Deep Oxidation Removal of Nitric Oxide and SO₂ via Singlet Oxygen and Hydroxyl Radicals in the LaCoO_3-δ/H₂O₂ System

This study proposes a novel LaCoO_3‑δ/H₂O₂ Fenton-like process for the efficient generation of nonradical singlet oxygen (¹O₂) and hydroxyl radicals (^•OH), enabling the deep oxidation of nitric oxide (NO), as well as simultaneous denitrification and desulfurization. A LaCoO_3‑δ perovskite material enriched with Co³⁺ ions and oxygen vacancies (OV) was successfully synthesized by using a one-step citric acid sol-gel method. OV enhances electron mobility and expedites the redox cycling of surface Co²⁺/Co³⁺ pairs, thereby promoting the generation of ^•OH and ^•O₂ ^-. The high Co³⁺ content further facilitates the transformation of ^•O₂ ^- into ¹O₂. Moreover, electron-rich centers and highly reactive lattice oxygen (O^2-) induced by abundant OV also contribute to the activation of H₂O₂, enhancing the production of ^•OH and ¹O₂. When combined with a comprehensive Na₂SO₃/NaOH absorption system, simultaneous removal efficiencies of 91.2% for NO and 100% for SO₂ were achieved under optimal experimental conditions while ensuring good operational stability. This innovative noniron-based Fenton-like system not only rivals the performance of typical iron-based Fenton-like systems but also provides new insights into the development of multipollutant deep oxidation removal technologies for application in coal-fired power plants.