  It has been known for many years that metallic nanoparticles can catalyse
various chemical reactions, both in the dark and under illumination, through
different mechanisms. In the last decade or so, many claims of plasmon-assisted
"hot" electron driven catalysis of bond-dissociation reactions have been put
forward. These claims were \XYZ{challenged} in a recent series of papers, where
both the underlying theory of "hot" electron generation and the use of specific
experimental setups to discover them in chemical reactions were examined in
detail. The conclusion that arose from these works is that as long as
temperature gradients exist inside the system (as for typical experimental
setups) a quantification of non-thermal effects is close to impossible.
Instead, a standard thermal theory was shown to be capable of explaining the
experimental findings quite accurately. Here, we review the central lines of
thought that led to these conclusions, from a personal perspective. We lay out
the key aspects of the theory, and point to the specific caveats one must be
aware of in performing photo-catalysis experiments. Finally, we provide some
future directions of study.
