Engineering surface defects on metal oxide supports could help promote the dispersion of active sites and catalytic performance of supported catalysts. Herein, a strategy of ZrO 2 doping was proposed to create rich surface defects on CeO 2 (CZO) and, with these defects, to improve Pt dispersion and enhance its affinity as single sites to the CZO support (Pt/CZO). The strongly anchored Pt single sites on CZO support were initially not efficient for catalytic oxidation of CO/C 3 H 6 . However, after a simple activation by H 2 reduction, the catalytic oxidation performance over Pt/CZO catalyst was significantly boosted and better than Pt/CeO 2 . Pt/CZO catalyst also exhibited much higher thermal stability. The structural evolution of Pt active sites by H 2 treatment was systematically investigated on aged Pt/CZO and Pt/CeO 2 catalysts. With H 2 reduction, ionic Pt single sites were transformed into active Pt clusters. Much smaller Pt clusters were created on CZO (ca. 1.2 nm) than on CeO 2 (ca. 1.8 nm) due to stronger Pt-CeO 2 interaction on aged Pt/CZO. Consequently, more exposed active Pt sites were obtained on the smaller clusters surrounded by more oxygen defects and Ce 3+ species, which directly translated to the higher catalytic oxidation performance of activated Pt/CZO catalyst in vehicle emission control applications.
Strong metal−support interactions (SMSIs) have a significant effect on the performance of supported noble-metal catalysts for volatile organic compound (VOC) elimination. Herein, the strength of the SMSI of Pt/OMS-2 between Pt and the OMS-2 support is regulated by simply changing calcination temperatures, and the catalyst calcined at 300 °C (Pt/OMS-2-300) performs the best in the catalytic combustion of toluene. Through systematic structural characterizations, it is revealed that much more Pt 2+ −O v −Mn δ+ species are formed in Pt/OMS-2-300, which can help facilitate the generation of more reactive oxygen species and promote lattice oxygen mobility. Moreover, the results of in situ DRIFTS experiments further confirm that abundant Pt 2+ −O v − Mn δ+ species at the Pt−MnO 2 interface on Pt/OMS-2-300 can better enhance the adsorption and activation of toluene, thus boosting the catalytic performance in toluene combustion. This newly developed strategy of thermal-driven regulation of the SMSI provides a novel perspective for constructing highly efficient catalysts for VOC emission control.
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