  The solar water splitting process assisted by semiconductor photocatalysts
attracts growing research interests worldwide for the production of hydrogen as
a clean and sustainable energy carrier. Due to their optical and electrical
properties several oxynitride materials show great promise for the fabrication
of efficient photocatalysts for solar water splitting. This study reports a
comparative investigation of particle- and thin films-based photocatalysts
using three different oxynitride materials. The absolute comparison of the
photoelectrochemical activities favors the particle-based electrodes due to the
better absorption properties and larger electrochemical surface area. However,
thin films surpass the particle-based photoelectrodes due to their more
suitable morphological features that improve the separation and mobility of the
photo-generated charge carriers. Our analysis identifies what specific insights
into the properties of materials can be achieved with the two complementary
approaches.
