Hierarchically Porous Graphitic Aerogels via Thermal Morphogenesis of Proteins for Environmental Remediation

Hierarchically porous monolithic graphitic sheet-based aerogels (HGA) with high surface area and ultralow density have drawn massive attention for applications in catalysis, energy storage/conversion, water purification, and beyond. However, syntheses of these materials rely on harsh and nonsustainable chemical reagents and/or template-based methods, while the resulting structures generally lack covalent integration, compromising their properties. Herein, we demonstrate a self-foaming mechanism for green and scalable synthesis of HGA using protein precursors. Rather than creating a solid composite and exchanging the sacrificial component with a gas phase, we create a gas phase first and then convert the liquid into a solid phase. The controlled heating of protein induces intrinsic foaming via softening, gas evolution, and carbonization/graphitization, resulting in an HGA composed of a sheet and fiber-like framework. Our investigation of processing-structure-property relationships elucidates the interplay between synthesis variables and aerogel structure/properties, enabling deliberate control over microstructural features. Notably, we demonstrate more than an order-of-magnitude variation in density and over a 7-fold increase in compressive strength by controlling the synthesis protocol. This study opens doors to a green and scalable approach to synthesizing HGAs with customizable microstructures and properties, making them promising for a broad spectrum of applications such as environmental remediation and energy storage.