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In our publications, emerged in the last time, we dealt with the systematic examination of platinum, which is the mostly used catalyst in fuel cells, changing the electrochemical measurement circumstances and methods. The applied methods involve nanogravimetry, a valuable tool to detect the changes, related with the change in the surface mass or adsorption / desorption processes occurring on the electrode surface. We examined the effects of changing the scan rate, the potential interval, the rate of platinization, the pH and the temperature. The electrochemical methods were the cyclic voltammetry, the chronoamperomety and chronocoulometry.

Platinum nugget
source: Wikipedia

These techniques combined with the electrochemical quartz crystal nanobalance are more effective to study the changes of the state of the electrode surface. With help of the above methods we showed that platinum can dissolve at high temperatures (above 60 °C) without the absence of any complexing agents in acidic media. At low temperatures depending on the scan rate and the positive potential limit platinum can also dissolve in another way. This kind of dissolution was also detected by inductively coupled plasma mass spectrometry. Novel representations related to the current vs. potential and surface mass change vs. potential functions have also been introduced to the better visualization of the relationship between the mass change and the charge transferred. The effect of the surface roughness, which is of great importance regarding the real characteristics of the catalyst, and the pH occurring at the membrane, caused by Nafion^®, were simulated with the platinization of the electrode and the change of the sulfuric acid concentration respectively.