SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4371-6
The sluggish kinetics of the oxygen reduction reaction (ORR) necessitates platinum-based catalysts, but their high cost and scarcity drive the search for platinum-group metal-free (PGM-free) alternatives. Fe−N−C catalysts with atomically dispersed Fe−N4 sites are promising, yet their practical performance is limited by buried active sites and poor mass transport. Here, a crumpled, multi-scale porous Fe−N−C catalyst (Fe−N−PCG) is synthesized via spray pyrolysis coupled with high-temperature metal etching. The crumpled morphology, formed by capillary compression during rapid solvent evaporation, and in-plane mesopores from Fe nanoparticle etching, synergistically enhance site accessibility and mass transport. Fe−N−PCG achieves a site density (SD) of 2.74×10^19 sites g−1 and Fe utilization (UFe) of 51.7%. As a gas diffusion electrode, it delivers a mass transport overpotential (ηmt) of 67 mV at 800 mA cm−2. In zinc-air batteries, Fe−N−PCG exhibits a peak power density of 296.1 mW cm−2 at 500 mA cm−2, outperforming Pt/C (241 mW cm−2 at 438 mA cm−2). At 50 mA cm−2, it delivers a discharge voltage of 1.19 V and a specific capacity of 815 mAh g−1, surpassing Pt/C (1.13 V, 715 mAh g−1). These results demonstrate that morphology and porosity engineering can concurrently optimize intrinsic activity, site utilization, and mass transport, offering a rational design strategy for high-performance PGM-free catalysts.
New Carbon Materials•2026•DOI: 10.1016/S1872-5805(25)61036-5
Large graphene oxide (LGO) sheets offer significant advantages over smaller ones in various applications, yet their production via Hummers-type oxidation of large natural graphite flakes remains challenging due to difficulties in achieving full oxidation and avoiding fragmentation. This study provides the first direct evidence that large graphite flakes (up to 1 mm) can be completely oxidized without fragmentation under static conditions, as revealed by in-situ monitoring. The oxidation process is governed by diffusion of the oxidizer between layers, described by Fick's law, where a high oxidizer concentration gradient increases the diffusion rate. By minimizing the amount of concentrated H2SO4 solvent, we achieved a semi-solid state that elevates oxidizer concentration, facilitating Mn(VII) diffusion and enabling complete oxidation of gram-scale large flakes with significantly reduced reagent consumption. Reaction temperature was optimized to balance graphite oxidation and Mn(VII) self-decomposition. Using this approach, 200-, 100-, and 50-mesh natural graphite were fully oxidized with reduced H2SO4 and KMnO4 usage. After exfoliation, LGO with average lateral sizes of 27.3, 58.7, and 116.2 μm were obtained, respectively, with 100% conversion and yield over 165%. This work not only provides a scalable, cost-effective strategy for LGO production but also advances the fundamental understanding of Hummers-type oxidation.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2024112102
Based on the 2022 activity data of non-road mobile sources in Hebei Province, this study employed the emission factor method recommended by the Guidelines to estimate emissions of CO, HC, NOx, PM2.5, PM10, and SO2. A comprehensive emission inventory was established, followed by spatial and uncertainty analyses. Scenario analysis, aligned with the 14th Five-Year Plan policies, was used to project emissions for 2030. The results indicate that non-road mobile sources in Hebei emitted 76.1×10^3 t of CO, 20.6×10^3 t of HC, 164.0×10^3 t of NOx, 8.5×10^3 t of PM2.5, 9.0×10^3 t of PM10, and 2.4×10^3 t of SO2. Agricultural machinery was the dominant contributor to CO, HC, PM2.5, and PM10, accounting for over 60.0% of CO emissions. Railway locomotives were the primary source of NOx, contributing 50.9%. For SO2, agricultural machinery and railway locomotives contributed 39.0% and 44.4%, respectively. The highest emitting cities were Tangshan (21.3%), Shijiazhuang (15.7%), Cangzhou (11.6%), and Handan (11.6%). Ship emissions were concentrated in Tangshan Port; civil aviation emissions were mainly in Shijiazhuang, Tangshan, Qinhuangdao, and Handan; railway emissions were distributed in Shijiazhuang, Baoding, and Handan. Under the updated emission standard scenario, NOx and PM10 emissions in 2030 could be reduced by approximately 35.0%. The phase-out of old machinery yielded the largest reduction in CO (36.0%), while both electrification and phase-out scenarios significantly impacted HC emissions.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3487-x
