In operando studies of Ru(III) and Ti(III) oxidation at calcination of electrode coatings

Important results from the project

Energy efficient electrodes for chlorine, oxygen, or hydrogen production are a prioritized area of development. It is therefore important to apprehend detailed information regarding the calcination process behind the stable and catalytic active metal oxides. In the present study is the calcination process explored through synchrotron radiation based XPS with the aim to learn more about how Ru(III) and Ti(III) react with oxygen at industry relevant conditions. The results will contribute to improving the production of energy efficient RuO2-based electrode coatings.

Expected long term effects

We have, through in operando XPS at industry relevant conditions, followed the change in shapes of the XPS spectra for oxygen (O), titanium (Ti), ruthenium (Ru), and chlorine (Cl) and with that the kinetic reactions of the Ru(III) and Ti(III) oxidation when forming electrocatalytic metal oxides. The project has provided new insights regarding the calcination process and further analysis will provide details that will contribute to the optimization process for more efficient and energy saving production of electrocatalytic electrode coatings.

Approach and implementation

Ti substrates have been coated with RuCl3+TiCl3 under controlled conditions at the Permascand research laboratory. Further heat treatments, with temperatures up to 520 °C, have been performed at 1 mbar atmosphere consisting of an oxygen/nitrogen gas mixture in a reactor cell at the HIPPIE beamline at the synchrotron radiation facility MAX IV in Lund. The composition in the coatings was analyzed during the heat treatment through X-ray photoelectron spectroscopy (XPS). Data treatments and analysis have been performed at Uppsala Synchrotronix AB in collaboration with Permascand AB.