Jeong Hojin, Shin Dongjae, Kim Beom-Sik, Bae Junemin, Shin Sangyong, Choe Chanyeong, Han Jeong Woo, Lee Hyunjoo
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea.
Angew Chem Int Ed Engl. 2020 Nov 9;59(46):20691-20696. doi: 10.1002/anie.202009776. Epub 2020 Sep 3.
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 (Pt : 16.6 at %) to highly metallic states (Pt : 83.8 at %). The Pt SACs with controlled oxidation states were then employed for oxidation of CO, CH , 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.
单原子催化剂（SACs）已成为多相催化领域中颇具前景的材料。先前的研究报道了关于SACs和纳米颗粒（NPs）活性相对水平的有争议结果。这些研究主要关注金属原子排列的影响，而未考虑SACs的氧化态。在此，我们将Pt单原子固定在缺陷氧化铈上，并控制Pt SACs的氧化态，从高氧化态（Pt：16.6 at %）到高金属态（Pt：83.8 at %）。然后将具有可控氧化态的Pt SACs用于CO、CH或NO的氧化反应，并将它们的活性与Pt NPs的活性进行比较。高氧化态的Pt SACs表现出比Pt NPs更差的活性，而金属态的Pt SACs则显示出更高的活性。在300 °C下还原的Pt SAC对所有氧化反应均表现出最高活性。具有可控氧化态的Pt SACs揭示了活性与SACs之间一个关键的缺失环节。
