Simple Immersing Method of Nanocoating on Uneven Surfaces Applicable to Highly Durable Ta3N5 Nanorod Photoelectrode for Water Splitting

Uniform nanolayer coatings on photoelectrodes for water splitting are effective in improving their durability by isolating the semiconductor from direct contact with liquid electrolytes. Achieving a thin and uniform coating across the entire surface of nanostructured uneven photoelectrodes using wet processes remains a challenge. This study provides a strategy for the spontaneous formation of a uniform nanolayer of NiFeO x electrocatalyst on Ta3N5 nanorods (NRs) photoelectrodes mediated by acetonitrile (CH3CN) solvent and bulky metal ethylhexanoate complexes. Following the NiFeO x deposition through a spin-coating method on Ta3N5 NRs, the sample is immersed in CH3CN solvent for 12 h. This treatment effectively results in complete coverage of the complex structured surface of Ta3N5 NRs by the NiFeO x nanolayer. The nanocoating ensures the protection of Ta3N5 NRs and contributes to enhanced durability. This distinctive surface modification is applied to semitransparent Ta3N5 NRs photoanodes which is applicable to photovoltaic–photoelectrochemical tandem cells. This simple immersion method of bulky metal complexes into a thin and uniform layer on rough surfaces would have potential for various applications including (photo)­electrochemical reactions and corrosion inhibitions.