Recently, the coupling of ferroelectrics with electrochemical reactions has attracted increasing interest for harvesting waste heat. The change of polarization of a ferroelectric with temperature can be used to influence chemical reactions, especially when the material is cycled near its Curie temperature. In this perspective, we introduce the principle of pyroelectric controlled electrochemical processes by harvesting waste heat energy and explore their potential electrochemical applications, such as water treatment, air purification, and hydrogen generation. As an emerging approach for driving electrochemical reactions, the presence of thermal fluctuations and/or transient waste heat in the environment has the potential to be the primary thermal input for driving the change in polarization of a pyroelectric to release charge for such reactions. There are a number of avenues to explore, and we summarize strategies for forming multi-functional or hybrid materials and future directions such as selecting pyroelectrics with low Curie temperature (<100 C), improved heat conductivity, enhanced surface area or porosity, tailored microstructures, and systems capable of operating over a broader temperature range.

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 2 generation and wastewater treatment. We exploit low Curie temperature (T c ) ferroelectrics for polarization-driven electrochemical reactions, where the large changes in polarization and high activity of a ferroelectric near its T c 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 c . Such work provides an effective strategy for water splitting/treatment systems that employ low T c ferroelectrics under the action of mechanical stress or/and thermal fluctuations.

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The reduction of CO2 into useful hydrocarbon chemicals has attracted significant attention in light of the depletion in fossil resources and the global demand for sustainable sources of energy. In...

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