We report facile synthesis of low-band-gap mesoporous C 4 Np articles and their use as responsive bifunctional oxygen catalysts for visible-light-sensitive (VLS) rechargeable Zn-air battery (RZAB) and polymer-air battery (RPAB). Compared to widely studied g-C 3 N 4 ,C 4 Nshows asmaller band gap of 1.99 eV,with alarger photocurrent response,and it can function as visible-light-harvesting antenna and bifunctional oxygen reduction/evolution (ORR/OER) catalysts,e nabling effective photocoupling to tune oxygen catalysis.T he C 4 Nenabled VLS-RZAB displays al ow charge voltage of 1.35 V under visible light, which is belowt he theoretical RZAB voltage of 1.65 V, corresponding to ahigh energy efficiency of 97.78 %. Pairing aC 4 Nc athode with ap olymer anode also endows an VLS-RPAB with light-boosted charge performance. It is revealed that the ORR and OER active sites in C 4 Na re separate carbon sites near pyrazine-nitrogen atoms and photogenerated energetic holes can activate OER for improved reaction kinetics.

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As a novel polymer, polyurethane (PU) has been widely applied in leather, synthetic leather, and textiles due to its excellent overall performance. Nevertheless, conventional PU is flammable and its combustion is accompanied by severe melting and dripping, which then generates hazardous fumes and gases. This defect limits PU applications in various fields, including the leather industry. Hence, the development of environmentally friendly, flame-retardant PU is of great significance both theoretically and practically. Currently, phosphorus-nitrogen (P-N) reactive flame-retardant is a hot topic in the field of flame-retardant PU. Based on this, the preparation and flame-retardant mechanism of flame-retardant PU, as well as the current status of flame-retardant PU in the leather industry were reviewed.

Polymer materials are ubiquitous in daily life. While polymers are often convenient and helpful, their properties often obscure the fire hazards they may pose. Therefore, it is of great significance in terms of safety to study the flame retardant properties of polymers while still maintaining their optimal performance. Current literature shows that although traditional flame retardants can satisfy the requirements of polymer flame retardancy, due to increases in product requirements in industry, including requirements for durability, mechanical properties, and environmental friendliness, it is imperative to develop a new generation of flame retardants. In recent years, the preparation of modified two-dimensional nanomaterials as flame retardants has attracted wide attention in the field. Due to their unique layered structures, two-dimensional nanomaterials can generally improve the mechanical properties of polymers via uniform dispersion, and they can form effective physical barriers in a matrix to improve the thermal stability of polymers. For polymer applications in specialized fields, different two-dimensional nanomaterials have potential conductivity, high thermal conductivity, catalytic activity, and antiultraviolet abilities, which can meet the flame retardant requirements of polymers and allow their use in specific applications. In this review, the current research status of two-dimensional nanomaterials as flame retardants is discussed, as well as a mechanism of how they can be applied for reducing the flammability of polymers.

We report facile synthesis of low-band-gap mesoporous C 4 Np articles and their use as responsive bifunctional oxygen catalysts for visible-light-sensitive (VLS) rechargeable Zn-air battery (RZAB) and polymer-air battery (RPAB). Compared to widely studied g-C 3 N 4 ,C 4 Nshows asmaller band gap of 1.99 eV,with alarger photocurrent response,and it can function as visible-light-harvesting antenna and bifunctional oxygen reduction/evolution (ORR/OER) catalysts,e nabling effective photocoupling to tune oxygen catalysis.T he C 4 Nenabled VLS-RZAB displays al ow charge voltage of 1.35 V under visible light, which is belowt he theoretical RZAB voltage of 1.65 V, corresponding to ahigh energy efficiency of 97.78 %. Pairing aC 4 Nc athode with ap olymer anode also endows an VLS-RPAB with light-boosted charge performance. It is revealed that the ORR and OER active sites in C 4 Na re separate carbon sites near pyrazine-nitrogen atoms and photogenerated energetic holes can activate OER for improved reaction kinetics.