One-step green synthesis of multi-morphological carbon nanotube forests for superior microwave absorption and electrocatalysis

Porous carbon materials with multiscale distinctive morphologies hold significant promise in electromagnetic wave stealth/protection and catalysis; however, formidable challenges are highly verbose and resource/time-consuming fabrication processes. Here, we report a one-step solvent/template-free self-expanding carbonization strategy for rapidly fabricating porous carbon foams (Ni/CNT) with zero-dimensional (0D) nanoparticles, one-dimensional (1D) nanotube forests, and three-dimensional (3D) hollow microvesicles. Owing to the multi-morphological structure and low-density feature, the resulting porous carbon foam Ni/CNT-800 achieves a minimum reflection loss of −56.48 dB and an effective bandwidth of 5.44 GHz at a low filler loading of only 9 wt%. Moreover, altering the electronic structure and surface chemistry of carbon foam by phosphorus doping enables a highly reduced durable overpotential (η) of 275 mV for oxygen evolution reaction. This work emphasizes a straightforward strategy for the facile design and efficient fabrication of carbon-based materials with unique multiscale porous morphologies, customizable functions, and various applications.