Research on the Adsorption Behavior of NH₃-SCR on Cu-Doped CePO₄-H Surface Based on DFT Calculations AITranslate

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Chinese Library Classification Number:TQ426.82[化学工程]

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Ce-based catalysts possess high oxygen storage capacity and excellent high-temperature thermal stability,showing outstanding performance in denitration reactions.To address the issue of poor low-temperature adsorption activity of Ce sites in the CePO₄-H(hexagonal cerium phosphate)catalyst toward NH₃ and NO molecule,Cu-doped CePO₄-H catalysts were prepared by impregnation method.The effects of varying Cu contents on the denitration performance and phase composition of the catalysts were investigated.Based on the first-principles density functional theory(DFT),the adsorption behaviors of NH₃ and NO during the NH₃-SCR reaction on the Cu-doped CePO₄-H(100)crystal plane were systematically studied by the PBE functional.The experimental results show that the CePO₄-H catalysts before and after Cu doping exhibit the characteristics of typical hexagonal CePO₄ phase.After Cu doping,the NOx conversion rate of the CePO₄-H catalyst is enhanced,the active temperature window is broadened,and the NH₃-SCR catalytic denitration performance is significantly improved.The theoretical results show that both NH₃ and NO molecules can be adsorbed on the Ce and Cu active sites of Cu-doped CePO₄-H catalysts,and the adsorption configurations of both NH₃ and NO molecules on the Ce active sites exhibit higher stability.Compared with the undoped CePO₄-H catalyst,Cu doping significantly enhances the chemical adsorption capacity of the catalyst for NO,while the enhancement of its adsorption capacity for NH₃ is relatively modest.The adsorption of NH₃ on Cu active sites is physical adsorption,whereas the adsorption of NO is typical chemical adsorption.By regulating the electronic structure of the CePO₄-H catalyst surface,Cu doping increases the adsorption energy of reactant molecules,thereby significantly improving the catalytic activity of the NH₃-SCR reaction.This study provides experimental data and theoretical support for improving the NH₃-SCR denitration performance of CePO₄-H catalysts.