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• Nacre-like GO-PTA paper is prepared by evaporation-induced self-assembly method. • Fire sensor-based GO-PTA exhibits ultrasensitive and durable warning response. • Enhancement in fire resistance of GO is attributed to in situ phosphorus doping. A novel nacre-like flame-retardant paper based on graphene oxide (GO), and phytic acid (PTA) is fabricated via evaporation-induced self-assembly. This facile method is time saving and low energy consuming. A facile approach is proposed to improve thermal oxidative stability of GO paper by in situ phosphorus doping during flame exposure. Then fire-alarm system is designed based on the high-temperature thermal reduction characteristic of GO. The GO paper functionalized with PTA (GO-PTA) can provide ultrasensitive, reliable and longtime fire early-warning signal. Fire alarm can be triggered at approximately 0.50 s when GO-PTA samples are attacked by fire. Phosphorus atoms are in situ doped into graphene layers during fire exposure, endowing GO-PTA paper with outstanding thermal oxidative stability, and thus alarm duration time of GO is greatly improved. The work develops advanced fire detection and early-warning sensors that provide reliable and continuous signals, which provide more available time for fire evacuation. [ABSTRACT FROM AUTHOR]

Melamine-phytate (MEL-PA) nanoflakes are formed by supramolecular self-assembly technology using melamine (MEL) and bio-based phytic acid (PA) as the building blocks. This work explores the possibility of this two-dimensional nanomaterial as flame retardant. The layered MEL-PA with the loading of 1, 2 and 3 wt% are incorporated into polypropylene (PP) matrix. MEL-PA is dispersed well in the PP matrix. Thermal stability and flame retardant performance of PP/MEL-PA composites are investigated. Compared with neat PP, the addition of 2 wt% MEL-PA decreases the peak heat release rate from 756 to 608 kW/m2. Char yield of PP is improved by MEL-PA, and the chemical structure and graphitization degree of residual char are studied to reveal flame retardant mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • FC@NF and T@CF were prepared by LBL self-assembly and soaking methods, respectively. • Fire-retardant performance and mechanism of FC@NF were investigated. • FCF-TENG was fabricated for self-powered sensing in fire scenarios. The fabrics commonly used in architectural decorative materials pose significant fire hazards due to their flammability and rapid fire spread. Moreover, the traditional fire-alarm systems may fail to function properly in complex fire environments owing to power supply disruptions. In this study, we developed a low-cost and eco-friendly flame-retardant conductive fabric-based triboelectric nanogenerator (FCF-TENG) by integrating flame-retardant conductive nylon fabric and polytetrafluoroethylene soaked cotton fabric. This nanogenerator exhibits excellent flame-retardant properties and remarkable energy-harvesting capabilities. The nylon fabric, treated with layer-by-layer self-assembly method, possesses outstanding self-extinguishing capability and melt-dripping resistance. Additionally, the electrical performance of FCF-TENG significantly improves, with a 10-fold boost in conductivity, and the open-circuit voltage increases by 84% to 92 V. Besides, by incorporating the rectifier circuit, the FCF-TENG is capable of completely charging a 1 μF capacitor within 30 s. Furthermore, the FCF-TENG was successfully applied as a self-powered sensor in the fire-alarm system and served as a safety exit indicator for evacuees and fire rescue. This work presents an effective and innovative application of multifunctional smart textiles for energy harvesting and self-powered sensing. [ABSTRACT FROM AUTHOR]

• Facile preparation of N -doped AC with high N -content was reported. • N -doped AC and AC were compared in terms of physical properties, CO 2 adsorption. • Correlations between CO 2 uptake and specific pore size section, N -content was analyzed. • N -doped AC exhibited better CO 2 adsorption capacity and selectivity than AC. Activated carbons (AC) were prepared by carbonization and KOH activation using rice husk as feedstock. The effects of impregnation ratios and activation temperatures on the properties of AC were investigated. Under optimum conditions, BET surface area, total pore volume and micropore volume of AC are as high as 1495.52 m2/g, 0.786 cm3/g and 0.447 cm3/g, respectively. Surface modification with chitosan as nitrogen source was performed simultaneously during KOH activation process. XPS and FT-IR analyses show that N -species was successfully incorporate into AC. Compared with AC-5 (general AC), CAC-5 (modified AC) exhibits better CO 2 adsorption performance, reaching 5.83 mmol/g at 273 K and 1 bar, which can be attributed to the formation of the CO 2 -philic active sites on AC surface by N -species. The linear correlations between CO 2 uptake, micropore volume within specific size section and N -content was investigated. The isosteric heat of CO 2 adsorption for CAC-5 (average 30.21 kJ/mol) is much higher than that of AC-5 (average 14.48 kJ/mol). The adsorption behavior of CAC-5 can be well described by Freundlich model. The high IAST selectivity factor for N -doped ACs indicates their excellent adsorption selectivity for CO 2 over N 2. Both physisorption and chemisorption are present in CO 2 adsorption process of N -doped ACs. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract To overcome the shortcomings of inefficiency in the preparation of covalent organic frameworks (COFs) nanosheets by ball milling, a gram-scale method to preparing COFs nanosheets with butyl lithium as the intercalation agent has been proposed. A significant advantage of COFs nanosheets that display good interface compatibility has been discovered through experiments. Due to their special organic crystalline structure and hydrogen bonding effects, COFs nanosheets without any modification show good interface compatibility, good dispersibility and enhancement in the mechanical properties of PVA matrix even at the loading as high as 9.6 wt%. Meanwhile, thermal, hydrophobic and flame retardant performances of PVA/COFs nanosheets nanocomposite have also been strengthened. This work should provide a guidance for the preparation of multifunctional nanocomposites with high loading. [ABSTRACT FROM AUTHOR]