3D white graphene foam scavengers: Vesicant-assisted foaming boosts the gram-level yield and forms hierarchical pores for superstrong pollutant removal applications

Abstract

Three-dimensional (3D) nanostructures assembled with one- or few-layered ultrathin two-dimensional (2D) crystals have triggered great interest in energy and environmental applications. Here, we introduce a gas-foaming process in an hexagonal boron nitride (h-BN) ceramic material to fabricate 3D white graphene (WG) foams without using any catalysts or templates for superstrong pollutant removal applications. Importantly, the introduction of vesicants guaranteed the reproducibility and yield (>500 cm3). Interestingly, these 3D WG foams possessed a vesicular structure with hierarchical pores ranging from nm to μm scales and with ultrathin walls consisting of mono- or few-layered BN membranes with planar sizes as large as 100 μm. Consequently, such microstructure merits of hierarchical pores and ultrathin walls endowed them not only very low density (2.1 mg cm-3) but also superstrong adsorption ability, illustrated by capacitances up to 190 times its own weight toward a wide range of environment contaminations, including various oils and dyes. Thus, the 3D h-BN WG foams prepared by vesicant-assisted foaming should have great potential as outstanding environmental scavengers.