Electrocatalysis of H2 evolution by thermally prepared ruthenium oxide. Effect of precursors: Nitrate vs. chloride

Ruthenium oxide (formally RuO2) was deposited on Ti by thermal decomposition of Ru chloride as well as Ru nitrate. Electrodes were prepared in a range of temperatures, 260–550 °C, and characterized by SEM and cyclic voltammetry. The voltammetric charge q*, obtained by integration of the CV curves, was recorded as a function of calcination temperature. q* is higher for nitrate than for chloride. H2 evolution was used as a probe reaction to test the electrocatalytic properties. Polarization curves were recorded and analyzed to obtain Tafel slopes. Results showed that the oxide from nitrate is more electrocatalytic than that from chloride. This is in part due to the more extended surface area of the former, but electronic factors related to the particle size are also evident. q* was recorded after each run of experiments and compared with the values before to monitor the stability of the oxide layer.