FSU Jena / AG Schneidewind
A. Eith, N. Brezhneva, E. Abedini, J. Schneidewind

Background

In photocatalytic overall water splitting, water is split into hydrogen and oxygen directly
using the energy of light, in a reaction that is mediated by a photocatalyst. Measuring the
formation of oxygen under reaction conditions (in situ) provides insights into the mechanism
of the reaction.

Set-Up/Sample

The experimental set-up consists of a custom-made 3D-printed chamber, which holds the photoreactor, allowing for precise control of irradiation parameters, as well as temperature control using a thermostat. The photoreactor is equipped with adapters for a TROXROB oxygen probe and a PT100 for temperature compensation. Adapters for a hydrogen sensor and second temperature sensor are also available.

Using this setup we investigated photocatalytic overall water splitting using Rh2-yCryO3/Al:SrTiO3 as photocatalyst with irradiation by a UV LED (365 nm). The photocatalyst is dispersed in water and the TROXROB sensor is mounted in either the gas or liquid phase. As shown in Fig. 2, this set-up allows us to monitor the formation of oxygen with high temporal resolution. The collected data can be used to construct detailed kinetic models to describe the water splitting reaction.

FIG. 2 Exemplary oxygen and hydrogen evolution data (liquid and gas phase) with fits from kinetic model.

Conclusion

Using the TROXROB sensor allows for measuring oxygen evolution from photocatalytic water splitting directly under reaction conditions, which provides insights into the reaction mechanism.