Demonstration of Enhanced Piezo-Catalysis for Hydrogen Generation and Water Treatment at the Ferroelectric Curie Temperature.

Hydrogen can contribute significantly to the energy mix of the near future, as it is an attractive replacement for fossil fuels due to its high energy density and low greenhouse gas emission. A fascinating approach is to use the polarization change of a ferroelectric due to an applied stress or temperature change to achieve piezo- or pyro-catalysis for both H generation and wastewater treatment. We exploit low Curie temperature (T) ferroelectrics for polarization-driven electrochemical reactions, where the large changes in polarization and high activity of a ferroelectric near its T provides a novel avenue for such materials. We present experimental evidence for enhanced water splitting and rhodamine B degradation via piezo-catalysis by ultrasonic excitation at its T. Such work provides an effective strategy for water splitting/treatment systems that employ low T ferroelectrics under the action of mechanical stress or/and thermal fluctuations.