Deepak Kunwar, Shulan Zhou, Andrew DeLaRiva, Eric J Peterson, Haifeng Xiong, Sen Lin, Stephen C. Purdy, Rik ter Veen, Yong Wang, Abhaya K. Datye
University of New Mexico
Single atom catalysts have attracted attention because of improved atom efficiency, higher reactivity and better selectivity. A major challenge is to achieve high surface concentrations while preventing these atoms from agglomeration at elevated temperatures. Here we investigate the formation of Pt single atoms on an industrial catalyst support. Using a combination of surface sensitive techniques, density functional theory, X-ray absorption spectroscopy and electron microscopy, we demonstrate that cerium oxide can support Pt single atoms at high metal loading (3 wt% Pt), without forming any clusters or 3D aggregates. The mechanism of trapping involves a reaction of the mobile PtO2 with under-coordinated cerium cations present at step edges, allowing Pt to achieve a stable square planar configuration. These findings provide insight into the capture of mobile single atom species present during catalyst sintering and regeneration, helping explain the remarkable sinter-resistance of ceria supported metal catalysts.