The Effect of Zeolite Counter Ion on a Pd/H-CHA Methane Oxidation Catalyst with Remarkable Tolerance Towards SO2

Abstract Zeolites are investigated for complete methane oxidation to reduce sintering and deactivation of the active PdO nanoparticles. Pd/H-CHA is shown to have good low-temperature activity and remarkable tolerance to SO 2 . After an induction period with loss of activity, the activity is recovered and the catalyst withstands more than 200 h on stream with 1000 ppm methane in the presence of 2 ppm SO 2 . The zeolite counter ions play a key role, and the literature indicates that ion exchange with alkali metals provides better water tolerance. Here we show, however, that the alkali ion exchanged Pd-CHA possess inferior sulfur tolerance compared to the parent Pd/H-CHA since the recovery of the catalytic effect is blocked. Deactivation by simultaneous SO 2 and water remains an unsolved challenge for complete methane oxidation catalysts. Graphical abstract A Pd/CHA catalyst for methane oxidation is shown to have remarkable resistance towards SO 2 in the feed gas and to lose it upon ion exchange with alkali metal ions.