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

Pt-based catalysts are promising for the selective catalytic reduction of NO_x 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% N₂ selectivity in 3% O₂ at 200 °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.