Abstract Lithium-ion batteries release harmful, toxic, and potentially explosive gases during the thermal runaway process. Accordingly, the development of high-performance gas sensors for real-time monitoring is crucial for effective battery safety assessment. In this study, we propose a strategy based on first-principles calculations, employing transition metal (TM = Co, Rh, Ir) to modify twin T-graphene (TTG), and systematically investigate its adsorption behavior and sensing mechanisms towards three representative thermal runaway gases (TRGs): CO, C 2 H 2 , and C 2 H 4 . The results reveal that Co, Rh, and Ir atoms can be stably anchored on the TTG surface via covalent interactions, significantly enhancing its adsorption toward the three target gases. Strong hybridization between TM-d orbitals and the C-2p orbitals of the gas molecules is identified as the main driving force for chemisorption and the associated enhancement in electrical response. Furthermore, TTG–Rh exhibits outstanding sensitivity toward C 2 H 2 , with a work function variation rate of 15.55%, whereas TTG–Ir shows pronounced chemisorption toward CO and C 2 H 4 , accompanied by bandgap changes of up to 100%. Additionally, H 2 , CO 2 , and CH 4 exhibit relatively weak adsorption on TM–TTG systems, suggesting good selectivity for CO, C 2 H 2 , and C 2 H 4 . Analysis of recovery time suggests that TTG–Rh is more suitable as a reusable gas-sensing material under high-temperature conditions, while TTG–Ir is better suited as a disposable sensor or an efficient adsorbent. Overall, this study provides a solid theoretical foundation for the rational design and development of high-performance TTG-based gas sensors or scavengers for TRGs.

Developing candidate materials with specific recognition and efficient adsorption is highly valuable for both the environment and ecology. Covalent organic frameworks (COFs) are an ideal multifunctional candidate material due to their structure, functional modification, and excellent physical and chemical properties. However, most COF monomers can coordinate with various metal ions, thus limiting their application in accurate identification. Herein, we designed a double-bridged porphyrin-based covalent organic framework (Tp-PDA-COF) by introducing double-bridging monomers to orderly connect the 5,10,15,20-tetra(4-aminophenyl)porphyrin (TAPP) center to construct the 2D tetragonal topological structure with an excellent fluorescence property. The designed topology effectively reduces spatial hindrance, and the specific electron cloud density can optimize metal ligand orbitals, achieving effective capture and specific coordination recognition, which achieves sensitive detection of Cu2+ through obvious fluorescence chromaticity change with a detection limit of 40.76 nM. Furthermore, incorporating poly(vinyl alcohol) polymer into the COF increases interlayer spacing and suppresses π-π stacking, forming a fluorescent Tp-PDA-COF aerogel. Owing to the selective coordination of Cu2+ and the synergistic adsorption of gel structure, Tp-PDA-COF aerogel has an ultrahigh adsorption capacity for Cu2+ (1902 mg/g). This work provides a structural design strategy for regulating functional COFs with specific recognition and adsorption capabilities.

Under thermal runaway conditions, lithium-ion batteries in new energy systems are prone to releasing hazardous, toxic, and explosive gases. Accordingly, the development of high-performance gas sensors for real-time monitoring is crucial for effective assessment of battery safety. In this study, we propose a strategy based on first-principles calculations, employing Rh-X (X = C, B, Si) pairs to modify g-CN monolayer, and systematically investigate its adsorption behavior and sensing mechanism towards six representative thermal runaway gases (TRGs): CO, CO2, H2, C2H2, C2H4, and CH4. The results reveal that Rh-X pairs can be stably anchored within the g-CN pore via the formation of robust covalent bonds, significantly enhancing TRG adsorption performance. Electronic structure analysis indicates that strong hybridization between Rh-4d orbital and the C-2p orbitals of CO, C2H2, and C2H4 molecules serves as the primary driving force for chemisorption and pronounced conductivity changes. In terms of gas sensing performance, RhBN monolayers exhibit exceptional sensitivity to C2H4, with bandgap and work function variation rates of 44.30% and 13.85%, respectively. Notably, RhSiN demonstrates superior chemisorption characteristics for both CO and C2H4, with bandgap variation rates reaching 38.35% and 87.61%, respectively. Recovery time analysis further shows that RhCN enables rapid detection and regeneration for C2H2 at room temperature, whereas RhBN and RhSiN are more suitable as sensing materials for CO, C2H2, or C2H4 under high-temperature conditions. This study provides a theoretical foundation for the design of novel g-CN-based gas-sensitive materials for monitoring TRGs.

