Functional CeOx nanoglues for robust atomically dispersed catalysts
Functional CeOx nanoglues for robust atomically dispersed catalysts
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DOI：
10.1038/s41586-022-05251-6
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发表时间：
2022-10-26
期刊：
影响因子：
64.8
通讯作者：
Liu, Jingyue
中科院分区：
文献类型：
--
作者：
Li, Xu;Pereira-Hernandez, Xavier Isidro;Liu, Jingyue
单原子催化剂(1)特别有效地利用了昂贵的贵金属，并能产生独特的性能（1-3）。然而，应用通常受到有限的催化剂稳定性的影响，这是由于烧结（3,4）。虽然通过将金属原子锚定在氧化物载体上可以抑制烧结（1,5,6），但强金属-氧相互作用通常会留下太少的金属位点用于反应物结合和催化（6,7），并且当暴露在足够高的还原条件下时，即使是氧化物锚定的单原子催化剂最终也会烧结（4,8,9）。本研究表明，通过将原子分散的金属原子限制在氧化物纳米团簇或“纳米胶”上，可以增强锚定的有益效果，而氧化物纳米团簇或“纳米胶”本身分散并固定在坚固的高表面积支撑上。我们演示了将分离的和有缺陷的CeOx纳米胶岛接枝到高表面积的SiO2上的策略；纳米胶将每个寄主平均隔离一个铂原子。我们发现Pt原子在高温氧化和还原环境下都保持分散，并且活性催化剂的CO氧化活性显著提高。我们将还原条件下稳定性的提高归因于支撑结构和Pt原子对CeOx的亲和力比对SiO2的亲和力强得多，这确保了Pt原子可以移动，但仍然局限于各自的纳米胶岛。使用功能纳米胶来限制原子分散的金属并同时增强其反应性的策略是普遍的，我们预计这将使单原子催化剂更接近实际应用。
Single-atom catalysts(1) make exceptionally efficient use of expensive noble metals and can bring out unique properties(1-3). However, applications are usually compromised by limited catalyst stability, which is due to sintering(3,4). Although sintering can be suppressed by anchoring the metal atoms to oxide supports(1,5,6), strong metal-oxygen interactions often leave too few metal sites available for reactant binding and catalysis(6,7), and when exposed to reducing conditions at sufficiently high temperatures, even oxide-anchored single-atom catalysts eventually sinter(4,8,9). 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.