Negatively Charged Single-Atom Pt Catalyst Shows Superior SO2 Tolerance in NOx Reduction by CO

Pt-based catalysts are promising for the selective catalytic reduction of NOx by CO (CO-SCR), but some technical issues hinder their practical application, including the high Pt loading needed, high reduction temperature, and the low tolerance toward SO2. Here, we report a novel Pt catalyst for CO-SCR, which has negatively charged single-atom Pt embedded on CuO squares, and the latter is supported on CoAlO nanosheets. This Pt-CuO/CoAlO catalyst with an ultra-low Pt loading (0.02 wt %) exhibited 91% NO conversion and 80% N-2 selectivity in 3% O-2 at 200 degrees C. More importantly, it showed almost no activity loss in 200 ppm SO2 over a 15 h test. The theoretical calculations reveal that the negatively charged Pt has a stronger NO adsorption ability than the positively charged Pt, and Cu serves as the CO adsorption site. The much-weakened SO2 adsorption on Pt-CuO/CoAlO relative to the NO and CO adsorption effectively avoids the catalyst poisoning by SO2.

Automated summary

This study reports a novel Pt catalyst for CO-SCR, which consists of negatively charged single-atom Pt embedded on CuO squares supported on CoAlO nanosheets. This catalyst showed excellent performance in terms of NO conversion, N-2 selectivity, and tolerance toward SO2 poisoning, owing to the unique structure and electronic properties.