Controlling the Oxidation State of Pt Single Atoms for Maximizing Catalytic Activity

• Published in: Angewandte Chemie International Edition Vol. 59; no. 46; pp. 20691 - 20696
• Main Authors: Jeong, Hojin, Shin, Dongjae, Kim, Beom‐Sik, Bae, Junemin, Shin, Sangyong, Choe, Chanyeong, Han, Jeong Woo, Lee, Hyunjoo
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 09.11.2020
• Edition: International ed. in English
• Subjects: Catalysis; Catalysts; Catalytic activity; ceria; Cerium oxides; CO oxidation; Nanoparticles; Oxidation; oxidation state; platinum; single-atom catalysts (SACs); Valence
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202009776

Single‐atom catalysts (SACs) have emerged as promising materials in heterogeneous catalysis. Previous studies reported controversial results about the relative level in activity for SACs and nanoparticles (NPs). These works have focused on the effect of metal atom arrangement, without considering the oxidation state of the SACs. Here, we immobilized Pt single atoms on defective ceria and controlled the oxidation state of Pt SACs, from highly oxidized (Pt0: 16.6 at %) to highly metallic states (Pt0: 83.8 at %). The Pt SACs with controlled oxidation states were then employed for oxidation of CO, CH4, or NO, and their activities compared with those of Pt NPs. The highly oxidized Pt SACs presented poorer activities than Pt NPs, whereas metallic Pt SACs showed higher activities. The Pt SAC reduced at 300 °C showed the highest activity for all the oxidations. The Pt SACs with controlled oxidation states revealed a crucial missing link between activity and SACs. The oxidation state of Pt single‐atom catalysts (SACs) was controlled from highly oxidized to highly metallic states by reducing Pt single atoms deposited on defective ceria at various temperatures. The optimum oxidation state of the Pt SAC was found for maximizing the catalytic activity for the oxidation of CO, CH4, and NO.