難題を解決：研究者が重要鉱物の使用量を減らしながら触媒を改良する新しい方法を発見 A sticky situation resolved: researchers discover a new method to improve catalyst while reducing critical mineral use
2022-10-26 アメリカ・パシフィック・ノースウェスト国立研究所(PNNL)
研究チームは、金属原子を二酸化ケイ素の支持体に固定された酸化セリウムの「島」上に注意深く配置することによって、この問題を解決しました。この構成により、個々の金属原子がしっかりと固定されるようになった。
この発見は、自動車の排ガス規制や、燃料、肥料などの生産など、さまざまな種類の産業応用に重要な意味を持つ可能性がある。
＜関連情報＞
- https://www.pnnl.gov/news-media/less-platinum-faster-chemical-reactions
- https://www.nature.com/articles/s41586-022-05251-6
機能性CeOxナノグルーを用いた堅牢な原子分散型触媒の開発 Functional CeOx nanoglues for robust atomically dispersed catalysts
Xu Li,Xavier Isidro Pereira-Hernández,Yizhen Chen,Jia Xu,Jiankang Zhao,Chih-Wen Pao,Chia-Yu Fang,Jie Zeng,Yong Wang,Bruce C. Gates & Jingyue Liu
Nature Published:26 October 2022
DOI:https://doi.org/10.1038/s41586-022-05251-6
Abstract
Single-atom catalysts1 make exceptionally efficient use of expensive noble metals and can bring out unique properties1,2,3. However, applications are usually compromised by limited catalyst stability, which is due to sintering3,4. Although sintering can be suppressed by anchoring the metal atoms to oxide supports1,5,6, strong metal–oxygen interactions often leave too few metal sites available for reactant binding and catalysis6,7, and when exposed to reducing conditions at sufficiently high temperatures, even oxide-anchored single-atom catalysts eventually sinter4,8,9. Here we show that the beneficial effects of anchoring can be enhanced by confining the atomically dispersed metal atoms on oxide nanoclusters or ‘nanoglues’, which themselves are dispersed and immobilized on a robust, high-surface-area support. We demonstrate the strategy by grafting isolated and defective CeOx nanoglue islands onto high-surface-area SiO2; the nanoglue islands then each host on average one Pt atom. We find that the Pt atoms remain dispersed under both oxidizing and reducing environments at high temperatures, and that the activated catalyst exhibits markedly increased activity for CO oxidation. We attribute the improved stability under reducing conditions to the support structure and the much stronger affinity of Pt atoms for CeOx than for SiO2, which ensures the Pt atoms can move but remain confined to their respective nanoglue islands. The strategy of using functional nanoglues to confine atomically dispersed metals and simultaneously enhance their reactivity is general, and we anticipate that it will take single-atom catalysts a step closer to practical applications.
