Perfect Broadband Sound Absorption on a Graphene-Decorated Porous System with Dual-3D Structures.

Noise is a threat to human life quality and an invisible killer that causes many chronic diseases. The vast majority of porous sound absorbers are single-phased, which limits their sound absorption potential. Herein, a graphene-decorated porous system (GDPS) prepared using the immersion-hydrothermal-freezing self-assembly method is reported as an efficient sound absorber based on its unique consecutive double three-dimensional (dual-3D) structure. Due to the increased tortuosity and other gain effects, the novel structure can achieve the perfect broadband absorption at a wide bandwidth in which the sound absorption coefficient exceeds 0.9 easily. Within the effective thicknesses, the widest perfect absorption bandwidth of 814-6400 Hz is realized. Moreover, a higher graphene concentration and the addition of a polymer are found to be able to decrease the absorption frequency to the lowest values of 1979 and 1544 Hz, respectively. The design of a unique dual-3D structure opens up new strategies and applications to use graphene aerogels in noise and vibration applications.