Nanocrystalline Boron-Doped Diamond as a Corrosion-Resistant Anode for Water Oxidation via Si Photoelectrodes


Nanocrystalline boron-doped diamond (BDD) layers protect underlying photoelectrodes (Si) over a wide pH range (1–14) in aqueous electrolyte solutions. Si|BDD photoelectrodes show no sign of performance degradation after a continuous PEC treatment in neutral, acidic, and basic electrolytes. The deposition of a cobalt phosphate (CoPi) oxygen evolution catalyst onto the BDD layer significantly reduces the overpotential for water oxidation.

Schematic illustration of a photoelectrode based on a boron doped diamond electrode and buried pn-junction Si solar cell for water oxidation and reduction. The PV component (np-Si) is responsible for incident light absorption and charge separation across the pn-junction, whereas oxygen evolution occurs at the boron doped diamond electrode/electrolyte surface and hydrogen evolves at the externally wired metal cathode.