  Recently, the coupling of ferroelectrics with electrochemical reactions has
attracted increasing interest for harvesting waste heat. The change of
polarisation 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 purificiation 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 polarisation 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 {\deg}C), improved heat conductivity, enhanced surface area or porosity,
tailored microstructures and systems capable of operating over a broader
temperature range.
