ES22-Fabusova

Author: Fabušová, Diana - Advanced Technologies Research Institute, Faculty of Materials Science and Technology in Trnava, Slovak University of Technology in Bratislava, 917 24 Trnava, Slovakia

Title: Ab Initio Study of Impact of Pressure and Temperature on Stability and Polymorphism of PdO2

Abstract: Palladium is an important catalyst in many catalytic reactions with a diversity of technological applications. Apart from the pure metal, catalytic activity is being increasingly attributed also to palladium oxides, which however remain poorly characterized. The only thoroughly studied and technologically exploited palladium oxide phase is PdO. In our present study we focus on theoretical investigation of crystal structures of PdO2 using Density Functional Theory (DFT) modeling. Formation of only one PdO2 polymorph was reported under elevated hydrostatic pressure and temperature and a rutile structure was proposed [1, 2]. This is contrary to the numerous polymorphs that are known in case of its heavier counterpart PtO2, which suggests that PdO2 should also be stabilized in a variety of structures. In our study, we predict the thermodynamically stable polymorphs of PdO2 at ambient and high pressures within the pressure range 0 ‚Äì 10 GPa and explain the role of pressure and temperature on the stability of rutile type structure using both standard and hybrid DFT functionals [3, 4].  Furthermore, our study demonstrates how the rutile type structure becomes destabilized at low temperatures whereas decompression drives a transition to a new porous structural type that is unknown in case of PtO2.

Acknowledgement: The European Regional Development Fund, Research and Innovation Operational Programme, for project No. ITMS2014+: 313011W085; Scientific Grant Agency of the Slovak Republic, grant No. VG 1/0223/19; the Slovak Research and Development Agency, grant No. APVV-18-0168; Aurel supercomputing infrastructure in CC of Slovak Academy of Sciences acquired in projects ITMS 26230120002 and 26210120002 funded by ERDF; PRACE FENIX Project fnxp070004 at TGCC high performance computing infrastructure, France.

[1] I. S. Shaplygin, G. L. Aparnikov, V. B.Lazarev, Zhurnal Neorganicheskoi Khimii, 23, 884 (1978)
[2] G. I. Goncharenko, V. B. Lazarev, I. S. Shaplygin, Zhurnal Neorganicheskoi Khimii, 30, 3032 (1985)
[3] D. Fabušová°, Bachelor thesis 2020, available at https://opac.crzp.sk/
[4] D. Fabušová°, Master thesis to be defended in June 2020, subsequently available at https://opac.crzp.sk/

Other authors: Tokár Kamil - Advanced Technologies Research Institute, Faculty of Materials Science and Technology in Trnava, Slovak University of Technology in Bratislava, 917 24 Trnava, Slovakia and Institute of Physics, Slovak Academy of Sciences, 845 11 Bratislava, Slovakia Derzsi Mariana - Advanced Technologies Research Institute, Faculty of Materials Science and Technology in Trnava, Slovak University of Technology in Bratislava, 917 24 Trnava, Slovakia