Morphological and electrochemical investigation of RuO2–Ta2O5 oxide films prepared by the Pechini–Adams method

Abstract

Preparation methods can profoundly affect the structural and electrochemical properties of electrocatalytic coatings. In this investigation, RuO 2 -Ta 2 O 5 thin films containing between 10 and 90 at.% Ru were prepared by the Pechini-Adams method. These coatings were electrochemically and physically characterized by cyclic voltammetry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The composition and morphology of the oxide were investigated before and after accelerated life tests (ALT) by EDX and SEM. SEM results indicate typical mud-flat-cracking morphology for the majority of the films. High resolution SEMs reveal that pure oxide phases exhibit nanoporosity while binary compositions display a very compact structure. EDX analyses reveal considerable amounts of Ru in the coating even after total deactivation. XRD indicated a rutile-type structure for RuO 2 and orthorhombic structure for Ta 2 O 5 . XPS data demonstrate that the binding energy of Ta is affected by Ru addition in the thin films, but the binding energy of Ru is not likewise influenced by Ta. The stability of the electrodes was evaluated by ALT performed at 750 mA cm -2 in 80°C 0.5 mol dm -3 H 2 SO 4 . The performance of electrodes prepared by the Pechini-Adams method is 100% better than that of electrodes prepared by standard thermal decomposition.

Application of Ti/RuO2–Ta2O5 electrodes in the electrooxidation of ethanol and derivants: Reactivity versus electrocatalytic efficiency

“…DSA ® -type electrodes are frequently prepared by thermal decomposition of the precursor metal salts dissolved in HCl:H 2 O 1:1 or isopropanol, a method known as standard thermal decomposition [3,[10][11][12][13][14][15][16][17][18]. Another route for the preparation of DSA ® -type electrodes is the thermal decomposition of polymeric precursors (DPP) [19][20][21][22][23][24][25]. It has been shown that DSA ® -type electrodes prepared by the DPP route are more stable and electrocatalytically activity than those obtained by the STD route [23][24][25].…”

“…Another route for the preparation of DSA ® -type electrodes is the thermal decomposition of polymeric precursors (DPP) [19][20][21][22][23][24][25]. It has been shown that DSA ® -type electrodes prepared by the DPP route are more stable and electrocatalytically activity than those obtained by the STD route [23][24][25].…”

“…These electrodes exhibit outstanding mechanic stability and reasonable electrocatalytic activity concerning OER [12,25].…”

“…Duplicate samples were prepared for each electrode composition. The precursor mixtures were applied by brushing on both sides of a pre-treated Ti-support (10 mm × 10 mm × 0.25 mm) [12,18,25]. After application of each coating, the electrode was heated in air to 130-140 • C for 10 min, for polymerization to occur, and then fired at 450 • C for 5 min under a 5-dm 3 min −1 O 2 -flux.…”

“…Duplicate samples were prepared for each electrode composition. Details of electrode preparation and final mounting are described elsewhere [12,18,25].…”