Negatively Charged Single-Atom Pt Catalyst Shows Superior SO<sub>2</sub> Tolerance in NO<sub><i>x</i></sub> Reduction by CO
Yongjun Ji, Shaomian Liu, Shaojia Song, Wenqing Xu, Liang Li, Yu Zhang, Wenxing Chen, Huifang Li, Jingang Jiang, Tingyu Zhu, Zhenxing Li, Ziyi Zhong, Dingsheng Wang, Guangwen Xu, Fabing Su
Abstract
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% 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. The much-weakened SO2 adsorption on Pt–CuO/CoAlO relative to the NO and CO adsorption effectively avoids the catalyst poisoning by SO2.