Strong and Ultrahigh Temperature-Resistant Metal Oxide Nanobelt Aerogels

Abstract

Metal oxide aerogels, inorganic cousins of the highly commercialized metalloid oxide silica aerogels, exhibit distinct properties specific to each type. Nevertheless, they share a common challenge with silica aerogels—brittleness and low mechanical strength due to their particulate necklace-like structure. In contrast, polymer aerogels often boast significantly enhanced mechanical properties thanks to their nanofibrillated networks. To enhance the mechanical properties of metal oxide aerogels, the metal oxide formation with a polymeric nanostructure is micro-templated. This method transforms the necklace-like particulate microstructure of metal oxide aerogels (e.g., Al₂O₃ Cr₂O₃, and Fe₂O₃) into a polymer-like nanobelt structure. Remarkably, even after removing the polymer template through calcination at 600 °C, the nanobelt structure remains intact. These metal oxide nanobelt (MNB) aerogels exhibit exceptional compressibility while retaining their mesoporous structure. As a demonstration, the resulting Al-MNB aerogel can withstand compression up to 80% strain without fracturing while preserving its porous nanobelt structure and a high specific surface area of 228 m² g⁻¹ and a pore volume of 0.7 cm³ g⁻¹ after heat treatment at 1300 °C. This work introduces an innovative strategy for creating a distinctive polymer-like nanobelt microstructure, paving the way for novel applications of metal oxide aerogels with unique structures and enhanced performance.