Kim Jae Hyung, Yoon Sinmyung, Baek Du San, Kim Jihun, Kim Jinjong, An Kwangjin, Joo Sang Hoon
School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea.
Clean Fuel Research Laboratory, Korea Institute of Energy Research, 152 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea.
JACS Au. 2022 May 26;2(8):1811-1817. doi: 10.1021/jacsau.2c00090. eCollection 2022 Aug 22.
Os-based catalysts present remarkable catalytic activity; however, their use has been limited by the undesirable side reactions that generate highly toxic and volatile OsO even at room temperature. Herein, we demonstrate that the thermal stability of Os-based catalysts can be dramatically improved by downsizing Os nanoparticles (NPs) into atomically dispersed species. We observed that Os NPs were converted into OsO after calcination at 250 °C followed by sublimation, whereas single Os sites retained their structure after calcination. Temperature-programmed oxidation analysis confirmed that Os NPs started to undergo oxidation at 130 °C, whereas atomically dispersed Os preserved its state up to 300 °C. The CO oxidation activity of the atomically dispersed Os catalyst at 400 °C (100% conversion) was stably preserved over 30 h. By contrast, the activity of Os NP catalyst declined drastically. This study highlights the unique catalytic behavior of atomically dispersed catalysts, which is distinct from that of NP-based catalysts.
基于锇的催化剂具有显著的催化活性；然而，其应用受到了不良副反应的限制，即使在室温下也会产生剧毒且易挥发的四氧化锇。在此，我们证明通过将锇纳米颗粒（NPs）缩小为原子分散物种，可以显著提高基于锇的催化剂的热稳定性。我们观察到，在250°C煅烧后升华，锇纳米颗粒会转化为四氧化锇，而单个锇位点在煅烧后保留了其结构。程序升温氧化分析证实，锇纳米颗粒在130°C开始发生氧化，而原子分散的锇在300°C之前保持其状态。原子分散的锇催化剂在400°C时的CO氧化活性（100%转化）在30小时内稳定保持。相比之下，锇纳米颗粒催化剂的活性急剧下降。这项研究突出了原子分散催化剂独特的催化行为，这与基于纳米颗粒的催化剂不同。
