Electrodeposition of Ni-doped FeOOH oxygen evolution reaction catalyst for photoelectrochemical water splitting

The oxygen evolution reaction (OER) is one important bottleneck in the development of economical photoelectrochemical (PEC) water splitting materials. To help address this we report the electrodeposition of Ni-doped FeOOH (Ni:FeOOH) as an OER electrocatalyst. The deposition method is applicable to a wide range of photoanodes and catalytic films as thin as a few nanometers can be easily grown. The Ni:FeOOH films with 5–20% Ni content reach 10 mA cm−2 in 0.1 M NaOH at an overpotential ranging from 420–460 mV initially, and improve with anodization at 10 mA cm−2 to below 400 mV. Deposition on triple junction solar cells results in a full PEC system with higher performance and a more cathodic peak power potential compared to undoped FeOOH electrocatalysts.