Developing candidate materials with specific recognition and efficient adsorption is highly valuable for both the environment and ecology. Covalent organic frameworks (COFs) are an ideal multifunctional candidate material due to their structure, functional modification, and excellent physical and chemical properties. However, most COF monomers can coordinate with various metal ions, thus limiting their application in accurate identification. Herein, we designed a double-bridged porphyrin-based covalent organic framework (Tp-PDA-COF) by introducing double-bridging monomers to orderly connect the 5,10,15,20-tetra(4-aminophenyl)porphyrin (TAPP) center to construct the 2D tetragonal topological structure with an excellent fluorescence property. The designed topology effectively reduces spatial hindrance, and the specific electron cloud density can optimize metal ligand orbitals, achieving effective capture and specific coordination recognition, which achieves sensitive detection of Cu2+ through obvious fluorescence chromaticity change with a detection limit of 40.76 nM. Furthermore, incorporating poly(vinyl alcohol) polymer into the COF increases interlayer spacing and suppresses pi-pi stacking, forming a fluorescent Tp-PDA-COF aerogel. Owing to the selective coordination of Cu2+ and the synergistic adsorption of gel structure, Tp-PDA-COF aerogel has an ultrahigh adsorption capacity for Cu2+ (1902 mg/g). This work provides a structural design strategy for regulating functional COFs with specific recognition and adsorption capabilities.

Sweat-based metabolic monitoring offers a non-invasive alternative to blood tests, but its clinical utility is limited by the limited catalytic efficiency of current nanozyme sensors. Bimetallic nanozymes, with their intermetallic synergy, hold promise to overcome this limitation, yet rational design strategies remain underexplored. Herein, we report a Cu-doped Co-Al layered double oxide (Co2AlCu0.7 LDO) with an ultrathin hexagonal nanosheet morphology that exhibits exceptional peroxidase-like activity (Km = 0.30 mM, Vmax = 2.932 × 10-6 M s-1). Mechanistic studies reveal that the intrinsic Co-Al bimetallic framework provides a synergistic electronic basis, while Cu doping optimizes the d-band center of metal active sites and introduces abundant oxygen vacancies, which act as synergistic active centers to facilitate H2O2 activation and dramatically enhance peroxidase-like activity. By immobilizing biomarker-specific oxidases onto the LDO nanosheets, we constructed an enzyme-nanozyme cascade reactor for sensitive detection of cholesterol, uric acid, and glucose. For point-of-care translation, this reactor was integrated into a colorimetric sponge coupled with smartphone imaging and machine learning, yielding a portable platform and a conceptual wristwatch for non-invasive sweat analysis. This work not only provides novel design strategies for high-performance bimetallic nanozymes but also expands its potential as advanced functional biomaterials for next-generation biosensing platforms of clinical diagnostics and therapeutic monitor.

Metalu2013organic frameworks (MOFs), as an emerging class of porous crystalline materials, exhibit immense potential in the field of energy storage and conversion due to their high specific surface area, tunable pore structures, and abundant active sites. This review summarizes the latest research progress of MOFs in next-generation energy technologies. Spanning from nanoscale design to macroscopic applications, the structureu2013performance relationships and critical roles of MOFs in electrochemical energy storage, electrocatalysis, and photocatalysis are systematically explored. Initially, nanoscale design principles and controllable synthesis strategies for MOFs are introduced, covering the selection of metal nodes and organic linkers, the modulation of pore size and geometry, and surface functionalization. Subsequently, the applications of MOFs in electrochemical energy storage systems, such as lithium-ion batteries, sodium-ion batteries, supercapacitors, and fuel cells, are discussed. Furthermore, their superior performance in electrocatalytic reactions, including the hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, and carbon dioxide reduction reaction, is highlighted. In addition, the potential of MOFs in photocatalytic fields, such as photocatalytic water splitting for hydrogen production, carbon dioxide reduction, and pollutant degradation, is examined. Finally, the major challenges hindering the transition of MOFs from laboratory research to scalable applications are summarized, and their significant role in driving the energy revolution and achieving sustainable development goals is envisioned. Through this review, new insights and directions are provided for MOF research in the energy sector, aiming to facilitate their widespread application in future energy technologies.

