An effective model for describing NOx adsorption and desorption on a PtPd/CeO2-ZrO2 passive NOx adsorber is presented. The kinetic parameters are evaluated from the available experimental data obtained during NOx adsorption/desorption experiments including CO2 and H2O in the feed, performed at 80, 120 and 160 °C both in the presence and in the absence of reducing agents (CO or C2H4 ). The model describes the temperature dependence of the NOx adsorption rate and capacity, the impact of CO, and dynamics of the NOx desorption events. The model predicts formation of nitrites, nitrates, and additional storage enabled in the presence of CO. Thermal decomposition of the stored NOx species results in two main desorption peaks. Nitrites are desorbed at lower temperatures while nitrates are thermally more stable. The evolution of nitrite and nitrate species in the model corresponds with the measured DRIFTS spectra of the catalyst surface. The presence of CO significantly improves the rate of NOx adsorption and storage efficiency at low temperatures, most probably due to reduction of oxidic Pt and Pd nanoparticles. The developed model captures well the observed trends and can be utilized for simulations of PNA performance under real operating conditions.

中文翻译：

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PtPd/CeO2-ZrO2被动NOx吸附器NOx吸附和解吸的有效模型

提出了描述 PtPd/CeO2-ZrO2 被动 NOx 吸附器上 NOx 吸附和解吸的有效模型。动力学参数根据 NOx 吸附/解吸实验期间获得的可用实验数据进行评估，包括进料中的 CO2 和 H2O，在 80、120 和 160 °C 下在还原剂（CO 或 C2H4）存在和不存在的情况下进行. 该模型描述了 NOx 吸附速率和容量的温度依赖性、CO 的影响以及 NOx 解吸事件的动力学。该模型预测亚硝酸盐、硝酸盐的形成以及在 CO 存在下启用的额外存储。存储的 NOx 物质的热分解导致两个主要解吸峰。亚硝酸盐在较低温度下解吸，而硝酸盐在热上更稳定。模型中亚硝酸盐和硝酸盐物种的演变与催化剂表面测量的 DRIFTS 光谱相对应。CO 的存在显着提高了低温下 NOx 的吸附速率和储存效率，这很可能是由于氧化 Pt 和 Pd 纳米颗粒的还原。开发的模型很好地捕捉了观察到的趋势，可用于模拟实际操作条件下的 PNA 性能。