Influence of Pt-Cu synergistic action and TiO2 core–shell structure on NH3-SCO and anti-aging performance

As the most effective after-treatment technology for NH 3 emission control in road vehicles, Ammonia Slip Catalyst still faces challenges such as insufficient catalytic activity and low selectivity to the reaction product N 2 . Especially, the performance bottleneck in anti-aging greatly limits the commercial application of the catalyst, and there are still research gaps. Based on this, this study aims to reconstruct the structure − activity relationship of the catalyst by directionally constructing TiO 2 with a multi − scale channel core − shell structure as the support based on introducing different contents of Pt and Cu dual active components, and to explore the regulation and improvement mechanism of the catalytic performance including anti − aging property under the multi − dimensional synergistic effect. The results indicate that by enhancing the mass transfer capability of the catalyst with three-dimensional mass transfer channels and the influence of the dual active components, Pt 5 -Cu 1 /TiO 2 with a Pt − Cu content ratio of 5:1 achieves the best catalytic activity and N 2 selectivity. The Density Functional Theory calculation results show that due to the relatively low free energy of the key intermediate HNO, the Pt content plays a dominant role in the formation of N 2 O. Based on the relatively low free energy of the key intermediate NH 2 and the sequential dehydrogenation order, the thermodynamic conditions for the N 2 formation pathway under the catalytic action of Cu are extremely favorable, with relatively small kinetic barriers. Compared with Pt, the NO X formation pathway under the catalytic action of Cu has a smooth energy decrease and is more likely to occur, but it is also affected by the complex competition in the synergistic effect of the dual active components. The 17.69 % content of Pt 4+ in the active components of the catalyst after aging is the main reason for the decline in activity. The thicker shell layer reduces the collapse of the core–shell structure at high temperatures, laying a stable structure–activity relationship foundation for maintaining high activity. The prepared Pt 5 -Cu 1 /TiO 2 still meets the emission regulation limits after aging, showing good anti-aging performance.