study evaluated in-situ anaerobic bioremediation of CAHs-contaminated groundwater in a low-permeability bedrock fracture zone at depths up to 40 m. A self-developed anaerobic dechlorinating culture (BS-1), containing Dehalococcoides, Desulfitobacterium, and Dehalogenimonas, was injected alongside carbon sources (sodium citrate and emulsified vegetable oil) and nutrients. Pressurized nitrogen gas injection enhanced the distribution of amendments, achieving a radius of influence of 5.0 m. Over 399 days of monitoring, the combined use of slow-release and soluble carbon sources maintained anaerobic conditions (ORP < -100 mV) for over one year, providing sustained electron donors. The emulsified vegetable oil reduced injection frequency and operational costs. The BS-1 culture effectively dechlorinated vinyl chloride, cis-1,2-dichloroethylene, trichloroethylene, and chloroform, achieving removal efficiencies exceeding 95%. At times, groundwater quality met the Class IV standard of GB/T 14848-2017. This study demonstrates a green, economical, and effective solution for CAH-contaminated site remediation, with significant engineering application potential.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3862-x
Hexagonal boron nitride (hBN) is indispensable for next-generation electronics and quantum technologies, yet controlled synthesis of isotopically engineered hBN with macroscopic scalability and atomic-level precision remains challenging. Here, we present a plasma-enhanced chemical vapor deposition (PECVD) method using elemental boron (B) and nitrogen (N) precursors to achieve wafer-scale growth and precise isotopic control of hBN films. High-quality hBN films are synthesized on Cu substrates via optimized B evaporation and N2 plasma activation. The growth mechanism involves an oxygen-mediated pathway for B transport and a layer-by-layer (Frank-van der Merwe) mode for multilayer formation. By employing isotopically enriched B powders (10B and 11B) and N2 gases (14N2 and 15N2), we demonstrate tunable isotopic compositions with phonon mode shifts quantitatively matching harmonic oscillator predictions. Furthermore, we realize unprecedented in-plane h10BN-h11BN heterostructures through dynamic B source switching during growth. This PECVD strategy establishes a transformative synthesis platform merging industrial-scale production capacity with atomic-scale isotopic precision, enabling new opportunities to engineer thermal transport, optical response, and quantum coherence in two-dimensional materials.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4162-0
The urea oxidation reaction (UOR) offers a low-energy pathway for hydrogen production via water electrolysis, but Ni-based catalysts suffer from Ni self-oxidation reaction (NSOR) that wastes energy and poisons active sites via strong CO2 adsorption. Here, we design MoN/Ni heterostructures to optimize the electronic structure of Ni sites, suppressing NSOR. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy confirm the formation of electron-rich Mo and electron-deficient Ni active pairs. In-situ spectroscopy, electrochemical tests, and density functional theory calculations reveal that electron-rich Mo sites enhance urea adsorption, while electron-deficient Ni sites prevent NSOR, facilitating urea activation, intermediate conversion, and CO2 desorption. The synergistic effect yields a current density of 100 mA cm−2 at only 1.39 V vs. RHE in 1 M KOH + 0.33 M urea, outperforming many NiOOH-based catalysts. This work introduces a novel high-performance catalyst with electron-rich/electron-deficient active pairs for efficient UOR.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4073-2
Precise control of molecular orientation in nonfullerene acceptors is crucial yet challenging for achieving both high efficiency and long-term stability in organic solar cells (OSCs). Here, we report a molecular dimerization strategy to regulate orientation and charge-transport anisotropy in ambipolar M-series acceptors. Using the edge-on-oriented small-molecule acceptor MC16 as a model, dimerization into DMC16 effectively suppresses over-aggregation and molecular diffusion while inducing a predominant face-on packing orientation. This orientation transition reverses the transport anisotropy from lateral to vertical directions, enabling balanced ambipolar charge transport and efficient carrier extraction. Consequently, DMC16-based OSCs exhibit a markedly enhanced power conversion efficiency together with outstanding thermal stability, retaining 94% of the initial efficiency after 1800 h at 85 °C and 74% after an additional 1000 h at 120 °C. When introduced as a third component in PM6:M36 ternary blends, DMC16 further optimizes blend morphology and stability, delivering an efficiency of 19.04% and over 15% in 10.15 cm2 modules. These results demonstrate that dimerization-induced molecular orientation control provides an effective pathway to simultaneously enhance efficiency, stability, and scalability in OSCs.