Preparation and dispersity of carbon nanospheres by carbonizing polyacrylonitrile microspheres

Abstract

Polyacrylonitrile microspheres of about 240 nm were synthesized and used as a precursor for preparing carbon nanospheres (CNs) by oxidation and sequential carbonization. The relationship between preparation conditions and sphere properties (dispersity and yield) were investigated. For oxidation, a slow heating rate resulted in good dispersity and high final temperature led to high yield of carbon. For carbonization, a slow heating rate and a fast flow rate of protection gas were good for the high dispersity of CNs. Under optimized conditions of 0.1 °C min⁻¹ to 300 °C for oxidation and 3 °C min⁻¹ to 1000 °C for carbonization under N₂ protection of 1.8 L min⁻¹, CNs with 180 nm diameter, 4.51% nitrogen content, high purity, and good dispersity were fabricated. Moreover, after being further treated at 2800 °C, graphitized CNs with high crystal structures were obtained.