Taking the Heat Off of Plasmonic Chemistry

TL;DR

This paper discusses the challenge of distinguishing true plasmonic photocatalytic effects from photothermal effects in plasmonic chemistry, proposing best practices and a classification framework to clarify their roles.

Contribution

It introduces a classification of plasmonic chemistry into photocatalysis and photosynthesis, emphasizing the importance of thermodynamic criteria to identify genuine photochemical effects.

Findings

Photothermal effects can mimic plasmonic photocatalysis.

Photosynthetic reactions require Gibbs free energy input.

Best practices are proposed for analyzing photothermal contributions.

Abstract

Several chemical reactions catalyzed by plasmonic nanoparticles show enhanced rates under visible-light-excitation of the localized surface plasmon resonance of the nanoparticles. But it has been argued that there is an associated photothermal effect that can complicate the analysis and/or interpretation of the nature of the role played by plasmon excitation. This Viewpoint discusses this dilemma and provides some best practices for accounting for photothermal contributions in plasmon-excitation-driven chemistry. A classification of plasmonic chemistry into plasmonic photocatalysis and plasmonic photosynthesis is also proposed. It is argued that photosynthetic reactions, which require a Gibb's free energy input, constitute an ultimate test of the non-thermal, photochemical action of plasmon excitation.