Bohigues Benjamin, Rojas-Buzo Sergio, Salusso Davide, Xia Yu, Corma Avelino, Bordiga Silvia, Boronat Mercedes, Willhammar Tom, Moliner Manuel, Serna Pedro
Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, València, Spain.
Department of Chemistry and NIS Centre, University of Turin, Via Giuria 7, Turin, Italy.
Nat Commun. 2025 Aug 12;16(1):7451. doi: 10.1038/s41467-025-62726-6.
The use of redox active metal oxides to support noble metals is critical in the design of highly-active CO oxidation catalysts for gas emissions control. Unfortunately, supports promoting the activity, such as CeO, tend also to promote acute catalyst deactivation by turning highly-active metallic Pt clusters into less-active PtO species, under practical reaction conditions (high-temperature and/or the excess of O). This leads to a problematic activity/stability tradeoff where Pt/CeO catalysts, highly-active, and Pt on non-reducible supports, highly stable, are bookends. Herein, we report a method to trap Pt at V-shaped pockets/stepped sites of CeO that break this undesired correlation by showing both high activity and stability in the CO oxidation reaction. XAS, CO-DRIFT, XPS, HAADF-STEM, and DFT are used to infer that the generation of low order metallic Pt clusters connected to two crystallographic planes of the support is key to inhibit (deactivating) re-oxidation paths of the metal, as a result of the high-energy required to form disordered/distorted PtO ensembles at these positions. This new material allows, thus, to operate outside the commonly observed, limiting, activity/stability tradeoff.
在设计用于气体排放控制的高活性一氧化碳氧化催化剂时，使用氧化还原活性金属氧化物负载贵金属至关重要。不幸的是，在实际反应条件（高温和/或氧气过量）下，促进活性的载体（如CeO）往往也会促使高活性的金属Pt簇转变为活性较低的PtO物种，从而导致催化剂急剧失活。这导致了一个有问题的活性/稳定性权衡，其中高活性的Pt/CeO催化剂和非还原性载体上的高稳定性Pt处于两端。在此，我们报告了一种将Pt捕获在CeO的V形口袋/台阶位点的方法，该方法通过在一氧化碳氧化反应中表现出高活性和稳定性打破了这种不期望的相关性。利用X射线吸收光谱（XAS）、一氧化碳漫反射红外傅里叶变换光谱（CO-DRIFT）、X射线光电子能谱（XPS）、高角度环形暗场扫描透射电子显微镜（HAADF-STEM）和密度泛函理论（DFT）推断，与载体的两个晶面相连的低阶金属Pt簇的生成是抑制金属（失活）再氧化路径的关键，因为在这些位置形成无序/扭曲的PtO组合需要高能量。因此，这种新材料能够在常见的、有限的活性/稳定性权衡之外运行。
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