Plasma Driven Boudouard Reaction for Efficient Chemical Storage

Abstract

Conversion of CO₂ into CO with electricity is a straightforward method to convert intermittent sustainable electricity into storable chemical energy. Despite much research efforts worldwide, it has not yet simultaneously achieved acceptable CO₂ conversion and energy efficiency. Here we demonstrate that the Boudouard reaction, CO₂ + C → 2CO, driven by thermal plasma allows CO₂ conversion exceeding 95% and electrical energy efficiencies of 70% for CO production, which are much higher than that seen so far by conventional method. The improved performance is benefit from plasma excitation of the CO₂, with which CO₂ is firstly decomposed into CO, O and O₂ by arc discharge, then the free oxygen in the mixture combust with carbon to form CO, and residual CO₂ is reduced by carbon due to high plasma temperature. Therefore, the endothermic Boudouard reaction is partially replaced by exothermic reaction, and the electric energy to produce plasma is reused.

Keywords: Boudouard reaction, thermal plasma, CO₂ conversion, energy efficiency