Continuous carbon fiber-reinforced ZrB2-SiC ceramic matrix composites are promising thermal protection materials for hypersonic vehicles and reusable spacecraft. Although injection-assisted vacuum impregnation (IVI) offers advantages such as shorter processing cycles, lower costs, and reduced fiber damage compared to conventional methods, phenolic/acetone-based IVI systems yield composites (designated as CPS) with limited ceramic contents. To address this, an aqueous slurry-based IVI approach was developed, producing composites designated as CHS. After a single IVI cycle, CHS achieved a ZrB2 phase volume fraction of 25 vol.%, 47% higher than CPS, while reducing processing time by 49%. After chemical vapor infiltration, CVI-CHS composite exhibited a room-temperature compressive strength of 106.78±10.53 MPa, representing a 28% improvement over CVI-CPS. Crack propagation analysis revealed discontinuous zigzag patterns under compression, dominated by fiber bridging and pull-out energy dissipation mechanisms. Flexural results revealed both composites retain considerable strength (111.15±12.46 and 83.15±12.03 MPa) along with low flexural modulus (13.00±2.41 and 13.52±6.99 GPa) and high strain tolerance (1.32%±0.018% and 1.07%±0.34%). It is attributed to the anisotropy of fiber preforms and the elastic modulus mismatch among different phases, which hindered effective constraint of fibers by the matrix and, in turn, facilitated mitigation of stress concentration. Additionally, CVI-CPS demonstrated superior X-band electromagnetic interference (EMI) shielding (34–36 dB) compared to CVI-CHS (22–27 dB), resulting from synergistic effects between pyrolitic and deposited carbon in the matrix of the former. Both composites showed enhanced EMI shielding efficiency with increasing temperature up to 600°C. This eco-friendly aqueous IVI strategy enables high-performance, cost-effective thermal protection materials with higher ceramic loading and tunable multifunctional properties.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025022102
Organophosphate pesticides (OPs), the most extensively used insecticides globally, are ubiquitous in environmental matrices and agricultural products, leading to widespread human exposure. This systematic review evaluates the impact of OP exposure on pregnancy complications and adverse birth outcomes, synthesizing evidence from 58 epidemiological studies published between January 2001 and July 2024. Exposure assessment methods, including biomarkers such as urinary dialkyl phosphates, are critically examined. The review finds significant associations between OP exposure and increased risks of spontaneous abortion, gestational diabetes mellitus, gestational hypertension, preeclampsia, preterm birth, and adverse birth outcomes such as low birth weight and reduced head circumference. Potential mechanisms include paraoxonase 1 (PON1) genotype polymorphisms affecting detoxification capacity, oxidative stress, inflammation, metabolic disruption, and altered placental gene networks. The review highlights inconsistencies across studies due to variability in exposure assessment, timing, and population susceptibility. Future research should prioritize longitudinal designs, repeated biomarker measurements, and consideration of PON1 genetic variants to clarify causal relationships and susceptible windows. This comprehensive synthesis provides critical insights for regulatory policies and clinical interventions aimed at mitigating maternal and child health risks from OP exposure.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025032006
A thiol-functionalized Ti3C2Tx (SH-Ti3C2Tx) material was synthesized via chemical bonding of dithiothreitol (DTT) onto Ti3C2Tx MXene for the adsorptive removal of As(III) from water. Characterization by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) confirmed a typical two-dimensional layered structure with DTT covalently attached. The adsorption of As(III) on SH-Ti3C2Tx followed the Langmuir isotherm model, indicating monolayer adsorption. At pH 7, the maximum adsorption capacity reached 55.6 mg·g−1, which is 2.8 times higher than that of pristine Ti3C2Tx (20 mg·g−1). X-ray photoelectron spectroscopy (XPS) revealed that As(III) uptake primarily occurred via formation of As–S bonds. To enable continuous treatment, SH-Ti3C2Tx was loaded onto melamine sponge via electrostatic interactions to fabricate a flow-through adsorption column (SH-Ti3C2Tx@MS). This column achieved removal efficiencies of 99.5% for both high (100 mg·L−1) and low (100 μg·L−1) As(III) concentrations, reducing effluent As(III) to below the World Health Organization guideline of 10 μg·L−1. The spent column could be regenerated using 1 mol·L−1 NaOH solution, retaining over 80% of its initial removal efficiency after five consecutive adsorption–desorption cycles. The SH-Ti3C2Tx material demonstrates significant potential for efficient and reusable removal of As(III) from contaminated waters.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4006-4
Hydrogels, despite their potential in flexible electronics and wearable sensors, often suffer from inadequate mechanical robustness under sustained loading. This study aims to overcome this limitation by developing a novel nanocomposite hydrogel system through the integration of calcium-polyoxometalate sub-nanometer wires (Ca-POM SNWs) into a polyvinyl alcohol (PVA) matrix. Utilizing a H2O/ethylene glycol (EG) binary solvent, the hydrogel achieves uniform dispersion of Ca-POM SNWs, which enhances mechanical properties through dual reinforcement mechanisms: stress dissipation via polymer-mimetic flexibility and crystallinity improvement via hydrophobic ligand-induced chain alignment. The resulting PVA/Ca-POM hydrogel exhibits exceptional performance, including a 2.4-fold increase in fracture stress (0.85 MPa), 3.8-fold toughness enhancement (2.76 MJ m−3), and high ionic conductivity (3.6 S m−1). As a strain sensor, it achieves a gauge factor of 2.56 with rapid response, enabling precise detection of both large joint movements and subtle physiological vibrations. A prototype Morse code communication system further demonstrates its potential in assistive healthcare technologies, facilitating barrier-free, real-time communication between disabled patients and clinicians. This work highlights a breakthrough in inorganic-organic interface compatibility, offering a versatile platform for next-generation wearable technologies and extreme-environment applications. The innovative design principles and multifunctional performance underscore its significance in advancing soft material engineering.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202608025
