Paul Scherrer Institut (PSI), CH-5232, Villigen, Switzerland.
ETH Zurich, Institute for Chemical and Bioengineering, CH-8093, Zurich, Switzerland.
Nat Commun. 2018 Jun 29;9(1):2545. doi: 10.1038/s41467-018-04748-x.
Increasing the use of natural gas engines is an important step to reduce the carbon footprint of mobility and power generation sectors. To avoid emissions of unburnt methane and the associated severe greenhouse effect of lean-burn engines, the stability of methane oxidation catalysts against steam-induced sintering at low temperatures (<500 °C) needs to be improved. Here we demonstrate how the combination of catalyst development and improved process control yields a highly efficient solution for complete methane oxidation. We design a material based on palladium and hierarchical zeolite with fully sodium-exchanged acid sites, which improves the support stability and prevents steam-induced palladium sintering under reaction conditions by confining the metal within the zeolite. Repeated short reducing pulses enable the use of a highly active transient state of the catalyst, which in combination with its high stability provides excellent performance without deactivation for over 90 h in the presence of steam.
提高天然气发动机的使用量是减少移动和发电领域碳足迹的重要步骤。为了避免未燃烧的甲烷排放和贫燃发动机相关的严重温室效应，需要提高甲烷氧化催化剂在低温（<500°C）下抗蒸汽诱导烧结的稳定性。在这里，我们展示了如何通过催化剂开发和改进的工艺控制相结合，为完全甲烷氧化提供高效解决方案。我们设计了一种基于钯和具有完全钠离子交换酸位的分级沸石的材料，该材料通过将金属限制在沸石内，提高了载体的稳定性并防止了反应条件下蒸汽诱导的钯烧结。重复的短还原脉冲使催化剂能够利用高度活跃的瞬态，这种高度活跃的瞬态与高稳定性相结合，在存在蒸汽的情况下提供了超过 90 小时的出色性能，而不会失活。
