Three-dimensional RGO/CNTs/GDY assembled microsphere: Bridging-induced electron transport enhanced microwave absorbing mechanism

As a new type of carbon allotrope, graphdiyne (GDY) is a promising material with highly conjugated conductive structure and excellent chemical stability. This indicates the great potential of GDY as a microwave absorbing material. Herein, we realize the simple one-step assembly of zero-dimensional GDY particles, one-dimensional carbon nanotubes (CNTs) and two-dimensional reduced graphene oxide (RGO) through ultrasonic spray method and carbonization technology, and obtained RGO/CNTs/GDY microspheres (RCG) with three-dimensional porous structure. CNTs can bridge RGO and GDY, forming a complete conductive network and providing pathways for electron migration. Benefiting from the unique three-dimensional assembly structure, high specific surface area, suitable impedance matching and strong dissipation ability, RCG shows excellent microwave absorption performance. By adjusting the assembly ratio and optimizing the filler loading, RCG-2 (RGO: CNTs: GDY = 4:1.5:1, 17.5%) with outstanding microwave absorption properties is obtained. The minimum reflection loss (RL_min) reached −51.8 dB at the matching thickness of 1.6 mm and the maximum effective absorption bandwidth (EAB) covered 5.4 GHz. The novel loss mechanism of bridge-induced electron transfer enhanced microwave absorption is proposed. It provides a new way to manufacture advanced microwave absorbers.