SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3660-5
High-sensitivity piezoelectric ceramics with high piezoelectric constants (d33) are crucial for miniaturized, low-power, and high-efficiency transducers. However, conventional performance enhancement relies on intrinsic parameter modulation, which is limited and blind. This study introduces a performance-driven metamaterials creation model to develop structure-function-integrated piezoelectric materials. We systematically investigated the effects of metastructure design on d33 across two-dimensional straight rod (SR) structures, three-dimensional dot-matrix (Octa) structures, complex triply periodic minimal surface (TPMS) structures, and hybrid Octa&SR structures. The results demonstrate that metastructures combining high polarization charge conversion efficiency with low compression modulus (stiffness) effectively enhance d33. The SR structure exhibited optimal polarization charge conversion, the Fks-Shellular (FksS) structure within TPMS showed low stiffness, and the Octa&SR structure combined both properties. Notably, all three structures displayed exceptional piezoelectric performance. Specifically, the FksS structure achieved a substantial d33 of 194 pC/N, a 24% enhancement over conventional solid BaTiO3, while maintaining isotropic and stress-insensitive properties. This work elucidates the mechanism for designing piezoelectric metastructures, offering a novel pathway for developing high-performance, high-failure-strength piezoelectric materials.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3654-5
Hydrogen production by photosynthetic green algae is an efficient biological process that utilizes light energy to convert water and carbon dioxide into clean and renewable energy. In this paper, we constructed a hybrid system combining graphitic carbon nitride (g-C3N4) and Chlorella pyrenoidosa (Chlorella), in which g-C3N4 serves as an extracellular electron source and Chlorella acts as a biological reactor for specific hydrogen production. In particular, the electronic structure of carbon nitride was optimized by means of hydrothermal alkalization and copper ion doping, expanded the light absorption range and enhanced the light response ability. g-C3N4, as an extracellular electron source, can provide electrons for Chlorella to improve hydrogen production performance which is 3.7 times that of bare Chlorella. The construction of a biological hybrid system is a feasible optimization strategy for the hybrid system to promote the synergistic effect of the hybrid system by regulating the properties of non-living components.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3708-y
Polar two-dimensional (2D) perovskites, with their excellent semiconductor properties, intrinsic anisotropy, and bulk photovoltaic effect, have emerged as promising candidates for self-driven polarization-sensitive photodetectors. However, these self-driven polarized detectors typically require fabrication along the spontaneous polarization direction to maintain device operation in the self-driven mode, which imposes additional limitations. Herein, we demonstrate multidirectional self-driven polarization-sensitive photodetection by constructing 2D perovskite-based asymmetric contact devices, Ag/2D perovskite/C. The built-in electric field, originating from the difference in work functions, acts as the driving force for the separation and transport of photogenerated carriers. Notably, this approach does not necessitate a specific direction, thereby enabling multidirectional self-driven photodetection. Under excitation by linearly polarized light, our devices exhibit impressive polarization-sensitive discrimination in multiple directions, achieving polarization ratios of 3.3 and 3.1 along the a and b-axes, respectively. Our work enriches the approaches enabling self-driven polarization-sensitive photodetection, free from the previous limitations.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202507027
Ammonia nitrogen (NH3-N) is a common water pollutant that can induce eutrophication and threaten aquatic ecosystems and human health. Accurate monitoring is essential for water safety. This study applied a self-developed gas-permeable membrane-based conductivity sensor (GPMCS) for real-time in-situ monitoring of NH3-N in two water bodies. In the Qunying River (surface river water), GPMCS captured concentration fluctuations linked to pump operations and sewage intrusion, with mean inlet and outlet concentrations of 4.67 and 3.42 mg/L, respectively. In Swan Lake (landscape aquaculture water), concentrations reached up to 11.16 mg/L, with site means of 6.42 and 7.04 mg/L, influenced by aquaculture activities, weather, and location. GPMCS results correlated strongly with national standard methods (r1=0.8132, r2=0.7483), confirming accuracy and reliability. Compared to existing techniques, GPMCS offers high selectivity, strong anti-interference, portability, no sample pretreatment, low cost, and environmental friendliness, making it suitable for long-term in-situ monitoring. This technology provides robust support for sustainable water environment management.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202607020
