The spatiotemporal features of the multifunctional monolithic lean hydrocarbon NO_x trap (LHCNT), for eliminating NO_x (x = 1 and 2) and ethylene (C₂H₄), are examined using spatially resolved mass spectrometry (SpaciMS), spanning the sequentially positioned passive NO_x adsorber (PNA; Pd/SSZ-13), hydrocarbon trap (HCT; Pd/BEA), and oxidation catalyst (OC; Pt/Al₂O₃–CeO₂). The overall LHCNT performance is captured in temporal trapping efficiency profiles, which show the integral NO and C₂H₄ uptake followed by delayed NO release along with NO and ethylene oxidation. Spatially resolved transient concentration profiles spanning uptake, release, and conversion of NO, H₂, and C₂H₄, alone or as mixtures in feeds containing H₂O, provide detailed insight into the transient coupling not attainable with effluent concentration monitoring alone. The PNA serves as the primary zone for NO uptake, followed by the OC and HCT. NO oxidation to NO₂ occurs during NO uptake in the PNA due to Pd(II) reduction, while more extensive oxidation occurs in the OC at higher temperature. C₂H₄ uptake and oxidation occur in each of the functions with oxidation occurring the earliest (lowest temperature) in the OC. NO uptake in the PNA and HCT is negligibly affected by H₂ but protracted oxidation of H₂ during the temperature ramp delays NO release, suggesting persistence of NO bound on Pd(I). Both the PNA and HCT exhibit excellent C₂H₄ uptake, which diminishes in the presence of NO. Spatially resolved concentration data reveal several interesting features, such as high-temperature, sequential NO oxidation (by O₂ to NO₂) and C₂H₄ oxidation (by NO₂ to NO + CO₂) in the PNA. Simulated warmup experiments reveal that the LHCNT NO trapping is enhanced with C₂H₄ addition but that a reduction in space velocity may be needed to improve performance. A previously developed PNA model predicts satisfactorily the main features of spatially resolved NO and NO + C₂H₄ data.

中文翻译：

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序贯三区整料中的氮氧化物和碳氢化合物捕集和转化：时空特征

使用空间分辨质谱 (SpaciMS) 检查用于消除 NO _x（x = 1 和 2）和乙烯（C ₂ H ₄ ）的多功能整体式贫碳氢化合物 NO _x捕集器 (LHCNT) 的时空特征，连续跨越定位被动式 NO _x吸附器（PNA；Pd/SSZ-13）、碳氢化合物捕集器（HCT；Pd/BEA）和氧化催化剂（OC；Pt/Al ₂ O ₃ –CeO ₂）。LHCNT 的整体性能在时间捕获效率曲线中捕获，该曲线显示了完整的 NO 和 C ₂ H ₄吸收后延迟 NO 释放以及 NO 和乙烯氧化。_{跨越 NO、H 2}和 C ₂ H ₄的吸收、释放和转化的空间分辨瞬态浓度曲线，单独或作为含 H ₂ O 进料中的混合物，提供了对仅通过流出物浓度监测无法实现的瞬态耦合的详细了解。PNA 是吸收 NO 的主要区域，其次是 OC 和 HCT。由于 Pd(II) 还原，在 PNA 吸收 NO 期间，NO 氧化为 NO ₂，而在较高温度下，OC 中发生更广泛的氧化。C ₂ H ₄吸收和氧化发生在每个功能中，氧化发生在 OC 中最早（最低温度）。PNA 和 HCT 中的 NO 摄取受 H _{2的影响可忽略不计，但在温度斜坡期间 H 2}的长时间氧化会延迟 NO 释放，这表明 NO 持续存在于 Pd(I) 上。PNA 和 HCT 都表现出出色的 C ₂ H ₄吸收，在 NO 存在的情况下会降低。空间分辨的浓度数据揭示了几个有趣的特征，例如高温、连续的 NO 氧化（通过 O ₂到 NO ₂）和 C ₂ H ₄氧化（通过 NO ₂到 NO + CO ₂) 在 PNA 中。模拟预热实验表明，添加 C ₂ H ₄可增强 LHCNT NO 捕获，但可能需要降低空间速度以提高性能。先前开发的 PNA 模型令人满意地预测了空间分辨 NO 和 NO + C ₂ H ₄数据的主要特征。