To evaluate heavy metal contamination and human health risks in desert lakes, this study analyzed concentrations of seven heavy metals (Hg, Pb, Cu, Zn, Cd, Cr, As) in Hongjiannao Lake, Northern Shaanxi, from 2013 to 2024. The absolute principal component score-multiple linear regression (APCS-MLR) model quantitatively apportioned pollution sources, and a health risk assessment model evaluated non-carcinogenic and carcinogenic risks. Results showed average concentrations of the seven metals did not exceed background values, but 28.57% of sampling points exceeded background for As, with a maximum exceedance factor of 1.92. Total average concentration decreased from 112.51 μg/L (2013–2016) to 58.80 μg/L (2017–2024), attributed to the 2016 closure of small coal mines and ecological restoration around the 4A scenic area. Source apportionment identified four sources: industrial (35.44%), agricultural (24.67%), natural (23.65%), and traffic (16.23%), indicating industrial dominance. Non-carcinogenic risks were negligible, but carcinogenic risks exceeded the alert value (1×10⁻⁴), with adults at higher risk than children. Oral ingestion was the primary exposure pathway. As and Cd were key control elements, with exceedance rates of 100% and 16.67%, respectively. These findings provide a theoretical basis for health risk prevention and environmental management.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4097-3
The on-demand patterning of two-dimensional transition metal dichalcogenides (TMDs) with tailored edges is critical for electronic and optoelectronic applications but remains technically challenging. Here, we report a stress-guided anisotropic etching strategy for producing large-area, well-ordered MoS2 nanostructures, including nano-ribbons and nano-squares, without templates. By applying uniaxial cumulative stress followed by selective thermal etching, MoS2 monolayers are statistically etched into ribbon-like structures whose width inversely correlates with applied stress magnitude. The newly etched edges are macroscopically straight or serrated, predominantly Mo-zigzag terminated, and enhance photoluminescence by a factor of ~8.0. The edge type depends on the angle between stress direction and crystallographic orientation, corroborated by theoretical calculations. Biaxial stressing generates well-defined nano-squares, offering a scalable, versatile patterning route for engineering 2D materials with tailored functional edges, promising for electrocatalytic and optoelectronic applications.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4029-4
Chemical sensing technology is pivotal in modern industry and daily life, with sensor performance critically reliant on nanomaterials. While sensors based on traditional nanomaterials, such as inorganic semiconductors and organic conductive polymers, have achieved commercialization, they face persistent challenges. As an emerging subclass, conductive metal-organic frameworks (c-MOFs) not only inherit the core advantages of traditional MOFs—high specific surface area, porosity, and tunable composition/structure—but also offer adjustable electrical conductivity, rendering them ideal for sensing applications. This review systematically elucidates the construction and properties of c-MOFs across microscopic crystalline and macroscopic micro-nano structural scales. Special emphasis is placed on the structural design and regulation of c-MOFs for analytical sensing, and the intrinsic structure-performance relationship is clarified to achieve higher sensitivity, selectivity, response speed, and long-term stability, as well as other performance metrics. Finally, we comprehensively summarize the typical applications of c-MOFs-based sensors, covering environmental and safety monitoring, photoelectric detection, and health monitoring and diagnosis. At the same time, the key challenges existing in this field, such as the controllable preparation of high-quality single-crystal materials, the theoretical analysis of intrinsic electrically conductive mechanisms, and the balance between macroscopic material stability and the processing performance of devices, were evaluated. The future research directions should focus on developing new ligands and metal combinations to optimize the band structure, deepening the exploration of the mechanisms of emerging physical effects such as piezoelectricity, and promoting the integration and application of materials in practical scenarios such as flexible electronics and wearable devices.