Method for Preparing a Sintering Resistant Alkali Metal-Zeolite Supported Metal Catalyst for Methane Oxidation

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This patent describes a method for creating a highly stable and sintering-resistant metal catalyst, supported on an alkali-metal-exchanged zeolite, for the catalytic oxidation of methane. The invention's method involves forming nanocages in zeolites, removing acidic sites and extra-framework aluminum, loading with precious metals (such as palladium), and then neutralizing acid sites with alkali metals. The resulting material is resistant to degradation from sintering and dealumination, enabling sustained high catalytic activity, even in the presence of steam and at high temperatures.

Use CasesContent extracted from patent full text and abstract with AI.

• Exhaust gas aftertreatment systems for methane-fueled (natural gas) vehicles to reduce greenhouse gas emissions.
• Catalytic converters for power plants or generators burning natural gas or methane-rich biofuels.
• Industrial abatement of methane emissions from processes or chemical plants.
• Air purification systems handling trace methane leakage near landfills or biogas plants.
• Catalytic oxidation systems for safety management in environments with methane leakage or risk (e.g., mining, oil and gas).

BenefitsContent extracted from patent full text and abstract with AI.

• Highly improved catalyst stability at elevated temperatures and in steam-rich environments, reducing need for frequent replacement.
• Resistance to metal particle sintering and zeolite dealumination, preventing rapid deactivation and performance loss.
• Enhanced methane conversion efficiency, potentially lowering emissions of a potent greenhouse gas.
• Lower operational costs due to increased catalyst lifetime and reduced metal (precious metal) usage.
• Adaptation to harsh operating conditions typical for automotive, industrial, or power generation sectors.
• Enables the practical use of natural gas and biogas as cleaner fuels without exacerbating methane-related environmental risks.

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Patent Abstract

It is the objective of the present invention to provide a method for preparing a sintering resistant alkali-zeolite supported metal catalyst for catalytic methane oxidation that does not degrade by particle sintering and zeolite framework dealumination. This objective is achieved according to the present invention by a method for producing a precious metal/metal cation zeolite catalyst, hereinafter referred to as PM/MC-zeolite catalyst, for selective catalytic methane oxidation, comprising the steps of: a) treating a parent zeolite under desilication conditions in order to form mesopores (hereinafter referred to as nanocages) resulting in a desilicated zeolite; b) treating the desilicated zeolite in order to selectively extract extra-framework aluminum and surface framework aluminum, respectively, resulting in an acidic H-zeolite; c) loading the acidic H-zeolite with a precious metal compound by ion-exchange, impregnation or other technique and subsequent calcination resulting in an acidic PM/H-zeolite; d) neutralizing the strong acid sites of the PM/H-zeolite by a basic alkali metal salt or a base, and thus stabilize the precious metal within the nanocages of the zeolite. This method yields a hydrothermally stable sintering resistant methane oxidation catalyst. Both problems mentioned above are solved by the synthetic approach based on the removal of the acid sites of the parent PM/H-zeolite by post-exchanging it with an alkali cation, which resulted in capturing nano-sized PM particles within a zeolitic hierarchical structure and stabilization of the framework aluminum.