In Situ Oxygen Detection During Photocatalytic Overall Water Splitting

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 PyroScience oxygen probe and a sensor for temperature compensation. Adapters for a hydrogen sensor and second temperature sensor are also available.

Results

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 oxygen 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.

Conclusion

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

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

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