Seo Yaeun, Lee Min Woo, Kim Hyun Jae, Choung Jin Woo, Jung ChangHo, Kim Chang Hwan, Lee Kwan-Young
Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-Gu, Seoul 02841, South Korea.
Central Technology R&D Institute, Hyundai Oilbank Co., Ltd, 17-10 Mabok-ro 240beon-gil, Giheung-gu, Yongin-si, Gyeonggi-do 16891, South Korea.
J Hazard Mater. 2021 Aug 5;415:125373. doi: 10.1016/j.jhazmat.2021.125373. Epub 2021 Feb 24.
To achieve high fuel efficiency and low emission in automobiles, it is necessary to develop highly active diesel oxidation catalysts (DOCs). Pd/CeO catalysts have been widely used as active catalysts for CO and CH oxidation reactions. Additionally, Ag has been reported to enhance the oxygen storage capacity (OSC) of CeO, which contributes to the oxidation ability of Pd/CeO. In this study, Pd/Ag-CeO catalysts were used for CO and CH oxidation reactions. When CeO was doped with appropriate amounts of Ag, reducibility and CO desorption rate were increased, which confirmed the high OSCs of Ag-doped catalysts. However, Ag particles were formed and the Ce/Ce ratio decreased when CeO was doped with excess amounts of Ag. In addition, reduced Pd (Pd), which is an active species for CH oxidation, was formed and maintained even under oxidative reaction conditions. Since the removal of CH is important for the oxidation of CO and CH, the catalyst with the highest Pd fraction (Pd/0.1Ag-CeO and Pd/0.3Ag-CeO) presented improved catalytic activity. Consequently, the optimal amount of Ag enhanced the OSC of Pd/Ag-CeO catalysts and formed active Pd species under oxidative conditions, which resulted in the excellent catalytic activity of Pd/Ag-CeO for the CO and CH oxidation reaction.
为了在汽车中实现高燃油效率和低排放，开发高活性柴油氧化催化剂（DOCs）是必要的。钯/二氧化铈催化剂已被广泛用作一氧化碳和碳氢化合物氧化反应的活性催化剂。此外，据报道银可以提高二氧化铈的储氧能力（OSC），这有助于钯/二氧化铈的氧化能力。在本研究中，钯/银-二氧化铈催化剂用于一氧化碳和碳氢化合物氧化反应。当二氧化铈掺杂适量的银时，还原性和一氧化碳脱附速率增加，这证实了掺银催化剂具有高储氧能力。然而，当二氧化铈掺杂过量的银时，会形成银颗粒且铈/铈比降低。此外，即使在氧化反应条件下，也会形成并保持作为碳氢化合物氧化活性物种的还原态钯（Pd）。由于碳氢化合物的去除对于一氧化碳和碳氢化合物的氧化很重要，具有最高钯含量的催化剂（钯/0.1银-二氧化铈和钯/0.3银-二氧化铈）表现出更高的催化活性。因此，银的最佳用量提高了钯/银-二氧化铈催化剂的储氧能力，并在氧化条件下形成了活性钯物种，这导致钯/银-二氧化铈对一氧化碳和碳氢化合物氧化反应具有优异的催化活性。
