CoNi nanoparticles encapsulated by nitrogen-doped carbon nanotube arrays on reduced graphene oxide sheets for electromagnetic wave absorption

Because of the unique physicochemical properties of three-dimensional (3D) architecture, it has attracted wide attention in the field of electromagnetic wave absorption. However, it is difficult to grow carbon nanotube (CNT) arrays on reduced graphene oxide (rGO) sheets due to ultrathin feature of rGO sheets. In this work, we grow CoNi nanoparticle-encapsulated within nitrogen-doped CNT (NCNT) arrays on ultrathin rGO sheets (3D CoNi/N-GCT) through a simple vacuum freeze-drying process and subsequent carbonization at a high temperature. The unique 3D architectures have large surfaces, abundant defects, various interfaces and void spaces, and nitrogen dopants. Benefitting from these advantages, the 3D CoNi/N-GCT shows excellent absorption properties toward electromagnetic wave. We find that the dielectric loss of our designed sample can be modulated by the metal composition and the morphology, leading to the controllable electromagnetic wave absorption property of the 3D CoNi/N-GCT. Our strategy opens a novel strategy for development 3D architectures for electromagnetic wave absorption.