The oxygen evolution reaction (OER) is considered to be the kinetically limiting step in water splitting, as it involves multiple electron and bond breaking processes and requires high overvoltages.
Single-atom catalysts offer maximum atomic utilization and potentially the highest activity. Previous systems have been based predominantly on carbon supports, whose electronic structure is influenced by heteroatoms and which are oxidatively unstable under OER conditions.
The new catalyst is based on a transition metal carbide (e.g., WCₓ) as a carrier material. Tungsten carbide in particular has metallic surface properties and is therefore suitable for stabilizing catalytically active single atoms for both the OER and the hydrogen evolution reaction (HER). In contrast to carbon-based single-atom systems, the metal centers are not embedded in an amorphous carbon matrix, but are on a highly ordered crystalline WCₓ surface. It is produced via a metal–dopamine–tungstate precipitate with calcination at 700–1100 °C.
| Parameter |
Value |
Benchmark |
| OER η @10 mA cm⁻² |
201 mV (WCₓ-FeNi) |
lower than WCₓ-Ni |
| TOF @300 mV |
2,18 s⁻¹ |
higher than monometallic systems |
| HER η @10 mA cm⁻² |
10–22 mV (WCₓ-Ru₂) |
>50× mass activity vs Pt/C |
• Alkaline water electrolysis (OER and HER)
• Electrolyzers with high current density
• Electrode coating for industrial electrolysis cells
• Replacement or reduction of precious metal-based catalysts
• Combined OER/HER systems with WCₓ-based electrodes
Schematic representation of the WCx-FeNi catalyst, carbon-coated. (© TUB)
