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

We propose a plasma chemical looping CO splitting (PCLCS) approach that enables highly efficient CO conversion into O-free CO at mild temperatures. PCLCS achieves an impressive 84% CO conversion and a 1.3 mmol g CO yield, with no O 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 CeZrO oxygen carrier (OC). Systematic experiments and density functional theory (DFT) calculations unveil the pivotal role of plasma in activating and partially decomposing CO, yielding a mixture of CO, O/O, and electronically/vibrationally excited CO*. Notably, these excited CO* species then efficiently decompose over the oxygen vacancies of the OCs, with a substantially reduced activation barrier (0.86 eV) compared to ground-state CO (1.63 eV), contributing to the synergy. This work offers a promising and energy-efficient pathway for producing O-free CO from inert CO through the tailored interplay of plasma and OCs.