Sensors based on multiple fluorescence materials have been widely applied in detection because of reliability and reproducibility. High-performance on-site sensing strategies are vital to public safety and human health. Here, by modifying the carbon dots (CDs) with melamine (MA) molecules, we developed a novel dual-recognition fluorescence sensor for efficient and sensitive detection of salbutamol. Upon increasing salbutamol concentration, the fluorescence intensity of blue emission under 365 nm excitation decreased, while the yellow emission under 460 nm kept enhancing. The quench of blue emission leads to the yellow fluorescence enhancement by Fluorescence resonance energy transfer (FRET) from monodisperse CDs to clustered CDs. Both the two emission-intensity showed linear relationship with salbutamol concentration within a certain concentration range. Dual detection of fluorescence signals under 365 nm and 460 nm, with detection limits (3 delta/K) as low as 7.12 and 16.67 nM, is possible. Machine learning is then employed to analyze its detection performance. Therefore, the quantitative detection of salbutamol can be achieved. Moreover, the dual-recognition assay endows salbutamol detection built-in self-calibration to ensure high assay sensitivity and precision. We demonstrated the application in the fluorescence tracking of salbutamol in real samples with satisfactory results. The study would anticipate this dual-recognition fluorescence sensing system would inspire fast high-precision sensor design for environmental, safety and health monitoring.

The thermal runaway of lithium-ion batteries (LIBs) releases a mixture of toxic and explosive gases, posing severe safety risks. High-performance sensors are critical for the early detection of these thermal runaway gases (TRGs) to prevent accident escalation. Herein, we systematically investigate Fe-X (X = C, P, S) atomic pair-modified g-CN (FCN, FPN, FSN) monolayers as potential sensing materials for six TRGs (CO, CO2, H2, C2H2, C2H4, and CH4) using first-principles calculations. The results demonstrate that the Fe-X pairs can be stably anchored onto the g-CN monolayer, and this co-doping strategy significantly enhances its adsorption and sensing capabilities. Furthermore, the key TRGs such as CO, C2H2, and C2H4 undergo strong chemisorption, inducing substantial changes in the electronic properties of the modified monolayers and signifying excellent sensing potential. Notably, the materials exhibit tailored functionalities; for instance, FCN and FSN are identified as promising candidates for reusable, room-temperature (298 K) H2 detection due to their fast desorption performance. This study underscores that atomic pair co-doping is a powerful approach to design g-CN-based materials with high sensitivity and selectivity, offering a theoretical foundation for the development of advanced sensors for LIBs safety monitoring.

Highlighted with moldability and flexibility, nanofibrous sensors have attracted great attention and promising for smart textiles and monitoring. Most reported ones were fabricated by blending functional materials with polymers, lacking effective functional design and synthesis technology to ensure excellent performance to avoid interference. Inspired by this, we report the preparation of the intrinsic dual-color fluorescent MOFs via one-step hydrothermal treatment strategy, and incorporated with carboxymethyl cellulose to fabricate MOFs@cellulosenanofiber membrane sensor via in-situ growth. The MOFs endow it with various outstanding optical properties, and the well-maintained fibrous structure reserves the superior hydrophilicity and flexibility. The resulting sensor features high sensitivity, visualization (red to blue fluorescence), low detection limit (0.01 %), excellent repeatability (5 cycles) and short response time (within 1 s) to trace water. Application tests in different environments (including humid and flowing water environment) have validated its effectiveness in real-time fluorescence sensing and excellent anti-counterfeiting capacity, showcasing the significant potential in environment monitoring. Moreover, through the integration of deep learning algorithms, we aimed to improve the accuracy and sensitivity of this detection method. It provides a new reliable, economical, and environmentally friendly pathway to fabricate nano-fiber sensor with tunable optical properties for functional materials.

