One-pot synthesis of stable cationic gold species highly active in the CO oxidation confined into mordenite-like zeolite

The presence of cationic gold species is a key factor for the CO oxidation over the supported gold catalysts based on non-reducible metal oxides. The deactivation of such catalysts is mainly associated with the Au nanoparticles (AuNPs) sintering and the concomitant reduction of cationic Au species. Here we report the high catalytic stability at the CO oxidation of the cationic Au species confined into a mordenite-like zeolite matrix prepared by a one-pot synthesis method. The sample with lowest Au loading (0.32 % wt.) exhibited the higher catalytic performance and stability during CO oxidation. Detailed FTIR analysis showed that the CO oxidation on sample with low Au content (0.32 wt%) occurred preferentially via CO interaction with the cationic interface Au-hydroxyl (Au1+-OH- ) species to produce CO2(g) via decarboxylation. In contrast, the sample with a high Au content (1.56 wt%) displayed lower CO oxidation ability, which was associated with a low content and less stability of cationic gold species. Proposed synthesis method permits to obtain in a one-pot way stable cationic gold species highly effectively for the CO oxidation.

Automated summary

The presence of cationic gold species is crucial for the CO oxidation over non-reducible metal oxide-supported gold catalysts, and the deactivation of such catalysts is mainly due to the sintering of Au nanoparticles and the reduction of cationic Au species. In this study, we report the high catalytic stability of cationic Au species confined in a mordenite-like zeolite matrix prepared by a one-pot synthesis method for CO oxidation. The sample with the lowest Au loading (0.32 wt%) exhibited the highest catalytic performance and stability during CO oxidation.