Highly selective ammonia oxidation to nitric oxide over supported Pt nanoparticles

Tailored Pt nanoparticles were prepared in strong alkaline ethylene glycol solution and deposited on α-Al2O3, γ-Al2O3, and CeO2–TiO2. The resulting supported catalytic materials were applied for ammonia oxidation between 473 and 1073 K in the temporal analysis of products reactor. Although the catalysts possessed only 0.005 wt.% Pt, they were active and selective for nitric oxide formation. The NO selectivity obtained over Pt/CeO2–TiO2 between 873 and 1073 K was around 98% and exceeded that of industrially relevant Pt wire. Both alumina-supported catalysts were less selective. Pt/CeO2–TiO2 also showed the highest NO selectivity in steady-state ambient pressure tests. The superior performance of Pt/CeO2–TiO2 is related to a synergy effect between the noble metal and the support since they provide adsorbed and lattice oxygen species for selective NH3 oxidation to NO in a complementary fashion.

Supported catalysts possessing very low amount (0.005 wt.%) of Pt as nanoparticles (NP) show high activity and selectivity for NH3 oxidation to NO. The selectivity is determined by the ability of NP and supporting material for providing adsorbed and lattice oxygen for NH3 activation in a complementary fashion.Figure optionsDownload high-quality image (87 K)Download as PowerPoint slideHighlights
► Supported Pt nanoparticles (NP) are active and selective for NH3 oxidation to NO.
► NO selectivity is strongly influenced by supporting material.
► NO selectivity obtained over Pt/CeO2–TiO2 exceeds that of Pt wire.
► Oxygen species adsorbed on Pt NP and lattice oxygen of support oxidize NH3 to NO.