(157b) Thermally Stable, Regenerable Single Atom Catalysts Via Atom Trapping

Thermally Stable, Regenerable Single Atom Catalysts
via Atom Trapping

Abhaya Datye

University
of New Mexico, Albuquerque, NM, USA

Single atom catalysts show great promise in terms of
efficient utilization of precious metals, improved reactivity and selectivity. 
However, single atom catalysts can deactivate due to sintering and formation of
nanoparticles when the catalyst is exposed to harsh reaction conditions. 
Stabilization of single atom catalysts and their regeneration requires suitable
trapping sites on the catalyst support.  Our work has focused on alumina
supports, which are extensively used in industrial catalysis. 

In recent work we found that La-stabilized alumina was able
to stabilize atomically dispersed Pd, leading to high activity for CO oxidation[1]. 
The Pd when atomically dispersed is bound to the alumina through surface oxygen
atoms on the alumina surface.  Lanthanum oxide which is added to alumina to
stabilize the support helps to anchor the atomically dispersed Pd, making it
possible to regenerate the catalyst. In the case of the Pt-Sn/alumina
catalysts, we noticed a similar behavior, where the presence of Sn in
atomically dispersed form on the alumina made it possible to regenerate the
catalyst and restore catalyst activity and selectivity [2]. 
The Pt/alumina treated under similar conditions could not be regenerated to a
significant extent.  The major difference between these two catalysts is the
presence of atomically dispersed Sn which is stable after multiple cycles of
propane dehydrogenation and provides sites for trapping the Pt [2]. 

This lecture will provide additional examples how atom
trapping can help in the generation of single atom catalysts that are thermally
stable and regenerable. 

References

[1] E.J. Peterson, A.T. DeLaRiva, S. Lin, R.S. Johnson, H. Guo, J.T. Miller, J. Hun
Kwak, C.H.F. Peden, B. Kiefer, L.F. Allard, F.H. Ribeiro, A.K. Datye,
Low-temperature carbon monoxide oxidation catalysed by regenerable atomically
dispersed palladium on alumina, Nat Commun, 5 (2014).

[2] H.N. Pham, J.J.H.B. Sattler, B.M. Weckhuysen,
A.K. Datye, Role of Sn in the Regeneration of Pt/γ-A_l2O₃
Light Alkane Dehydrogenation Catalysts, ACS Catal., 10.1021/acscatal.5b02917 
(2016).