Recent developments in plasmon-assisted photocatalysis -- a personal perspective

TL;DR

This paper reviews recent debates on plasmon-assisted photocatalysis, emphasizing that thermal effects often explain experimental results better than non-thermal hot electron mechanisms, and discusses future research directions.

Contribution

It critically examines the theory behind hot electron-driven catalysis claims and advocates for a thermal explanation of experimental findings, providing a personal perspective on the field.

Findings

Thermal effects can often explain photocatalytic results without invoking hot electrons.

Quantifying non-thermal effects is challenging due to temperature gradients.

Theoretical analysis supports thermal explanations over hot electron mechanisms.

Abstract

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.