Browsing by Author "Nehasil, V."

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The role of Rh dispersion in gas sensing effects observed in SnO2 thin films [Articol]
(Elsevier, 2019) Korotcenkov, Ghenadii; Nehasil, V.
In the present work the effect of surface modification by rhodium on the conductivity response of the SnO2 films to reducing gases such as CO and H2 and oxidizing gas ozone was analyzed. SnO2 films, subjected to surface modification, were deposited by spray pyrolysis, while Rh was deposited using a micro electron beam evaporation. The thickness of the Rh coating varied in the range of 0–0.1 ML. It was found that there is an optimal thickness of Rh, which gives an improvement in the sensor response and a decrease in the recovery time. An explanation of the observed effects was proposed. It was assumed that the atomically dispersed state of rhodium is most active in gas–sensing effects. The transformation from the atomic state to the cluster state reduces the efficiency of the surface functionalization of SnO2 with rhodium.
XPS study of the SnO2 films modified with Rh [Articol]
(John Wiley and Sons, 2018) Korotcenkov, Ghenadii; Brinzari, Vladimir; Hanyš, P.; Nehasil, V.
In this paper, we have analyzed the effect of the rhodium surface modification on the surface state of SnO2 films. SnO2 films, subjected for the surface modification, were deposited by spray pyrolysis, while Rh was deposited by using a microelectron beam evaporation. The thickness of the Rh coating varied in the range 0 to 0.1 monolayer. An explanation of the observed effects was proposed. Basing on the results of X‐ray photoelectron spectroscopy, it was assumed that at a small thickness of the rhodium covering, Rh was in a the well‐dispersed state, close to atomically dispersed state. The growth in the size of the nanoparticles began mainly when the thickness of the Rh covering exceeeded 0.01 monolayer. The size of clusters did not exceed 0.5 to 1.0 nm.