Construction of relay reaction system by Co@S-1 and In-Ce/H-Beta for selective catalytic reduction of nitrogen oxides with methane

Selective catalytic reduction of nitrogen oxides with methane (CH4-SCR) is an effective way to simultaneously eliminate NOx and CH4 emissions. Development of efficient CH4-SCR reaction system with high NOx reduction activity and selectivity is highly desirable for its commercial application. Herein, a two-part relay reaction system, including sequentially Co@S-1 and In-Ce/H-Beta catalysts, is designed for boosting CH4-SCR. In this system, the Co@S-1 with high redox ability boosts NO oxidation to NO2 and generates key intermediate CH3NO2 that can partially be in situ oxidized and the excessive can migrate to In-Ce/H-Beta. Meanwhile, the inner synergistic effect between InO+ and CeO2 species on In-Ce/H-Beta not only exhibits fair CH4-SCR performance, also facilitates the formation of NO- 3 species to react with the migrated CH3NO2 from Co@S-1. Benefiting from the combination between outer active sites synergy and inner active sites synergy, the simultaneous efficient conversion of NOx (T50 = 380 ℃) and CH4 (T50 = 425 ℃) with well durability is achieved.