Passive NO_x adsorber (PNA) is an efficient strategy for reducing vehicular NO_x emission during cold-start period, and current studies on PNA development are limited to materials containing precious metals (Pt, Pd, and Ag, etc.). Herein, Co–Mn–Mg–Al mixed metal oxides were prepared from layered double hydroxides (LDHs) and utilized as a new type of PNA. Although Co–Mg–Al oxides exhibited excellent NO_x adsorption capabilities because Co species promoted the generation of active oxygen species, their NO_x adsorption performance deteriorated substantially with decreasing adsorption temperature below 150 °C and they required high temperatures over 400 °C to release the adsorbed NO_x. Conversely, Mn–Mg–Al oxides retained their adsorption performance regardless of adsorption temperature and allowed for NO_x desorption at relatively low temperatures by decreasing the thermal stability of the adsorbed NO_x species. Notably, Co–Mn–Mg–Al mixed oxides exhibited high NO_x adsorption performance at low temperatures between 50 and 150 °C and were passively regenerated via thermal treatment within a temperature range of 200–350 °C owing to the synergistic effects of Co and Mn. The developed LDH-based PNA materials presented excellent cyclic NO_x adsorption performances for long-term operation, and dynamic tests indicated that NO_x adsorbed onto Co–Mn–Mg–Al mixed oxides was effectively released with increasing temperature even in the presence of NO and O₂.

被动式NOx_吸附器（PNA）是减少车辆冷启动期间NOx排放的有效策略，目前PNA开发的研究仅限于含有贵金属（Pt、Pd和Ag等）的_材料。在此，由层状双氢氧化物（LDH）制备Co-Mn-Mg-Al混合金属氧化物并用作新型PNA。虽然Co-Mg-Al氧化物由于Co物质促进了活性氧的生成而表现出优异的NOx吸附能力，但随着吸附温度降低到150℃以下，它们的NOx_吸附性能大幅恶化，并且需要超过400℃的高温才能释放吸附的_NOx。_{相反，无论吸附温度如何，Mn-Mg-Al氧化物都保留其吸附性能，并且通过降低吸附的NO x}物质的热稳定性，允许在相对较低的温度下解吸NO _x。值得注意的是，Co-Mn-Mg-Al混合氧化物在50~150°C的低温下表现出高NOx吸附性能，并且由于Co的协同作用，在200~350°C的温度范围内通过热处理被动再生_。和锰。所开发的LDH基PNA材料表现出优异的长期运行循环NO _{x吸附性能，动态测试表明NO x即使在NO和O 2}存在的情况下，随着温度的升高，吸附在Co-Mn-Mg-Al混合氧化物上的Co-Mn-Mg-Al混合氧化物也能有效释放。