Effective catalytic decomposition of nitrous oxide over highly active and stable bimetallic CoIn-mordenite zeolite

Abstract

In this study, a bimetallic CoIn-mordenite (MOR) catalyst was prepared via simple wet ion exchange, and its ability to decompose nitrous oxide (N2O) was examined. The incorporation of a trace amount of In into Co-MOR catalyst greatly enhanced its catalytic activity and stability. CoIn-MOR decomposed more than 90% of N2O at 450 °C under simulated conditions of typical nitric acid emissions, and high activity was maintained for longer than 100 h under these strict conditions. The excellent activity of the bimetallic CoIn-MOR catalyst was attributed to strong synergistic effect between In and Co, which re-located cobalt oxides into β ion exchange sites. Those β-type Co ions are the most active sites for N2O decomposition due to the cooperation of N2O splitting by two neighboring Co ions in MOR. Higher amount of surface NOx species are in situ formed, which facilitate the removal of atom O and result in NO-assisted N2O decomposition and greatly improves the activity. Moreover, extended X-ray absorption fine structure analysis indicated that β-type Co ions exhibited stronger coordination to framework oxygens after. In addition, preventing their migration into CoOx clusters. Thus, high activity was maintained.