Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA, USA.
Department of Earth System Science, Stanford University, Stanford, CA, USA.
Nat Mater. 2022 Nov;21(11):1290-1297. doi: 10.1038/s41563-022-01376-1. Epub 2022 Oct 24.
Stable catalysts are essential to address energy and environmental challenges, especially for applications in harsh environments (for example, high temperature, oxidizing atmosphere and steam). In such conditions, supported metal catalysts deactivate due to sintering-a process where initially small nanoparticles grow into larger ones with reduced active surface area-but strategies to stabilize them can lead to decreased performance. Here we report stable catalysts prepared through the encapsulation of platinum nanoparticles inside an alumina framework, which was formed by depositing an alumina precursor within a separately prepared porous organic framework impregnated with platinum nanoparticles. These catalysts do not sinter at 800 °C in the presence of oxygen and steam, conditions in which conventional catalysts sinter to a large extent, while showing similar reaction rates. Extending this approach to Pd-Pt bimetallic catalysts led to the small particle size being maintained at temperatures as high as 1,100 °C in air and 10% steam. This strategy can be broadly applied to other metal and metal oxides for applications where sintering is a major cause of material deactivation.
稳定的催化剂对于解决能源和环境挑战至关重要，特别是在恶劣环境下的应用（例如高温、氧化气氛和蒸汽）。在这些条件下，负载型金属催化剂会由于烧结而失活——这是一个初始小纳米颗粒生长成具有较小活性表面积的较大颗粒的过程——但稳定它们的策略可能会导致性能下降。在这里，我们报告了通过将铂纳米颗粒封装在氧化铝骨架内制备的稳定催化剂，氧化铝骨架是通过在浸渍有铂纳米颗粒的多孔有机骨架内沉积氧化铝前体制备的。这些催化剂在氧气和蒸汽存在的 800°C 下不会烧结，而传统催化剂在这种条件下会烧结到很大程度，同时表现出相似的反应速率。将这种方法扩展到 Pd-Pt 双金属催化剂，在空气中高达 1100°C 和 10%蒸汽的温度下，仍能保持小颗粒尺寸。这种策略可以广泛应用于其他金属和金属氧化物，以解决烧结是材料失活的主要原因的问题。
