Scalable production and functionalization of TMD nanosheets for bioinspired, ultrastrong, repeatable fire warning nanopapers

Abstract

Emerging smart fire alarm sensors (FAS) are crucial for monitoring fire hazards and have garnered increasing attention in fire safety field. However, developing low-cost yet high-performance FAS materials with mechanical flexibility, environmental tolerance, flame retardancy, and reliable fire warning capabilities via a simple and sustainable approach remains a major challenge. Here, we report a simple yet effective tannic acid (TA)-assisted mechanochemical exfoliation method for producing few-layer modified molybdenum disulfide (TA-MoS₂) nanosheets with excellent water dispersibility and long-term storage stability. Besides, the method's universality was further validated with other transition metal dichalcogenides (TMDs), including MoSe₂, WSe₂, and WS₂. By integrating one-dimensional (1D) phosphorylated-cellulose nanofibrils (P-CNFs) with two-dimensional (2D) TA-MoS₂ nanosheets, we fabricated P-CNFs/TA-MoS₂ nanocomposite papers with a hierarchical biomimetic structure. The optimized paper demonstrated exceptional mechanical flexibility and strength (∼118 MPa), solvent resistance, and flame retardancy. Notably, it achieved a rapid fire alarm response (<3 s) and reliable cyclic fire warning performance. These outstanding properties make such MoS₂-based hybrid network a promising candidate for FAS materials in fire safety and protection. Furthermore, the TA-TMDs synthesized via this strategy hold significant potential in electronics, biomedicine, catalysis, and energy sectors.