Le Samantha L, O'Connor Christopher R, Kim Taek-Seung, Reece Christian
Rowland Institute at Harvard, Harvard University, Cambridge, MA, USA.
Department of Chemistry, Tufts University, Medford, MA, USA.
Angew Chem Int Ed Engl. 2025 Apr 1;64(14):e202423880. doi: 10.1002/anie.202423880. Epub 2025 Jan 28.
The dynamic response of heterogeneous catalytic materials to their environment opens a wide variety of possible surface states which may have increased catalytic activity. In this work, we find that it is possible to generate a surface state with increased catalytic activity over metallic 2 nm Pt nanoparticles by performing a thermal treatment of the CO*-covered Pt catalyst. This state is characterised by its ability to oxidise CO to CO at room temperature. By combining pressure pulse experiments with in situ spectroscopy we correlate the formation of this high-activity state with the desorption of weakly bound CO* molecules from well-coordinated Pt sites. This high-activity state is metastable, degrading after elevated thermal treatments or upon readsorption of CO at room temperature. We conclude that this metastable state is highly localised to the surface of the nanoparticle, however its exact atomic structure remains open to speculation.
多相催化材料对其环境的动态响应开启了多种可能的表面状态，这些表面状态可能具有增强的催化活性。在这项工作中，我们发现通过对覆盖有CO的Pt催化剂进行热处理，可以在2 nm的金属Pt纳米颗粒上产生具有增强催化活性的表面状态。这种状态的特征在于其在室温下将CO氧化为CO₂的能力。通过将压力脉冲实验与原位光谱相结合，我们将这种高活性状态的形成与弱结合的CO分子从配位良好的Pt位点解吸相关联。这种高活性状态是亚稳态的，在高温处理后或在室温下重新吸附CO时会降解。我们得出结论，这种亚稳态高度局限于纳米颗粒的表面，但其确切的原子结构仍有待推测。
