Catalysts for Methane Oxidation in the Presence of SO₂

Natural gas is an interesting fuel for ships in coastal zones, where high sulfur marine fuels cannot be used. However, slip of unburnt methane from the engine poses another emission problem, as CH4 is a green-house gas with an atmospheric potential 26-28 times that of CO2 [1] and it should be mitigated from the exhaust gas.

Catalytic oxidation of CH4 to CO2 and H2O in the after treatment system can be a promising solution, but an efficient catalyst that remains sufficiently active under real exhaust gas conditions (350-550 °C, 5-10 vol.% H2O and 1-2 ppm SO2) is still being sought with the inhibition from SO2 being a major issue.

In this contribution, Rh and Pd were studied as promising active materials distributed on three different supports, i.e. zeolite (ZSM-5), silica, and alumina.