A comprehensive exploration about the effects of O2, SO2 and NO on As2O3 adsorption over Cu/γ-Al2O3 SCR catalyst: A DFT study

Identifying the mechanisms by which gas components influence arsenic deposition over a SCR catalyst is an important issue to protect the catalyst from arsenic poisoning. In this work, the effects of O-2, SO2, and NO on arsenic adsorption over a Cu/gamma-Al2O3 catalyst were calculated via density functional theory (DFT) method. Results revealed that O-2 facilitated the As2O3 retention on Cu/gamma-Al2O3 surface due to the formation of adsorbed O atoms. The positive effect of SO2 on As2O3 adsorption was reflected by the formation of SO42 and HSO4, which changed the potential field of substrate surface. Specifically, HSO4 enhanced the adsorption activities of surface atoms. However, NO3 did not show a significant impact on As2O3 adsorption when NO was introduced. From thermodynamic and adsorption selectivity analysis, the adsorption activities of different surfaces were in the order of O-Cu/gamma-Al2O3 > SO42-Cu/gamma-Al2O3 > O-2-Cu/gamma-Al2O3 > NO3-Cu/gamma-Al2O3 > HSO4-Cu/gamma-Al2O3. However, the adsorption selectivity weakened with increasing temperature. Results from this work can help improve the arsenic resistance of SCR catalysts. (C) 2021 Elsevier Ltd. All rights reserved.