Plasma Chemical Looping: Unlocking High-Efficiency CO₂ Conversion to Clean CO at Mild Temperatures

Abstract

We propose a plasma chemical looping CO₂ splitting (PCLCS) approach that enables highly efficient CO₂ conversion into O₂-free CO at mild temperatures. PCLCS achieves an impressive 84% CO₂ conversion and a 1.3 mmol g^-1 CO yield, with no O₂ detected. Crucially, this strategy significantly lowers the temperature required for conventional chemical looping processes from 650 to 1000 °C to only 320 °C, demonstrating a robust synergy between plasma and the Ce_0.7Zr_0.3O₂ oxygen carrier (OC). Systematic experiments and density functional theory (DFT) calculations unveil the pivotal role of plasma in activating and partially decomposing CO₂, yielding a mixture of CO, O₂/O, and electronically/vibrationally excited CO₂*. Notably, these excited CO₂* species then efficiently decompose over the oxygen vacancies of the OCs, with a substantially reduced activation barrier (0.86 eV) compared to ground-state CO₂ (1.63 eV), contributing to the synergy. This work offers a promising and energy-efficient pathway for producing O₂-free CO from inert CO₂ through the tailored interplay of plasma and OCs.