Surface chemistry and photoelectrochemistry-Case study on tantalum nitride

Solar water splitting promises a solution to challenges associated with the intermittent nature of solar energy. Of different implementations, photoelectrochemical water splitting, where one or more photoelectrodes harvest light and catalyze water splitting, represents a convenient platform to understand the governing principles of charge behaviors, especially at the light absorber|H₂O interface. This Perspective recognizes and discusses the importance of the photoelectrode surface to solar water splitting performance. It presents discussions within the context of a prototypical water splitting material, Ta₃N₅, which has gained growing attention lately for its outstanding initial performance. Insights into the mechanisms by which Ta₃N₅ functions are presented, followed by examples of recent efforts to circumvent the issues that Ta₃N₅ decays rapidly under solar water splitting conditions. Our visions on the future directions of semiconductor-based solar water splitting will be presented at the end.