DFT Study of NH3 and NO Adsorption on Copper-Aluminate Catalysts

The selective catalytic reduction (SCR) reaction belongs to the gas-solid multiphase reaction, and the adsorption of NH₃ and NO play an important role in the reaction. The adsorption behaviors of NH₃ and NO were studied with the diffuse reflectance infrared transform spectroscopy (DRIFTS) methods; these results showed that there were obvious adsorption phenomena of NH₃ and NO on the catalysts. NH₃ could be strongly adsorbed on the catalysts, resulting in coordinated NH₃ and NH₄ ⁺. NO adsorption led to the formation of bridging bidentate nitrate, chelating bidentate nitrate, and chelating nitro. In this study, the interaction of NH₃ and NO molecules with the Cu²⁺ present on the CuAl₂O₄(100) surface had been investigated by using a periodic density functional theory (DFT). The results showed that the adsorption of all the molecules on the Cu²⁺ site is energetically favourable, whereas NO bound was more stronger than that of NH³ with the adsorption site, and key information about the structural and energetic properties was also addressed.