A Study of CeSnO and Pd/CeSnO as Low-Temperature NO Adsorbers with Excellent Hydrothermal Stability

In the present work, we report on two passive NO adsorber (PNA) material candidates: the novel support CeSnO with and without Pd loading. The NO adsorption and storage capacities of fresh and hydrothermally aged CeSnO and Pd/CeSnO were investigated. The results show that CeSnO exhibits a rather large NO uptake and storage capacity (28.9 μmol/g), while the loading of Pd on CeSnO can further increase the storage capacity to 37.6 μmol/g and affect the desorption temperature of NO. It was found that the NO desorption temperature of Pd/CeSnO was compatible with the efficient operating window of selective catalytic reduction (SCR) catalysts. After a hydrothermal aging treatment at 800 °C for 12 h, the NO adsorption and storage capacities of CeSnO and Pd/CeSnO increased, indicating excellent hydrothermal stability. The interaction of Pd with CeSnO, the state of Pd species, and the structure of CeSnO and Pd/CeSnO are studied by combination of the characterization results.