Enhancing Activity and Stability of Pd-on-TiO2 Single-Atom Catalyst for Low-Temperature CO Oxidation through in Situ Local Environment Tailoring

• Published in: Journal of the American Chemical Society 2024-10, Vol.146 (41), p.28141-28152
• Main Authors: Lu, Yubing, Lin, Fan, Zhang, Zihao, Thompson, Coogan, Zhu, Yifeng, Doudin, Nassar, Kovarik, Libor, García Vargas, Carlos E., Jiang, Dong, Fulton, John L., Wu, Yiqing, Gao, Feng, Dohnálek, Zdenek, Karim, Ayman M., Wang, Huamin, Wang, Yong
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/jacs.4c07861

The development of efficient Pd single-atom catalysts for CO oxidation, crucial for environmental protection and fundamental studies, has been hindered by their limited reactivity and thermal stability. Here, we report a thermally stable TiO2-supported Pd single-atom catalyst that exhibits enhanced intrinsic CO oxidation activity by tunning the local coordination of Pd atoms via H2 treatment. Our comprehensive characterization reveals that H2-treated Pd single atoms have reduced nearest Pd–O coordination and form short-distanced Pd–Ti coordination, effectively stabilizing Pd as isolated atoms even at high temperatures. During CO oxidation, partial replacement of the Pd–Ti coordination by O or CO occurs. This unique Pd local environment facilitates CO adsorption and promotes the activity of the surrounding oxygen species, leading to superior catalytic performance. Remarkably, the turnover frequency of the H2-treated Pd single-atom catalyst at 120 °C surpasses that of the O2-treated Pd single-atom catalyst and the most effective Pd/Pt single-atom catalysts by an order of magnitude. These findings open up new possibilities for the design of high-performance single-atom catalysts for crucial industrial and environmental applications.