High Silica Pd/Catalysts with Enhanced Low Temperature Methane Oxidation Performance

Background:

Natural gas has garnered attention as a cleaner alternative fuel for vehicles compared to gasoline or diesel.  Natural gas vehicle (NGV) exhaust contains methane (CH₄) which is 25 times more harmful than carbon dioxide (CO₂) in global warming potential.  The conventional solution for CH₄ remediation is its catalytic oxidation using Pd/Al₂O₃ catalysts.  However, Pd/Al₂O₃ catalysts suffer from low conversions and deactivation through Pd sintering in typical exhausts of natural gas vehicles containing high amounts of water vapor (5-10%) at low temperatures (< 400ºC).

Technology Overview:

A promising support alternative for Pd/Al₂O₃ catalysts are zeolites that can act as molecular sieves through size limiting pores to restrict  Pd sintering.  Moreover, the hydrophobicity of zeolites can be increased by increasing the Si content to prevent water inhibition.  University at Buffalo and Syracuse University researchers have developed small-pore H-CHA (Si/Al > 137) and H-LTA (Si/Al > 39)  zeolites loaded with 1 wt.% Pd to achieve low temperature CH₄ oxidation performance.

Advantages:

• >90% CH₄ conversion below 400ºC in simulated natural gas exhaust feed.
• 100% CH₄ conversion at 450^ºC for more than 10 hours compared to 70% conversion over conventional Pd/Al₂O₃.

Applications:

• Catalytic converters for methane oxidation natural gas vehicles.
• Carbon monoxide (CO), hydrocarbon (HC) oxidation, and nitrogen oxide (NO) reduction (three-way catalysts) for diesel and gasoline vehicles.
• Catalytic converter for stationary natural gas engines or diesel engines.
• Catalytic converter for marine vessels.
• Steam or dry reforming of CH₄ to syngas.

Intellectual Property Summary:

• Provisional Patent Application 63/406,832 filed on September 15, 2022.

Stage of Development:

• Lab scale demonstration.

Licensing Status:

• Available for licensing and joint development.