Kitchen waste (KW) and excess sludge (ES) are urban biowastes with resource recovery potential, commonly treated via anaerobic digestion (AD) for methane production. However, KW mono-digestion suffers from acidification, while ES yields low methane. This study employed semi-continuous reactors to simulate practical AD, co-digesting KW and ES at a 4:1 volatile solids ratio with biochar addition (0.5, 1.0, 2.5, 5.0, 10.0 g/L). The optimal biochar dosage was 2.5 g/L, achieving cumulative biogas and methane volumes of 17.53 L and 11.63 L, respectively, representing 42.10% and 39.47% increases over the biochar-free control, and 34.45% and 43.30% enhancements relative to thermally hydrolyzed sludge. The methanogenic lag phase decreased from (5.65±0.11) d to (4.33±0.12) d. Process stability improved, with average volatile fatty acids (VFAs) during stable operation dropping from 1708 mg/L to 1033 mg/L. Microbial analysis revealed enhanced diversity and enrichment of Synergistetes and Syntrophomonas, indicating direct interspecies electron transfer (DIET) promotion. Biochar at low concentrations enhances AD by immobilizing microbes and facilitating electron transfer, while high concentrations (10 g/L) may inhibit methanogenesis due to fatty acid degradation blockage, yet total methane production remained above control. These findings demonstrate that biochar addition at 2.5 g/L effectively enhances methane production and process stability in KW-ES co-digestion.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202504023
The national standard GB/T 19515—2023, titled "Road vehicles - Recyclability and recoverability - Requirements and calculation methods," has been officially released and implemented. This standard is crucial for guiding automotive manufacturers in selecting recyclable materials for new products and enhancing the potential recyclability and recoverability of vehicles. This paper provides a comprehensive interpretation of the standard, covering its background, significance, technical requirements for the two rates (recyclability rate and recoverability rate), and the calculation methods. The standard aims to assist automotive enterprises in establishing a calculation system for these rates, thereby improving the recyclability performance of vehicles, reducing waste from end-of-life vehicles, and promoting the circular economy within the automotive industry. Key aspects include the alignment with international standards such as ISO 22628 and EU directives, the historical evolution of the standard from 2004 to 2023, and the detailed calculation methodology based on four stages of end-of-life vehicle processing: pre-treatment, dismantling, metal separation, and treatment of non-metallic residues. The paper also highlights the importance of design-phase considerations and the need for manufacturers to collect accurate material data from their supply chains. Future improvements to the standard are discussed, including expanding vehicle type coverage and refining material identification requirements.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4063-2
Quantum dot light-emitting diodes (QLEDs) are emerging as a leader in next-generation display technology. In principle, the efficiency of QLEDs is highly reliant on the radiative recombination rate of injected electrons and holes in the QD emissive layer. Within a solitary light-emitting cycle, a pre-negative-charged QD bursts into a fleeting sparkle upon encountering a hole, much like a lighted piston within a roaring engine. More pistons bring higher horsepower. The challenge of achieving highly efficient QLED lies in how to increase the number of pre-negatively charged QDs. To address these limitations, we developed a ZnO@ZnMgO core-shell nanoparticle (NP)-based electron transport layer (ETL). This design synergistically combines the high conductivity of ZnO core and the low defect density of the ZnMgO shell. Measured by electron-excited transient absorption, the average electron population (<N_e>) in the emissive layer for ZnO@ZnMgO and ZnMgO-based QLEDs was 0.61 and 0.33 at 4 V, respectively, which greatly increases the carrier recombination efficiency. As a result, green QLEDs achieve a peak EQE of 30.66%, maximum luminance of 1,615,039.85 cd/m2, and a low turn-on voltage of approximately 2 V. The T95 operational lifetime exceeded 29,000 h at 1,000 cd/m2. Currently, all parameters are at the top level within the QLED region.