(60f) Deconvoluting Transient Water Effects on the Activity of Pd Methane Combustion Catalysts

Methane (CH₄) catalytic combustion is a crucial reaction to remove unburned methane emitted from natural gas power plant or engines. The activation of CH₄ and complete oxidation to CO₂ and H₂O at low temperatures require a highly active catalyst due to the strongest C–H bond in CH₄ among all hydrocarbons. Supported Pd is well-known as the best material for methane combustion at a relatively low temperature. Unfortunately, water, one of the reaction products, dramatically hinders the activity of Pd catalysts at temperatures below 450 °C, since water adsorption on Pd is favored over its desorption. Furthermore, water accumulated on the support surface have been shown to block the oxygen transfer between Pd and support and deactivate the catalyst. In this work, we demonstrate that pre-treatment and thermal history of a sample can heavily affect catalyst performance studies in a predictable way due to water adsorption-desorption phenomena.