Oxynitride Thin Films versus Particle-Based Photoanodes: a Comparative Study for Photoelectrochemical Solar Water Splitting

TL;DR

This study compares oxynitride particle-based and thin film photocatalysts for solar water splitting, highlighting their respective advantages in absorption, surface area, and charge carrier mobility, to inform future material design.

Contribution

It provides a direct comparison of particle and thin film oxynitride photocatalysts, revealing their distinct strengths and insights into optimizing photoelectrochemical performance.

Findings

Particle electrodes have better absorption and larger surface area.

Thin films offer improved charge separation and mobility.

Both approaches provide complementary insights into material properties.

Abstract

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.