(694e) The Migration of Pt and Its Application in the Activation of C-H Bonds of Ethane

The shale-gas boom in US provides an opportunity to develop advanced catalysts and processes to enable the direct conversion of light alkanes, major constituents of shale-gas, into value-added chemicals, in which C-H bond activation is the key step. We have developed advanced catalysts, which consist of atomically dispersed Pt species supported on zeolite or alumina, for the activation of C-H bonds of ethane. The supported atomically dispersed Pt species can be prepared through the migration and re-distribution of Pt upon different post-synthesis treatments. By using different supports, ethane can be selectively converted to ethylene or aromatics, and the latter is of great industrial importance.¹

We have found that atomically dispersed Pt species anchored in micropores of zeolite can catalyze the direct conversion of ethane to aromatics. We can achieve >60% conversion of ethane with the BTX selectivity > 60%, under selected reaction conditions. The atomically dispersed catalysts have attracted significant scientific attention recently, owing to the high atom efficiency that these catalysts can achieve, but also improve the selectivity of certain reactions. However, it is usually a challenge task to prepare this type of catalysts.^2,3 Recently, Datye and co-authors have reported that the migration and trapping of Pt upon aging in air can be used to synthesize single-atom Pt catalysts.⁴ However, this synthesis must be performed at a rather high temperature (800 °C) for 10 hours. We have developed a novel approach to prepare atomically dispersed Pt species anchored in micropores of zeolite, through the migration and re-distribution of Pt, promoted by post-synthesis treatments with various gases under relatively mild conditions. The atomically dispersed Pt species consist of isolated Pt single atoms and subnanometer Pt nanoclusters, which are exceptional active for the C-H bond activation of ethane. Such atomically dispersed Pt species anchored in micropores of zeolite is extremely stable against high temperature treatments up to 650 °C. This approach for the preparation of atomically dispersed catalysts, through the migration and re-distribution, may have wide applications in heterogeneous catalysis.

References

1. Y. Xiang, H. Wang, J. Cheng, J. Matsubu, Catal. Sci. Technol., 8 (2018) 1500-1516.
2. L. Liu, U. Díaz, R. Arenal, G. Agostini, P. Concepción, A. Corma, Nature Mater., 16 (2017) 132-138.
3. J. Shan, M. Li, L. F. Allard, S. Lee, and M. Flytzani-Stephanopoulos, Nature, 551 (2017) 605-608.
4. J. Jones, H. Xiong, A. T. DeLaRiva, E. J. Peterson, H. Pham, S. R. Challa, G. Qi, S. Oh, M. H. Wiebenga, X. I. P. Hernández, Y. Wang, A. K. Datye, Science, 353 (2016) 150-154.