Influence of Titania Synthesized by Pulsed Laser Ablation on the State of Platinum during Ammonia Oxidation

Andrey Stadnichenko, Dmitry Svintsitskiy, Lidiya Kibis, Elizaveta Fedorova, Olga Stonkus, Elena Slavinskaya, Ivan Lapin, Elena Fakhrutdinova, Valery Svetlichnyi, Anatoly Romanenko, Dmitry Doronkin, Vasyl Marchuk (+2 others)
2020
A set of physicochemical methods, including X-ray photoelectron spectroscopy (XPS), X-ray diffraction, electron microscopy and X-ray absorption spectroscopy, was applied to study Pt/TiO$_{2}$ catalysts prepared by impregnation using a commercial TiO$_{2}$-P25 support and a support produced by pulsed laser ablation in liquid (PLA). The Pt/TiO$_{2}$-PLA catalysts showed increased thermal stability due to the localization of the highly dispersed platinum species at the intercrystalline boundaries
more » ... f the support particles. In contrast, the Pt/TiO$_{2}$-P25 catalysts were characterized by uniform distribution of the Pt species over the support. Analysis of Pt4f XP spectra shows that oxidized Pt$^{2+}$ and Pt$^{4+}$ species are formed in the Pt/TiO$_{2}$-P25 catalysts, while the platinum oxidation state in the Pt/TiO$_{2}$-PLA catalysts is lower due to stronger interaction of the active component with the support due to strong interaction via Pt-O-Ti bonds. The Pt4f XP spectra of the samples after reaction show Pt$^{2+}$ and metallic platinum, which is the catalytically active species. The study of the catalytic properties in ammonia oxidation showed that, unlike the catalysts prepared with a commercial support, the Pt/TiO$_{2}$-PLA samples show higher stability during catalysis and significantly higher selectivity to N$_{2}$ in a wide temperature range of 200–400 °C.
doi:10.5445/ir/1000121095 fatcat:zckvjhyw5feutefzpxq7eyaw54