Clay-based aerogel is a promising material in the field of thermal insulation and flame retardant, but obtaining claybased aerogel with high fire resistance, low thermal conductivity, hydrophobicity, and mechanical robustness remains a challenge. In this work, palygorskite-based aerogel was successfully fabricated via combining with a very small proportion of alginate to form a distinctive hierarchically meso−microporous structure. By employing ethanol solution (EA) replacement method and freeze-drying process, the resultant aerogel exhibited ultralow density (0.035−0.052 g/cm 3 ), practical mechanical strengths (0.7−2.1 MPa), and low thermal conductivity of 0.0332−0.165 W/mK (25−1000 °C). The hydrophobicity of aerogel was achieved by simple chemical vapor deposition of methyltrimethoxysilane (MTMS). The Pal-based aerogel showed good performance in both fire resistance with high limiting oxygen index up to 90%, and heat resistance with tolerance of flame up to 1000 °C for 10 min. This renewable Palbased aerogel with a 3D framework is a promising material to be applied in fields of construction and aerospace for thermal insulation and high fire resistance.

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Melamine formaldehyde (MF) foams, although widely used in heat insulation and as flame retardants due to their unique combination of low thermal conductivity and high flame retardancy, are prone to rapid collapse, which is extremely dangerous. Herein, we report a hydrophobic composite foam with a hierarchical structure. This foam was prepared through in situ incorporation of palygorskite and sodium alginate (Pal-SA) composite aerogels into the MF foam via the ambient pressure drying method and then through methyltrimethoxysilane (MTMS) chemical vapor deposition. The composite foam exhibited high-temperature thermal stability, excellent flame retardancy, and low smoke emission (2.5 m 2 / m 2 ), which is ∼17 times lower than that of the pure MF. The foam prepared in the present work has excellent application prospects in offshore oil-spill treatment, high-temperature insulation, and flame retardancy. Moreover, the results of this work may provide guidance for developing low-smoke flame-retardant materials.