Insight into the effect of clay mineral structure on clay-derived N-doped carbon materials and their efficient electrocatalytic performance

Abstract

This study aimed to use clay-organic pollutants complex as precursor to fabricate clay-derived N-doped carbon materials, which would reduce the environmental risk of the complex. Kaolinite, sepiolite, montmorillonite as well as iron-saturated montmorillonite were chosen as of the representative clay minerals source. And organic pollutant (tetracycline, TC) was chosen as carbon source. The results revealed the effect of the types of clay minerals and the interaction between TC and clay mineral on the structure and electrocatalytic performance of clay-derived N-doped carbon materials. With the template of layered structural montmorillonite and kaolinite, the obtained carbon materials (NC-MT and NC-KL) possess typically mesoporous structure. With the template of tunnel-like structural sepiolite, NC-SEP exhibited abundant hollow carbon bubbles and mesoporous structure features. Owing to the synergistic effect of iron oxide and montmorillonite in iron-saturated montmorillonite, NC-FEMT showed a graphene-like carbon nanosheet structure with abundant wrinkles and pores. TC might be more easily converted into N-doped clay-derived carbon material, which was partly intercalated into the interlayer of montmorillonite. Besides, the presence of Fe was good for the enhancement of graphitization degree and the generation of active nitrogen species. Moreover, the clay-derived N-doped carbon material presented good oxygen reduction reaction (ORR) electrocatalytic performance.