**Acknowledgements**

This work was performed in the frame of Mobility Project "Reduced semiconductor oxides for TCO, photocatalysis and gas sensing applications", 2019– 2021, between IlieMurgulescu Institute of Physical Chemistry of the Romanian Academy, Bucharest, Romania and Research Center for Natural Sciences, Hungarian Academy of Science Research Group of the Hungarian Academy of Science at the Budapest, Hungary. An NRDI K 124212 and an NRDI TNN\_16 123631 grants are acknowledged. The research within project No. VEKOP-2.3.2-16-2017-00013 was supported by the European Union and the State of Hungary, co-financed by the European Regional Development Fund. The research reported in this paper was supported by the BMENanotechnology and Materials Science TKP2020 IE grant of NKFIH Hungary (BME IE-NAT TKP2020)and Stipendium Hungaricum scholarship grant.
