Science China Materials最新文献

Seawater electrolysis (SWE) is a reusable and convenient avenue of producing hydrogen, offering a promising solution to the energy crisis and global warming. However, poor electrolytic efficiency and irreversible corrosion caused by high concentrations of chlorine severely hinders the commercialization of SWE. To address the above challenges, numerous strategies have been proposed in recent years, involving theoretical innovations, directional catalyst design and electrolyser modification. Herein, we provide a systematic summary of the chlorine-related challenges and solutions encountered in SWE. The chlorine-related theoretical knowledge and challenges in the SWE systems are first emphasized. Subsequently, we introduce multiple anodic chloride suppression strategies from three aspects, including directional regulation of oxygen evolution catalysts, optimization of electrolyte compositions, and ingenious upgrades of electrolytic cells. Finally, we explore the future challenges and development directions for the large-scale application of SWE technology. This review provides an in-depth analysis of the chlorine-related challenges encountered in the industrialization of SWE, aiming to accelerate the advancement of this technology toward practical applications.

Conventional heterogeneous photocatalysts often suffer from insufficient light absorption, rapid charge recombination, and a lack of specific reactive sites for efficient photocatalytic oxidation. To overcome these limitations, we propose a molecular polarization engineering approach utilizing structurally well-defined donor (D)-acceptor (A) covalent triazine frameworks (CTFs). The construction of dipole-induced built-in electric fields within the D-A-structured CTFs enables enhanced exciton dissociation and facilitates directional charge transfer. Specifically, the asymmetric A₁-D-A₂ moiety enhances molecular polarization in the dual-acceptor system CTF-TBT (A₁-D-A₂), enabling efficient charge separation through multiple electron-withdrawing units. This structural design promotes directional electron transfer toward the secondary acceptor (benzothiazole, A₂), while simultaneously concentrating holes on the donor unit. Consequently, the A₂ moiety acts as a site for efficient O₂ activation via electron accumulation, whereas the highly oxidized donor unit provides strongly positive holes (h⁺) that facilitate substrate oxidation. Experimental and DFT calculation results confirm that CTF-TBT demonstrates highly enhanced photocatalytic oxidation performance, which can be attributed to its multi-channel charge separation mechanism and spatially separated redox-active sites. This study highlights the effectiveness of molecular dipole engineering in designing heterogeneous photocatalysts with controlled charge transfer pathways and improved redox capabilities. The proposed design principles provide a universal approach for promoting solar-driven chemical synthesis applications.

The increasing severity of global water scarcity and atmospheric pollution has made the development of efficient and sustainable remediation materials a key research priority. High specific surface area, modulable pore architectures, and a large number of active sites make metal–organic frameworks (MOFs) highly promising for adsorption and catalytic processes. However, their applications are restricted by nanoparticle agglomeration, difficult recovery, and weak structures. Electrospinning offers an efficient strategy to alleviate these issues by embedding MOFs into polymeric nanofibers. The freestanding membranes exhibit three-dimensionally interconnected porous networks that enhance the MOFs dispersion, operation stability, and handling convenience. In this review, we summarize the design strategies, mechanistic understandings, and function performance of electrospun MOFs-based nanofibrous membranes in water purification (including pharmaceutical residues, heavy metal ions, synthetic dyes, and emulsified oils), and in air purification (including ultrafine particulate matter (PM) and volatile organic compounds (VOC)), compared with their counterparts. Moreover, we highlight recent advances in designing multifunctional synergistic systems, stimuli-responsive membranes, and materials with enhanced environmental resistance. Finally, emerging challenges and future research directions are discussed to provide insights for rationally designing advanced MOFs-integrated membrane technologies.

Near-infrared (NIR) spectroscopy has significantly advanced NIR light sources. However, creating NIR emitters with optimal luminescence properties, high thermal stability, and adjustable emission peaks poses a critical challenge for future smart NIR devices. We introduced a chemical unit cosubstitution strategy by incorporating Ca²⁺ and Sn⁴⁺ ions into the garnet structure. Through this approach, Y_3−yCa_yGa_4.95−ySn_yG₁₂:0.05Cr³⁺ (y = 0–1) phosphors were developed by modulating the A&C ligands, resulting in emission centers ranging from 708 to 768 nm. The modified local environment of Cr³⁺ accounts for the increased light intensity (2.71 times) and broadening observed. Furthermore, this study investigated the impact of varying Cr³⁺ concentrations (Y_2.6Ca_0.4Ga_4.6−xSn_0.4G₁₂:xCr³⁺) on the production of high-performance phosphors. Compared with Y₃Ga_4.93G₁₂:0.07Cr³⁺, the optimized phosphor exhibited exceptional external quantum efficiency (EQE = 34.96%). The luminescence enhancement is attributed to an increase in radiative transitions caused by octahedral Jahn-Teller distortion, whereas the notable thermal stability (91.3% at 423 K) is attributed to the presence of weak electron-phonon coupling (EPC) and oxygen vacancy (O_V) defects. Finally, by combining it with a 450 nm blue LED chip, we constructed a near-infrared phosphor-converted LED (NIR pc-LED) device with superior electroluminescence efficiency (18.8% @ 100 mA), increasing the ultralow quenching rate (< 5% intensity loss after 30 days of operation) and demonstrating remarkable performance in plant lighting applications.

