Yuanyuan Li: Multimodal approach for determining the electronic and atomic structure of ceria supported Pt single atoms catalyst

Single atoms catalysts (SACs) have been heavily investigated in the recent years because of their good catalytic properties (especially activity and selectivity) for many chemical reactions [1]. In addition to that, in SACs, the supported metals are used with extremely high efficiency compared to their nano counterparts. That is very important for noble metals, which are naturally scare yet widely used in industry for a vast number of important chemical reactions. Despite of the progress that has been made, there are fundamental questions remained unaddressed: what is the structure (electronic and atomic) that responsible for the improved catalytic properties? How does the structure respond to the reaction environment? Only by addressing these questions, are we able to improve synthesis processes to get desired catalysts.

The key to address the above-mentioned questions is the capability of characterizing the structure of single atoms catalysts. The challenge originates from: 1) for SACs, the weight loading of single atoms on the support is usually low, 2) the heterogeneity of the single atom sites owing to the surface heterogeneity of most solid supports, and 3) the complex structure of the single atoms system resulted from the strong correlation between the single atoms and the support. This work aimed to address those issues by developing synthesis methods for obtaining homogeneously distributed single atoms with high weight loadings and combining multiple experimental techniques (STEM, DRIFTS, XPS, RIXS, XAS) with calculation methods to study the electronic and atomic structure of single atoms with the presence of strong metal-support interactions. For demonstration, the specific system studied here is ceria supported Pt single atoms [2].

References:

1. A. Wang, J. Li, T. Zhang, Heterogeneous single-atom catalysis. Nature Reviews Chemistry 2, 65–81 (2018). https://doi.org/10.1038/s41570-018-0010-1
   
2. M. Kottwitz, Y. Li, R. M. Palomino, Z. Liu, Q. Wu, G. Wang, J. Huang, J. Timoshenko, S. D. Senanayake, M. Balasubramanian, D. Lu, R. G. Nuzzo, A. I. Frenkel, Local structure and electronic state of atomically dispersed Pt on nanosized CeO2 support, ACS Catalysis 9, 8738-8748 (2019). https://doi.org/10.1021/acscatal.9b02083