Microbubble effect-assisted electrolytic synthesis of hollow carbon spheres from CO2

Abstract

A one-step high-yield synthesis of well-developed hollow carbon spheres was achieved by an electrolytic conversion of CO₂ in a CaCO₃-containing LiCl–KCl melt at 450 °C. Manipulating the electrode potential induced the occurrence of a microbubble effect associated with the as-formed CO (intermediates of CO₃²⁻ reduction) in ultrathin carbon sheets, thereby triggering the growth of hollow structures. The SEM results reveal good plasticity of the carbon sheets at elevated temperatures. The micron-sized hollow carbon spheres showed favorable capacitive properties, and can be used as catalyst supports as well.