Effect of Air‐Aging on the Electrochemical Characteristics of TiO_xC_y Films for Electrocatalysis Applications

Abstract

We report on the electrochemical characteristics of pristine and air‐aged carbon‐modified titania electrodes in acidic electrolyte, which find applications as catalyst supports in electrocatalysis. Films with different chemical compositions (including TiO2, TiOx, TiO, TiC, C) are synthesized through a carbothermal treatment of compact anodic TiO2 on Ti substrates at different temperatures, and are analyzed with X‐ray photoelectron spectroscopy. Their activity towards heterogeneous outer‐sphere electron transfer and their stability against passivation and corrosion under anodic polarization are investigated by means of electrochemical impedance spectroscopy. It is found that a high fraction of TiC in the pristine carburized films in combination with a thin TiO2 surface layer yields high electron‐transfer kinetics even after aging for 9 months, and a high corrosion and passivation resistance until approximately 0.74VSHE. This finding is essential to the material‘s application as a catalyst support in general.

Superhydrophilicity and Antifouling Behavior in Electrochemically Oxidized Nanocrystalline Pseudographite

“…There are reports of air and water aging studies using a [Fe(CN) 6 ] 3−/4− redox probe, indicating that carbon electrodes become more resistive with minutes to hours of exposure. 7,47,58,60 This indicates that a change in the surface conductance properties occurs on a small time scale often affecting the subsurface layer, making surface regeneration extremely difficult. 7,58 3.5.…”

“…The HET rates were evaluated with CV peak potential separations (Δ E p ). , Previous literature indicates that VOCs passify carbon electrodes by exposure to an ambient laboratory atmosphere and interestingly also through aqueous solutions. ,, We examine both effects with Ox-GUITAR. There are reports of air and water aging studies using a [Fe­(CN) 6 ] 3–/4– redox probe, indicating that carbon electrodes become more resistive with minutes to hours of exposure. ,,, This indicates that a change in the surface conductance properties occurs on a small time scale often affecting the subsurface layer, making surface regeneration extremely difficult. , …”