Organic room‐temperature phosphorescent(RTP) materials typically exhibit superior luminescent properties, yet their instability, particularly in aqueous environments where phosphorescence is quenched, and under acidic, alkaline, or organic solvent conditions, restricts their application. Herein, a novel and convenient strategy is designed for constructing host–guest organic RTP materials by incorporating silane into urea‐derived products to form a siloxane network‐strengthened stable host matrix. The siloxane possesses excellent chemical stability and can be combined with the thermolytic products of urea through covalent bonds, enhancing the chemical resistance of the host. The host connects with the guest molecules through covalent bonds and hydrogen bonds, restricting non‐radiative loss, enhancing phosphorescent emission, and protecting the guest molecules from quenching in multiple chemical environments. The host–guest RTP material, prepared using (3‐aminopropyl) triethoxysilane, urea, and 2‐aminoterephthalic acid, exhibits blue phosphorescence with a lifetime of 891 ms, visible to the naked eye for 21 s. Notably, it maintains phosphorescent emission in water, organic solvents, and strong acid/alkali solutions while demonstrating excellent stability, as evidenced by its potential applications in afterglow displays and information encryption. This strategy provides valuable insights for designing stable RTP materials and broadens their potential application in complex environments.

The reduction of Re(VII) has been studied in alkaline KOH solution using electrochemical cyclic voltammetry (CV) and UV spectroscopy techniques in order to understand the chemical behavior of rhenium comprehensively. Electrochemical characteristic peak related to rhenium species were observed in cyclic voltammograms. The results showed that both hydroxide and O22− ions were involved in the reduction reaction of Re(VII). Increasing KOH molarities facilitates the reduction of Re(VII). The reduction process of Re(VII) in alkaline media follow a sequence Re(VII) → Re(V) → Re(IV), and pathway for the Re species can be described by: ReO4− → (ReO)O(OH)43− → ReO(OH)3−.

The dynamic concentration of drugs in blood reflects pharmacokinetics and is a key indicator of therapeutic efficacy and safety, emphasizing the need for real-time monitoring to guide individualized dosing and reduce adverse effects. Herein, a ratiometric fluorescent sensor is developed by functionalizing upconversion nanoparticles (UCNPs) with p-dimethylaminobenzaldehyde (p-DMAB) and integrating the resulting probe into a portable immunochromatographic device for the sensitive and rapid analysis of isoniazid dosage in whole blood. The unique properties of UCNPs, including near-infrared excitation, low background interference, and high photostability, together with the probe's high chemical specificity, enabling direct detection in whole blood without complex pretreatment. Upon a selective chemical reaction between isoniazid and the p-DMAB-modified UCNPs, the sensor exhibits a concentration-dependent fluorescence color change from blue to red, allowing clear discrimination of therapeutically relevant dosage ranges. To eliminate subjective visual errors and enable batch analysis, the platform integrates 3D printing with smartphone-based imaging and convolutional neural network modeling. The CNN algorithm quantitatively maps fluorescence intensity ratios to drug concentrations, effectively removing operator bias. This intelligent, low-cost, and user-friendly system offers a reliable solution for point-of-care therapeutic drug monitoring and can be adapted for other clinical drug targets, supporting personalized medicine and decentralized healthcare.

