Transforming petroleum asphalt into carbon fibers and related metal/oxide composites by electrospinning synthesis

Abstract

Petroleum asphalt, due to its low cost and high carbon content, is a promising precursor of high-value carbon materials. However, electrospinning-based fabrication requires complex pretreatment and substantial amounts of additives like polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), or polystyrene (PS), which limit asphalt utilization. Furthermore, comparative studies on different types of supported asphalt-based carbon fibers remain limited. Here, N,N-dimethylacetamide (DMA) was employed as a solvent to achieve a mass ratio of asphalt to PAN of 2 : 1, facilitating the preparation of asphalt-based carbon fibers loaded with various metal salts, including metalloporphyrin salts, nitrates, and metal oxides. Comparative analysis indicated that small amounts of nitrates promoted the formation of well-defined fiber morphologies, whereas oxides interacted with asphalt to create unique bead-on-string structures. Additionally, the presence of oxides delayed the release of gaseous products during carbonization, resulting in carbon fibers with finer diameters. Electrochemical evaluations demonstrated that the bead-on-string structures exhibited notable advantages in oxygen evolution reaction (OER) activity. These findings offer valuable insights into the design of carbon fibers with high asphalt content for advanced applications.