Maximizing catalytic activity and stability of platinum catalysts

Supported Pt catalysts are widely used industrially for elimination of harmful volatile compounds, with applications such as H2-SCR (selective catalytic reduction), CO oxidation, NO oxidation, ammonia oxidation (AMOX) as well as unsaturated hydrocarbon hydrogenation for pharmaceutical and organic chemistry. Typical catalysts use high loadings of PGM (typically ~2-5 wt%) to achieve high activity. However, decreasing PGM loading to 1 wt% and below, while maintaining high activity and stability, is needed since the materials with lower loadings of Pt are known to be inferior catalysts. We show that at low Pt loadings the size of particles is small, and they are fully oxidized, which inhibits their activity and stability. We further show that we can circumvent this bottleneck and maximize the activity and stability of Pt catalysts via a simple high-temperature thermal pre-treatment that unexpectedly yields 3D metallic Pt particles that are stable and active. The corresponding catalytic activity of these catalysts with the maximized number of active surface sites, consisting of oxidation-resistant metallic Pt surfaces, rivals the formulations with significantly higher Pt amounts (~6 times) for multiple industrially relevant reactions (H2-SCR, CO oxidation, NO oxidation, AMOX, unsaturated hydrocarbon hydrogenation). Using catalytic measurements, microscopy, and spectroscopy, we provide the atomic level insight into the active ensembles of these catalysts and a general strategy maximize the activity of platinum.