Despite the various advantages of upconversion nanoparticles (UCNPs), the paradoxes of high luminescence resonance energy transfer (LRET) efficiency and low quantum yield remain a bottleneck for broader sensing applications. Herein, novel sandwich-structured UCNPs (SWUCNPs, NaYbF4:(30%Gd)@NaYbF4:Er(2%)@NaYF4) with a core-middle shell-outer shell structure were synthesized. The SWUCNPs maintained a high LRET efficiency by confining the luminescent center of Er3+ in the middle shell. Moreover, the NaYbF4:(30%Gd3+) inner core significantly increased the absorption of excitation light, while the host lattice of NaYbF4 in the middle shell facilitated the energy transfer from the core to the emitting ions as well as further increased the absorption for 980 nm excitation light. Both the strategy of energy enrichment and optimizing the energy migration were beneficial to boosting the strong UCL and high LRET efficiency. Compared with the traditional SWUCNPs (NaYF4@NaYF4:Yb/Er@NaYF4), the upconversion luminescence (UCL) intensity of the as-prepared SWUCNPs was greatly improved, with the UCL at 540 nm increased by 56 times and the UCL at 655 nm increased by 117 times. In proof-of-concept applications, this innovative structure has been utilized for high-sensitivity detection of ascorbic acid. The strategy reported here opens a novel pathway toward the preparation of highly sensitive upconversion nanoprobes.

Monitoring and detection of air decomposition components (ADCs) is an effective approach for diagnosing the faults in air switchgear devices. Herein, the adsorption behavior of three ADCs (CO, NO, NO2) on pristine CSiN and Ag/Au-doped CSiN (Ag-CSiN and Au-CSiN) monolayers was investigated using first-principles calculations. The electronic properties of different adsorption systems were systematically analyzed. Moreover, the gassensing performance of these systems was evaluated by the analyses of conductivity, work function, and recovery time, which aims to explore the potential sensitive materials for monitoring the ADCs. The results reveal that the pristine CSiN exhibits weak adsorption towards CO and NOx. However, the doping of Ag and Au atoms significantly enhances the adsorption effects of CSiN monolayer, resulting in a transformation from physisorption to chemisorption, with the adsorption energy values ranging from - 0.73 eV to - 1.45 eV. The related adsorption mechanism is further elucidated through the analyses of density of states, band structures, charge density difference, and electron localization function. Furthermore, both Ag-CSiN and Au-CSiN exhibit excellent sensitivity towards CO and NO due to the moderate adsorption strength and significant changes in conductivity and work function. Specifically, Ag-CSiN exhibits a sensing response of 5.59 x 103 towards NO at 348 K, with a recovery time of 1.45 s. While Au-CSiN shows sensing responses of 498 and 6.00 x 105 towards CO and NO at 298 K, respectively, with recovery times of 2.20 s and 7.06 s. Therefore, Au-CSiN can be utilized a promising and recyclable gas sensor for detecting CO and NO at room temperature, and its sensing performance is unaffected by moisture in the air. This study offers a theoretical foundation for the design of novel gas sensors that can effectively diagnose the faults in air switchgear equipment.

Functionalized upconversion nanomaterials can overcome the drawbacks faced of strong background interference, photodamage, and spectral overlap by conventional optical labeling. Here, curcumin-functionalized upconversion hydrogel patch is designed with background-free and reversible for food freshness monitoring by ultra-sensitive response to biogenic amines. By loading the probes onto hydrogel patch, utilizing the good ductility to solve the problem of non-smooth surface coverage, thus accurately capturing biogenic amines. The presence of biogenic amines leads to the conversion of the diketone group on the probe to enolate ions, which triggers fluorescence resonance energy transfer (FRET) and ultimately causes the upconverted fluorescence to gradually change from green to red. The probe exhibits good detection capability for biogenic amines with a low limit of detection (LOD) of 2.73 mu m. Interestingly, the patch can be restored to its initial state after water rinsing, realizing reversible detection of biogenic amines. Additionally, combining the color recognition system of smartphone can convert the imaging signal into a data signal to achieve quantitative analysis and show a reliable assessment comparable to the results of high performance liquid chromatography (HPLC). This study demonstrates the practical applicability in real-time monitoring of freshness, suggests great potential in developing optical nano-sensing strategy to ensure food safety. A curcumin-functionalized upconversion hydrogel patch is designed here with background-free and reversible for food freshness monitoring imaging by ultra-sensitive response to biogenic amines, which demonstrates the practical applicability in real-time monitoring of freshness, suggests great potential in developing an optical nano-sensing strategy to ensure food safety. image

