Trends in Electrochemical Stability of Transition Metal Carbides and Their Potential Use As Supports for Low-Cost Electrocatalysts

Early transition metal carbides (TMCs) can be used as supports for platinum-group metals as low-cost electrocatalysts. The determination of electrochemical stability of TMCs is important to identify their potential use in electrochemical and photoelectrochemical applications. Various TMC thin films were synthesized and characterized with X-ray diffraction and photoelectron spectroscopy. Chronopotentiometric-titration measurements were used to map the stability regions of the TMC thin films over a wide pH range. The stability of the TMC thin films was correlated to the oxygen binding energy of the parent metal. All of the TMCs studied are stable for hydrogen evolution/oxidation; most are stable for alcohol oxidation, and titanium, tantalum, and zirconium carbides are stable for oxygen evolution/reduction reactions.