Surface modification of LaMnO3 perovskite supported on CeO2 using argon plasma for high-performance reduction of NO

Abstract

The ever-increasing industrial and motor vehicle activities led to the overwhelming emission of nitrogen oxides (NOx) to the atmosphere, posing a serious environmental challenge. Selective catalytic reactions, based on Perovskite-type metal oxide catalysts, are a proven method used to eliminate NOx compounds and prevent their discharge to the ecosystem. Herein, LaMnO3 nanocatalysts were synthesized by the sol-gel auto-combustion method and supported on CeO2 support using dry impregnation method and used in the simultaneous catalytic reduction process of NO and CO. As a novel idea, the prepared nanocatalysts were treated using argon non-thermal glow discharge plasma to alter the surface properties. The physicochemical properties of these particles were determined using FT-IR, XRD, EDX, FE-SEM, and BET analysis. The plasma treatment process managed to reduce surface impurities. Additionally, the dispersion of the perovskite nanoparticles over the ceria support and the specific surface area was improved, while the diameter of the nanocatalysts was declined. As a result, the plasma modified LaMnO3/CeO2 nanocatalysts improved the conversions of NO and CO by a maximum of 41.19 and 49.11 %, respectively. The produced nanocatalysts were highly stable during the reduction process and lost 3.94 % of their activity after 30 h of operation. The plasma-based surface modification process was utterly effective in boosting the catalytic performance, while it was relatively cheap and easy to carry out.