Methylglyoxal is considered a key indicator in evaluating wine flavor and quality, as well as an important marker for diabetic pathological syndromes. Rapid and accurate quantitative detection of methylglyoxal is essential in scenarios of wine production standards and human health monitoring. Herein, we report a visual method for detecting methylglyoxal via an NIR-excitable reversible ratiometric fluorescent hydrogel sensor, where NIR-excited upconversion nanoparticles serve as energy donors and eosin B acts as the energy acceptor, together forming an integrated ratiometric nanophotonic probe that ensures the accuracy of detection without being affected by various background fluorescence interference in different scenarios. The integrated optical probe is combined with a 3D network hydrogel to design a sensing patch that can be easily regenerated through simple treatment, exhibiting a distinct optical color response. Upon the addition of methylglyoxal, the G/R value of the sensing patch changes, enabling the real-time quantitative detection of methylglyoxal. Additionally, we combined the hydrogel sensing patch with a smartphone to create a portable sensing platform for the convenient visual detection of methylglyoxal. The probe and hydrogel sensing patch have detection limits for methylglyoxal as low as 59 and 75.4 nM, respectively. The portable sensing patch designed here provides an effective strategy for standardizing the wine production process and monitoring patient health.

Advancing a metal-free room temperature phosphorescent (RTP) material that exhibits multicolor emission, remarkable RTP lifetime, and high quantum yield still faces the challenge of achieving intersystem crossing between singly and triplet excited states, as well as the rapid decay of triplet excited states due to nonradiative losses. In this study, a novel strategy is proposed to address these limitations by incorporating o-phenylenediamine, which generates multiple luminescent centers, and long-chain polyacrylic acid to synthesize carbonized polymer dots (CPDs). These CPDs are then embedded in a rigid B2O3 matrix, effectively limiting nonradiative losses through the synergistic effects of polymer cross-linking and the rigid matrix. The resulting CPD-based materials exhibit remarkable ultralong phosphorescence in shades of blue and lime green, with a visible lifetime of up to 49 s and a high phosphorescence quantum yield. Simultaneously, this study demonstrates the practical applicability of these excellent material properties in anti-counterfeiting and information encryption.

Chromium ions exist in various valence states in the environment, and their pollution poses serious harm to social ecology and human health. The existing detection is mostly focused on Cr6+, while the detection related to Cr3+ is often overlooked. Cr3+ has a certain impact on soil, water, and the growth of animals and plants and even disrupts ecological balance. Accordingly, it is necessary to explore sensitive, convenient, and fast detection devices for Cr3+ in the environment. Here, we have designed a ratio fluorescence probe with porphyrin nanoparticles formed by block copolymers as the sensing core for ultra sensitive detection of Cr3+. The porphyrin nanoparticles can effectively bind with Cr3+ to form metal complexes, leading to ligand metal charge transfer (LMCT), which will result in a significant color change of the probe from red to blue. Furthermore, we have developed two portable fluorescence sensors for Cr3+ in soil and water, respectively. These portable sensing platforms based on designed nanoprobes and smartphones can convert the color information of fluorescent photos into digital information for real-time analysis. Thus, the method reported in this article can provide a possibility for rapid on-site and visual inspection of Cr3+ in soil and water from different regions.

Levofloxacin (LVFX) as a representative drug of quinolone antibiotics is widely used in clinical, and its residues enriched in water bodies and sideline products seriously damage human health. It is imperative to develop a real-time/on-site sensing method for monitoring residual antibiotics. Here, we report a portable sensing platform by utilizing a composite fluorescent nanoprobe constructed by the cerium ions (Ce3+) coordination functionalized CdTe quantum dots (QDs) for the visual and quantitative detection of LVFX residues. This fluorescent probe provides a distinct color variation from red to green, which shows a good linear relationship to LVFX residues concentrations in the range of 0-6.0 µmol/L with a sensitive limit of detection (LOD) of 16.3 nmol/L. The smartphone platform with Color Analyzer App installed, which could accomplish quantified detection of LVFX in water, milk, and raw pork with a LOD of 27.9 nmol/L. The facile sensing method we proposed realizes rapid visualization of antibiotics residual in the environment and provides a practical application pathway in food safety and human health.