Plasma Chemical Looping: Unlocking High-Efficiency CO 2 Conversion to Clean CO at Mild Temperatures.

We propose a plasma chemical looping CO ₂ splitting (PCLCS) approach that enables highly efficient CO ₂ conversion into O ₂ -free CO at mild temperatures. PCLCS achieves an impressive 84% CO ₂ conversion and a 1.3 mmol g ^-1 CO yield, with no O ₂ 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 _0.7 Zr _0.3 O ₂ oxygen carrier (OC). Systematic experiments and density functional theory (DFT) calculations unveil the pivotal role of plasma in activating and partially decomposing CO ₂ , yielding a mixture of CO, O ₂ /O, and electronically/vibrationally excited CO ₂ *. Notably, these excited CO ₂ * 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 ₂ (1.63 eV), contributing to the synergy. This work offers a promising and energy-efficient pathway for producing O ₂ -free CO from inert CO ₂ through the tailored interplay of plasma and OCs.
Competing Interests: The authors declare no competing financial interest.
(© 2024 The Authors. Published by American Chemical Society.)