Enhanced stability and electrocatalytic properties of Ti/Ru Ir1−O2 anodes produced by a new laser process

Ultra-fast synthesis of Ti/Ru0.3Ti0.7O2 anodes with superior electrochemical properties using an ionic liquid and laser calcination

“…The crystallite size of samples reduces from 10.7 nm to 5.4 nm for the IL anodes and from 11.8 nm to 10.6 nm for Pechini anodes when the laser heating method is used. The smaller crystallite size of the laser-prepared anodes is in good agreement with the results presented by Santos and coworkers for RuO2-IrO2 laser-prepared anodes [18].…”

“…Similar results have been reported in the literature for the formation of meta-stable solid-solution between RuO2 and TiO2 at the same proportion here studied (i.e., 30% RuO2: 70% TiO2), regardless of the synthesis methodology [28][29][30][31]. Additional peaks correspond to the titanium metal substrate appear as expected, frequently pointed out as characteristic of thin films, allowing X-ray penetration through coating [5,18,32,33]. The average crystallite size of the oxides in the coatings was calculated using the Scherrer equation and are summarized in Table 1.…”

“…This result agrees with the previous discussion on differences in the crystallite sizes varying with the synthesis conditions and can be strongly correlated with the XPS results, which showed the hydrous ruthenium oxide phase (i.e., RuOH) only for the laser-prepared anodes. Although previous literature found an increase in active sites when the mean crystallite size is reduced [18,41,42], as seen here, the formation of this hydrous phase is also well-known to contribute to the higher electronic conductivity and the increase in the voltammetric charge when present in the coating, due to the fast deprotonation/protonation reaction [34,[43][44][45]. According to the literature, at low scan rates, reactions occur in all active sites because the electrolyte can diffuse throughout the catalytic layer [26].…”

“…This value was adopted because a recent study proved to be a satisfactory mass for the production of RuO2-based MMOs [25]. The covering and subsequent heating procedure were repeated 8 times for all routes (Pechini and IL, regardless of the heating procedure), corresponding to a nominal thickness of around 2-3 μm [18].…”

“…Thus, seeking to reduce synthesis costs and promote enhancements in physical, electrochemical, and electrocatalytic properties of anodes, studies proposing alternative heating routes are of great interest. The use of CO2 laser as a heating source for MMO anodes production is still scarcely reported in the literature, where laser heating was used for thermal decomposition of metallic chlorides dissolved in HCl solutions [17] or Pechini method [4,[18][19][20]. The main advantages of this heating procedure are centered on fast processing, high heating rates, and easy operation.…”