Browse Publications Technical Papers 2013-01-2591

Pt/Pd Bimetallic Catalyst with Improved Activity and Durability for Lean-Burn CNG Engines 2013-01-2591

Compressed natural gas (CNG) has been regarded as an alternative fuel for current fossil fuels such as gasoline and diesel. Recently the increasing interest in shale gas is drawing more attention to CNG vehicles of which number is expected to increase.
Exhaust gas from CNG engines with lean combustion contains relatively low nitrogen oxides and particulate matters compared to conventional fossil fuel based engines. However, high amount of unburned methane, which has much higher greenhouse warming potential than CO2, limits the wide use of CNG for many applications. Even though Pd-based catalysts have been popularly studied in order to convert methane, their activity and durability have not been sufficient for practical applications to aftertreatment of lean burn CNG engines and the formation of a new Pd containing.
In the present study, we developed an improved Pd-based catalyst for CNG engines by introducing Pt and promoters to enhance methane oxidation activity at low temperature and long term durability. Pt was more active to oxidize paraffinic hydrocarbons that comprise ∼10% of total hydrocarbons in exhaust gas from lean burn CNG engines. Exotherm resulting from the paraffinic hydrocarbon oxidation by Pt could promote the remaining methane oxidation by Pd. Furthermore, potential causes for the deactivation of Pd-based catalyst were investigated from the various points of Pd-sintering by high temperature exposure, PdO decomposition, sulfation and coking, and the formation of new Pd containing compound. Optimal use of support material for Pd/Pt and promoters to keep Pd stable were identified as key factors for the design of more active and durable catalyst.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 16% off list price.
Login to see discount.
We also recommend:

Catalyst Development for Stoichiometric and Lean Bum Natural Gas Engines


View Details


Oxidation Catalysts for Natural Gas Engine Operating under HCCI or SI Conditions


View Details


Evaluation of 3-Way Catalytic Converters for the Reduction of CH4 in the Exhaust Stream of a CNG Fueled Vehicle


View Details