Sulfate-enhanced low-temperature activity of Pt/γ-Al2O3 for landfill gas deoxygen

Deoxygen is a crucial step for landfill gas (LFG) recycling and purification. Pt/γ-Al 2 O 3 is the most active catalyst for LFG deoxygen via catalytic methane oxidation . It is challenging but significant to further improve the performance of this type of catalyst. In regard of homogeneous and heterogeneous activation of methane by superacids , here we demonstrate LFG deoxygen via catalytic methane oxidation using a solid superacid catalyst, Pt/SO 4 2- /Al 2 O 3 , synthesized using pre-sulfated γ-Al 2 O 3 support by impregnated with sulfuric acid . In comparison to Pt/γ-Al 2 O 3 , Pt/SO 4 2- /Al 2 O 3 catalysts exhibit exceptionally improved activity and minimum complete O 2 conversion at a temperature of 264 ℃, a decrease of about 51 ℃. This value is superior to the state-of-the-art Pt-based deoxygen catalysts. Characterizations and theoretical calculations indicate that sulfation enhances the amount of acid sites on γ-Al 2 O 3 support and induces electron deficiency of the supported Pt species (+0.28|e|), thus boosting the low-temperature activity. Furthermore, the Pt/SO 4 2- /Al 2 O 3 catalyst maintained its initial activity after six runs without any detectable coke deposition. This discovery offers simple and effective strategies to precisely design higher performance application-oriented Pt based deoxygen catalysts.