Utilization of electrochemical treatment and surface reconstruction to achieve long lasting catalyst for NO removal.

The development of catalysts has seen tremendous growth recently but most strategies only report utilization of catalysts for a few initial cycles without taking into account the influence of oxygen poisoning. Here, the magnetic FeO@EDTA-Fe (MEFe, having a core FeO particle with EDTA-Fe coating) was investigated as a model catalyst for long-term recycling for the removal of nitrogen oxide (NO) from NO/O mixture, followed by NO recovery. The concentration of oxygen in the flue gas was found to have a strong impact on NO absorption and catalytic response. To circumvent the oxygen poisoning, the MEFe was subjected to electrochemical treatment in the presence of neutral red (N.R.) and NO removal efficiency was ∼95 % noted. Furthermore, the surface of the catalyst degraded significantly (p < 0.05) after 6-7 repetitive cycling due to surface catalytic reactions, surface poisoning, oxidation of metallic species as well as residual stresses. The MEFe surface was reconstructed after 7 cycles using EDTA solution and Fe source to achieve similar surface coating as the fresh MEFe catalyst. The reconstructed MEFe exhibited similar NO absorption capability as the fresh MEFe and the reconstruction loop was repeated several times to achieve long term cycling, which make the catalyst cost-effective. Hence, it is proposed that a successful regeneration process can be employed for promising, sustainable and long-lasting catalytic treatment of air pollutants.