Low-Temperature Oxidation Catalysts by High-Temperature Calcination of Pt/CeO2 and Cu/CeO2
Bo Peng, Pacific Northwest National Laboratory
The U.S. Department of Energy road map has set the goal for automotive treatment technologies to achieve 90% conversion of criteria pollutants at a temperature (T90) of 150 °C or lower. In addition, thermal durability is essential to survive harsh conditions encountered in automotive exhaust. To develop catalysts that comply with increasing regulations, our group has investigated the effect of high-temperature and conventional low-temperature calcination synthesis methods on low-temperature catalyst oxidation activity. Although the former method can produce thermally stable Pt single atom catalysts on CeO2, significant pollutant conversions at low-temperatures remained a challenge. In our recent work, scanning transmission electron microscopy (STEM), temperature-programmed (CO-TPR), and near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) were used to demonstrate how high-temperature calcination leads to a stronger Pt-CeO2 and Cu-CeO2 interaction, resulting in activation of surface lattice oxygen at lower temperatures and better low-temperature activity.