Hierarchically ordered porous g-C₃N₄ framework supported Ni nanoparticles for fire safety and thermal stealth application

It remains a challenge to develop multi-functional flame retardants to satisfy ever-growing demands in complex working environments. Herein, hierarchically ordered porous g-C₃N₄ framework decorated with nickel nanocrystals (Ni/MmCNs) was innovatively designed. Transmission electron microscopy images confirm the distinct 3D interconnected macro-/mesoporous structure and dispersed Ni nanoparticles on the framework, which are the keys to realizing the multi-functions of flame retardancy, thermal stealth, and mechanical performance enhancement. The cone calorimeter and bending tests results show that 5 wt% addition of Ni/MmCNs not only endows the epoxy nanocomposites with better fire safety including the delay of ignition time (t_ignition) and the reduction of heat and smoke release but also enhances the flexural strength compared with the pure epoxy. In addition, the Ni/MmCNs exhibits enhanced thermal insulation and infrared shielding functions, as evidenced by lower upper surface temperature under infrared detection.