Charge modulation of CNTs-based conductive network for oxygen reduction reaction and microwave absorption

Carbon nanotube (CNTs) based composite materials are popular in various fields. However, traditional strategies for the electric conductivity modulation of CNTs is complicated and improper in large-scale applications. Herein, a novel CNTs-based hollow microsphere is prepared through facile spray drying and one-step pyrolysis. This unique interpenetration microsphere conductive network is constructed by nitrogen-doped CNTs embedded with Co nanoparticles (Co-N-C), which is compactly entangled by commercial CNTs. By the strong charge polarization and electron redistribution on the surface of Co-N-C, the monohybrids exhibit excellent bifunctional applications. The Co-N-C/CNTsHS shows excellent oxygen reduction reaction (ORR) performance including the high half-wave potential (0.87V), outstanding stability and methanol tolerance. Benefited from the improved dielectric property of Co-N-C, the Co-N-C/CNTsHS exhibits superior microwave absorption (MA) performance, with a maximum reflection loss of -60.2 dB and the bandwidth of 5.1 GHz at a thickness of only 2.5 mm. The enhanced performance can be attributed to three dimension (3D) hollow mesoporous conductive networks, which accelerate electron transfer and modulate charge distribution of Co-N-C. This work puts forward a new idea of charge modulation of CNTs and lays a foundation for the preparation of excellent bifunctional materials. (C) 2021 Published by Elsevier Ltd.

Automated summary

In this study, a novel CNTs-based hollow microsphere was prepared through facile methods, with Co-N-C and commercial CNTs forming a unique conductive network to enhance the performance in oxygen reduction reaction and microwave absorption. Furthermore, optimization of electron transfer and charge distribution also laid a foundation for the preparation of excellent bifunctional materials.