Ammonia (NH3) slip from transportation and industrial sources contributes to secondary fine particulate matter formation and indirect greenhouse effects, posing growing environmental challenges. The selective catalytic oxidation (SCO) of NH3 to N2 offers an effective abatement route, yet conventional Pt-based catalysts suffer from high noble-metal demand and poor N2 selectivity. Here, we report a bifunctional Pt0.08-Cu/AEI zeolite catalyst synthesized through a mechanochemical ball-milling strategy, which integrates Pt oxidation and Cu reduction functionalities within a single zeolitic framework. Structural analyses reveal that metallic Pt nanoparticles are located on the external surface, while atomically dispersed Cu2+ and CuOx clusters reside within the micropores, enabling intimate Pt-Cu interfacial coupling. Operando DRIFTS-MS results uncover a coupled SCO-SCR mechanism, where NO generated-on Pt sites reacts with adsorbed NH3 on adjacent Cu Lewis acid sites to selectively produce N2, effectively suppressing NOx and N2O formation. Benefiting from this dual-site synergy, the Pt-Cu/AEI-BM1 catalyst with low-Pt content (0.08 wt %) achieves 90% NH3 conversion and >90% N2 selectivity at 200 °C under humid, high-space-velocity conditions. This study demonstrates a scalable and sustainable strategy for designing ultralow-Pt, high-selectivity catalysts for practical ammonia emission control.
He et al. (Fri,) studied this question.