Ni-rich layered oxide cathodes have emerged as pivotal candidates for next-generation lithium-ion batteries (LIBs) due to their exceptional capacity and energy density. However, their intrinsic susceptibility to both dynamic structural deterioration and solid-liquid interfacial degradation during cycling results in substantial capacity fade, posing critical challenges for commercialization. To address these limitations, we propose a synergistic strategy of lattice doping and in situ surface coating to simultaneously enhance the structural integrity and interfacial stability of Ni-rich cathode material (LiNi_0.9Co_0.05Mn_0.05O₂). The La and Y dopants act as pillars to reinforce the layered structure of the cathode, mitigating volume changes while expanding the c-axis spacing to facilitate Li⁺ diffusion. Meanwhile, the La₄NiLiO₈ and LiYO₂ coatings effectively protect the cathode from H₂O/CO₂ corrosion and electrolyte attack, while their high lithium-ion conductivity promotes Li⁺ transport. Consequently, the modified cathode delivers exceptional electrochemical metrics, including a high specific capacity (207.3 mA h g⁻¹), remarkable cycling stability (97.6% retention after 100 cycles), superior rate capability (152.1 mA h g⁻¹ at 10.0 C), and enhanced thermal stability. This work establishes a paradigm for multi-dimensional stabilization of Ni-rich cathodes via synergistic bulk and interface engineering, providing fundamental insights into designing high-performance energy storage systems.

Metal-organic frameworks (MOFs), characterized by their high specific surface area, structural tunability, and excellent biocompatibility, can be fabricated through versatile synthetic approaches. They exhibit tremendous potential in biomedical fields, including disease diagnosis and drug delivery, thus catering to the demands of biomedical advancement. However, the clinical translation of MOFs faces challenges such as poor stability in biological environments, ill-defined long-term biosafety profiles, and difficulties in large-scale production. This review first summarizes the synthetic methodologies and properties of MOFs tailored for biomedical applications, and then discusses the emerging applications of MOF-based materials in biomedicine, encompassing biosensing, targeted drug delivery, and tissue engineering scaffolds. Extensive research has demonstrated that the applications of MOF-related materials in biomaterials and medicine are expanding, including the detection of pathological biomarkers (e.g., those associated with Alzheimer’s disease) via fluorescent/electrochemical biosensing platforms. In terms of drug delivery, MOFs can encapsulate chemotherapeutic agents for targeted delivery and controlled release. For diagnostic purposes, the development of more highly sensitive and specific sensors for disease markers is anticipated to facilitate early diagnosis. In therapeutic applications, they can optimize drug delivery efficiency and broaden therapeutic modalities with innovative approaches. In tissue engineering, materials tailored to meet the requirements of various tissue repairs can be developed to promote tissue regeneration. This review provides novel strategies and directions for combating diseases and driving advancements in biomedicine.

Ammonia is a promising hydrogen carrier for a carbon-neutral energy economy, but its widespread application hinges on the development of highly efficient catalysts for low-temperature decomposition. Overcoming the high activation barriers for N–H bond cleavage, particularly for non-precious metal catalysts like cobalt, remains a formidable challenge. Herein, we report the design and synthesis of a novel Co catalyst supported on a Ce and N co-modified perovskite (Co@La_xCe_1−xAlO_3−yN_z). The optimized Co@La_xCe_1−xAlO_3−yN_z catalyst demonstrates exceptional performance, achieving 92.6% ammonia conversion with a hydrogen production rate of 9.7 mmol g⁻¹ min⁻¹ at a remarkably low temperature of 425 °C (gas hourly space velocity (GHSV) = 9000 mL h⁻¹ g_cat⁻¹). This represents a 125 °C reduction in operating temperature compared to conventional Co-based catalysts under similar conditions. Mechanistic investigations using isotopic labeling and in-situ diffuse reflectance infrared Fourier transform spectroscopy reveal that the synergistic modification of Ce and N creates a unique LA-L(A+B)-LB active site configuration. This structure significantly lowers the Schottky barrier at the metal-support interface, promoting facile hydrogen spillover. Crucially, the reaction proceeds via an interfacial Mars-van Krevelen mechanism, a stark contrast to the traditional Langmuir-Hinshelwood pathway on conventional Co catalysts. This study provides new insights for developing low-temperature Co-based catalysts for ammonia decomposition.

