Waste paper cellulose based-MoS2 hybrid composites: Towards sustainable green shielding

Abstract

Biodegradable materials with green shielding characteristics, where “green” represents large effective absorption and less secondary reflection are in great demand but up to date no attention has been given to fulfill both requirements. This requires meticulous microstructural design for independently controlling absorption-associated polarization loss and reflection-associated conduction loss. Herein, 2D-layered MoS2 with low conductivity was integrated by simple soaking and carbonization into waste cellulose paper to promote both absorption through optimizing dielectric loss and green shielding through minimizing reflection. The 2D large surface area guaranteed efficient contact with the host and therefore only 10 wt% MoS2 resulted in higher but moderate conductivity than cellulose paper ensuring low reflection-shielding effectiveness. Moreover, the cellulose fibers were bridged by MoS2 establishing a conductive network. Efficient conductive pathway and improvement of dielectric losses from interfacial polarization resulted in simultaneous EM absorption (~−15 dB) and green shielding (28 dB, green shielding index gs≈1). Therefore, the developed composites not only demonstrated environmental sustainability but also effectively suppressed secondary electromagnetic pollution.