Magnetic hyperthermia therapy (MHT) achieves precise tumor ablation by activating the magnetothermal conversion properties of functionalized biomaterials through an alternating magnetic field. Its advantages, such as non-invasiveness, low toxicity, and unrestricted tissue penetration depth, endow it with great potential in the treatment of tumors, including glioblastoma multiforme. The design of materials across scales, from macroscopic to nanoscopic, is the core key to optimizing and enhancing the effectiveness of MHT. By regulating the material size (optimizing the Néel-Brownian synergy), morphology (core-shell structure enhancing exchange coupling), and surface functionalization (e.g., PEG modification to improve stability), the specific absorption rate can be significantly increased for improved cancer MHT efficacy. Therefore, this paper systematically reviews the mechanism innovation and clinical applications of multiscale (macroscopic/microscopic/nanoscopic) functionalized biomaterials in MHT. Moreover, it looks ahead to the prospects of the integration of material engineering, cross-scale thermal control, and multimodal therapy, providing a theoretical framework for the development of material media in the next generation of tumor hyperthermia technology.

The molecular copolymerization of donor-acceptor (D-A) interactions has been effectively utilized to modulate the charge transfer dynamics in polymeric carbon nitride (PCN) photocatalysts, as demonstrated by recent studies. Herein, a D-A configured photocatalyst (TPCN) was constructed by copolymerizing 4,4′,4″-(1,3,5-triazine-2,4,6-triyl) trianiline (TAPT) as the electron donor with triazine units (electron acceptor). The unique propeller structure of TAPT, combined with the triazine framework, expanded the π-conjugated system and induced a strong built-in electric field (BIEF) across the D-A configuration. Theoretical calculations and transient absorption spectroscopy revealed that this synergistic effect, arising from the expanded π-conjugated structure and the BIEF generated by D-A interactions, facilitated intramolecular charge separation and widened the range of light absorption, indicating accelerated charge transfer and suppressed recombination in TPCN. The optimized TPCN3 sample exhibited dramatically enhanced photocatalytic H₂O₂ production (1.74 mmol g⁻¹ h⁻¹), representing a 13.4-fold increase over pristine PCN. Additionally, the TPCN3 sample also exhibited significantly faster degradation kinetics than PCN counterpart toward various emerging contaminants.

An ideal organic solar cell (OSC) should feature both a high donor/acceptor (D/A) interfacial area and a vertically phase-separated architecture. A high interfacial area facilitates exciton diffusion and dissociation into free charges, while vertical phase separation ensures efficient charge transport and collection at the electrodes. Traditional bulk heterojunctions (BHJs) offer a large D/A interfacial area but often lack adequate vertical phase separation. Conversely, quasi-planar heterojunctions (QPHJs) achieve vertical phase separation at the expense of limited D/A interfacial contact area, both of which impede device performance optimization. In this study, we introduce an in situ pore-forming strategy for polymer thin films. By incorporating an excess of additives as pore-forming agents into the donor layer, a nanoporous film with a fibrous nano-network structure is generated. The subsequent deposition of acceptor molecules fills these nanopores, creating a hybrid planar/bulk heterojunction (HP/BHJ) that synergizes the strengths of both quasi-planar and bulk heterojunctions. This innovative architecture attains performance enhancements through the following mechanisms: The nanopores induced by the pore-forming agents substantially augment the interfacial contact area, forming a three-dimensional D/A interfacial network that accelerates exciton dissociation; The close packing of molecular chains facilitated by the pore-forming agents minimizes carrier recombination and establishes low-defect charge transport channels, ensuring efficient vertical charge transport. Additionally, the layer-by-layer deposition approach fosters vertical phase separation, further promoting efficient charge transport. Binary OSCs fabricated using this strategy achieve a remarkable power conversion efficiency (PCE) of 20.0%, surpassing the efficiencies of conventional BHJ and QPHJ devices by a significant margin.